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  • 151. Beställ onlineKöp publikationen >>
    Knöös Franzén, Ludvig
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    An Ontological and Reasoning Approach to System of Systems2021Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    System-of-Systems (SoS) are all around us and are becoming more common in today’s highly interconnected world. Systems are connected with other systems and have strong dependencies with their operational environments. This leads to an increased level of complexity and risk during product development. A holistic view, and an SoS perspective, is consequently needed in order to develop an early understanding of the available design spaces for new system solutions. This thesis suggests a method that has been developed for this purpose, and to meet the demand for a more holistic product development. Overall, the method consists of two correlated approaches that show how a design space for SoSs can be generated and later processed with, for example, design space reductions. Search and Rescue (SAR) operations have been used as examples of typical SoSs throughout this work and in the development of the presented method. An architecture framework has been used to introduce a standardized and consistent way of understanding the relationships that exist between needs, capabilities and functions. This approach can consequently be used to generate a design space of functions to be performed to meet the overarching needs of an SoS. The second approach has been based on ontology and description logic reasoning. Ontology has here been used to represent an SoS design space with, for example, available SAR assets and their relationships with the operational environment. An SoS representation in an ontology model introduces additional expressiveness and the design space processing capabilities needed for a holistic design process and product development. Based on these results, this thesis and its suggested method and approaches contribute to holistic product development from an SoS perspective. 

    Delarbeten
    1. An Ontological Approach to System of Systems Engineering in Product Development
    Öppna denna publikation i ny flik eller fönster >>An Ontological Approach to System of Systems Engineering in Product Development
    2019 (Engelska)Ingår i: Linköping Electronic Conference Proceedings 162 (2019) / [ed] Dr. Ingo Staack and Prof. Petter Krus, Linköping: Linköping University Electronic Press, 2019, Vol. 162:4, s. 35-44Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper presents an approach to system-of-systems engineering for product development with the use of ontology. A proposed method for building as well as using ontology to generate and explore system-of-systems design spaces based on identified system-of-system needs is presented. The method is largely built to cover the first levels of related work, where a process for system of systems in the context of product development is introduced. Within this work, it is shown that scenarios for a system-of-systems can be used to identify needs and subsequently the system-of-systems capabilities that fulfils them. The allocation of capabilities to possible constituent systems is used to show the available design space. The proposed method of this paper therefore addresses these initial challenges and provides a framework for approaching the system-of-systems design space creation using ontology. A case study is used to test the method on a fictitious search and rescue scenario based on available resources and information from the Swedish Maritime Administration. The case study shows that a representation of a system-of-systems scenario can be created in an ontology using the method. The ontology provides a representation of the involved entities from the fictitious scenario and their existing relationships. Defined ontology classes containing conditions are used to represent the identified needs for the system-of-systems. The invocation of a description logic reasoner is subsequently used to classify and create an inferred ontology where the available system-of-systems solutions are represented as sub-classes and individuals of the defined classes representing the needs. Finally, several classes representing different possible system-of-systems needs are used to explore the available design space and to identify the most persistent solutions of the case study.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2019
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 162
    Nyckelord
    system-of-systems, ontology, description logic reasoning, design space generation
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175761 (URN)10.3384/ecp19162004 (DOI)978-91-7519-006-8 (ISBN)
    Konferens
    Proceedings of the 10th Aerospace Technology Congress
    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-05-11Bibliografiskt granskad
    2. A System of Systems Approach for Search and Rescue Missions
    Öppna denna publikation i ny flik eller fönster >>A System of Systems Approach for Search and Rescue Missions
    Visa övriga...
    2020 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    System-of-Systems Engineering (SoSE) has become a constantly growing field within product development for complex systems. Systems are becoming more and more connected with other systems and the operational environment in general. This takes the development process to new levels of complexity where high degrees of uncertainties are expected due to ever occurring changes in the operational environment, and other external factors such as politics, economy, and technology. This creates a need of being able to understand the influence of changes early in the development process and to facilitate the systems? perseverance. The focus of the development shifts from fulfilling specific requirements, to being able to meet needs and deliver capabilities over time. Additionally, modeling and simulation for complex systems and System-of-Systems (SoS) becomes a valued alternative to the economically prohibited and almost impossible prototype testing. In consideration of this problem, the presented work introduces a method for both modeling and simulation of a SoS. The method uses ontology with description logic reasoning to derive and narrow down a SoS design space which is further analyzed using Agent Based Simulation (ABS). A Search and Rescue (SAR) scenario is used as a case study to test the method. Measures of Effectiveness (MoE), based on the time it takes to find a rescue subject and the cost of doing so, are used to evaluate the SoS performances. The presented method is envisioned to be used early in the development of complex systems and SoS to increase the overall understanding of them.

    Ort, förlag, år, upplaga, sidor
    American Institute of Aeronautics and Astronautics, 2020
    Nyckelord
    Model Based System Engineering, Unified Modeling Language, Web Ontology Language, Extensible Markup Language, Ocean Currents, Helicopters, Air Vehicle, Probability Density Functions, Cyber Physical System
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175763 (URN)10.2514/6.2020-0455 (DOI)
    Konferens
    AIAA Scitech 2020 Forum
    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-11-02Bibliografiskt granskad
    3. A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning
    Öppna denna publikation i ny flik eller fönster >>A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning
    Visa övriga...
    2021 (Engelska)Ingår i: Aerospace, E-ISSN 2226-4310, Vol. 8, nr 4Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Aerospace systems are connected with the operational environment and other systems in general. The focus in aerospace product development is consequently shifting from a singular system perspective to a System-of-Systems (SoS) perspective. This increasing complexity gives rise to new levels of uncertainty that must be understood and managed to produce aerospace solutions for an ever-changing future. This paper presents an approach to using architecture frameworks, and ontologies with description logic reasoning capabilities, to break down SoS needs into required capabilities and functions. The intention of this approach is to provide a consistent way of obtaining the functions to be realized in order to meet the overarching capabilities and needs of an SoS. The breakdown with an architecture framework results in an initial design space representation of functions to be performed. The captured knowledge is then represented in an ontology with description logic reasoning capabilities, which provides a more flexible way to expand and process the initial design space representation obtained from the architecture framework. The proposed approach is ultimately tested in a search and rescue case study, partly based on the operations of the Swedish Maritime Administration. The results show that it is possible to break down SoS needs in a consistent way and that ontology with description logic reasoning can be used to process the captured knowledge to both expand and reduce an available design space representation.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2021
    Nyckelord
    system of systems, systems engineering, aerospace systems, architecture framework, ontology, description logic reasoning, search and rescue
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-175765 (URN)10.3390/aerospace8040118 (DOI)000642619100001 ()
    Anmärkning

    Funding: Swedish Innovation Agency (VINNOVA)Vinnova [NFFP7/2017-04838]

    Tillgänglig från: 2021-05-19 Skapad: 2021-05-19 Senast uppdaterad: 2023-05-11Bibliografiskt granskad
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  • 152.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Magnusson, Erik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Weight Penalty Methods for Conceptual Aircraft Design2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report addresses a project conducted at Saab Aeronautics during the spring of 2018. The goal of the project was to investigate aircraft weight estimations in the conceptual design phase. The work was divided into two major parts: finding new weight estimation techniques and implementing an existing technique called the Berry Weight Estimation in to the Pacelab APD software. Several weight estimation techniques were found during an extensive literature review but in the end, only one was chosen for further investigation. The chosen technique was the NASA Wing Weight Build-Up which proposed calculations for wing weights based on aircraft statistics. It contained material data tables for determining so called K-factors that were used to essentially scale the individual wing weight formulas. The data tables did not include K-factors up to a load factor of 9 which was a requirement from Saab. Extrapolations of the material data tables were done to approximate the missing values. The NASA wing weight build-up showed promising results with little deviation from the actual wing weight for a few chosen aircraft. This weight estimation technique was consequently chosen as a worthy candidate for a future implementation in the Pacelab APD software.

    The task of implementing the Berry Weight Estimation in Pacelab APD was divided into a fuselage- and a wing part. This was done to ease the implementation since it would resemble the original description of the method. The wing and fuselage weights were both calculated in two steps. The first step was to calculate a gross shell weight. This is the weight of an idealized structure without cut-outs or imperfections. The second step was to add so called weight penalties for various components within the wing or fuselage. Typical aircraft components had associating weight penalty functions described in the Berry Weight Estimation. Most of the implemented calculations used Pacelab APD to get involved parameters automatically. However, some of the needed parameters had to be user specified for the implemented Berry Weight Estimation to work. Once the implementation task was finished, several sensitivity studies were made to establish a perception about the involved parameters impact on the Berry Weight Estimation results. The new implementation gave benefits compared with the Berry Weight Estimation in Bex. One of these was the ability to perform extensive trade- and sensitivity studies. The sensitivity studies gave verdicts on the most influencing parameters of the implemented code and guide lines on future improvements of the calculations. These sensitivity studies show, among other things, that is recommended to increase the number of wing and fuselage stations significantly in order to get a converged result for the Berry Weight Estimation.

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  • 153.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Munjulury, Raghu Chaitanya
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Technical Management & Maintenance, Airframe & Vehicle Systems, Saab Aeronautics, Sweden.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ontology-Assisted Aircraft Concept Generation2022Ingår i: 33rd Congress of the International Council of the Aeronautical Sciences, Stockholm, Sweden, 2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for generating a geometrical representation of a concept aircraft from an ontology description. An ontology is used as an overarching knowledge base where entities, such as required functions, their design alternatives, and requirements can be represented. Description logic reasoning is then used to process the available design space and generate suitable concepts to fulfil desired functions, as well as indicate suitable approaches for a subsequent sizing procedure. As ontology representations are limited in terms of numerical calculation capabilities, the obtained concept information must be extracted for additional processing. Further investigations, such as statistical analyses, are consequently performed in order to expand the available information of the concept generated from the ontology. This expansion is performed to obtain estimates of required inputs for a continued geometrical sizing procedure. The outcome of the method is an estimation of the concept’s geometry and its characteristics. This information can from here be reintroduced into the ontology representation for further processing and to expand the original knowledge base. A case study is introduced to test the proposed method and to show how it can be used to estimate the characteristics of an already existing aircraft from basic requirements and configuration details. The results from the method and sizing are also compared with publicly available data for the reference aircraft to see how accurate the estimates were.

  • 154.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Schön, Sofia
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    Papageorgiou, Athanasios
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Filosofiska fakulteten.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Amadori, Kristian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten.
    Jouannet, Christopher
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    A System of Systems Approach for Search and Rescue Missions2020Konferensbidrag (Refereegranskat)
    Abstract [en]

    System-of-Systems Engineering (SoSE) has become a constantly growing field within product development for complex systems. Systems are becoming more and more connected with other systems and the operational environment in general. This takes the development process to new levels of complexity where high degrees of uncertainties are expected due to ever occurring changes in the operational environment, and other external factors such as politics, economy, and technology. This creates a need of being able to understand the influence of changes early in the development process and to facilitate the systems? perseverance. The focus of the development shifts from fulfilling specific requirements, to being able to meet needs and deliver capabilities over time. Additionally, modeling and simulation for complex systems and System-of-Systems (SoS) becomes a valued alternative to the economically prohibited and almost impossible prototype testing. In consideration of this problem, the presented work introduces a method for both modeling and simulation of a SoS. The method uses ontology with description logic reasoning to derive and narrow down a SoS design space which is further analyzed using Agent Based Simulation (ABS). A Search and Rescue (SAR) scenario is used as a case study to test the method. Measures of Effectiveness (MoE), based on the time it takes to find a rescue subject and the cost of doing so, are used to evaluate the SoS performances. The presented method is envisioned to be used early in the development of complex systems and SoS to increase the overall understanding of them.

