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  • 1.
    Amadori, Kristian
    et al.
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Jouannet, Christopher
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Berry, Patrick
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Development of a subscale flight testing platform for a generic future fighter2010Conference paper (Refereed)
    Abstract [en]

    One branch of the current research in aircraft design at Linköping University is focused on fast concept evaluation in early design stages. This covers multidisciplinary optimization using tools of different level of complexity and low-cost subscale flight testing. In some cases a flight test will provide more answers than several computations ever could. In order to achieve this goal a methodology is required to allow fast creation of subscale flying concepts and to obtain as much reliable information as possible from the tests. The methodology is currently being developed. One important part of it is the scaling methodology and the imposed requirements on manufacturing. The present paper presents the latest subscale demonstrator from Linköping University that has been built as part of the study initiated by the Swedish Material Board on a Generic Future Fighter aircraft.

  • 2.
    Amadori, Kristian
    et al.
    Linköping University, Department of Management and Engineering, Machine Design . Linköping University, The Institute of Technology.
    Jouannet, Christopher
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Machine Design . Linköping University, The Institute of Technology.
    A Framework for Aerodynamic and Structural Optimization in Conceptual Design2007In: 25th AIAA Applied Aerodynamics Conference, 25-28 June, Miami, FL, USA, AIAA , 2007, p. 4061-Conference paper (Other academic)
    Abstract [en]

    Aircraft design is an inherently multidisciplinary activity that requires different models and tools for various aspects of the design. At Linköping University a novel design framework is being developed to support the initial conceptual design phase of a new aircraft. In this work main attention has been paid to wing design, with respect to aerodynamic efficiency and loads, and to structural analysis. By linking together various modules via a user-friendly interface based on a spreadsheet, the framework allows multidisciplinary analysis and optimizations to be carried out. This paper will present the framework, give an overview of its development status and give an indication on the future work.

  • 3.
    Amadori, Kristian
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Machine Design.
    Jouannet, Christopher
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Krus, Petter
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Machine Design.
    Aircraft Conceptual Design Optimization2008In: International Congress of the Aeronautical Sciences ICAS,2008, Stockholm, Sweden: ICAS , 2008Conference paper (Refereed)
    Abstract [en]

    Aircraft design is an inherently multidisciplinary activity that requires different models and tools for various aspects of the design. At Linköping University a novel design framework is being developed to support the initial conceptual design phase of new aircraft. By linking together various modules via a userfriendly spreadsheet interface, the framework allows multidisciplinary analysis and optimizations to be carried out. The geometrical model created with a high-end CAD system, contains all the available information on the product and thus it plays a central role in the framework. In this work great attention has been paid to techniques that allow creating robust yet highly flexible CAD models. Two different case studies are presented. The first one is a hypothetic wing-box design that is studied with respect to aerodynamic efficiency and loads, and to structural analysis. In this study two approaches were compared. In one case the wing-box design was optimized with a fixed number of structural elements, where only dimensions and position were allowed to change. Then the same wing-box was analyzed allowing also the number of structural elements to vary. Thus only the parts that are required are left and a more efficient design can be obtained. In the second case study a mission simulation is performed on a UAV-type aircraft. Required data for the simulation are gathered from the CAD model and from aerodynamic analysis carried out with PANAIR, a high order panel code. The obtained data are then used as inputs parameters for flight simulation in order to determined hydraulic systems characteristics.  

  • 4.
    Amadori, Kristian
    et al.
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Jouannet, Christopher
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Use of Panel Code Modeling in a Framework for Aircraft Concept Optimization2006In: 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, 6-8 September, Portsmouth, Virginia, USA, 2006, p. 7084-Conference paper (Other academic)
    Abstract [en]

     

     

    In this study the use of a high-order panel code within a framework for aircraft concept design is discussed. The framework is intended to be a multidisciplinary optimization tool to be adopted from the very beginning of the conceptual design phase in order to define and refine the aircraft design, with respect to its aerodynamic, stability and control, structure and basic aircraft systems. The presented work is aimed at developing a module for aerodynamic analysis of concepts as a basis for a direct search optimization of the concept layout. The design criterion, used in the example presented here, is to minimize the maximum take-off weight required to fulfil the mission. Classic and simple equations are used together with the data generated by the panel code solver to calculate the aircraft’s performances. Weights are calculated by means of statistical group weight equations, but the weight could also be calculated from a CAD-model. The design of an Unmanned Combat Air Vehicle is used as test case for three different optimization algorithms: one gradient method based (Fmincon), one non-gradient based (Complex) and one Genetic Algorithm (GA). Comparison of results and performances shows that the Genetic Algorithm is best fitted for the specific problem, having the by far best hit rate, even if it is at a cost of longer computing time. The Complex algorithm requires less iterations and is also able to find the optimum solution, but with a worse hit rate, while Fmincon can not reach to a global optimum. The suggested optimized configuration for the aircraft is very similar to the Boeing X-45C and Northrop Grumman X-47B.

  • 5.
    Amadori, Kristian
    et al.
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Lundström, David
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Evaluation of Automatically Designed Micro Air Vehicles and Flight Testing2010Conference paper (Refereed)
    Abstract [en]

    The presented work is centered on the evaluation of Micro or Mini Air Vehicles (MAV) that have been automatically designed and manufactured. An in-house developed design framework uses several coupled computer software’s to generate the geometric design in CAD, a well as list of off the shelf components for the propulsion system, and computer code for autonomous flight ready to upload in the intended autopilot. The paper describes the experiences made so far regarding automation of the design process and of manufacturing. Furthermore, it presents results from evaluation and analysis of the optimization algorithm and flight testing, and from continuing work with the framework to achieve deeper understanding of the process and to fine-tune the design automation performance. The flight data is correlated to the predicted performances to validate the models and design process.

  • 6.
    Andersson, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Valve arrangement2008Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Valve arrangement for controlling the flow of fluid through a conduit and comprising a valve body with a first and a second valve port which serve, alternately, as input and output, and a valve cone arranged in the valve body which connects in its open position the valve ports with each other, and is actuatd by a holding force wihch is greater than the force acting on the pressurized fluid side of the valve cone and dependent on the medium pressure in the input port.

  • 7.
    Andersson, Lars
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Multi-robot Information Fusion: Considering spatial uncertainty models2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work presented in this thesis covers the topic of deployment for mobile robot teams. By connecting robots in teams they can perform a better job than each individual is capable of. It also gives redundancy, increases robustness, provides scalability, and increases efficiency. Multi-robot Information Fusion also results in a broader perspective for decision making. This thesis focuses on methods for estimating formation and trajectories and how these can be used for deployment of a robot team. The problems covered discuss what impact trajectories and formation have on the total uncertainty when exploring unknown areas. The deployment problem is approached using a centralized Kalman filter, for investigation of how team formation affects error propagation. Trajectory estimation is done using a smoother, where all information is used not only to estimate the trajectory of each robot, but also to align trajectories from different robots. Both simulation and experimental results are presented in the appended papers. It is shown that sensor placements can substantially affect uncertainty during deployment. When deploying a robot team the formation can be used as a tool for balancing error propagation among the robot states. A robust algorithm for associating rendezvous observations to align robot trajectories is also presented. Trajectory alignment is used as an efficient and cost-effective method for joining mapping information within robot teams. When working with robot teams, sensor placement and formation should be considered to obtain the maximum from the system. It is also of great value to mix robots with different characteristics since it is shown that using sensor fusion the robots can inherit each other’s characteristics if sensors are used correctly. Information sharing requires modularity and general models, which consumecomputational resources. Over time computer resources will become cheaper, allowing for distribution, and each robot will become more self-contained. Together with increased wireless bandwidth this will enable larger numbers of robots to cooperate.

    List of papers
    1. On Sensor Fusion Between a Pair Of Heterogeneous Robots
    Open this publication in new window or tab >>On Sensor Fusion Between a Pair Of Heterogeneous Robots
    2003 (English)In: Proceedings of the 6th International Conference on Information Fusion, Cairns, Australia, 8th–11th July, 2003, 2003, p. 1287-1294Chapter in book (Other (popular science, discussion, etc.))
    Abstract [en]

    This paper present work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of heterogeneous robots to solve a given task. That is, this research is focusing on how much each robot can increase the certainty about its own position and orientation in a global perspective as well as relative to other team members. It also, in some extent investigate what happens too the uncertainty and correlation within the group. The motive is to provide an insight into the utility of fusing position information communicated within the team, in aspect of increased accuracy. It also investigates in what way different usage of sensors will effect the results. Since the goal of the paper is insight, the minimum configuration of two robots and two landmarks is studied although the results are scalable to larger robot teams. The results show that by placing a camera on the moving robot measuring the bearing of a stationary robot gives better estimation of the moving robots orientation, which can be crucial for the solution of the association problem.

    Keywords
    Cooperative, Robot, Navigation, Distributed, Fusion, SLAM, CLAM
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15106 (URN)0-9721844-4-9 (ISBN)
    Available from: 2008-10-16 Created: 2008-10-16 Last updated: 2013-11-04Bibliographically approved
    2. On utilizing geometric formations for minimizing uncertainty in 3 robot teams
    Open this publication in new window or tab >>On utilizing geometric formations for minimizing uncertainty in 3 robot teams
    2004 (English)In: Proceedings of The 8th Conference on Intelligent Autonomous Systems, IAS-8, Amsterdam, Netherlands, 10th–12th March, 2004, , p. 100-110p. 100-110Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of robots to solve given tasks. The motive is to provide an insight into the utility in fusing position information communicated within the team, in aspect of increased accuracy in position and orientation estimate. The minimum configuration of three robots is studied. The robots are equipped with camera-like sensors that make omni directional bearing measurements to eachother. To reduce the free variables the formations are restricted so that two subordinate robots are located at the same distance to a master robot. For this configuration the information matrix is explored. A few formations are chosen and studied further, through simulations. The simulations show that there exists a breakpoint in traveled distance, where the formation minimizing orientation uncertainty for the master robot, changes from a column-formation to a line formation. The simulations also show that a line or column formations are not a good choice when balansed position uncertainty is required. In the case of balansing position uncertainty, a triangular formation is better.

    Publisher
    p. 100-110
    Keywords
    Geometric formations, minimize uncertainty
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15319 (URN)9781586034146 (ISBN)
    Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2013-11-04Bibliographically approved
    3. Effects on Uncertainty Utilizing Formation-Planning in Robot Teams
    Open this publication in new window or tab >>Effects on Uncertainty Utilizing Formation-Planning in Robot Teams
    2004 (English)In: Proceedings of The 5th Symposium on Intelligent Autonomous Vehicles, IAV 2004, Lisbon, Portugal, 5th–7th July 2004, 2004Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of robots to solve given tasks. The motive is to provide an insight into the utility in fusing position information communicated within the team, in aspect of increased accuracy in position and orientation estimate. The minimum configuration of three robots moving over a flat surface is studied. The robots are equipped with omni-directional cameralike sensors that make bearing measurements to each other. To reduce the free variables the formations are restricted so that two subordinate robots are located at the same distance to a master robot. For this configuration the information matrix is derived and studied. There are numerical results presented that indicate how the uncertainty of the master robot changes depending of the bearing to the subordinate robots and the distance traveled.

    Keywords
    Multi-Robot, Cooperative, Formation, Localization
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15320 (URN)
    Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2013-11-04Bibliographically approved
    4. C-SAM: Multi-Robot SLAM using Square Root Information Smoothing
    Open this publication in new window or tab >>C-SAM: Multi-Robot SLAM using Square Root Information Smoothing
    2008 (English)In: Proceedings of International Conference on Robotics and Automation, ICRA 2008, Pasadena, CA, USA, 19th–23rd May, IEEE Xplore , 2008, p. 2798-2805Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents collaborative smoothing and mapping (C-SAM) as a viable approach to the multi-robot map- alignment problem. This method enables a team of robots to build joint maps with or without initial knowledge of their relative poses. To accomplish the simultaneous localization and mapping this method uses square root information smoothing (SRIS). In contrast to traditional extended Kalman filter (EKF) methods the smoothing does not exclude any information and is therefore also better equipped to deal with non-linear process and measurement models. The method proposed does not require the collaborative robots to have initial correspondence. The key contribution of this work is an optimal smoothing algorithm for merging maps that are created by different robots independently or in groups. The method not only joins maps from different robots, it also recovers the complete robot trajectory for each robot involved in the map joining. It is also shown how data association between duplicate features is done and how this reduces uncertainty in the complete map. Two simulated scenarios are presented where the C-SAM algorithm is applied on two individually created maps. One basically joins two maps resulting in a large map while the other shows a scenario where sensor extension is carried out.

    Place, publisher, year, edition, pages
    IEEE Xplore, 2008
    Keywords
    C-SAM, SLAM, fusion, multi, robot
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15322 (URN)10.1109/ROBOT.2008.4543634 (DOI)978-1-4244-1646-2 (ISBN)
    Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2009-04-22Bibliographically approved
    5. Sensor Data Fusion for Terrain Exploration by Collaborating Unmanned Ground Vehicles
    Open this publication in new window or tab >>Sensor Data Fusion for Terrain Exploration by Collaborating Unmanned Ground Vehicles
    2008 (English)In: Proceedings of the 11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July, IEEE Xplore , 2008, p. 1214-1221Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents work in progress for the pre-Runners project. The goal is to experimentally demonstrate the value of unmanned ground vehicles (UGVs) in collaboration with a main vehicle in an outdoor setting. With uneven terrain and unexpected obstacles the main vehicle benefits from a priori information of the terrain ahead. This information can be gathered by a smaller, more agile, and risks tolerant autonomous “prerunner”. The results presented, represent the first steps toward the important task of determining the traversable surfaces and communicating the results within the team. The information sharing between vehicles is based on Collaborative Smoothing and Mapping (C-SAM). The horizontal position is also estimated within the C-SAM. In parallel the vertical component and orientation is estimated by a filter fusing data from odometry, an imu and two lasers to allow computation of traversability maps to be shared within the team.

    Place, publisher, year, edition, pages
    IEEE Xplore, 2008
    Keywords
    Collaboration, SLAM, SAM, sensor data fusion, data association, Kalman filtering, traversability estimation
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15323 (URN)978-3-8007-3092-6 (ISBN)
    Conference
    11th International Conference on Information Fusion, FUSION 2008, Cologne, Germany, 30th June–3rd July
    Note

    DOI does not work: 10.1109/ICIF.2008.4632348

    Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2018-03-09Bibliographically approved
    6. On Multi-robot Map Fusion by Inter-robot Observations
    Open this publication in new window or tab >>On Multi-robot Map Fusion by Inter-robot Observations
    2009 (English)In: In proceedings of 12th International Conference on Information Fusion, 2009Conference paper, Published paper (Other academic)
    Abstract [en]

    This paper addresses the problem of aligning and fusing maps built by multiple robots. The proposed method for solving the multi-robot map alignment problem relies on inter-robot observations to seed the alignment processing and find a transformation between the map reference frames. The method enables one to join maps from robots with or without initial correspondence. However, the poses of each robot during an inter-robot observation need to be synchronized. In this work the method is applied onto Collaborative Smoothing and Mapping (C-SAM), a smoothing approach for merging maps that are created by different robots independently or in teams. In contrast to traditional Extended Kalman Filter (EKF) or Particle Filtering (PF) methods the smoothing does not exclude any information and is therefore better equipped to deal with non-linear process and measurement models. The algorithm is also proven to be useful in two different experiments showing the robustness of the algorithm. The experiments show that alignment can be conducted using only inter-robot observation in both unguided terrain as well as in terrain with many false observations. The key contribution of this work is a robust algorithm for solving the association problem and eliminating false observations when doing multi-robot map alignment using inter-robot observations during a rendezvous.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-15324 (URN)000273560001076 ()
    Conference
    12th International Conference on Information Fusion
    Available from: 2008-10-31 Created: 2008-10-31 Last updated: 2010-08-12Bibliographically approved
  • 8.
    Andersson, Lars A. A.
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nygårds, Jonas
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    C-SAM: Multi-Robot SLAM using Square Root Information Smoothing2008In: Proceedings of International Conference on Robotics and Automation, ICRA 2008, Pasadena, CA, USA, 19th–23rd May, IEEE Xplore , 2008, p. 2798-2805Conference paper (Refereed)
    Abstract [en]

    This paper presents collaborative smoothing and mapping (C-SAM) as a viable approach to the multi-robot map- alignment problem. This method enables a team of robots to build joint maps with or without initial knowledge of their relative poses. To accomplish the simultaneous localization and mapping this method uses square root information smoothing (SRIS). In contrast to traditional extended Kalman filter (EKF) methods the smoothing does not exclude any information and is therefore also better equipped to deal with non-linear process and measurement models. The method proposed does not require the collaborative robots to have initial correspondence. The key contribution of this work is an optimal smoothing algorithm for merging maps that are created by different robots independently or in groups. The method not only joins maps from different robots, it also recovers the complete robot trajectory for each robot involved in the map joining. It is also shown how data association between duplicate features is done and how this reduces uncertainty in the complete map. Two simulated scenarios are presented where the C-SAM algorithm is applied on two individually created maps. One basically joins two maps resulting in a large map while the other shows a scenario where sensor extension is carried out.

  • 9.
    Andersson, Lars A. A.
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nygårds, Jonas
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Effects on Uncertainty Utilizing Formation-Planning in Robot Teams2004In: Proceedings of The 5th Symposium on Intelligent Autonomous Vehicles, IAV 2004, Lisbon, Portugal, 5th–7th July 2004, 2004Conference paper (Refereed)
    Abstract [en]

    This paper presents work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of robots to solve given tasks. The motive is to provide an insight into the utility in fusing position information communicated within the team, in aspect of increased accuracy in position and orientation estimate. The minimum configuration of three robots moving over a flat surface is studied. The robots are equipped with omni-directional cameralike sensors that make bearing measurements to each other. To reduce the free variables the formations are restricted so that two subordinate robots are located at the same distance to a master robot. For this configuration the information matrix is derived and studied. There are numerical results presented that indicate how the uncertainty of the master robot changes depending of the bearing to the subordinate robots and the distance traveled.

  • 10.
    Andersson, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Nygårds, Jonas
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    On Multi-robot Map Fusion by Inter-robot Observations2008Report (Other academic)
  • 11.
    Andersson, Lars
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nygårds, Jonas
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    On Multi-robot Map Fusion by Inter-robot Observations2009In: In proceedings of 12th International Conference on Information Fusion, 2009Conference paper (Other academic)
    Abstract [en]

    This paper addresses the problem of aligning and fusing maps built by multiple robots. The proposed method for solving the multi-robot map alignment problem relies on inter-robot observations to seed the alignment processing and find a transformation between the map reference frames. The method enables one to join maps from robots with or without initial correspondence. However, the poses of each robot during an inter-robot observation need to be synchronized. In this work the method is applied onto Collaborative Smoothing and Mapping (C-SAM), a smoothing approach for merging maps that are created by different robots independently or in teams. In contrast to traditional Extended Kalman Filter (EKF) or Particle Filtering (PF) methods the smoothing does not exclude any information and is therefore better equipped to deal with non-linear process and measurement models. The algorithm is also proven to be useful in two different experiments showing the robustness of the algorithm. The experiments show that alignment can be conducted using only inter-robot observation in both unguided terrain as well as in terrain with many false observations. The key contribution of this work is a robust algorithm for solving the association problem and eliminating false observations when doing multi-robot map alignment using inter-robot observations during a rendezvous.

  • 12.
    Andersson, Lars
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nygårds, Jonas
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    On Sensor Fusion Between a Pair Of Heterogeneous Robots2003In: Proceedings of the 6th International Conference on Information Fusion, Cairns, Australia, 8th–11th July, 2003, 2003, p. 1287-1294Chapter in book (Other (popular science, discussion, etc.))
    Abstract [en]

    This paper present work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of heterogeneous robots to solve a given task. That is, this research is focusing on how much each robot can increase the certainty about its own position and orientation in a global perspective as well as relative to other team members. It also, in some extent investigate what happens too the uncertainty and correlation within the group. The motive is to provide an insight into the utility of fusing position information communicated within the team, in aspect of increased accuracy. It also investigates in what way different usage of sensors will effect the results. Since the goal of the paper is insight, the minimum configuration of two robots and two landmarks is studied although the results are scalable to larger robot teams. The results show that by placing a camera on the moving robot measuring the bearing of a stationary robot gives better estimation of the moving robots orientation, which can be crucial for the solution of the association problem.