  • 155.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Filosofiska fakulteten.
    Jouannet, Christopher
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Overall Design and System Integration, Saab Aeronautics, Linköping, Sweden.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    An Ontological Approach to System of Systems Engineering in Product Development2019Ingår i: Linköping Electronic Conference Proceedings 162 (2019) / [ed] Dr. Ingo Staack and Prof. Petter Krus, Linköping: Linköping University Electronic Press, 2019, Vol. 162:4, s. 35-44Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an approach to system-of-systems engineering for product development with the use of ontology. A proposed method for building as well as using ontology to generate and explore system-of-systems design spaces based on identified system-of-system needs is presented. The method is largely built to cover the first levels of related work, where a process for system of systems in the context of product development is introduced. Within this work, it is shown that scenarios for a system-of-systems can be used to identify needs and subsequently the system-of-systems capabilities that fulfils them. The allocation of capabilities to possible constituent systems is used to show the available design space. The proposed method of this paper therefore addresses these initial challenges and provides a framework for approaching the system-of-systems design space creation using ontology. A case study is used to test the method on a fictitious search and rescue scenario based on available resources and information from the Swedish Maritime Administration. The case study shows that a representation of a system-of-systems scenario can be created in an ontology using the method. The ontology provides a representation of the involved entities from the fictitious scenario and their existing relationships. Defined ontology classes containing conditions are used to represent the identified needs for the system-of-systems. The invocation of a description logic reasoner is subsequently used to classify and create an inferred ontology where the available system-of-systems solutions are represented as sub-classes and individuals of the defined classes representing the needs. Finally, several classes representing different possible system-of-systems needs are used to explore the available design space and to identify the most persistent solutions of the case study.

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  • 156.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Amadori, Kristian
    Saab Aeronaut, Overall Design & Survivabil, S-58254 Linkoping, Sweden.
    Optimization Framework for Early Conceptual Design of Helicopters2022Ingår i: Aerospace, ISSN 2226-4310, Vol. 9, nr 10, artikel-id 598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work illustrates how a proposed method can be used to create optimization frameworks for early conceptual design studies and to increase overall knowledge at an early design stage. The method is intended to facilitate concept selection in challenging domains that typically involve multidisciplinary design problems with contradictory requirements. The main focus of the work presented here is on the conceptual design of helicopters; however, the method is intended to be applicable to early design studies in other domains as well. In short, statistics about existing helicopters are collected and compiled to provide a basis for various regression analyses. The purpose of this is to unravel relationships in the data and to obtain simple estimation models from statistical regressions that can be used in conjunction with existing formulas and equations to generate an initial helicopter design estimate. Models for each discipline, such as aerodynamics, are then created using the outcomes of the regression analyses and existing equations. Lastly, the method is used to define a multidisciplinary design optimization framework incorporating all the models obtained from the different disciplines. A case study based on search and rescue operations is used to test the proposed framework in order to obtain possible first suggestions for the baseline design of a new general-purpose search and rescue helicopter.

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  • 157.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Amadori, Kristian
    Saab Aeronautics, Linköping, Sweden.
    Jouannet, Christopher
    Saab Aeronautics, Linköping, Sweden.
    Ontology-Represented Design Space Processing2021Ingår i: AIAA AVIATION 2021 Forum, August 2-6, 2021, VIRTUAL EVENT, USA: American Institute of Aeronautics and Astronautics, 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for generating a design space intended for aircraft design with the use of ontologies. Aircraft design, seen from a System-of-Systems (SoS) perspective, gives an idea of the complicated relationships and complexities that need to be managed and understood to develop suitable systems for an ever-changing future. Holistic SoS analyzes are used to investigate customer and stakeholder needs that then can be broken down into capabilities and subsequently functions to be performed by involved Constituent Systems (CS), sub-systems and system elements. Ontologies with description logic reasoning capabilities are then used to represent the outcome of the breakdown. An ontology development and integration process can afterwards be used to merge different ontologies together and by that map the derived functions to means that can implement them. This results in an available SoS design space that can be further processed using a description logic reasoner. The outcome of the proposed method is a reduced available design space of functions to be performed and their respective design alternatives. Search and Rescue (SAR) operations based on the Swedish Maritime Administration (SMA) are used as a case study to test the proposed method and to illustrate how it can be utilized. At the end, a design space of alternatives for a new type of search aircraft is generated with ontology and description logic reasoning.

  • 158.
    Knöös Franzén, Ludvig
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Filosofiska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Jouannet, Christopher
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Overall Design and Survivability, Saab Aeronautics, Linköping, Sweden.
    Amadori, Kristian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska fakulteten. Overall Design and Survivability, Saab Aeronautics, Linköping, Sweden.
    A Breakdown of System of Systems Needs Using Architecture Frameworks, Ontologies and Description Logic Reasoning2021Ingår i: Aerospace, E-ISSN 2226-4310, Vol. 8, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aerospace systems are connected with the operational environment and other systems in general. The focus in aerospace product development is consequently shifting from a singular system perspective to a System-of-Systems (SoS) perspective. This increasing complexity gives rise to new levels of uncertainty that must be understood and managed to produce aerospace solutions for an ever-changing future. This paper presents an approach to using architecture frameworks, and ontologies with description logic reasoning capabilities, to break down SoS needs into required capabilities and functions. The intention of this approach is to provide a consistent way of obtaining the functions to be realized in order to meet the overarching capabilities and needs of an SoS. The breakdown with an architecture framework results in an initial design space representation of functions to be performed. The captured knowledge is then represented in an ontology with description logic reasoning capabilities, which provides a more flexible way to expand and process the initial design space representation obtained from the architecture framework. The proposed approach is ultimately tested in a search and rescue case study, partly based on the operations of the Swedish Maritime Administration. The results show that it is possible to break down SoS needs in a consistent way and that ontology with description logic reasoning can be used to process the captured knowledge to both expand and reduce an available design space representation.

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  • 159.
    Krantz, Dino
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Methodology and vibrational analysis for measurements on a VTOL RAPS2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this thesis a methodology for measuring vibrations has been produced andinvestigated for APID 60, a rotorcraft in a Vertical Take-off and landing remotelypiloted aircraft system (VTOL RPAS). A comparative study was carried out forthe purpose of identifying the methodology with respect to design modificationscommon to the APID 60. The pilot-study identified experimental modal analysis(EMA) as a feasible part of the methodology for experimentally extracting themodal parameters of a structure. The EMA was performed on the main frameof the APID 60 where an impact hammer test was chosen as the technique forextracting the response data. As a comparison a point mass was added to thestructure to alter the dynamic properties and the test was repeated.The results from the EMA was compared with a modal analysis performednumerically with a calculation software. Comparison of the results from EMAwith the modal analysis performed numerically indicates consistency. This confirmsa good reliability of the methodology produced. However, the structure onwhich the test were preformed is simple in terms of constant structural properties.Further work should therefore investigate whether this methodology of measuringvibrations could be successfully applied to a structure with higher complexity.

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  • 160.
    Kristensson, Malte
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Hassel, Jesper
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Development of a Power Hardware-in-the-Loop Test Rig for Gas Hydraulic Suspension in Heavy Duty Vehicles2022Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this thesis a Power-Hardware-in-the-Loop (PHiL) test rig is developed forhydro-pneumatic suspension by utilizing the physical suspension unit together with asimulated vehicle model in MATLAB Simulink. Power-Hardware-in-the-Loop is the termfor combining simulation models with power-transmitting hardware components inreal-time. This is useful when a system contains some parts that are complex and somethat are simpler to model. The simple parts of the system can be modelled andsimulated in conjunction with more complex parts consisting of physical objects. Thereason for keeping the items to be tested as physical components is their complexity andunknown characteristics that can be difficult to estimate. By utilizing PHiL, vehiclecomponents can be tested and developed without the need for the actual vehicle, whilekeeping the characteristics that the physical vehicle would bring.

    The process included development of a real-time enabled vehicle model, evaluation ofcontrol strategies as well as selection of hardware used for a small scale test rig.

    The project resulted in a functional small scale single wheel test rig. Validationexperiments confirmed that the rig produced results close to expectations. Thecommunication between the the test rig and the simulated model was accurate andshowed the potential for a full scale test rig. It can be concluded that a PHiL test rigcan be a suitable option to full vehicle testing. The vehicle model is fully customisable,so that the suspension units can be tested in various configurations of vehicles.

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  • 161.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Design Space Configuration for Minimizing Design Information Entropy2015Ingår i: ICoRD’15 - Research into Design Across Boundaries Volume 1: Theory, Research Methodology, Aesthetics, Human Factors and Education / [ed] Amaresh Chakrabarti, New Delhi, India: Springer India , 2015, s. 51-60Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In this paper concepts for quantitative theory of design are developed. The design process is viewed as a process of increasing the information of the product/system using concept from information theory. The creation and evolution of design space and information entropy are central concepts that are studied in this paper. Furthermore, axiomatic design is discussed in relation to this, and it is shown that the two fundamental axioms are likely to be dependent.

    The design information entropy is used as a state that reflects both complexity and refinement, and it is argued that it can be useful as some measure of design effort and design quality. It provides a tool to describe the relation between a design, and the design space from which it is derived as well as for quantitative description for various aspects of design, both structural information regarding architecture and connectivity, as well as for parameter values, both discrete and continuous. In this paper it is also shown to be useful as a measure of quality when configuring design spaces, such as in  product platforms, and when setting up parameterization for design.

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  • 162.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Design Space Configuration Through Analytical Parametrization2017Ingår i: Research into Design for Communities, Volume 1: Proceedings of ICoRD 2017 / [ed] Amaresh Chakrabarti, Debkumar Chakrabarti, Singapore: Springer , 2017, 1, s. 15-24Kapitel i bok, del av antologi (Refereegranskat)
  • 163.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Disruptive Innovations from Disruption2020Ingår i: Journal of Applied Economics and Business Research, E-ISSN 1927-033X, Vol. 10, nr 3, s. 129-130Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    n/a

    Ladda ner fulltext (pdf)
    fulltext
  • 164.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Dynamic Models for Transmission Lines and Hoses2019Ingår i: PROCEEDINGS OF DINAME 2017, SPRINGER-VERLAG BERLIN , 2019, s. 531-547Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper simplified models for hydraulic transmission lines and hoses, for both time and frequency domain simulation, are presented. Flexible hoses have, in addition to a higher capacitance, also an considerable damping effect, that can reduce noise and vibrations, and in this paper, efficient approximate models for flexible hoses are presented. In hydraulic transmission lines with laminar flow the losses can be divided into two parts. One term that is distributed friction, and one term that is frequency dependent. It is shown that in general, the effect from the hose wall dominate the frequency response characteristics over the frequency dependent friction. A very simple frequency dependent model of the damping term of the hose can then be combined with an equally simple model of the distributed friction to represent a simple but accurate model of a flexible hose for system simulation in the time domain.

  • 165.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Robust Modelling Using Bi-Lateral Delay Lines for High Speed Simulation of Complex Systems2011Ingår i: DINAME 2011: 14th International Symposium on Dynamic Problems in Mechanics / [ed] Agenor Toledo Fleury, 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A very effective method for modelling and simulation of large complex dynamic systems is represented by distributed modelling using transmission line elements (or bi-lateral delay lines). This method evolves naturally for calculation of pressures when hydraulic pipelines are modelled with distributed parameters, and it can be used to effectively partition the model to use local solvers for the differential equations in each component or subsystem. It is also applicable to other physical systems, such as mechanical, electrical, gas etc.

    One interesting application for distributed solvers using bi-lateral delay lines is in real time simulation, since they are very robust and usually quite large simulation times steps can be used. Modelling for real-time applications puts special requirements on robustness in the numerical methods used. In real-time applications there is no room for decreasing time step in numerically critical stages. Furthermore, if a system is relaying on a real-time simulation for its functionality, failure in the numerical properties is unacceptable. It is also in many applications possible to simulate the system faster than real time, which means that high fidelity system simulation can be used to plan ahead in control applications, and for simulation based optimisation.

    Since solvers can be embedded in components or subsystems, it is very straightforward to implement parallel processing using the multi-core processors which now is the standard for desk top computers. There is also an increasing need in many situations to resolve the time scale to finer details, where the effect of wave propagation needs to be modelled.

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    Robust Modelling Using Bi-Lateral Delay Lines for High Speed Simulation of Complex Systems
  • 166.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Transmission line modelling for system simulation2021Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This text is about system simulation using transmission line method, TLM, to obtain partitioned models that can be used with local solvers, and can be used for parallel processing. Relaying on local solvers also means that good scaling properties are obtained. This is exemplified with the modelling of diffrerent components for e.g. as electronic, hydraulic and mechanical systems.

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  • 167.
    Krus, Petter
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Braun, Robert
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Nordin, Peter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Aircraft System Simulation for Preliminary Design2012Ingår i: ICAS 2012 CD-ROM PROCEEDINGS / [ed] Professor I Grant, Optimage Ltd , 2012, s. Art.nr. ICAS2012-1.9.3-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Developments in computational hardware and simulation software have come to a point where it is possible to use whole mission simulation in a framework for conceptual/preliminary design. This paper is about the implementation of full system simulation software for conceptual/preliminary aircraft design. It is based on the new Hopsan NG simulation package, developed at the Linköping University. The Hopsan NG software is implemented in C++. Hopsan NG is the first simulation software that has support for multi-core simulation for high speed simulation of multi domain systems.

    In this paper this is demonstrated on a flight simulation model with subsystems, such as control surface actuators.

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  • 168.
    Krus, Petter
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, LiselottLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.Sethson, MagnusLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden2017Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    SICFP2017

    This is the proceedings of the 15th Scandinavian International Conference on Fluid Power held at Linköping University in Sweden on 7-9 June 2017. The theme of the conference was “Fluid Power in the Digital Age”. The contributions are well aligned with this theme, and are indeed reflecting the great developments. We are very grateful to the effort put in by the authors to produce such high quality papers, and also to those taking time to review papers to further enhance the quality. The contributions clearly shows that the fluid power industry, and academia, have both challenges as well as opportunities in keeping up with the evolving capabilities provided by the digitalization. It was with great joy to see old and new colleagues and friends attending our conference and the division of Fluid and mechatronic systems, at Linköping University. The conference is a bi-annual event, with alternating localization between Linköping in Sweden and Tampere in Finland. The process of hosting such an event is a great effort for our organization and I would like to thank all those involved in organizing this conference, and wish good luck with the next one to our Finnish colleagues. Thank you!

    Prof. Petter Krus

    Head of Division

    Fluid and Mechatronic Systems

    Review Process

    Each author attending the conference days had the opportunity to select from three different ways of presenting their contribution. Firstly, a reviewed process with at least two international reviewers of each contribution. The process resulted in most cases with feedback from the reviewers with comments spanning everything between diagram legends to scientific methods. Some proposed papers where rejected upon recommendations from reviewers. Secondly contributions where also presented in industry sessions where the review process where internal only by the staff of the division. A third extended abstract presentation format where also presented during the conference.

    This proceedings contain all presented contributions from the reviewed papers in the first section and thereafter the non-reviewed papers in second section. All reviewed papers are marked in the footer by the acceptance date.

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    Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linkï¿œping, Sweden
  • 169.
    Krus, Petter
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Sethson, MagnusLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.Ericson, LiselottLinköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    13th Scandinavian International Conference on Fluid Power, June 3-5, 2013, Linköping, Sweden2013Proceedings (redaktörskap) (Refereegranskat)
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    13th Scandinavian International Conference on Fluid Power, June 3-5, 2013, Linköping, Sweden
  • 170.
    Krus, Petter
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Ölvander, Johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Maskinkonstruktion. Linköpings universitet, Tekniska högskolan.
    Performance index and meta-optimization of a direct search optimization method2013Ingår i: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, Vol. 45, nr 10, s. 1167-1185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Design optimization is becoming an increasingly important tool for design, often using simulation as part of the evaluation of the objective function. A measure of the efficiency of an optimization algorithm is of great importance when comparing methods. The main contribution of this article is the introduction of a singular performance criterion, the entropy rate index based on Shannon's information theory, taking both reliability and rate of convergence into account. It can also be used to characterize the difficulty of different optimization problems. Such a performance criterion can also be used for optimization of the optimization algorithms itself. In this article the Complex-RF optimization method is described and its performance evaluated and optimized using the established performance criterion. Finally, in order to be able to predict the resources needed for optimization an objective function temperament factor is defined that indicates the degree of difficulty of the objective function.

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    fulltext
  • 171.
    Krus, Petter
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ölvander, johan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Rydberg, Karl-Erik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Drive Train Concept Selection for Industrial Robots2011Konferensbidrag (Övrigt vetenskapligt)
  • 172.
    Kärnell, Samuel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Fluid Power Pumps and the Electrification: With a Focus on Discrete Displacement Control in Load Handling Applications2020Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    More and more vehicles are being electrified. Mobile working machines and heavy trucks are not excluded, and these machines are often hydraulically intense. Electrification entails new requirements for the hydraulic system and its components, and these requirements must be taken into consideration.

    Hydraulic systems have looked similar for a long time, but now there is an opportunity to advance. Many things change when a diesel engine is replaced with an electric motor. For example, variable-speed control becomes more relevant, electric regeneration becomes possible, and the use of multiple prime movers becomes an attractive alternative. The noise from the hydraulic system will also be more noticeable when the diesel engine is gone. Furthermore, the introduction of batteries to the system makes the energy more valuable, since batteries are heavy and costly compared to a diesel tank. Therefore, it is commercially viable to invest in the hydraulic system.

    This thesis revolves around the heart of the hydraulic system, that also is the root of all evil. That is the pump. Traditionally, a pump has had either a fixed displacement or a continuously variable displacement. Here, the focus is on something in between, namely a pump with discrete displacement. The idea of discrete displacement is far from unique, but has not been investigated in detail in combination with variable speed before. In this thesis, a novel design for a quiet pump with discrete displacement is presented and analysed. The results show that discrete displacement is relevant from an energy perspective for machines working extensively at high pressure levels and with low flow rates, and that a few discrete values are enough to make a significant difference. However, for other cycles, the possible energy gains are very limited, but the discrete displacement can be a valuable feature if downsizing the electric machine is of interest.

    Delarbeten
    1. Simulation and validation of a wobble plate pump with a focus on check valve dynamics
    Öppna denna publikation i ny flik eller fönster >>Simulation and validation of a wobble plate pump with a focus on check valve dynamics
    2018 (Engelska)Ingår i: 2018 Global Fluid Power Society PhD Symposium (GFPS), Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Digital hydraulic piston pumps that use electrically controlled on/off valves to individually control the flow from each piston is a promising technique as these pumps are highly efficient at part displacement and respond quickly. However, digital pumps can still use check valves on the inlet, a fact that makes analysing wobble plate pumps (WPP) and their check valves interesting. Here, we measured the cylinder pressures of a WPP and compared these results with results from a simulation model we developed. In addition, we used linear analysis to investigate how different design parameters affect the valves behaviour. From the measurements we found that the cylinder pressure is clearly affected the flow from other pistons and also that the system is not as stiff as expected. From the linear analysis, a criterion of how to design the valve to avoid instability was derived.

    Ort, förlag, år, upplaga, sidor
    Institute of Electrical and Electronics Engineers (IEEE), 2018
    Nyckelord
    wobble plate pump, digital pump, check valve, efficiency, pressure pulsations
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:liu:diva-156228 (URN)10.1109/GFPS.2018.8472400 (DOI)000462072500042 ()2-s2.0-85055699972 (Scopus ID)9781538647851 (ISBN)
    Konferens
    Global Fluid Power Society PhD Symposium (GFPS), Samara, Russia, 18-20 July 2018
    Projekt
    STEALTH – Sustainable Electrified Load Handling
    Anmärkning

    Funding Agencies|Swedish Energy Agency [44427-1]

    Tillgänglig från: 2019-04-09 Skapad: 2019-04-09 Senast uppdaterad: 2020-05-25Bibliografiskt granskad
    2. As Simple as Imaginable - An Analysis of Novel Digital Pump Concepts
    Öppna denna publikation i ny flik eller fönster >>As Simple as Imaginable - An Analysis of Novel Digital Pump Concepts
    2019 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper focuses on how digital displacement can be achieved in a wobble plate pump by connecting thecylinders in the pump to different groups and using by-pass valves to control the flow from each group. The ideais to make a simple and inexpensive electronically controlled pump. The paper deals with two main aspects, thecylinder configuration and the valve configuration. The cylinder configuration refers to how the cylinders in thepump can be grouped and how different groupings will affect the flow pulsations. The valve configuration refersto the by-pass solution. Two principally different solutions are analysed: one that uses 3-way by-pass valvesand one that makes use of check valves in combination with 2-way on/off-valves. A comprehensive simulationmodel has been used as a tool for analysing flow pulsations for the different design configurations. The resultsshow that a cylinder configuration with 3+6 cylinders delivers low flow pulsations for all three displacementsettings. However, if more displacement settings are desired, an interesting finding is that a configuration with3+6+12 cylinders is only slightly better than a configuration with 2+4+8 cylinders, from a pulsation amplitudepoint of view. This is due to the pre-compression in the cylinders. Regarding the valve configuration, it hasbeen shown that both of the analysed configurations might suffer from problems during switching, especially ifthe valves are slow.

    Nyckelord
    Digital hydraulics, digital displacement, pumps
    Nationell ämneskategori
    Teknik och teknologier Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-162202 (URN)
    Konferens
    The Sixteenth Scandinavian International Conference on Fluid Power
    Projekt
    STEALTH – Sustainable Electrified Load Handling
    Tillgänglig från: 2019-11-22 Skapad: 2019-11-22 Senast uppdaterad: 2020-05-25
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  • 173. Beställ onlineKöp publikationen >>
    Kärnell, Samuel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    On Electrified Fluid Power Systems in Mobile Machinery2022Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    High power density in combination with flexible power distribution possibilities and extreme robustness are reasons why fluid power has been the preferred technology in mobile machinery, such as excavators and cranes, since the mid-20th century. In principle, the machines have been powered by a combustion engine which powers a pump, with the output from the pump being distributed to different functions via valves. However, a transformation is currently underway. Combustion engines are being replaced by electric motors, and batteries able to store energy corresponding to several hours of operation are often desired. Since batteries tend to be heavy and expensive, reducing the energy consumption is getting higher priority than ever before. There are applications where electrification means that hydraulic components are replaced by electric counterparts, but fluid power has characteristics that are highly desirable in mobile machinery. Therefore, many hydraulic actuators will remain. Conventional hydraulic systems, which are known for their inefficiency, should, however, be adapted to the new conditions brought about by electrification. The question, and the overall subject of this thesis, is: how? The research has focused on two main topics: pump-controlled systems, which are systems where each actuator has its own supply unit, and the use of variable displacement pumps in electrified systems.