  • 13.
    Andersson, Lars
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nygårds, Jonas
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    On utilizing geometric formations for minimizing uncertainty in 3 robot teams2004In: Proceedings of The 8th Conference on Intelligent Autonomous Systems, IAS-8, Amsterdam, Netherlands, 10th–12th March, 2004, , p. 100-110p. 100-110Conference paper (Refereed)
    Abstract [en]

    This paper presents work in progress, aiming to find models that can be used as guidelines in how to best deploy a team of robots to solve given tasks. The motive is to provide an insight into the utility in fusing position information communicated within the team, in aspect of increased accuracy in position and orientation estimate. The minimum configuration of three robots is studied. The robots are equipped with camera-like sensors that make omni directional bearing measurements to eachother. To reduce the free variables the formations are restricted so that two subordinate robots are located at the same distance to a master robot. For this configuration the information matrix is explored. A few formations are chosen and studied further, through simulations. The simulations show that there exists a breakpoint in traveled distance, where the formation minimizing orientation uncertainty for the master robot, changes from a column-formation to a line formation. The simulations also show that a line or column formations are not a good choice when balansed position uncertainty is required. In the case of balansing position uncertainty, a triangular formation is better.

  • 14.
    Axin, Mikael
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Braun, Robert
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Dell'Amico, Alessandro
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Eriksson, Björn
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Nordin, Peter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Pettersson, Karl
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Staack, Ingo
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Next Generation Simulation Software using Transmission Line Elements2010In: Fluid Power and Motion Control / [ed] Dr D N Johnston and Professor A R Plummer, Centre for Power Transmission and Motion Control , 2010, p. 265-276Conference paper (Refereed)
    Abstract [en]

    A suitable method for simulating large complex dynamic systems is represented by distributed modelling using transmission line elements. The method is applicable to all physical systems, such as mechanical, electrical and pneumatics, but is particularly well suited to simulate systems where wave propagation is an important issue, for instance hydraulic systems. By using this method, components can be numerically isolated from each other, which provide highly robust numerical properties. It also enables the use of multi-core architecture since a system model can be composed by distributed simulations of subsystems on different processor cores.

    Technologies based on transmission lines has successfully been implemented in the HOPSAN simulation package, develop at Linköping University. Currently, the next generation of HOPSAN is developed using an object-oriented approach. The work is focused on compatibility, execution speed and real-time simulation in order to facilitate hardware-in-the-loop applications. This paper presents the work progress and some possible features in the new version of the HOPSAN simulation package.

  • 15.
    Axin, Mikael
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Eriksson, Björn
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Energy Efficient Load Adapting System Without Load Sensing: Design and Evaluation2009Conference paper (Refereed)
    Abstract [en]

    In load sensing systems, the pump pressure is controlled in a closed loop control mode. In this paper, a system solution where the displacement of the pump is controlled directly from the operator's demand is studied. Both the stability and the response is thereby improved. It also implies a better energy efficiency since the pump pressure will be adapted according to the point of operation with no additional pressure margin needed. In some mobile applications, pressure compensation is required to avoid load interference. When using common pre compensators in a displacement controlled system, the pump and the valve will both control the flow. A better solution would be to control the flow by the pump and utilize the valve as a flow divider. This can be achieved by using flow sharing compensators. It also allows further energy savings since the maximum restriction area of the main spool at one of the loads can be utilized independent of the flow delivered by the pump. This paper addresses the problem with using common pre compensators in displacement controlled systems and analyses and compares both a traditional load sensing system and an open controlled pump solution with flow sharing compensators. Measurements on a wheel loader application equipped with the system presented in this paper shows a decreased energy consumption of 14 % for the working hydraulics compared to a load sensing system during a short loading cycle, provided that the pump is not saturated.

  • 16.
    Berry, Patrick
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Aircraft Conceptual Design Methods2010 (ed. 1)Book (Other academic)
    Abstract [en]

    Aircraft Conceptual Design Synthesis means design by fitness-for-purpose. Design engineers can jump off from the point of given parameters and requirements - required performance, payloads and other factors. This is the first book for the aeronautical designer devoted to guiding the reader through this highly effective conceptual design synthesis process. This forms the procedure for the initial stage of the aircraft design process - the interpretation of a requirement into the preliminary layout. A logical design sequence is developed utilizing original modules to represent propulsion, lift, drag, mass, and performance. Aircraft Conceptual Design Synthesis includes a disk of spreadsheets that provides core data. Unlike existing approaches, the design synthesis method can be applied to novel aircraft concepts.CONTENTS INCLUDE* The design process* Aircraft configuration* Flight regime and powerplant considerations* Fuselage layout* Configuration of the wing* Basic lift, drag and mass representations* Performance estimation* Parametric analysis and optimisation* Analysis of concept design  "This is an important landmark book and in my view will become a standard by which others will be compared" - Dr E C P Ransom, Kingston University, UK

  • 17.
    Berry, Patrick
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Ahmad, Shakeel
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Sport Aviation of the Future. Possible Concepts for Future Sport Aircraft using Differrent Environmental Friendly Propulsion Concepts 2010In: ICAS 2010, 2010, p. 10-Conference paper (Other academic)
  • 18.
    Björn, Eriksson
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Rösth, Marcus
    MCD Parker Hannifin AB.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Energy saving system utilizing LQ-technique design2009In: Proceedings of the Seventh International Conference on Fluid Power Transmission and Control: ICPF 2009 / [ed] Yongxiang, Lu and Qingfeng, Wang and Wei, Li and Bingfeng, Ju, Beijing: Beijing World Publishing Corporation , 2009, p. 224-229Conference paper (Refereed)
    Abstract [en]

    This paper deals with the control of individual metering systems. This paper deals with the control of an individual metering system that could be used for reducing metering losses by enabling recuperation and regeneration operation. A system that utilizes individual metering is more flexible than a conventional system since there are more control signals and thereby more outputs to control. Energy saving aspects is among the main reasons for the research on this kind of system, but there is also an opportunity of improvements of the dynamics compared to a conventional system. In this paper an approach with LQtechnique are presented for improvements of system dynamics. Since all states in the system can not be measured a state observer is also considered in the control design. These work present simulations, implementations in a real world forwarder application and results from verifying experiments.

  • 19.
    Boström, Jörgen
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Hagäng, Per
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Energianalys av tryckluftsystem: så kan Billerud Skärblacka AB spara energi på tryckluft2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Compressed air is a low efficiency media, and is thus very expensive to produce. This thesis work began by mind mapping how to create savings on the compressed air system at Billerud Skärblacka AB. Certain issues have been chosen for further studies.

    In order to identify the consumption of compressed air at PM 8 and 9, several measurements were made. At PM 8 there were not found any pressure drop, only large pressure variations for short periods of time. The causes of these pressure variations were not established. At PM 9 a registered pressure drop of around 1 bar was found. The cause of the pressure drop at PM9 was not found. A solution for the pressure drop was presented, which also could give an opportunity to reduce the nominal pressure in the compressed air system. An idea for improvement of the compressed air system structure has also been presented.

    A search for leakages on the compressed air system was carried out both at PM 8 and PM 9. Leakages at PM8 seem to be lower than at PM9. The search for leakages pointed out that those leakages on the compressed air system reduces the efficiency of the compressed air system.

    There are some large scale consumers of compressed air at Billerud, for example one function at PM8 and the cleaning function of timber trucks. One idea for reducing electrical consumption is to replace compressed air with a high pressure fan at PM8. In the report more suggestions for saving electrical energy regarding the other large scale consumers are presented.

  • 20.
    Braun, Robert
    Linköping University, Department of Management and Engineering. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Hardware-in-the-Loop Simulation of Aircraft Actuator2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Advanced computer simulations will play a more and more important role in future aircraft development and aeronautic research. Hardware-in-the-loop simulations enable examination of single components without the need of a full-scale model of the system. This project investigates the possibility of conducting hardware-in-the-loop simulations using a hydraulic test rig utilizing modern computer equipment. Controllers and models have been built in Simulink and Hopsan. Most hydraulic and mechanical components used in Hopsan have also been translated from Fortran to C and compiled into shared libraries (.dll). This provides an easy way of importing Hopsan models in LabVIEW, which is used to control the test rig. The results have been compared between Hopsan and LabVIEW, and no major differences in the results could be found. Importing Hopsan components to LabVIEW can potentially enable powerful features not available in Hopsan, such as hardware-in-the-loop simulations, multi-core processing and advanced plotting tools. It does however require fast computer systems to achieve real-time speed. The results of this project can provide interesting starting points in the development of the next generation of Hopsan.

  • 21.
    Conte, Gianpaolo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    Hempel, Maria
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    Rudol, Piotr
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    Lundström, David
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Duranti, Simone
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, AUTTEK - Autonomous Unmanned Aerial Vehicle Research Group .
    Wzorek, Mariusz
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    Doherty, Patrick
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, KPLAB - Knowledge Processing Lab.
    High Accuracy Ground Target Geo-Location Using Autonomous Micro Aerial Vehicle Platforms2008In: Proceedings of the AIAA Guidance, Navigation, and Control Conference (GNC), AIAA , 2008Conference paper (Refereed)
    Abstract [en]

    This paper presents a method for high accuracy ground target localization using a Micro Aerial Vehicle (MAV) equipped with a video camera sensor. The proposed method is based on a satellite or aerial image registration technique. The target geo-location is calculated by registering the ground target image taken from an on-board video camera with a geo- referenced satellite image. This method does not require accurate knowledge of the aircraft position and attitude, therefore it is especially suitable for MAV platforms which do not have the capability to carry accurate sensors due to their limited payload weight and power resources.  The paper presents results of a ground target geo-location experiment based on an image registration technique. The platform used is a MAV prototype which won the 3rd US-European Micro Aerial Vehicle Competition (MAV07). In the experiment a ground object was localized with an accuracy of 2.3 meters from a ight altitude of 70 meters.

  • 22.
    Danielsson, Olov
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Karlsson, Johan
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Radialtätning till Retarder2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis has the overall objective to develop the optimum sealing system between the retarder and transmission. Today, there is a pressure-relief and two radial seals separation between the retarder and transmission. It has been found that carbon residue formation may occur between retarder axle and seal lips with, in some cases, leakage as a result.

    We have in this thesis tried to explain the phenomenon of carbon residue, how it is formed and why it can be seen just on the seals? A rig test was conducted where we show how friction, speed, transmission temperature and mitigation phases of the retarder affects temperatures in the sealing environment. Factors affecting the coke structure are reported, together with proposals for measures that provide a mitigating seal environment. The material is PTFE, which is standard in the seals today; we believe meets all requirements for the sealing material.

    The final recommendation is a tripartite cooperation between Scania, a petroleum company and an additive manufacturer where the different base oils and additive tested as multi-factorial experiments to identify what gives the best results. On transmission side we recommend to ensure a constant oil flow to the seal.

  • 23.
    Dell'Amico, Alessandro
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Pohl, Jochen
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Modeling and Simulation for Requirement Generation of Heavy Vehicles Steering Gears2010In: Fluid Power and Motion Control (FPMC 2010) / [ed] D N Johnston and A R Plummer, Centre for Power Transmission and Motion Control , 2010, p. 475-490Conference paper (Refereed)
    Abstract [en]

    Today’s passenger vehicles are becoming more and more safe as more steering related active safety functions are being introduced. As an example, lane keeping assist functions or even electronic vehicle stability with steering intervention can be mentioned. However, the same trend can yet not be witnessed for heavy vehicles, which is, among others, due to a lesser degree of controllability of the steering system. While electric power assisted steering has been introduced in passenger cars in recent years on a broader basis, electric power assisted steering is yet not suitable for heavy vehicles due to heavier loads on the steering rack. Heavy vehicles thus lack a freely programmable steering system.The purpose of this paper is to generate and evaluate the requirements of future hydraulic actuation concepts for heavy vehicles, where emphasis is put on the required steering actuator linearity and bandwidth. Both actuator response and linearity are decisive for transmitting a proper steering feel to the driver. In this study we provide a structured approach to derive the required bandwidth as a function of the system sizing and provide a simulation supported method for deriving the requirements of linearity and accuracy.

  • 24.
    Eliasson, Emanuel
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    Fusing Laser and Radar Data for Enhanced Situation Awareness2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With an increasing traffic intensity the demands on vehicular safety is higher than ever before. Active safety systems that have been developed recent years are a response to that. In this master thesis Sensor Fusion is used to combine information from a laser scanner and a microwave radar in order to get more information about the surroundings in front of a vehicle. The Extended Kalman Filter method has been used to fuse the information from the sensors. The process model consists partly of a Constant Turn model to describe the motion of the ego vehicle as well as a tracked object. These individual motions are then put together in a framework for spatial relationships to describe the relationship between them. Two measurement models have been used to describe the two sensors. They have been derived from a general sensor model. This filter approach has been used to estimate the position and orientation of an object relative the ego vehicle. Also velocity, yaw rate and the width of the object have been estimated. The filter has been implemented and simulated in Matlab. The data that has been recorded and used in this work is coming from a scenario where the ego vehicle is following an object in a quite straight line. Where the ego vehicle is a truck and the object is a bus. One important conclusion from this work is that the filter is sensitive to the number of laser beams that hits the object of interest. No qualitative validation has been made though.

  • 25.
    Ericson, Liselott
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Flow Pulsations in Fluid Power Machines - a Measurement and Simulation Study2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stricter requirements for better working environment involve noise and vibration control of hydraulic machines. The operational conditions for hydraulic machines, such as pressure and rotational speed, are also increasing and this makes it even more difficult to develop a quiet, vibration-free machine due to the interdependence between noise and escalating operational conditions. The thesis investigates machines working in different driving modes and under different operational conditions.

    A so-called cross-angle is proposed for motor as well as pump/motor applications with variable displacement angles. The cross-angle is intended to reduce the overall noise level in the machine's working area. Other noise reduction features are also considered for machines working in different modes.

    To facilitate the system integrator's ability to design quiet systems, methods to determine the source flow and source impedance of the machine are essential. The source flow is assumed to be created at the valve plate and the internal impedance related to the high pressure port are completely independent of the rest of the system. Knowledge of these properties makes it possible to foresee the noise properties of a system already on the design phase. A novel source flow measurement method, the source admittance method, is investigated here. The method is considered to be robust and easy to use to suit industry requirements.

    List of papers
    1. The source admittance method A new measurement method for hydrostatic pump flow pulsation
    Open this publication in new window or tab >>The source admittance method A new measurement method for hydrostatic pump flow pulsation
    2006 (English)In: Proc. of the 4th FPNI - PhD Symposium Sarasota, Vol 1, Sarasota: Coastal Printing , 2006, p. 297-309Conference paper, Oral presentation only (Refereed)
    Abstract [en]

    Two main drawbacks with hydraulic systems are noise and vibrations, mainly created from flow pulsations in positive displacement pumps. The flow ripple can be divided in two parts; kinematic and compressible. Kinematic flow ripple is created due to the limited number of pumping elements. Compressible flow ripple is created due to cornpressibility effects in the pumping chambers and is the dominating effect at high pressures. There are well proven methods to decrease noise in specific operation conditions, but there is an urgent need for new techniques in machines working under varying operation conditions. There is also a need for improved measurement methods to be used in product development and to judge new inventions to decrease noise.

    Simulation techniques are useful in the early stages of the development process. There are useful and accurate simulation models capable of predicting source flow ripple in hydrostatic pumps and thereby useful for optimisation purposes. Simulation results are, however, of less practical use before they are experimentally verified . The experimental methods must be simple and straightforward if they are to be accepted in industry.

    This paper describes a new method to measure source flow. It is called the source admittance method. Compared to earlier methods such as the two-microphone method, the main benefit is that there is no need for a model of the outlet channel - the source flow is measured through an additional pressure transducer inside the pump. The method works very well with a tested fixed bent-axis pump with a rather simple outlet channel. Experiments have also been performed with a variable in-line pump with added complexity to the out let channel. Although the overall impression is positive, these experiments show that the method needs to be further to be used for such machines. In both cases, the new method is compared with earlier verified simulation models and with measurements based on the two-microphone method. Apart from the mentioned discrepancies in a narrow frequency range, agreement is very good.

    Place, publisher, year, edition, pages
    Sarasota: Coastal Printing, 2006
    Keywords
    Flow pulsations, measurement, hydrostatic pump, two-microphone method
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-36611 (URN)31745 (Local ID)1-4243-0499-7 (ISBN)31745 (Archive number)31745 (OAI)
    Conference
    4th FPNI - PhD Symposium Sarasota. Sarasota, Fl, US, June 2006.
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-20
    2. The source admittance method for pumps with complex outlet channels
    Open this publication in new window or tab >>The source admittance method for pumps with complex outlet channels
    2007 (English)In: Proc. of the 10th Scandinavian International Conference on Fluid Power (SICFP'07), vol 1, Tampere: Tampere University of Technologi , 2007, p. 279-293Conference paper, Published paper (Refereed)
    Abstract [en]

    The source admittance method offers a new way to measure flow ripple. Compared to earlier methods such as the two-microphone method, the main benefit is that there is no need for a model of the outlet channel - the source flow is measured through an additional pressure transducer inside the pump. This makes the source admittance method easier to use and less modelling skill is needed. Furthermore, the method is more reliable because the somce flow is measured, i.e. pressure at the creation spot, directly. In earlier studies, the method proved to work very well for pumps with simple discharge channels but less well for pumps with complex discharge channels.

    The experimental test object is a pump with a simple outlet channel. Its internal impedance can easily be changed in a controlled manner; complexity can thus be added step by step. The paper contributes to the understanding of how complexity of the pump's discharge channel influences the usefulness of the source admittance method.

    Place, publisher, year, edition, pages
    Tampere: Tampere University of Technologi, 2007
    Keywords
    Fluid power
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-40967 (URN)54782 (Local ID)978-952-15-1761-7 (ISBN)54782 (Archive number)54782 (OAI)
    Conference
    10th Scandinavian International Conference on Fluid Power (SICFP'07). Tampere, Finland, May 2007.
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-20
    3. Flow pulsation reduction for variable displacement motors using cross-angle
    Open this publication in new window or tab >>Flow pulsation reduction for variable displacement motors using cross-angle
    2007 (English)In: Power Transmission and Motion Control (PTMC 2007) / [ed] D. N. Johnston, and A. Plummer, Essex: Hadleys Ltd , 2007, p. 103-116Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper considers using the cross-angle in variable displacement hydraulic machines. The cross-angle is a fixed displacement angle around the axis perpendicular to the normal displacement direction. The cross-angle changes the angles to the pistons top and bottom dead centres as a function of the fraction of displacement in such a way that the valve plate timing is varied and different pre-compression and decompression angles are obtained. A non-gradient optimisation technique, the Complex method, is used together with a comprehensive simulation model in order to find the optimal cross-angle for a variable displacement hydraulic motor. The paper shows that the cross-angle can be used to reduce noise in variable displacement motors. One issue that makes the motor application more difficult is the increased dependence between outlet and inlet flow ripple which is not found in pump applications. Furthermore, the paper discusses how to use the cross-angle for machines which can work both as a motor and a pump.

    Place, publisher, year, edition, pages
    Essex: Hadleys Ltd, 2007
    Keywords
    Cross-angle flow pulsations noise hydraulic pump hydraulic motor
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-40965 (URN)54778 (Local ID)978-0-86197-140-4 (ISBN)54778 (Archive number)54778 (OAI)
    Conference
    Power Transmission and Motion Control (PTMC 2007), 12-14 September, Bath, UK
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-20
  • 26.
    Ericson, Liselott
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Project: Attenuation of pump flow pulsations by hydraulic RC filters2010Report (Other academic)
    Abstract [en]

    The work has been performed at Johannes Kepler University of Linz at the Institute of Machine Design and Hydraulic Drives. A novel method is to create a RC-type hydraulic filter between the pump and load. R stand for resistor and C for capacitor which creates a passive electrical low-pass filter. In hydraulic terms, the capacity of the filter is the cavity of the pump's delivery channel and the resistive part is the orifice which connects the pump to the external system. This system may not minimise the overall hydraulic noise however the attenuator's goal is to minimise the pulsations at the load.In the project a simulation model have been developed in HOPSAN. The flow pulsation created in the radial piston pump is extensively modelled. Furthermore, the RC-filter including the external system is modelled. The simulation model has been verified with some pressure pulsation measurements.The simulations show a reduction of the pressure pulsations at the load. However, the pressure drop associated with the superimposed flow variation is much smaller than predicted by the steady-state orifice equation. Further investigations and measurements need to be done do increase the accuracy of the orifice equation.

  • 27.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Johansson, A.
    Pump and Motor Division, Parker Hannifin Corp., Flygmotorv. 2, 461 82 Trollhättan, Sweden.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Noise reduction by means of non-uniform placement of pistons in a fluid power machine2010Manuscript (preprint) (Other academic)
    Abstract [en]

    In conventional machines, the pulsations are periodic and originate from the uniform placement of a given number of pistons. This paper discusses the possibilities to introduce non-uniform placement of the pistons. The pulsations periodicity is thus changed, which can have a major impact on the noise level and how the noise is experienced. A number of approaches are presented, evaluated and ranked and the usefulness of the modifications is assessed. This study employs a transfer function methodology to map simulated internal pump dynamics, such as piston forces and bending moments, to audible noise. Using these transfer functions, it is possible for instance to predict how changed valve plate timing affects simulated piston forces and bending moments and in turn how this will affect audible noise. Copyright © 2009 by ASME.