    A large proportion of the losses in many conventional hydraulic systems is due to the simultaneous operation of functions that require different pressure levels. One way to avoid these losses is to use pump-controlled systems. How these systems should be designed is, however, far from obvious. In this thesis, different types of pump-controlled systems are compared, both statically and dynamically.

    Regarding variable displacement pumps, they have had a natural place in many conventional systems, but electrification may change this, since speed-control can now also be used for flow- and pressure control. However, there are still aspects relating to energy consumption and component dimensioning, among other things, that makes variable pumps relevant. These aspects are investigated here, and different types of variable pumps are reviewed.

    Delarbeten
    1. Classification and Review of Variable Displacement Fluid Power Pumps and Motors
    Öppna denna publikation i ny flik eller fönster >>Classification and Review of Variable Displacement Fluid Power Pumps and Motors
    2023 (Engelska)Ingår i: International Journal of Fluid Power, ISSN 1439-9776, Vol. 24, nr 2, s. 207-246Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Displacement control of positive displacement machines has been a part of fluid power since the early days. Some of the early hydraulic presses already used two different displacement settings, though this was realised by using two different pumps rather than changing the displacement. Later, radial motors with variable stroke length appeared, followed by other designs of variable machines, such as swashplate machines, bent-axis machines, and variable vane machines. All these solutions control the displacement by varying the volume difference of the displacement element – but there are other ways of achieving this. Most have not passed the research state, but some are commercially available. In this paper, different ways of varying the displacement are presented and classified. The classification divides concepts into either control of displaced fluid or control of usage of displaced fluid. In turn, these concepts can be either on system level or displacement element level. This results in four main classes, which to some extent can describe the characteristics of the control.

    Ort, förlag, år, upplaga, sidor
    River Publishers, 2023
    Nyckelord
    variable displacement, hydraulic pumps, positive displacement machines, review
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-193538 (URN)10.13052/ijfp1439-9776.2423 (DOI)000992827500004 ()
    Anmärkning

    Funding: Swedish Energy Agency [44427-3]

    Tillgänglig från: 2023-05-04 Skapad: 2023-05-04 Senast uppdaterad: 2023-06-15Bibliografiskt granskad
    2. Digital pumps in speed-controlled systems: an energy study for a loader crane application
    Öppna denna publikation i ny flik eller fönster >>Digital pumps in speed-controlled systems: an energy study for a loader crane application
    2020 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.

    Ort, förlag, år, upplaga, sidor
    Dresden: , 2020
    Nyckelord
    Digital pumps, Loader crane, Speed-controlled system
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-169404 (URN)10.25368/2020.71 (DOI)
    Konferens
    12th International Fluid Power Conference (12. IFK). Dresden, October 12 – 14, 2020
    Projekt
    STEALTH - Sustainable Electrified Load Handling
    Forskningsfinansiär
    Energimyndigheten, 44427-1
    Tillgänglig från: 2020-09-14 Skapad: 2020-09-14 Senast uppdaterad: 2022-08-19Bibliografiskt granskad
    3. Analysis of a Digital Pump With Variable Speed Drive
    Öppna denna publikation i ny flik eller fönster >>Analysis of a Digital Pump With Variable Speed Drive
    2022 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    The interest in speed-control of hydraulic pumps is increasing with the electrification of mobile machinery. With speed-control at hand, it is tempting to use fixed pumps where variable pumps earlier have been used. However, it can be beneficial to use variable pumps in combination with variable speed since it can allow downsizing of electric machines and reduce losses. But there are downsides with conventional variable pumps, such as increased complexity, cost, and low efficiency. Digital pumps (i.e., pumps with a discrete number of displacement settings) can address these problems. This paper is focused on the performance of a digital pump, both efficiency-wise and from a dynamic perspective. Shunt-based concepts that can improve the dynamics during switching are proposed. Simulation results show that the concepts can reduce the disruption in output flow during switchings.

    Nationell ämneskategori
    Annan maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-189982 (URN)10.1115/FPMC2022-88503 (DOI)978-0-7918-8633-5 (ISBN)
    Konferens
    BATH/ASME 2022 Symposium on Fluid Power and Motion Control
    Forskningsfinansiär
    Energimyndigheten, 44427-3
    Tillgänglig från: 2022-11-14 Skapad: 2022-11-14 Senast uppdaterad: 2022-11-15
    4. Pump-Controlled Actuators with Dump Valves
    Öppna denna publikation i ny flik eller fönster >>Pump-Controlled Actuators with Dump Valves
    2021 (Engelska)Ingår i: Proceedings of the 17:th Scandinavian International Conference on Fluid Power, Linköping, 2021Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Linköping: , 2021
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 182
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-181230 (URN)10.3384/ecp182 (DOI)978-91-7929-013-9 (ISBN)
    Konferens
    The 17th Scandinavian International Conference on Fluid Power, SICFP’21
    Forskningsfinansiär
    Energimyndigheten, 44427-3
    Tillgänglig från: 2021-11-23 Skapad: 2021-11-23 Senast uppdaterad: 2022-08-19
    5. Hysteresis Control in Pump-Controlled Systems: A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits
    Öppna denna publikation i ny flik eller fönster >>Hysteresis Control in Pump-Controlled Systems: A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits
    2022 (Engelska)Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 2, artikel-id 424Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    There is growing interest in using electric motors as prime movers in mobile hydraulic systems. This increases the interest in so-called pump-controlled systems, where each actuator has its own drive unit. Such architectures are primarily appealing in applications where energy efficiency is important and electric recuperation is relevant. An issue with pump-controlled systems is, however, mode-switch oscillations which can appear when the pressure levels in the system are close to the switching condition. In this paper, the mode-switching behavior of different generalized closed and open circuit configurations is investigated. The results show that the choice of where to sense the pressures has a huge impact on the behavior. They also show that, if the pressure sensing components are properly placed, closed and open circuits can perform very similarly, but that mode-switch oscillations still can occur in all circuits. Active hysteresis control is suggested as a solution and its effectiveness is analyzed. The outcome from the analysis shows that active hysteresis control can reduce the risk for mode-switch oscillations significantly.

    Ort, förlag, år, upplaga, sidor
    MDPI, 2022
    Nyckelord
    pump-controlled systems; mode-switch oscillations; hysteresis control
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-182259 (URN)10.3390/en15020424 (DOI)000747489000001 ()
    Forskningsfinansiär
    Energimyndigheten, 44427-3
    Anmärkning

    Funding: Swedish Energy AgencySwedish Energy AgencyMaterials & Energy Research Center (MERC) [44427-3]

    Tillgänglig från: 2022-01-11 Skapad: 2022-01-11 Senast uppdaterad: 2023-08-28
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  • 174.
    Kärnell, Samuel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    The History and Future of Fluid Power Pumps and Motors2022Ingår i: Proceedings of the 6th Workshop on Innovative Engineering for Fluid Power (WIEFP 2022), 2022, s. 51-56Konferensbidrag (Refereegranskat)
    Abstract [en]

    Positive displacement pumps have been around for thousands of years, but it was first in the beginning of the 19th century they started to be used for power transmission purposes. At that time, the fluid was water, and the applications were primarily presses. During the century, the technology developed and towards its end, fluid power systems were used to transmit power to hundreds or even thousands of consumers within several cities. However, in the 20th century, these large-scale fluid power transmission systems were outcompeted by the electric grid. But at the same time, the focus for fluid power was shifted towards self-contained, oil-based systems, which were suitable in many mobile applications powered by combustion engines. Once again, fluid power systems are now undergoing a transition. This especially apply to mobile applications, where combustion engines are being replaced by electric motors. This puts new requirements on the hydraulic systems as well as the pumps and motors that are to be used. Electrification means increased focus on energy efficiency, and speed-control becomes more relevant than before. New system designs are therefore highly relevant. Depending on the architecture that is chosen, different requirements will be set on the pumps and motors. Aspects such as multi-mode operation, high- and low-speed performance, and displacement control will be discussed in this paper.

  • 175.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Analysis of a Digital Pump With Variable Speed Drive2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    The interest in speed-control of hydraulic pumps is increasing with the electrification of mobile machinery. With speed-control at hand, it is tempting to use fixed pumps where variable pumps earlier have been used. However, it can be beneficial to use variable pumps in combination with variable speed since it can allow downsizing of electric machines and reduce losses. But there are downsides with conventional variable pumps, such as increased complexity, cost, and low efficiency. Digital pumps (i.e., pumps with a discrete number of displacement settings) can address these problems. This paper is focused on the performance of a digital pump, both efficiency-wise and from a dynamic perspective. Shunt-based concepts that can improve the dynamics during switching are proposed. Simulation results show that the concepts can reduce the disruption in output flow during switchings.

  • 176.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    As Simple as Imaginable - An Analysis of Novel Digital Pump Concepts2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper focuses on how digital displacement can be achieved in a wobble plate pump by connecting thecylinders in the pump to different groups and using by-pass valves to control the flow from each group. The ideais to make a simple and inexpensive electronically controlled pump. The paper deals with two main aspects, thecylinder configuration and the valve configuration. The cylinder configuration refers to how the cylinders in thepump can be grouped and how different groupings will affect the flow pulsations. The valve configuration refersto the by-pass solution. Two principally different solutions are analysed: one that uses 3-way by-pass valvesand one that makes use of check valves in combination with 2-way on/off-valves. A comprehensive simulationmodel has been used as a tool for analysing flow pulsations for the different design configurations. The resultsshow that a cylinder configuration with 3+6 cylinders delivers low flow pulsations for all three displacementsettings. However, if more displacement settings are desired, an interesting finding is that a configuration with3+6+12 cylinders is only slightly better than a configuration with 2+4+8 cylinders, from a pulsation amplitudepoint of view. This is due to the pre-compression in the cylinders. Regarding the valve configuration, it hasbeen shown that both of the analysed configurations might suffer from problems during switching, especially ifthe valves are slow.

  • 177.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Classification and Review of Variable Displacement Fluid Power Pumps and Motors2023Ingår i: International Journal of Fluid Power, ISSN 1439-9776, Vol. 24, nr 2, s. 207-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Displacement control of positive displacement machines has been a part of fluid power since the early days. Some of the early hydraulic presses already used two different displacement settings, though this was realised by using two different pumps rather than changing the displacement. Later, radial motors with variable stroke length appeared, followed by other designs of variable machines, such as swashplate machines, bent-axis machines, and variable vane machines. All these solutions control the displacement by varying the volume difference of the displacement element – but there are other ways of achieving this. Most have not passed the research state, but some are commercially available. In this paper, different ways of varying the displacement are presented and classified. The classification divides concepts into either control of displaced fluid or control of usage of displaced fluid. In turn, these concepts can be either on system level or displacement element level. This results in four main classes, which to some extent can describe the characteristics of the control.