  • 28.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Johansson, A.
    Pump and Motor Division, Parker Hannifin Corp., Flygmotorv. 2, 461 82 Trollhättan, Sweden.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Noise reduction by means of non-uniform placement of pistons in a fluid power machine2010In: Proceedings of the ASME Dynamic Systems and Control Conference 2009, DSCC2009, 2010, no PART B, p. 1293-1300Conference paper (Refereed)
    Abstract [en]

    In conventional machines, the pulsations are periodic and originate from the uniform placement of a given number of pistons. This paper discusses the possibilities to introduce non-uniform placement of the pistons. The pulsations periodicity is thus changed, which can have a major impact on the noise level and how the noise is experienced. A number of approaches are presented, evaluated and ranked and the usefulness of the modifications is assessed. This study employs a transfer function methodology to map simulated internal pump dynamics, such as piston forces and bending moments, to audible noise. Using these transfer functions, it is possible for instance to predict how changed valve plate timing affects simulated piston forces and bending moments and in turn how this will affect audible noise. Copyright © 2009 by ASME.

  • 29.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Measurement of Free Air in the Oil Close to a Hydraulic Pump2009In: JFPS International Journal of Fluid Power System, ISSN 1881-5286, Vol. 2, no 2, p. 39-44Article in journal (Refereed)
    Abstract [en]

    Noise is a well-known challenge in hydraulic systems and hydrostatic pumps are one of the largest noise contributors in a hydraulic system. The existing noise reduction features, such as pressure relief groove and pre-compression filter volume, are more or less dependent on the working condition. It is essential to know the amount of free air when designing a quiet pump; however, it is not evident how much free air the oil contains. The free air content is different if the suction port is boost pressured or self-priming. The amount of free air in a well-designed system can be as low as 0.5% while in others up to 10%.This paper uses the three-transducer method to measure the amount of free air in the oil. The oil's compressibility can be measured for different working conditions and the free air content can then be calculated. The pre-study is performed with an extensive simulation model. Various noise reduction features' sensitivity to free air content is considered.

  • 30.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Measurement of Free Air in the Oil Close to a Hydraulic Pump2008In: Proceedings of the 7th JFPS International Symposium on Fluid Power, Vol. 3, Toyama: JFPS , 2008, p. 647-652Conference paper (Other academic)
    Abstract [en]

     Noise is a well-known challenge in hydraulic systems and hydrostatic pumps are one of the largest noise contributors in a hydraulic system. The existing noise reduction features, such as pressure relief groove and pre-compression filter volume, are more or less dependent on the working condition. It is essential to know the amount of free air when designing a quiet pump; however, it is not evident how much free air the oil contains. The free air content is different if the suction port is boost pressured or self-priming. The amount of free air in a well-designed system can be as low as 0.5% while in others up to 10%. This paper uses the three-transducer method to measure the amount of free air in the oil. The oil's compressibility can be measured for different working conditions and the free air content can then be calculated. The pre-study is performed with an extensive simulation model. Various noise reduction features' sensitivity to free air content is considered.

  • 31.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems.
    The source admittance method for pumps with complex outlet channels2007In: Proc. of the 10th Scandinavian International Conference on Fluid Power (SICFP'07), vol 1, Tampere: Tampere University of Technologi , 2007, p. 279-293Conference paper (Refereed)
    Abstract [en]

    The source admittance method offers a new way to measure flow ripple. Compared to earlier methods such as the two-microphone method, the main benefit is that there is no need for a model of the outlet channel - the source flow is measured through an additional pressure transducer inside the pump. This makes the source admittance method easier to use and less modelling skill is needed. Furthermore, the method is more reliable because the somce flow is measured, i.e. pressure at the creation spot, directly. In earlier studies, the method proved to work very well for pumps with simple discharge channels but less well for pumps with complex discharge channels.

    The experimental test object is a pump with a simple outlet channel. Its internal impedance can easily be changed in a controlled manner; complexity can thus be added step by step. The paper contributes to the understanding of how complexity of the pump's discharge channel influences the usefulness of the source admittance method.

  • 32.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Unsteady Flow through Valve Plate Restrictor in a Hydraulic Pump/Motor Unit2010Manuscript (preprint) (Other academic)
    Abstract [en]

    Noise is a well known challenge in hydraulic systems. Hydrostatic machines are among the largest noise contributors in a hydraulic system.The noise from the machine originates from flow pulsations at the discharge and suction ports, as well as pulsations in piston forces and bending moments.

    This article investigates the dynamic behaviour of unsteady flow through a valve plate in an axial piston pump. The proposed extension of the steady state restrictor equation includes a dynamic internal mass term and a resistance. The results from 1D model are validated with a 3D CFD model. Different valve plates’ configurations and pump sizes are easily simulated with the two simulation models. The simulation results show very good comparison with experimental tests. The proposed method is verified with a hydraulic pump application but it can probably also apply for original restrictors too.

  • 33.
    Ericson, Liselott
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems .
    Ölvander, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Machine Design.
    Palmberg, Jan-Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems.
    En effektiv metod för att reducera flödespulsationer från variabla hydraulmaskiner2007In: Hydraulikdagar 07,2007, Linköping: Linköpings universitet , 2007Conference paper (Other academic)
    Abstract [sv]

     Den här presentationen behandlar en metod som effektivt reducerar flödespulsationer i variabla hydraulmaskiner, genom att förskjuta dödpunktens läge. Det realiseras genom att införa en fast inklinationsvinkel vinkelrätt mot den normala deplacementsvinkeln. Genom att förskjutningsvinkeln ändrar kolvarnas dödpunkt kommer förkompressionen och efterexpansionen att variera när deplacementet ändras. Tidigare arbeten visar, både teoretiskt och experimentellt, fördelarna med förskjutningsvinkeln för pumpar men inga utförligare utredningar för maskiner som arbetar både som motor och pump.

  • 34.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Flow pulsation reduction for variable displacement motors using cross-angle2007In: Power Transmission and Motion Control (PTMC 2007) / [ed] D. N. Johnston, and A. Plummer, Essex: Hadleys Ltd , 2007, p. 103-116Conference paper (Refereed)
    Abstract [en]

    This paper considers using the cross-angle in variable displacement hydraulic machines. The cross-angle is a fixed displacement angle around the axis perpendicular to the normal displacement direction. The cross-angle changes the angles to the pistons top and bottom dead centres as a function of the fraction of displacement in such a way that the valve plate timing is varied and different pre-compression and decompression angles are obtained. A non-gradient optimisation technique, the Complex method, is used together with a comprehensive simulation model in order to find the optimal cross-angle for a variable displacement hydraulic motor. The paper shows that the cross-angle can be used to reduce noise in variable displacement motors. One issue that makes the motor application more difficult is the increased dependence between outlet and inlet flow ripple which is not found in pump applications. Furthermore, the paper discusses how to use the cross-angle for machines which can work both as a motor and a pump.

  • 35.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    On optimal design of hydrostatic machines2008In: Proceedings of the 6th International Fluid Power Conference, IFK, Vol WS, 2008, p. 273-286Conference paper (Refereed)
    Abstract [en]

    Noise is a well known challenge for hydraulic systems and hydrostatic machines is one of the largest noise contributors in a hydraulic system. The noise from the machine originates from flow pulsations in the discharge and suction ports, as well as pulsations in piston forces and bending moments. To the design a quite hydraulic machine is a difficult task where many different objectives need to be considered. This paper presents a generic method for how optimization based on simulation models could be used to design quieter hydraulic machines. In order to stay competitive on a global market an efficient product development process is essential for all manufacturing industries. By using simulation-s tools in the design process, the product can be analysed before the actual product is manufactured. Furthermore, in order to find an optimal design of the machine with respect to noise, a comprehensive dynamic simulation model is needed. The model contains all important noise contributors. In the paper, the simulation models are used together with a non-gradient optimization method in order to find the best possible design. A vital part when using optimization to support design is always to formulate the objective function. As mentioned above, noise is generated from different sources and all these sources need to be considered when the objective function is formulated. For example a design that minimizes flow pulsations in the suction port will surely perform badly in some other objective. Therefore noise minimization could be looked upon as a typical multi-objective optimization problem. It is also not evident how the different objective should be ranked because the observed noise level is strongly depending on the system in which the machine is to be used. The paper also considers whether the objective function should be formulated in time or frequency domain. Traditionally, simulation of machine performance is conducted in the time domain, but the human ear hears noise in the frequency domain and perceives high and low frequencies differently. Furthermore, transformation from piston forces into emitted noise is much higher at high-frequency content than low-frequency content. This makes it natural to formulate the objective function in frequency domain, which raises the question of how the different harmonic should be ranked. In the paper a number of different approaches to formulate the objective function is presented and evaluated. The objectives considered are flow pulsation in both discharge and suction ports, as well as pulsation in piston forces and bending moments. Furthermore, the objectives are studied in both time and frequency domain. The design application is a variable hydraulic machine of bent axis type with nine pistons, which is operated both as a pump and a motor. However, the methods presented in the paper could be applied to other types of hydraulic machines as well. 

  • 36.
    Ericson, Liselott
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design . Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Johansson, Andreas
    Pump and motor division Parker Hannifin AB.
    Prediction and Optimisation of Audible Noise from Fluid Power Machines2009In: The Seventh International Conference on Fluid Power Transmission and Control, Hangzhou, Beijing: Beijing World Publishing Corporation , 2009, p. 911-918Conference paper (Refereed)
    Abstract [en]

    In this study, a transfer function methodology is employed for mapping simulated internal pump dynamics, such as piston forces and bending moments, on to audible noise. Using these transfer functions, it is possible to predict how, for instance, changed valve plate timing affects simulated piston forces and bending moments and in turn how that will affect audible noise. Hence, it is possible to design an objective function that directly reflects audible noise. The transfer functions are experimentally obtained and are valid for a specific machine shell and to some minor extent the room’s acoustical properties. Simulation of the internal pump dynamics, and optimisations, are carried out using a pump model developed in the simulation tool HOPSAN. The design application is a fixed hydraulic machine of bent axis type with seven pistons. The theory outlined and the method proposed in the paper can also be applied to other types of hydraulic machines. The paper shows how different noise reduction features affect the sound pressure level and also motor mode compared to pump mode.