  • 178.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Control of an Asymmetric Cylinder With Two Individually Controlled Pump/Motors2023Ingår i: Proceedings of the ASME/BATH 2023Symposium on Fluid Power and Motion Control, 2023Konferensbidrag (Refereegranskat)
    Abstract [en]

    Pump-controlled asymmetric cylinders need some kind ofcompensation for the difference between the in- and outlet flow.This can be done by using valves or additional pump/motors.An advantage with using valves is that only one pump/motor isrequired, but problems with mode-switch oscillations are morelikely to occur. On the other hand, cylinder areas should bewell matched with the pump/motor displacements for pump/motorcompensation if the pump/motors are fixed and connected to thesame shaft. However, this problem is avoided if the pump/motorsare individually controlled. Furthermore, with individually controlledpump/motors, it is possible to control the pressure in one ofthe cylinder chambers and the piston speed simultaneously. Thispaper is focusing on such architectures. There are several possibleconfigurations for architectures and control strategies for individuallycontrolled pump/motors, and some are compared here.Results show that one of the configurations is more efficient thanthe others, but that it is less efficient than valve-compensation (assuminglarge valves). A controller design where one pump/motoris used to control the speed and another to control the pressureis suggested. Results show that the controller should be adaptedbased on the mode of operation.

  • 179.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Hysteresis Control in Pump-Controlled Systems: A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 2, artikel-id 424Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is growing interest in using electric motors as prime movers in mobile hydraulic systems. This increases the interest in so-called pump-controlled systems, where each actuator has its own drive unit. Such architectures are primarily appealing in applications where energy efficiency is important and electric recuperation is relevant. An issue with pump-controlled systems is, however, mode-switch oscillations which can appear when the pressure levels in the system are close to the switching condition. In this paper, the mode-switching behavior of different generalized closed and open circuit configurations is investigated. The results show that the choice of where to sense the pressures has a huge impact on the behavior. They also show that, if the pressure sensing components are properly placed, closed and open circuits can perform very similarly, but that mode-switch oscillations still can occur in all circuits. Active hysteresis control is suggested as a solution and its effectiveness is analyzed. The outcome from the analysis shows that active hysteresis control can reduce the risk for mode-switch oscillations significantly.

    Ladda ner fulltext (pdf)
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  • 180.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Fernlund, Emil
    Hudiksvalls hydraulikkluster.
    Lagerstedt, Fabian
    Huddig.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Pump-Controlled Actuators with Dump Valves2021Ingår i: Proceedings of the 17:th Scandinavian International Conference on Fluid Power, Linköping, 2021Konferensbidrag (Refereegranskat)
  • 181.
    Kärnell, Samuel
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Rankka, Amy
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Dell'Amico, Alessandro
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Digital pumps in speed-controlled systems: an energy study for a loader crane application2020Konferensbidrag (Refereegranskat)
    Abstract [en]

    Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.

  • 182.
    Landberg, Magnus
    et al.
    Saab Aeronaut, Linkoping, Sweden.
    Braun, Robert
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Sethson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    THE HYDRAULIC INFINITE LINEAR ACTUATOR APPLIED TO ELEVATORS IN MID-RISE BUILDINGS2018Ingår i: PROCEEDINGS OF THE BATH/ASME SYMPOSIUM ON FLUID POWER AND MOTION CONTROL, 2018, AMER SOC MECHANICAL ENGINEERS , 2018, artikel-id V001T01A030Konferensbidrag (Refereegranskat)
    Abstract [en]

    Hydraulic elevators with conventional long -stroke hydraulic cylinders are limited for use in low-rise buildings, up to five floors, due to low hydraulic stiffness, low natural frequency, low hydraulic pressure and large oil volume. With a new hydraulic actuation technology jointly invented at Linkoping University and SAAB named the Hydraulic Infinite Linear Hydraulic Actuator (HILA), these short -comings for hydraulic actuators can be reduced and hydraulic elevators can be offered for mid rise buildings. The HILA technology provides long strokes, high system pressure, compactness and small chamber volumes. The actuator has a higher stiffness and a higher natural frequency compared to conventional hydraulic cylinders. The higher system pressure allows for an even more compact system design, with lower flow levels and a smaller reservoir. The HILA technology combines two short -stroke cylinders with two engaging and disengaging clamping mechanisms into one actuator with long stroke length. The motion of each single short stroke piston linked together by the clamping mechanisms creates the motion of the piston rod. In this way the two pistons are moving along the rod in a kind of rope climbing motion. The challenge is to implement a control system which can provide a smooth motion without unacceptable jerk at load shift as seen with ordinary directional valves. Earlier research work on HILA technology has shown that a control system with fast servo valves can fulfil these requirements. This study shows promising results from simulation analysis combined with optimization techniques, using slightly modified standard directional hydraulic valves.

  • 183.
    Landberg, Magnus
    et al.
    Saab Aeronaut, Linkoping, Sweden.
    Hochwallner, Martin
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    NOVEL LINEAR HYDRAULIC ACTUATOR2015Ingår i: PROCEEDINGS OF THE ASME/BATH SYMPOSIUM ON FLUID POWER AND MOTION CONTROL, 2015, ASME Press, 2015, nr V001T01A054Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the area of linear motion, infinite stroke only is provided by electric actuators today, until now there has been no hydraulic alternative. The novel linear hydraulic actuator consists of two double acting cylinders with a common piston rod. The working principle of this actuator for short movements is that at least one piston is connected to the piston rod and the actuator works like an ordinary hydraulic double acting cylinder. For longer movements one of the pistons is connected alternatively to the piston rod providing the drive. In this way the two pistons are moving the piston rod alternatingly in a kind of rope climbing motion. The critical element is the clamping mechanism which is an already known machine element but used in this new application. Advantages of this concept are as follows: The actuator is compact. Very long strokes and piston rods are allowed without side effects of common cylinders. This property is the origin of the name "infinite cylinder". The cylinder has small chamber volumes and so high hydraulic stiffness and low capacitance. It has also potentially no external leakage. The cylinder can provide twice the rated force for short strokes. Applications for this feature are the plate opening stroke of injection molding machines, or presses with low work to travel stroke ratio, like a press brake. The paper includes a detailed description of the design and the working principle. One critical component is the clamping mechanism which temporarily connects the pistons to the piston rod. The clamping mechanism together with the piston represents a new kind of machine element in the mechanical engineering field. Here the focus will be on the function and the control strategy. With simulation the proposed control strategy and function will be presented and the performance analyzed. The simulation model is backed up by first results from experiments on the early prototype. The experiments carried out so far on the hydraulic clamping mechanism, which is the critical component in the system show very promising results that the required function can be achieved. Furthermore, the function of the whole cylinder has been simulated with good result. For the full paper results from a functioning prototype is also to be expected.

  • 184.
    Landberg, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Saab Aeronautics, Linköping, Sweden.
    Sethson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    The Hydraulic Infinite Linear Actuator with Multiple Rods2017Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson, Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 279-293Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Future hydraulic actuation systems can be significantly improved by utilisation of a new type of hydraulic linear actuator technology. By enabling multiple actuating elements, integrated in a compact and lightweight single unit controlled by ordinary directional valves it is possible to achieve a high position accuracy. This is a new way to generate and distribute mechanical linear movement and force by using hydraulic actuators in a cost effective way, in less responsive closed loop systems. This is a variant on the Hydraulic Infinite Linear Actuator, HILA, invention. The technology also represents a new sort of digital hydraulics. The presented technology provides typical hydraulic actuator characteristics with high system pressure and potentially no external oil leakage. It is based on a well-known hydraulic clamping element technology used in a new way, where the piston and the piston rod can quickly be coupled and uncoupled by means of the clamping element in a failsafe way by using well defined incremental steps. HILA in its simplest usage, provides new features to hydraulic cylinders such as providing very long strokes, high rod speed, and small chamber volumes which means high stiffness and low capacitance. The aim of this study is to present a fundamentally new way of using hydraulic actuators. The invention is called the Hydraulic Infinite Linear Actuator with Multiple Rods, HILA MR. The study presents the idea, principles and feasible combinations of the technology. Also applications in the aircraft and robotic field will be presented. 

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    The Hydraulic Infinite Linear Actuator with Multiple Rods
  • 185. Beställ onlineKöp publikationen >>
    Larsson, Felix
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Evaluation of Aircraft Actuator Technologies2023Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The flight control actuation system is one of the most critical systems in an aircraft. A failure of this system cannot occur, since it would have catastrophic consequences. The environment it operates in is considered as highly demanding, with temperatures ranging from -50 to +60 degrees Celsius, speeds from 0 to Mach 2+ and G-forces from -3 up to 9. At the same time, the system shall be as small and lightweight as possible, since every gram and cm3 will decrease the available payload and/or increase the total aircraft size, which in turn increase the fuel-burn. The preferred choice of technology for actuators has, since the late 1930s, been hydraulics. Hydraulic actuators are characterized by high power density, high technical maturity, high safety, and high response. With emerging benefits from the electric domain, research during the last decade has been focusing on electrified alternatives as the future alternative for actuators. 

    With varying requirements on the actuators depending on the type of air-craft platform, it is not trivial when it is a better alternative to electrify the actuators. For example, with smaller platforms, the forces acting on the actuators will be lower in comparison with larger aircraft. The purpose of this thesis was to investigate if, and when certain technology may be the preferred alternative with regards to size and weight, performance, power consumption and thermal characteristics. Also, it was investigated how to compare different topologies which utilize different technologies, and how certain technology may affect the requirements of surrounding systems in the platform. 

    This work has led to three different approaches for comparison and evaluation of actuator technology that can be applied in early conceptual design of aircraft platforms. The first approach can be used to ensure comparability of the topologies to be studied. The second approach focuses on modeling of performance and thermal impact and can be applied to study static and dynamic behavior of different technologies. The third approach can be used to study how size and weight of actuators will be affected by operational requirements, with special emphasis on high-level modeling with few inputs. 

    Delarbeten
    1. An ontological approach for classifying aircraft actuators
    Öppna denna publikation i ny flik eller fönster >>An ontological approach for classifying aircraft actuators
    2021 (Engelska)Ingår i: Proceedings of ICAS2021, Shanghai, China, 6th-10th September, 2021., 2021Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Today, electrification is a widely discussed topic within all fields of engineering and especially in the field ofaeronautics. Whether electrification of aircraft systems is the only viable option to overcome environmentalissues is a highly complex question which involves many aspects. In this paper, fundamental differences between electrified and hydraulic aircraft actuators are mapped, compared and discussed to understand how andif these systems can be compared without misleading results.

    In this paper, different actuator architectures were collected from literature, classified and analyzed by usingan ontological approach. The classification was created by utilizing defined classes where the class definitioncorresponded to the functional requirements which had to be fulfilled by the actuator architecture.

    This work has shown that ontologies can sufficiently be used for classification of actuator architectures. Thebuilt in reasoner can be used to sort a large set of actuators into comparable classes. Meanwhile, the ontologydefines a framework where important information of the actuators and their components can be stored andstructured.

    Nyckelord
    Aircraft actuators, EMA, EHA, SHA, Ontology
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-192461 (URN)9781713841012 (ISBN)
    Konferens
    32nd Congress of the International Council of the Aeronautical Sciences (ICAS 2021)
    Tillgänglig från: 2023-03-20 Skapad: 2023-03-20 Senast uppdaterad: 2023-03-30Bibliografiskt granskad
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    presentationsbild
  • 186.
    Larsson, Felix
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Johansson, Christian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Digital hydraulic actuator for flight control2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In aviation industry, one of the most important aspects is weight savings. This since with a lowered weight, the performance of the aircraft can be increased together with increased fuel savings and thus lowered running costs. One way of saving weight is to reduce energy consumption, since with lowered energy consumption, lowered mass of fuel is required etc.

    Most aircraft are today maneuvered with hydraulic systems due to its robustness and power density. It is the primary source of power for primary and secondary flight controls. The control of a conventional system which is using proportional valves is done by altering flow by restricting it to the extent where the desired output is achieved, which implies heat losses since the full performance of its supply is wasted through the valve.