  • 37.
    Eriksson, Björn
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Control Strategy for Energy Efficient Fluid Power Actuators: Utilizing Individual Metering2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents a solution enabling lower losses in hydraulic actuator systems. A mobile fluid power system often contains several different actuators supplied with a single load sensing pump. One of the main advantages is the need of only one system pump. This makes the fluid power system compact and cost-effective.

    A hydraulic load often consists of two ports, e.g. motors and cylinders. Such loads have traditionally been controlled by a valve that controls these ports by one single control signal, namely the position of the spool in a control valve. In this kind of valve, the inlet (meter-in) and outlet (meter-out) orifices are mechanically connected. The mechanical connection makes the system robust and easy to control, at the same time as the system lacks flexibility. Some of the main drawbacks are

    The fixed relation between the inlet and outlet orifices in most applications produce too much throttling at the outlet orifice under most operating conditions. This makes the system inefficient.

    The flow directions are fixed for a given spool position; therefore, no energy recuperation and/or regeneration ability is available.

    In this thesis a novel system idea enabling, for example, recuperation and regeneration is presented. Recuperation is when flow is taken from a tank, pressurized by external loads, and then fed back into the pump line. Regeneration is when either cylinder chambers (or motor ports) are connected to the pump line. Only one system pump is needed. Pressure compensated (load independent), bidirectional, poppet valves are proposed and utilized.

    The novel system presented in this thesis needs only a position sensor on each compensator spool. This simple sensor is also suitable for identification of mode switches, e.g. between normal, differential and regenerative modes. Patent pending.

    The balance of where to put the functionality (hardware and/or software) makes it possible to manoeuvre the system with maintained speed control in the case of sensor failure. The main reason is that the novel system does not need pressure transducers for flow determination. Some features of the novel system:

    Mode switches The mode switches are accomplished without knowledge about the pressures in the system

    Throttle losses With the new system approach, choice of control and measure signals, the throttle losses at the control valves are reduced

    Smooth mode switches The system will switch to regenerative mode automatically in a smooth manner when possible

    Use energy stored in the loads The load, e.g. a cylinder, is able to be used as a motor when possible, enabling the system to recuperate overrun loads

    The system and its components are described together with the control algorithms that enable energy efficient operation. Measurements from a real application are also presented in the thesis.

    List of papers
    1. Study on Individual Pressure Control in Energy Efficient Cylinder Drives
    Open this publication in new window or tab >>Study on Individual Pressure Control in Energy Efficient Cylinder Drives
    2006 (English)In: 4th FPNI-Ph.D. Symphosium, FPNI’06, Sarasota, United States, 13th–17th June, 2006, M. Ivantysynova (ed.), 2006, p. 77-99Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper deals with energy efficient mobile valves with cylinder loads. In recent years, the need for energy efficient fluid power systems has increased. The reason is the increasing price of oil as well as tougher environmental regulations. One way of achieving an energy efficient directional valve is to use individually controlled meter-in and meter-out orifices and transfer functionality from hardware to the software controller. This type of solution makes it possible to keep metering losses low. Energy recovery is also made possible since both speed and lowest cylinder chamber pressure can be controlled. The challenge in such a controller is to decouple the chamber pressures in the MIMO (multi-input-multi-output) hydraulic system into independent SISO (single-input-single-output) systems. In this paper, a decoupling based on a linear analysis of the physical system has been implemented and tested in a cylinder position control application. The controller is evaluated in terms of performance and robustness. In the near future, this project will continue with other approaches as well, as there are several interesting control approaches available.

     

    Keywords
    Fluid power, separate metering, decouped control
    National Category
    Information Systems
    Identifiers
    urn:nbn:se:liu:diva-12537 (URN)1-42430-499-7 (ISBN)
    Note
    Volume 1, No. 4Available from: 2008-09-12 Created: 2008-09-12 Last updated: 2018-01-12
    2. The Dynamic Properties of a Poppet Type Hydraulic Flow Amplifier
    Open this publication in new window or tab >>The Dynamic Properties of a Poppet Type Hydraulic Flow Amplifier
    2007 (English)In: 10th Scandinavian International Conference on Fluid Power, SICFP´07 / [ed] J. Vilenius and K. T. Koskinen, Tampere, Finland: Tampere University of Technology , 2007, p. 161-178Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper examines the dynamic properties of a two-stage flow control valve of the "Valvistor" brand. There are several benefits to this: the valve ha a high closed loop bandwidth, the design allows big flow capacities etc. An attractive feature of this two-stage valve is that the pilot flow contributes to the total flow giving higher steady state flow efficiency. This paper presents an analythical model of this particular type of valve. A simplified model with relevant approximations is also presented. Measurements on the valve were made to validate the valve model. The paper also includes a further discussion about the pros and cons of the valve in open and closed loop applications.

    Place, publisher, year, edition, pages
    Tampere, Finland: Tampere University of Technology, 2007
    Keywords
    Fluid power, Valvistor, dynamic model
    National Category
    Information Systems
    Identifiers
    urn:nbn:se:liu:diva-12538 (URN)
    Conference
    10th Scandinavian International Conference on Fluid Power, SICFP´07, 21st–23rd May, Tampere, Finland
    Available from: 2008-09-12 Created: 2008-09-12 Last updated: 2018-01-12
    3. A Novel Valve Concept Including the Valvistor Poppet Valve
    Open this publication in new window or tab >>A Novel Valve Concept Including the Valvistor Poppet Valve
    2007 (English)In: The Tenth Scandinavian International Conference on Fluid Power / [ed] J. Vilenius and K. T. Koskinen, Tampere, Finland: Tampere University of Technology , 2007, p. 355-364Conference paper, Published paper (Refereed)
    Abstract [en]

    These days, energy efficient mobile fluid power systems are of great interest. A mobile system containing several different cylinder drives supplied with a single load sensing pump (LS-pump) has a number of advantages as well as disadvantages. One fo the main advantages is the need of only one system pump. This makes the fluid power system compact and cost-effective. A challenge is to keep the hydraulic losses at a low level, especially losses at smaller loads. This paper introduces a fail-safe proportional valve element that is based on the Valvistor poppet valve. Due to the demands of flexibility the poppet valve is bi-directional. The valve has an innovative hydro-mechanic layout that makes it fail-safe, unwanted lowering loads, for example, never occur. The new valve includes simple sensors that are suitable for identificaiton of mode switches, e g between normal, differential and regenerative modes. It is also possible to manoevre the system with maintained velocity control in case of sensor failure. In a less complex system the concept has benefits as well. For example in systems where fail-safe bi-directional on/off valves are needed, then without mode sensing capabilities.

    Place, publisher, year, edition, pages
    Tampere, Finland: Tampere University of Technology, 2007
    Keywords
    Fluid power, poppet valve, Valvistor, bi-directional, fail-safe
    National Category
    Information Systems
    Identifiers
    urn:nbn:se:liu:diva-12539 (URN)
    Conference
    10th Scandinavian International Conference on Fluid Power, SICFP´07, 21st–23rd May, Tampere, Finland
    Available from: 2008-09-12 Created: 2008-09-12 Last updated: 2018-01-12
  • 38.
    Eriksson, Björn
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Mobile Fluid Power Systems Design: with a Focus on Energy Efficiency2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This work deals with innovative energy efficient fluid power systems for mobile applications. The subjects taken up concern to what extent and how energy losses can be reduced in mobile working hydraulics systems. Various measures are available for increasing energy efficiency in these kinds of systems. Examples include:

    Flow controlled systems The pump controller is switched from a load sensing toa displacement controlled one. The displacement is controlled in an open loopfashion directly from the operator’s demand signals. This reduces energy consumptionat the same time as dynamic issues that are attached to LS systemscan be avoided.

    Individual metering valve systems Flexibility is increased by removing the mechanicalcoupling between the meter-in and meter-out orifices in directionalvalves. An overview of this kind of system is given in the thesis. A designproposal that has been implemented is also presented. Initial test results areshown. Patents for this particular system have been applied for.

    Displacement control Metering losses are reduced by removing the directional valves.One pump is used for each load in such systems. This hardware layout involvesconsiderable changes compared to conventional systems. Displacementcontrolled systems are not studied in this work.

    In mobile applications, overall efficiency is often poor and losses are substantial. The measures listed above can help improve this significantly in such applications. A flow dividing system can decrease energy consumption by about 10% and an individual metering system by about 20%. Losses in pump controlled systems are difficult to give a figure for; the losses are rather attached to the pumps and motors and not to the system layout. However, the losses for these systems are presumably even lower than for individual metering systems. The main focus in this work is on individual metering systems but questions about which components and so on are also treated. For example, the Valvistor valve concept has been studied as part of this work.

     

    List of papers
    1. Individual Metering Fluid Power Systems: Challenges and Opportunities
    Open this publication in new window or tab >>Individual Metering Fluid Power Systems: Challenges and Opportunities
    2011 (English)In: Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, ISSN 0959-6518, E-ISSN 2041-3041, Vol. 225, no 12, p. 196-211Article in journal (Refereed) Published
    Abstract [en]

    A review of recent and current research on individual metering fluid power systems is presented. An overview of different systems and their pros and cons is given. General challenges related to independent metering fluid power systems are discussed. The major choices in the design of these systems are the hardware layout and the control strategy. The evolution of existing independent metering fluid power systems from the 1970s until the present day is also presented.

    Place, publisher, year, edition, pages
    Professional Engineering Publishing, 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-61360 (URN)000288805000002 ()
    Conference
    Proceedings of the Sixth International Fluid Power Conference, IFK’08, March 31 - April 2, Dresden, Gemany
    Note

    DOI does not work: 10.1243/09596518JSCE1111

    Available from: 2010-11-16 Created: 2010-11-16 Last updated: 2018-03-12
    2. A High Energy Efficient Mobile Fluid Power System: Novel System Layout and Measurements
    Open this publication in new window or tab >>A High Energy Efficient Mobile Fluid Power System: Novel System Layout and Measurements
    2008 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

    This is one of the earliest publications of the proposed energy efficient individual metering system shown in chapter 5, section 5.3.3. This paper introduces the novel system design, which utilizes independent meter-in and meter-out valves. This system design has the potential to increase energy efficiency considerably in a system that consists of a pump  connected to more than one fluid power actuator. The system proposed here is not dependent on pressure transducers for either flow control or mode selection. The main difference between the work presented in this paper and earlier work is the control strategy. The output signal choices in the closed loops are new. Some functionality is kept in hardware to avoid  critical sensor dependency. The presented system uses pressure compensators to achieve desired flows.

    Keywords
    efficiency, energy saving, mobile system, fluid power
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-42262 (URN)62135 (Local ID)62135 (Archive number)62135 (OAI)
    Conference
    Proceedings of the Sixth International Fluid Power Conference, IFK’08, March 31 - April 2, Dresden, Gemany
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2015-08-31Bibliographically approved
    3. Energy saving system utilizing LQ-technique design
    Open this publication in new window or tab >>Energy saving system utilizing LQ-technique design
    2009 (English)In: Proceedings of the Seventh International Conference on Fluid Power Transmission and Control: ICPF 2009 / [ed] Yongxiang, Lu and Qingfeng, Wang and Wei, Li and Bingfeng, Ju, Beijing: Beijing World Publishing Corporation , 2009, p. 224-229Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper deals with the control of individual metering systems. This paper deals with the control of an individual metering system that could be used for reducing metering losses by enabling recuperation and regeneration operation. A system that utilizes individual metering is more flexible than a conventional system since there are more control signals and thereby more outputs to control. Energy saving aspects is among the main reasons for the research on this kind of system, but there is also an opportunity of improvements of the dynamics compared to a conventional system. In this paper an approach with LQtechnique are presented for improvements of system dynamics. Since all states in the system can not be measured a state observer is also considered in the control design. These work present simulations, implementations in a real world forwarder application and results from verifying experiments.

    Place, publisher, year, edition, pages
    Beijing: Beijing World Publishing Corporation, 2009
    Keywords
    fluid power, independent metering, energy savings, lq, flow amplifying poppet (fap), Valvistor, poppet valve
    National Category
    Vehicle Engineering
    Identifiers
    urn:nbn:se:liu:diva-52028 (URN)978-775062-8213-0 (ISBN)
    Conference
    7th International Conference on Fluid Power Transmission and Control
    Available from: 2009-11-30 Created: 2009-11-30 Last updated: 2015-08-31
    4. How to handle auxiliary functions in energy efficient, single pump, flow sharing mobile systems
    Open this publication in new window or tab >>How to handle auxiliary functions in energy efficient, single pump, flow sharing mobile systems
    2010 (English)In: 7th International Fluid Power Conference Aachen: Efficiency Through Fluid Power, Workshop Proceedings, Vol. 1 / [ed] Hubertus Murrenhoff, Aachen: Apprimus Wissenschafts Verlag , 2010, Vol. 1, p. 65-78Conference paper, Published paper (Refereed)
    Abstract [en]

    Interest has increasingly shifted from load-sensing (pressure controlled) systems to flow controlled systems. In this paper an interesting configuration that uses pre-compensated valves with flow sharing properties is studied. The fundamental difference between a traditional load sensing (LS) system and a flow controlled system is that the pump is controlled based on the operator’s total flow demand rather than maintaining a certain margin pressure over the maximum load pressure. One of the main advantages with flow controlled systems is the absence of the feedback of the highest load pressure to the pump. Flow controlled systems also present some challenges, one being how to handle auxiliary functions with unknown flow demands. Auxiliary functions are typically support legs, external power takeouts etc. This paper analyses one kind of flow controlled system and shows one way of dealing with auxiliary functions.

    Place, publisher, year, edition, pages
    Aachen: Apprimus Wissenschafts Verlag, 2010
    Keywords
    fluid power, load sensing, flow control, energy efficiency
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58146 (URN)978-39-4056-590-7 (ISBN)
    Conference
    The 7th International Fluid Power Conference, 22th- 24th March, Aachen, Germany
    Available from: 2010-08-04 Created: 2010-08-04 Last updated: 2015-08-31Bibliographically approved
    5. A Novel Valve Concept Including the Valvistor Poppet Valve
    Open this publication in new window or tab >>A Novel Valve Concept Including the Valvistor Poppet Valve
    2008 (English)In: Ventil : revija za fluidno tehniko in avtomatizacijo, ISSN 1318-7279, Vol. 14, no 5, p. 433-442Article in journal (Other academic) Published
    Abstract [en]

    These days, energy efficient mobile fluid power systems are of great interest. A mobile system containing several different cylinder drives supplied with a single load sensing pump (LS-pump) has a number of advantages as well as disadvantages. One of the main advantages is the need of only one system pump. This makes the fluid power system compact and cost-effective. A challenge is to keep the hydraulic losses at low level, especially losses at smaller loads. This paper introduces a fail-safe proportional valve element that is based on the Valvistor poppet valve. Due to the demands of flexibility the poppet valve is bi-directional. The valve has an innovative hydro-mechanical layout that makes it fail-safe, unwanted lowering loads, for example, never occur. The new valve includes simple sensors that are suitable for identification of mode switches, e g between normal, differential and regenerative modes. It is also possible to maneuver the system with maintainted velocity control in the case of sensor failure. In a less complex system the concept has benefits as well. For example in systems where fail-safe-bi-directional on/off valves are needed, then without mode sensing capabilities.

    Keywords
    fluid power, poppet valve, Valvistor, bi-directional, fail-safe
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-43301 (URN)73431 (Local ID)73431 (Archive number)73431 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2015-08-31Bibliographically approved
    6. The Dynamic Properties of a Poppet Type Hydraulic Flow Amplifier
    Open this publication in new window or tab >>The Dynamic Properties of a Poppet Type Hydraulic Flow Amplifier
    2007 (English)In: 10th Scandinavian International Conference on Fluid Power, SICFP´07 / [ed] J. Vilenius and K. T. Koskinen, Tampere, Finland: Tampere University of Technology , 2007, p. 161-178Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper examines the dynamic properties of a two-stage flow control valve of the "Valvistor" brand. There are several benefits to this: the valve ha a high closed loop bandwidth, the design allows big flow capacities etc. An attractive feature of this two-stage valve is that the pilot flow contributes to the total flow giving higher steady state flow efficiency. This paper presents an analythical model of this particular type of valve. A simplified model with relevant approximations is also presented. Measurements on the valve were made to validate the valve model. The paper also includes a further discussion about the pros and cons of the valve in open and closed loop applications.

    Place, publisher, year, edition, pages
    Tampere, Finland: Tampere University of Technology, 2007
    Keywords
    Fluid power, Valvistor, dynamic model
    National Category
    Information Systems
    Identifiers
    urn:nbn:se:liu:diva-12538 (URN)
    Conference
    10th Scandinavian International Conference on Fluid Power, SICFP´07, 21st–23rd May, Tampere, Finland
    Available from: 2008-09-12 Created: 2008-09-12 Last updated: 2018-01-12
    7. Hopsan NG, A C++ Implementation using the TLM Simulation Technique
    Open this publication in new window or tab >>Hopsan NG, A C++ Implementation using the TLM Simulation Technique
    2010 (English)In: Proceedings of The 51st Conference on Simulation and Modelling (SIMS2010), Oulu, Finland, 2010Conference paper, Published paper (Refereed)
    Abstract [en]

    The Hopsan simulation package, used primarily for hydro-mechanical simulation, was first released in 1977. Modeling in Hopsan is based on a method using transmission line modeling, TLM. In TLM, component models are decoupled from each other through time delays. As components are decoupled and use distributed solvers, the simulation environment is suitable for distributed simulations. No numerical errors are introduced at simulation time when using TLM; all errors are related to modeling errors. This yields robust and fast simulations where the size of the time step does not have to be adjusted to achieve a numerically stable simulation. The distributive nature of TLM makes it convenient for use in multi-core approaches and high speed simulations. The latest version of Hopsan was released in August 2002, but now the next generation of this simulation package is being developed. This paper presents the development version of Hopsan NG and discusses some of its features and possible uses.

    Place, publisher, year, edition, pages
    Oulu, Finland: , 2010
    Keywords
    Hopsan, TLM, transmission lines, distributed modeling, distributed solvers
    National Category
    Other Computer and Information Science
    Identifiers
    urn:nbn:se:liu:diva-60644 (URN)
    Conference
    Conference of Scandinavian Simulation Society, sims’10, 14th–15th October, Oulu, Finland
    Projects
    HiPO
    Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2018-08-02
  • 39.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Andersson, Bo
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    The Dynamic Properties of a Poppet Type Hydraulic Flow Amplifier2007In: 10th Scandinavian International Conference on Fluid Power, SICFP´07 / [ed] J. Vilenius and K. T. Koskinen, Tampere, Finland: Tampere University of Technology , 2007, p. 161-178Conference paper (Refereed)
    Abstract [en]

    This paper examines the dynamic properties of a two-stage flow control valve of the "Valvistor" brand. There are several benefits to this: the valve ha a high closed loop bandwidth, the design allows big flow capacities etc. An attractive feature of this two-stage valve is that the pilot flow contributes to the total flow giving higher steady state flow efficiency. This paper presents an analythical model of this particular type of valve. A simplified model with relevant approximations is also presented. Measurements on the valve were made to validate the valve model. The paper also includes a further discussion about the pros and cons of the valve in open and closed loop applications.

  • 40.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Larsson, Jonas
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    A Novel Valve Concept Including the Valvistor Poppet Valve2007In: The Tenth Scandinavian International Conference on Fluid Power / [ed] J. Vilenius and K. T. Koskinen, Tampere, Finland: Tampere University of Technology , 2007, p. 355-364Conference paper (Refereed)
    Abstract [en]

    These days, energy efficient mobile fluid power systems are of great interest. A mobile system containing several different cylinder drives supplied with a single load sensing pump (LS-pump) has a number of advantages as well as disadvantages. One fo the main advantages is the need of only one system pump. This makes the fluid power system compact and cost-effective. A challenge is to keep the hydraulic losses at a low level, especially losses at smaller loads. This paper introduces a fail-safe proportional valve element that is based on the Valvistor poppet valve. Due to the demands of flexibility the poppet valve is bi-directional. The valve has an innovative hydro-mechanic layout that makes it fail-safe, unwanted lowering loads, for example, never occur. The new valve includes simple sensors that are suitable for identificaiton of mode switches, e g between normal, differential and regenerative modes. It is also possible to manoevre the system with maintained velocity control in case of sensor failure. In a less complex system the concept has benefits as well. For example in systems where fail-safe bi-directional on/off valves are needed, then without mode sensing capabilities.