    In previous research, more energy efficient hydraulic systems called digital hydraulics has been investigated. In difference with conventional hydraulics, digital hydraulics uses low cost, high frequency on/off valves, which either are fully opened, or fully closed, instead of proportional valves to achieve the desired output. With this comes the benefit of no energy losses due to leakage and restriction control.

    The downsides with digital hydraulics is the controlabillity. One way of controlling it is by using several pressure sources which outputs different pressure levels. By using the on/off valves in different combinations, different outputs can be achieved in a discrete manner.

    In this thesis, the aim was to remove the impact of the discrete force steps which are present in digital hydraulics by creating concepts with hybrid solutions containing both digital hydraulics and restrictive control.

    Three concepts were developed and investigated using simulation. The energy consumption and performance was analysed and compared with a reference model, the concepts redundancy compared to conventional systems was discussed and finally the concepts were tested with an aircraft simulation model.

    The concepts were found to reduce the energy consumption with different magnitude depending on the load cycle. The performance was found to be almost as good as the reference model. The redundancy compared with conventional systems should be possible to maintain with slight modifications, but further investigation is needed.

    It was found that one of the most important aspects regarding energy consumption is which combination of supply pressures is used to supply the system since it influences leakage and flow due to compression.

    Ladda ner fulltext (pdf)
    Digital_Hydraulic_Actuator_For_Flight_Control
  • 187.
    Larsson, Felix
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Medicinska fakulteten. Saab AB, Linköping, Sweden.
    Reichenwallner, Christopher
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Medicinska fakulteten.
    Dell'Amico, Alessandro
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Saab AB, Linköping, Sweden.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    An ontological approach for classifying aircraft actuators2021Ingår i: Proceedings of ICAS2021, Shanghai, China, 6th-10th September, 2021., 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today, electrification is a widely discussed topic within all fields of engineering and especially in the field ofaeronautics. Whether electrification of aircraft systems is the only viable option to overcome environmentalissues is a highly complex question which involves many aspects. In this paper, fundamental differences between electrified and hydraulic aircraft actuators are mapped, compared and discussed to understand how andif these systems can be compared without misleading results.

    In this paper, different actuator architectures were collected from literature, classified and analyzed by usingan ontological approach. The classification was created by utilizing defined classes where the class definitioncorresponded to the functional requirements which had to be fulfilled by the actuator architecture.

    This work has shown that ontologies can sufficiently be used for classification of actuator architectures. Thebuilt in reasoner can be used to sort a large set of actuators into comparable classes. Meanwhile, the ontologydefines a framework where important information of the actuators and their components can be stored andstructured.

  • 188. Beställ onlineKöp publikationen >>
    Larsson, L. Viktor
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Control Aspects of Complex Hydromechanical Transmissions: with a Focus on Displacement Control2017Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with control aspects of complex hydromechanical transmissions. The overall purpose is to increase the knowledge of important aspects to consider during the development of hydromechanical transmissions to ensure transmission functionality. These include ways of evaluating control strategies in early design stages as well as dynamic properties and control aspects of displacement controllers, which are key components in these systems.

    Fuel prices and environmental concerns are factors that drive research on propulsion in heavy construction machinery. Hydromechanical transmissions are strong competitors to conventional torque-converter transmissions used in this application today. They offer high efficiency and wide speed/torque conversion ranges, and may easily be converted to hybrids that allow further fuel savings through energy recuperation. One challenge with hydromechanical transmissions is that they offer many different configurations, which in turn makes it important to enable evaluation of control aspects in early design stages. In this thesis, hardware-in-the-loop simulations, which blend hardware tests and standard software-based simulations, are considered to be a suitable method. A multiple-mode transmission applied to a mid-sized construction machine is modelled and evaluated in offline simulations as well as in hardware-in-the-loopsimulations.

    Hydromechanical transmissions rely on efficient variable pumps/motors with fast, accurate displacement controllers. This thesis studies the dynamic behaviour of the displacement controller in swash-plate axial-piston pumps/motors. A novel control approach in which the displacement is measured with an external sensor is proposed. Performance and limitations of the approach are tested in simulations and in experiments. The experiments showed a significantly improved performance with a controller that is slightly more advanced than a standard proportional controller. The implementation of the controller allows simple tuning and good predictability of the displacement response.

    Delarbeten
    1. Simulation Aided Design and Testing of Hydromechanical Transmissions
    Öppna denna publikation i ny flik eller fönster >>Simulation Aided Design and Testing of Hydromechanical Transmissions
    2014 (Engelska)Ingår i: The 9th JFPS International Symposium on Fluid Power, Matsue, 2014, 2014Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper demonstrates the use of high-speed simulation in transmission conceptual design and presents a transmission test bed for hardware-in-the-loop simulations of hydromechanical transmission concepts. Complex transmissions, such as multiple-mode hydromechanical transmissions and hydraulic hybrid transmissions, present new difficulties and costs in the development process. There is today a greater demand for more efficient product development and more work has shifted towards simulation. The Hopsan simulation package allows robust, high-speed simulations suitable for both offline and hardware-in-the-loop simulation. New simulation models for hydromechanical transmissions are developed and used to simulate a known two-mode transmission concept. The same concept is also tested in hardware-in-the-loop simulations in the proposed transmission test bed. Results show good agreement with the hardware tests and highlight the proficiency of the simulation tools.

    Nyckelord
    Hydromechanical Transmission, Hardware-in-the-loop, Hopsan
    Nationell ämneskategori
    Rymd- och flygteknik
    Identifikatorer
    urn:nbn:se:liu:diva-126561 (URN)4-931070-10-8 (ISBN)
    Konferens
    the 9th JFPS International Symposium on Fluid Power in Matsue, Shimane Japan, on October 28-31, 2014
    Tillgänglig från: 2016-03-30 Skapad: 2016-03-30 Senast uppdaterad: 2018-03-21
    2. Mode Shifting in Hybrid Hydromechanical Transmissions
    Öppna denna publikation i ny flik eller fönster >>Mode Shifting in Hybrid Hydromechanical Transmissions
    2015 (Engelska)Ingår i: ASME/BATH 2015 Symposium on Fluid Power and Motion Control, ASME Press, 2015, s. 13-Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Demands for low cost sustainable solutions have increased the use of and interest in complex hydromechanical transmissions for heavy off-road vehicles. In transmissions with multiplemodes, an important condition is to maintain the tractive force during the mode shifting event. For hybrid hydromechanical transmissions, with a direct connection to a hydraulic accumulator, the impressed system pressure caused by the hydraulic accumulator has not yet been observed to interfere with this condition. In this paper, a black box model approach is used to modify the hydraulic system after obtaining knowledge regarding how it is affected by a mode shift. A comparative study is carried out where a full vehicle model of a mobile working machine is simulated with two different hydraulic systems. The results show that different system solutions imply different demands on the included components, and that the mode shifting event is not a negligible factor in heavy hydraulic hybrid vehicles.

    Ort, förlag, år, upplaga, sidor
    ASME Press, 2015
    Nyckelord
    Mode shifting, hydromechanical transmissions, fluid power, heavy construction machinery
    Nationell ämneskategori
    Annan maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-126556 (URN)10.1115/FPMC2015-9583 (DOI)000373970500045 ()978-0-7918-5723-6 (ISBN)
    Konferens
    ASME/BATH 2015 Symposium on Fluid Power and Motion Control, Chicago, Illinois, USA, October 12–14, 2015
    Projekt
    Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
    Forskningsfinansiär
    Energimyndigheten, P39367-1
    Tillgänglig från: 2016-03-30 Skapad: 2016-03-30 Senast uppdaterad: 2019-08-21
    3. Modelling of the Swash Plate Control Actuator in an Axial Piston Pump for a Hardware-In-the-Loop Simulation Test Rig
    Öppna denna publikation i ny flik eller fönster >>Modelling of the Swash Plate Control Actuator in an Axial Piston Pump for a Hardware-In-the-Loop Simulation Test Rig
    2016 (Engelska)Ingår i: Proceedings of the 9th FPNI Ph.D. Symposium on Fluid Power, FPNI2016, ASME Press, 2016, artikel-id UNSP V001T01A044Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Hydraulic hybrid system solutions are promising in the quest for energy efficiency in heavy construction machines. Hardware-in-the-loop simulations, where hardware is included in software simulations in real time, may be used to facilitate the development process of these systems without the need to build expensive prototypes. In this paper, the displacement actuator of a prototype pump used in a hardware-in-the-loop simulation test rig is modelled and validated against hardware, in order to draw conclusions regarding its dynamic behaviour in a future control design. The results show that the dynamic response of the modelled displacement actuator is mainly determined by the system pressure as well as the response and geometry of the control valve.

    Ort, förlag, år, upplaga, sidor
    ASME Press, 2016
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-133328 (URN)10.1115/FPNI2016-1570 (DOI)000398986900044 ()978-0-7918-5047-3 (ISBN)
    Konferens
    The 9th FPNI Ph.D. Symposium on Fluid Power
    Projekt
    Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
    Forskningsfinansiär
    Energimyndigheten, P39367-1
    Anmärkning

    The authors would like to thank the Swedish Energy Agency for contributing funds for the research project. Thanks also go to Bosch Rexroth for providing the prototype machines.

    Tillgänglig från: 2016-12-20 Skapad: 2016-12-20 Senast uppdaterad: 2020-09-04
    4. Displacement Control Strategies of an In-Line Axial-Piston Unit
    Öppna denna publikation i ny flik eller fönster >>Displacement Control Strategies of an In-Line Axial-Piston Unit
    2017 (Engelska)Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 244-253Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    The need for efficient propulsion in heavy vehicles has led to an increased interest in hybrid solutions. Hydraulic hybrids rely on variable hydraulic pumps/motors to continuously convert between hydraulic and mechanical power. This process is carried out via the implementation of secondary control which, in turn, is dependent on a fast displacement controller response. This paper reports on a study of a prototype axial piston pump of the in-line type, in which the displacement is measured with a sensor and controlled using a software-based controller. A pole placement control approach is used, in which a simple model of the pump is used to parametrise the controller using desired resonance and damping of the closed loop controller as input. The controller’s performance is tested in simulations and hardware tests on the prototype unit. The results show that the pole placement approach combined with a lead-compensator controller architecture is flexible, easy to implement and is able to deliver a fast response with high damping. The results will in the future be used in further research on full-vehicle control of heavy hydraulic hybrids.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2017
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 144
    Nyckelord
    Hydraulic hybrids, displacement control, pole placement
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-139854 (URN)10.3384/ecp17144244 (DOI)9789176853696 (ISBN)
    Konferens
    The 15th Scandinavian International Conference on Fluid Power, SICFP’17, June 7-9, 2017, Linköping, Sweden
    Tillgänglig från: 2017-08-17 Skapad: 2017-08-17 Senast uppdaterad: 2019-08-21Bibliografiskt granskad
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  • 189. Beställ onlineKöp publikationen >>
    Larsson, L. Viktor
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Control of Hybrid Hydromechanical Transmissions2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with control aspects of complex hybrid hydromechanical transmissions for heavy mobile working machines. Control problems are identified and solved to facilitate the implementation and use of these systems.

    Fuel prices and environmental concerns have increased the interest in hybrid hydromechanical transmissions for heavy mobile working machines. Hybridisation, the introduction of a secondary energy source in the transmission, offers attractive improvements in terms of both fuel efficiency and performance. These improvements are, in turn, enabled by software control. A complex transmission architecture has several components that need to interact in a stable manner. In addition, optimal utilisation of the added energy source is required to maximise fuel savings. Meanwhile, there is a strong trend towards automation, where many of the operator’s difficult control tasks need to be managed by computers. Sophisticated control strategies are therefore needed, along with a deeper understanding of dynamic properties.

    Previous research on the control of hybrid hydromechanical transmissions has primarily focussed on on-road applications. The working conditions of heavy working machines place different requirements on the transmission, which is also reflected in the control strategy.

    This thesis highlights the importance of fast response of the variable displacement pump/motors used in hybrid hydromechanical transmissions. Their central position in the interface between hydraulics and mechanics makes their dynamic performance a limiting factor both for the stability of the transmission control loops and in the realisation of smooth mode shifts in multiplemode transmissions. Dynamic models and control strategies for displacement actuators are derived and validated in simulation and experiments. A linear model for dynamic analysis of a general hybrid hydromechanical transmission for heavy working machines is derived and a powertrain control strategy based on decoupled control is proposed. The strategy is verified in simulations and experiments in hardware-in-the-loop simulations, and may be used in a working machine with or without a human operator.

    Delarbeten
    1. Mode Shifting in Hybrid Hydromechanical Transmissions
    Öppna denna publikation i ny flik eller fönster >>Mode Shifting in Hybrid Hydromechanical Transmissions
    2015 (Engelska)Ingår i: ASME/BATH 2015 Symposium on Fluid Power and Motion Control, ASME Press, 2015, s. 13-Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Demands for low cost sustainable solutions have increased the use of and interest in complex hydromechanical transmissions for heavy off-road vehicles. In transmissions with multiplemodes, an important condition is to maintain the tractive force during the mode shifting event. For hybrid hydromechanical transmissions, with a direct connection to a hydraulic accumulator, the impressed system pressure caused by the hydraulic accumulator has not yet been observed to interfere with this condition. In this paper, a black box model approach is used to modify the hydraulic system after obtaining knowledge regarding how it is affected by a mode shift. A comparative study is carried out where a full vehicle model of a mobile working machine is simulated with two different hydraulic systems. The results show that different system solutions imply different demands on the included components, and that the mode shifting event is not a negligible factor in heavy hydraulic hybrid vehicles.

    Ort, förlag, år, upplaga, sidor
    ASME Press, 2015
    Nyckelord
    Mode shifting, hydromechanical transmissions, fluid power, heavy construction machinery
    Nationell ämneskategori
    Annan maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-126556 (URN)10.1115/FPMC2015-9583 (DOI)000373970500045 ()978-0-7918-5723-6 (ISBN)
    Konferens
    ASME/BATH 2015 Symposium on Fluid Power and Motion Control, Chicago, Illinois, USA, October 12–14, 2015
    Projekt
    Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
    Forskningsfinansiär
    Energimyndigheten, P39367-1
    Tillgänglig från: 2016-03-30 Skapad: 2016-03-30 Senast uppdaterad: 2019-08-21
    2. Modelling of the Swash Plate Control Actuator in an Axial Piston Pump for a Hardware-In-the-Loop Simulation Test Rig
    Öppna denna publikation i ny flik eller fönster >>Modelling of the Swash Plate Control Actuator in an Axial Piston Pump for a Hardware-In-the-Loop Simulation Test Rig
    2016 (Engelska)Ingår i: Proceedings of the 9th FPNI Ph.D. Symposium on Fluid Power, FPNI2016, ASME Press, 2016, artikel-id UNSP V001T01A044Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Hydraulic hybrid system solutions are promising in the quest for energy efficiency in heavy construction machines. Hardware-in-the-loop simulations, where hardware is included in software simulations in real time, may be used to facilitate the development process of these systems without the need to build expensive prototypes. In this paper, the displacement actuator of a prototype pump used in a hardware-in-the-loop simulation test rig is modelled and validated against hardware, in order to draw conclusions regarding its dynamic behaviour in a future control design. The results show that the dynamic response of the modelled displacement actuator is mainly determined by the system pressure as well as the response and geometry of the control valve.

    Ort, förlag, år, upplaga, sidor
    ASME Press, 2016
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-133328 (URN)10.1115/FPNI2016-1570 (DOI)000398986900044 ()978-0-7918-5047-3 (ISBN)
    Konferens
    The 9th FPNI Ph.D. Symposium on Fluid Power
    Projekt
    Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
    Forskningsfinansiär
    Energimyndigheten, P39367-1
    Anmärkning

    The authors would like to thank the Swedish Energy Agency for contributing funds for the research project. Thanks also go to Bosch Rexroth for providing the prototype machines.

    Tillgänglig från: 2016-12-20 Skapad: 2016-12-20 Senast uppdaterad: 2020-09-04
    3. Displacement Control Strategies of an In-Line Axial-Piston Unit
    Öppna denna publikation i ny flik eller fönster >>Displacement Control Strategies of an In-Line Axial-Piston Unit
    2017 (Engelska)Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 244-253Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    The need for efficient propulsion in heavy vehicles has led to an increased interest in hybrid solutions. Hydraulic hybrids rely on variable hydraulic pumps/motors to continuously convert between hydraulic and mechanical power. This process is carried out via the implementation of secondary control which, in turn, is dependent on a fast displacement controller response. This paper reports on a study of a prototype axial piston pump of the in-line type, in which the displacement is measured with a sensor and controlled using a software-based controller. A pole placement control approach is used, in which a simple model of the pump is used to parametrise the controller using desired resonance and damping of the closed loop controller as input. The controller’s performance is tested in simulations and hardware tests on the prototype unit. The results show that the pole placement approach combined with a lead-compensator controller architecture is flexible, easy to implement and is able to deliver a fast response with high damping. The results will in the future be used in further research on full-vehicle control of heavy hydraulic hybrids.

    Ort, förlag, år, upplaga, sidor
    Linköping: Linköping University Electronic Press, 2017
    Serie
    Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 144
    Nyckelord
    Hydraulic hybrids, displacement control, pole placement
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-139854 (URN)10.3384/ecp17144244 (DOI)9789176853696 (ISBN)
    Konferens
    The 15th Scandinavian International Conference on Fluid Power, SICFP’17, June 7-9, 2017, Linköping, Sweden
    Tillgänglig från: 2017-08-17 Skapad: 2017-08-17 Senast uppdaterad: 2019-08-21Bibliografiskt granskad
    4. A General Approach to Low-Level Control of Heavy Complex Hybrid Hydromechanical Transmissions
    Öppna denna publikation i ny flik eller fönster >>A General Approach to Low-Level Control of Heavy Complex Hybrid Hydromechanical Transmissions
    2018 (Engelska)Ingår i: BATH/ASME 2018 Symposium on Fluid Power and Motion Control, ASME Press, 2018Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    This paper focuses on the low-level control of heavy complex hydraulic hybrids, taking stability and the dynamic properties of the included components into account. A linear model which can describe a high number of hybrid configurations in a straightforward manner is derived and used for the development of a general multiple input multiple output (MIMO) decoupling control strategy. This strategy is tested in non-linear simulations of an example vehicle and stability requirements for the low-level actuators are derived. The results show that static decoupling may be used to simplify the control problem to three individual loops controlling pressure, output speed and engine speed. In particular, the pressure and output speed loops rely on fast displacement controllers for stability. In addition, it was found that the decoupling is facilitated if the hydrostatic units have equal response. The low-level control of heavy complex hydraulic hybrids may thus imply other demands on actuators than what is traditionally assumed.

    Ort, förlag, år, upplaga, sidor
    ASME Press, 2018
    Nyckelord
    Control, Multiple input multiple output control, heavy hydraulic hybrids, hydromechanical transmissions
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-154306 (URN)10.1115/FPMC2018-8877 (DOI)000460491500042 ()2-s2.0-85058056485 (Scopus ID)978-0-7918-5196-8 (ISBN)
    Konferens
    BATH/ASME 2018 Symposium on Fluid Power and Motion Control, Bath, United Kingdom, September 12-14, 2018
    Forskningsfinansiär
    Energimyndigheten, P39367-2
    Anmärkning

    Funding agencies: Swedish Energy Agency

    Tillgänglig från: 2019-02-04 Skapad: 2019-02-04 Senast uppdaterad: 2021-08-21Bibliografiskt granskad
    5. Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines
    Öppna denna publikation i ny flik eller fönster >>Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines
    2019 (Engelska)Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 9, artikel-id 1683Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Fuel efficiency has become an increasingly important property of heavy mobile working machines. As a result, Hybrid Hydromechanical Transmissions (HMTs) are often considered for the propulsion of these vehicles. The introduction of hybrid HMTs does, however, come with a number of control-related challenges. To date, a great focus in the literature has been on high-level control aspects, concerning optimal utilization of the energy storage medium. In contrast, the main topic of this article is low-level control, with the focus on dynamic response and the ability to realize requested power flows accurately. A static decoupled Multiple-Input-Multiple-Output (MIMO) control strategy, based on a linear model of a general hybrid HMT, is proposed. The strategy is compared to a baseline approach in Hardware-In-the-Loop (HWIL) simulations of a reference wheel loader for two drive cycles. It was found that an important benefit of the decoupled control approach is that the static error caused by the system’s cross-couplings is minimized without introducing integrating elements. This feature, combined with the strategy’s general nature, motivates its use for multiple-mode transmissions in which the transmission configuration changes between the modes. 

    Ort, förlag, år, upplaga, sidor
    MDPI, 2019
    Nyckelord
    hydromechanical transmissions, hybridization, control, construction machinery; decoupled control, hardware-in-the-loop
    Nationell ämneskategori
    Annan maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-157504 (URN)10.3390/en12091683 (DOI)000469761700099 ()
    Forskningsfinansiär
    Energimyndigheten, P39367-2
    Anmärkning

    Funding agencies: Swedish Energy Agency (Energimyndigheten) [P39367-2]

    Tillgänglig från: 2019-06-14 Skapad: 2019-06-14 Senast uppdaterad: 2023-08-28Bibliografiskt granskad
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  • 190.
    Larsson, L. Viktor
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Modellering och simulering av en hydraulmekanisk power-splittransmission med två moder2015Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Strängare krav på lägre bränsleförbrukning och miljöpåverkan har lett till att tillverkare av tunga arbetsmaskiner i allt högre utsträckning ser sig om efter mer energieffektiva transmissioner. Som en konsekvens har komplexa hydraulmekaniska power-splittransmissioner blivit allt mer intressanta som alternativ till de mer traditionella koncepten. Genom att kombinera den klassiska hydrostaten med en mekanisk länk höjs verkningsgraden samtidigt som en kontinuerligt varierbar utväxling kan realiseras. Införandet av olika växelsteg (moder) gör transmissionen än mer mångsidig, samtidigt som designrymden utvidgas. Detta medför att modellering och simulering har blivit ett viktigt verktyg under utvecklingsprocessen, eftersom transmissionernas egenskaper kan studeras i detalj utan att behöva tillverka dyra prototyper. På så sätt kan viktiga beslut fattas, och slutsatser dras, i ett tidigt skede i utvecklingen. I denna artikel beskrivs hur både linjäriserade och olinjära modeller av en power-splittransmission med två moder för en traktorgrävare tagits fram. De olinjära modellerna har implementerats och simulerats i det Flumes-utvecklade simuleringsprogrammet Hopsan. Förslag ges på en enkel reglerstrategi, och ett antal viktiga slutsatser om konceptet kan dras och stå till grund för hur konceptet skall tas vidare i utvecklingsprocessen.

    Ladda ner fulltext (pdf)
    fulltext
  • 191.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Lejonberg, Robert
    Control Optimisation of a Pump-Controlled Hydraulic System using Digital Displacement Pumps2021Ingår i: Proceedings of the 17:th Scandinavian International Conference on Fluid Power, SICFP’21, June 1-2, 2021, Linköping, Sweden, 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    When dealing with electrification of working machines, energy-efficient operation is key to maximise the usage of the limited capacity of on-board batteries. Previous research indicate that plenty is gained by reducing component and system losses by means of design. In contrast, this paper focuses on how to maximise energy efficiency by means of control optimisation. Dynamic programming with backward-facing simulationis used to find the optimal electric motor speed trajectory for a scooptram machine equipped with pump control, using digital displacement pumps with dynamic flow sharing as enabling technology. The results show that low shaft speed is preferred to minimise drag losses from parasitic components, partly facilitated by the relatively high and operation point-independent efficiencies of the pumps and electricmotor. The results indicate energy reduction of 5 - 9 %, where higher figures could beexpected for other, more hydraulic-intense applications, such as excavators.

  • 192.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Uebel (Pettersson), Karl
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Volvo Construction Equipment.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 9, artikel-id 1683Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fuel efficiency has become an increasingly important property of heavy mobile working machines. As a result, Hybrid Hydromechanical Transmissions (HMTs) are often considered for the propulsion of these vehicles. The introduction of hybrid HMTs does, however, come with a number of control-related challenges. To date, a great focus in the literature has been on high-level control aspects, concerning optimal utilization of the energy storage medium. In contrast, the main topic of this article is low-level control, with the focus on dynamic response and the ability to realize requested power flows accurately. A static decoupled Multiple-Input-Multiple-Output (MIMO) control strategy, based on a linear model of a general hybrid HMT, is proposed. The strategy is compared to a baseline approach in Hardware-In-the-Loop (HWIL) simulations of a reference wheel loader for two drive cycles. It was found that an important benefit of the decoupled control approach is that the static error caused by the system’s cross-couplings is minimized without introducing integrating elements. This feature, combined with the strategy’s general nature, motivates its use for multiple-mode transmissions in which the transmission configuration changes between the modes. 

    Ladda ner fulltext (pdf)
    energies-12-01683
  • 193.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    A General Approach to Low-Level Control of Heavy Complex Hybrid Hydromechanical Transmissions2018Ingår i: BATH/ASME 2018 Symposium on Fluid Power and Motion Control, ASME Press, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper focuses on the low-level control of heavy complex hydraulic hybrids, taking stability and the dynamic properties of the included components into account. A linear model which can describe a high number of hybrid configurations in a straightforward manner is derived and used for the development of a general multiple input multiple output (MIMO) decoupling control strategy. This strategy is tested in non-linear simulations of an example vehicle and stability requirements for the low-level actuators are derived. The results show that static decoupling may be used to simplify the control problem to three individual loops controlling pressure, output speed and engine speed. In particular, the pressure and output speed loops rely on fast displacement controllers for stability. In addition, it was found that the decoupling is facilitated if the hydrostatic units have equal response. The low-level control of heavy complex hydraulic hybrids may thus imply other demands on actuators than what is traditionally assumed.

  • 194.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Displacement Control Strategies of an In-Line Axial-Piston Unit2017Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden / [ed] Petter Krus, Liselott Ericson and Magnus Sethson, Linköping: Linköping University Electronic Press, 2017, Vol. 144, s. 244-253Konferensbidrag (Refereegranskat)
    Abstract [en]

    The need for efficient propulsion in heavy vehicles has led to an increased interest in hybrid solutions. Hydraulic hybrids rely on variable hydraulic pumps/motors to continuously convert between hydraulic and mechanical power. This process is carried out via the implementation of secondary control which, in turn, is dependent on a fast displacement controller response. This paper reports on a study of a prototype axial piston pump of the in-line type, in which the displacement is measured with a sensor and controlled using a software-based controller. A pole placement control approach is used, in which a simple model of the pump is used to parametrise the controller using desired resonance and damping of the closed loop controller as input. The controller’s performance is tested in simulations and hardware tests on the prototype unit. The results show that the pole placement approach combined with a lead-compensator controller architecture is flexible, easy to implement and is able to deliver a fast response with high damping. The results will in the future be used in further research on full-vehicle control of heavy hydraulic hybrids.

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  • 195.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Hardware-in-the-loop Simulation of Complex Hybrid Hydromechanical Transmissions2018Ingår i: WIEFP2018 – 4th Workshop on Innovative Engineering for Fluid Power, November 28-30, Sao Paulo, Brazil, Linköping, 2018, Vol. 156, s. 69-73, artikel-id 014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fuel efficiency and environmental concerns are factors that drive the development of complex solutions for propulsion in heavy working machines. Although these solutions, such as power-split hydromechanical transmissions and hydraulic hybrids, indeed are promising in terms of energy efficiency, they also tend to increase the dependency on accurate, stable control. The realization of this aspect, in turn, relies on continuous testing throughout the development process, usually carried out on expensive, time-consuming prototypes. To lower the development costs and time, hardware-in-the-loop (HWIL) simulations may be introduced as a middle-way between pure prototyping and computer-based simulations. In this concept, some parts of the transmission are represented as hardware while others are included as mathematical models running in real-time in a data acquisition system. This mix of hardware and software allows for high versatility while maintaining a high level of reliability of the results. This paper reports on parts of a study on HWIL simulations of heavy complex hybrid hydromechanical transmissions. Control algorithms for the hardware/model interface in a test rig are derived and their performance are evaluated in HWIL simulations of a mid-sized wheel loader. The results show the importance of fast rig controllers to capture the fast dynamics of the software simulations. It was also found that an important aspect of HWIL simulations is that they are well aligned with their purpose. If so, the simulation yields more reliable knowledge, which is of higher use in the design process of these complex systems. To summarize, HWIL simulations may, if implemented properly, be an important asset in the development of heavy complex hybrid hydromechanical transmissions.

  • 196.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Modelling of the Swash Plate Control Actuator in an Axial Piston Pump for a Hardware-In-the-Loop Simulation Test Rig2016Ingår i: Proceedings of the 9th FPNI Ph.D. Symposium on Fluid Power, FPNI2016, ASME Press, 2016, artikel-id UNSP V001T01A044Konferensbidrag (Refereegranskat)
    Abstract [en]

    Hydraulic hybrid system solutions are promising in the quest for energy efficiency in heavy construction machines. Hardware-in-the-loop simulations, where hardware is included in software simulations in real time, may be used to facilitate the development process of these systems without the need to build expensive prototypes. In this paper, the displacement actuator of a prototype pump used in a hardware-in-the-loop simulation test rig is modelled and validated against hardware, in order to draw conclusions regarding its dynamic behaviour in a future control design. The results show that the dynamic response of the modelled displacement actuator is mainly determined by the system pressure as well as the response and geometry of the control valve.

  • 197.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system.
    Lejonberg, Robert
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Optimisation of a Pump-Controlled Hydraulic System using Digital Displacement Pumps2021Ingår i: International Journal of Fluid Power, ISSN 1439-9776Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When electrifying working machines, energy-efficient operation is key to maximise the use of the limited capacity of on-board batteries. Previous research indicate high energy savings by means of component and system design. In contrast, this paper focuses on how to maximise energy efficiency by means of both design and control optimisation. Simulation-based optimisation and dynamic programming are used to find the optimal electric motor speed trajectory and component sizes for a scooptram machine equipped with pump control, enabled by digital displacement pumps with dynamic flow sharing. The results show that a hardware configuration and control strategy that enable low pump speed minimise drag losses from parasitic components, partly facilitated by the relatively high and operation point-independent efficiencies of the pumps and electric motor. 5–10% cycle energy reductions are indicated, where the higher figure was obtained for simultaneous design and control optimisation. For other, more hydraulic-intense applications, such as excavators, greater reductions could be expected.

  • 198.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Lejonberg, Robert
    Epiroc Rock Drills AB, Sweden.
    Ericson, Liselott
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Optimisation of a Pump-Controlled Hydraulic System using Digital Displacement Pumps2022Ingår i: International Journal of Fluid Power, ISSN 1439-9776, Vol. 23, nr 1, s. 53-78Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When electrifying working machines, energy-efficient operation is key to maximise the use of the limited capacity of on-board batteries. Previous research indicate high energy savings by means of component and system design. In contrast, this paper focuses on how to maximise energy efficiency by means of both design and control optimisation. Simulation-based optimisation and dynamic programming are used to find the optimal electric motor speed trajectory and component sizes for a scooptram machine equipped with pump control, enabled by digital displacement pumps with dynamic flow sharing. The results show that a hardware configuration and control strategy that enable low pump speed minimise drag losses from parasitic components, partly facilitated by the relatively high and operation point-independent efficiencies of the pumps and electric motor. 5-10% cycle energy reductions are indicated, where the higher figure was obtained for simultaneous design and control optimisation. For other, more hydraulic-intense applications, such as excavators, greater reductions could be expected.

  • 199.
    Larsson, L. Viktor
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Pettersson, Karl
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Volvo Construction Equipment.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Mode Shifting in Hybrid Hydromechanical Transmissions2015Ingår i: ASME/BATH 2015 Symposium on Fluid Power and Motion Control, ASME Press, 2015, s. 13-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Demands for low cost sustainable solutions have increased the use of and interest in complex hydromechanical transmissions for heavy off-road vehicles. In transmissions with multiplemodes, an important condition is to maintain the tractive force during the mode shifting event. For hybrid hydromechanical transmissions, with a direct connection to a hydraulic accumulator, the impressed system pressure caused by the hydraulic accumulator has not yet been observed to interfere with this condition. In this paper, a black box model approach is used to modify the hydraulic system after obtaining knowledge regarding how it is affected by a mode shift. A comparative study is carried out where a full vehicle model of a mobile working machine is simulated with two different hydraulic systems. The results show that different system solutions imply different demands on the included components, and that the mode shifting event is not a negligible factor in heavy hydraulic hybrid vehicles.

  • 200.
    Larsson, Roger
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten. Saab Aeronaut, SE-58254 Linkoping, Sweden.
    Sobrón Rueda, Alejandro
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Lundström, David
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Enqvist, Martin
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska fakulteten.
    A Method for Improved Flight Testing of Remotely Piloted Aircraft Using Multisine Inputs2020Ingår i: AEROSPACE, ISSN 2226-4310, Vol. 7, nr 9, artikel-id 135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unless a segregated airspace and the corresponding clearances can be afforded, flight testing of remotely piloted aircraft is often done near the ground and within visual line-of-sight. In addition to the increased exposure to turbulence, this setup also limits the available time for test manoeuvres on each pass, especially for subscale demonstrators with a relatively high wing loading and flight speed. A suitable testing procedure, efficient excitation signals and a robust system identification method are therefore fundamental. Here, the authors use ground-based flight control augmentation to inject multisine signals with low correlation between the different inputs. Focusing on initial flight-envelope expansion, where linear regression is common, this paper also describes the improvement of an existing frequency-domain method by using an instrumental variable (IV) approach to better handle turbulence and measurement noise and to enable real-time identification analysis. Both simulations and real flight tests on a subscale demonstrator are presented. The results show that the combination of multisine input signals and the enhanced frequency-domain method is an effective way of improving flight testing of remotely piloted aircraft in confined airspace.

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