  • 41.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Larsson, Jonas
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Study on Individual Pressure Control in Energy Efficient Cylinder Drives2006In: 4th FPNI-Ph.D. Symphosium, FPNI’06, Sarasota, United States, 13th–17th June, 2006, M. Ivantysynova (ed.), 2006, p. 77-99Conference paper (Refereed)
    Abstract [en]

    This paper deals with energy efficient mobile valves with cylinder loads. In recent years, the need for energy efficient fluid power systems has increased. The reason is the increasing price of oil as well as tougher environmental regulations. One way of achieving an energy efficient directional valve is to use individually controlled meter-in and meter-out orifices and transfer functionality from hardware to the software controller. This type of solution makes it possible to keep metering losses low. Energy recovery is also made possible since both speed and lowest cylinder chamber pressure can be controlled. The challenge in such a controller is to decouple the chamber pressures in the MIMO (multi-input-multi-output) hydraulic system into independent SISO (single-input-single-output) systems. In this paper, a decoupling based on a linear analysis of the physical system has been implemented and tested in a cylinder position control application. The controller is evaluated in terms of performance and robustness. In the near future, this project will continue with other approaches as well, as there are several interesting control approaches available.

     

  • 42.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Nordin, Peter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Hopsan NG, A C++ Implementation using the TLM Simulation Technique2010In: Proceedings of The 51st Conference on Simulation and Modelling (SIMS2010), Oulu, Finland, 2010Conference paper (Refereed)
    Abstract [en]

    The Hopsan simulation package, used primarily for hydro-mechanical simulation, was first released in 1977. Modeling in Hopsan is based on a method using transmission line modeling, TLM. In TLM, component models are decoupled from each other through time delays. As components are decoupled and use distributed solvers, the simulation environment is suitable for distributed simulations. No numerical errors are introduced at simulation time when using TLM; all errors are related to modeling errors. This yields robust and fast simulations where the size of the time step does not have to be adjusted to achieve a numerically stable simulation. The distributive nature of TLM makes it convenient for use in multi-core approaches and high speed simulations. The latest version of Hopsan was released in August 2002, but now the next generation of this simulation package is being developed. This paper presents the development version of Hopsan NG and discusses some of its features and possible uses.

  • 43.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    How to handle auxiliary functions in energy efficient, single pump, flow sharing mobile systems2010In: 7th International Fluid Power Conference Aachen: Efficiency Through Fluid Power, Workshop Proceedings, Vol. 1 / [ed] Hubertus Murrenhoff, Aachen: Apprimus Wissenschafts Verlag , 2010, Vol. 1, p. 65-78Conference paper (Refereed)
    Abstract [en]

    Interest has increasingly shifted from load-sensing (pressure controlled) systems to flow controlled systems. In this paper an interesting configuration that uses pre-compensated valves with flow sharing properties is studied. The fundamental difference between a traditional load sensing (LS) system and a flow controlled system is that the pump is controlled based on the operator’s total flow demand rather than maintaining a certain margin pressure over the maximum load pressure. One of the main advantages with flow controlled systems is the absence of the feedback of the highest load pressure to the pump. Flow controlled systems also present some challenges, one being how to handle auxiliary functions with unknown flow demands. Auxiliary functions are typically support legs, external power takeouts etc. This paper analyses one kind of flow controlled system and shows one way of dealing with auxiliary functions.

  • 44.
    Eriksson, Björn
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Rösth, Marcus
    MCD Parker Hannifin AB.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    An LQ-Control Approach for Independent Metering Systems2009In: 11th Scandinavian International Conference on Fluid Power, SICFP'09, Linköping, Sweden, 2nd-4th June, Linköping, 2009Conference paper (Refereed)
    Abstract [en]

    This paper deals with the control of an individual metering fluid power system. There are a number of reasons to use individual metering technology, one is flexibility. In traditional valves there is a mechanical connection between the meter-in orifice and the meter-out orifice. By control this orifices individually one valve can be used in different applications without hard- ware modifications. Instead of change spool the software is changed. Since there are more control signals and thereby more outputs to control there is also an opportunity of improve- ments of the dynamics compared to a conventional system. In this paper an approach with LQ-technique is presented for improvements of system dynamics. Since all states in the sys- tem can not be measured a state observer is also considered in the control design. These work present simulations, implementations in a real world forwarder application and results from ve- rifying experiments.

  • 45.
    Filla, Reno
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    A Methodology for Modeling the Influence of Construction Machinery Operators on Productivity and Fuel Consumption2009In: Proceedings from the Human-Computer Interaction HCI International 2009, San Diego (CA), USA: Digital Human Modeling, Berlin / Heidelberg: Springer , 2009, p. 614-623Conference paper (Refereed)
    Abstract [en]

    This paper is concerned with modeling the actions of a human operator of construction machinery and integrating this operator model into a large, complex simulation model of the complete machine and its environment. Because human operators to a large degree affect how the machine is run, adaptive operator models are a necessity when the simulation goal is quantification and optimization of productivity and energy efficiency.

    Interview studies and test series have been performed to determine how professionals operate wheel loaders. Two models using different approaches were realized and integrated into a multi-domain model for dynamic simulation. The results are satisfactory and the methodology is easily usable for other, similar situations.

  • 46.
    Filla, Reno
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    An Event-driven Operator Model for Dynamic Simulation of Construction Machinery2005In: Proceedings form the Ninth Scandinavian International Conference on Fluid Power, Linköping, Sweden, 2005Conference paper (Other academic)
    Abstract [en]

    Prediction and optimisation of a wheel loader's dynamic behaviour is a challenge due to tightly coupled, non-linear subsystems of different technical domains. Furthermore, a simulation regarding performance, efficiency, and operability cannot be limited to the machine itself, but has to include operator, environment, and work task. This paper presents some results of our approach to an event-driven simulation model of a human operator. Describing the task and the operator model independently of the machine's technical parameters, gives the possibility to change whole sub-system characteristics without compromising the relevance and validity of the simulation.

  • 47.
    Filla, Reno
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Anläggningsmaskiner: Hydrauliksystem i multidomäna miljöer2003Conference paper (Other academic)
    Abstract [sv]

    I hjullastare och liknande maskiner konkurrerar arbetshydrauliken och drivlinan om dieselmotorns vridmoment. Balansen mellan dessa tre  system präglas av en hög dynamik, vilket är en avgörande skillnad mot vad som är fallet i person- och lastbilar. Bedömning av hur väl denna balans kan upprätthållas och kontrolleras är huvudpunkten i förarens subjektiva bedömning av en maskins körbarhet.

    I artikeln diskuteras möjligheter till en objektiv kvantifiering av körbarhet. En mätmetod presenteras samt nya sätt att visualisera denna så viktiga balans mellan maskinens delsystem.

  • 48.
    Filla, Reno
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology. Volvo Construction Equipment AB, Eskilstuna.
    Hybrid Power Systems for Construction Machinery: Aspects of System Design and Operability of Wheel Loaders2009In: ASME 2009 International Mechanical Engineering Congress and Exposition: Volume 13: New Developments in Simulation Methods and Software for Engineering Applications; Safety Engineering, Risk Analysis and Reliability Methods; Transportation Systems, The American Society of Mechanical Engineers (ASME) , 2009, Vol. 13, p. 611-620Conference paper (Refereed)
    Abstract [en]

    This paper will examine the wheel loader as a system with two parallel energy conversion systems that show a complex interaction with each other and with the power source. Using a systematic design approach, several principle design solutions for hybridization can be found.

    Furthermore, the human operator with his/her control actions needs to be considered as part of the total system. This paper will therefore also connect to results from ongoing and previous research into operator workload and operability.

  • 49.
    Filla, Reno
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems . Linköping University, The Institute of Technology.
    Operator and Machine Models for Dynamic Simulation of Construction Machinery2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    VIRTUAL PROTOTYPING has been generally adopted in product development in order to minimise the traditional reliance on testing of physical prototypes. It thus constitutes a major step towards solving the conflict of actual increasing development cost and time due to increasing customer demands on one side, and the need to decrease development cost and time due to increasing competition on the other. Particularly challenging for the off-road equipment industry is that its products, working machines, are complex in architecture. Tightly coupled, non-linear sub-systems of different technical domains make prediction and optimisation of the complete system’s dynamic behaviour difficult.

    Furthermore, in working machines the human operator is essential for the performance of the total system. Properties such as productivity, fuel efficiency, and operability are all not only dependent on inherent machine properties and working place conditions, but also on how the operator uses the machine. This is an aspect that is traditionally neglected in dynamic simulations, because the modelling needs to be extended beyond the technical system.

    The research presented in this thesis focuses on wheel loaders, which are representative for working machines. The technical system and the influence of the human operator is analysed, and so-called short loading cycles are described in depth. Two approaches to rule-based simulation models of a wheel loader operator are presented and used in simulations. Both operator models control the machine model by means of engine throttle, lift and tilt lever, steering wheel, and brake only – just as a human operator does. Also, only signals that a human operator can sense are used in the models. It is demonstrated that both operator models are able to adapt to basic variations in workplace setup and machine capability. Thus, a “human element” can be introduced into dynamic simulation of working machines, giving more relevant answers with respect to operator-influenced complete-machine properties such as productivity, fuel efficiency, and operability already in the concept phase of the product development process.

    List of papers
    1. Using Dynamic Simulation in the Development of Construction Machinery
    Open this publication in new window or tab >>Using Dynamic Simulation in the Development of Construction Machinery
    2003 (English)In: Proceedings from the Eighth Scandinavian International Conference on Fluid Power, Tampere, Finland, Vol. 1, May 7–9, 2003, p. 651-667Conference paper, Published paper (Other academic)
    Abstract [en]

    As in the car industry for quite some time, dynamic simulation of complete vehicles is being practiced more and more in the development of off-road machinery. However, specific questions arise due not only to company structure and size, but especially to the type of product. Tightly coupled, non-linear subsystems of different domains make prediction and optimisation of the complete system's dynamic behaviour a challenge. Furthermore, the demand for versatile machines leads to sometimes contradictory target requirements and can turn the design process into a hunt for the least painful compromise. This can be avoided by profound system knowledge, assisted by simulation-driven product development. This paper gives an overview of joint research into this issue by Volvo Wheel Loaders and Linkoping University on that matter, lists the results of a related literature review and introduces the term "operateability". Rather than giving detailed answers, the problem space for ongoing and future research is examined and possible solutions are sketched.

    Keywords
    simulation, complex systems, integrated product development
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13368 (URN)
    Conference
    The Eighth Scandinavian International Conference on Fluid Power, May 7-9, Tampere, Finland
    Available from: 2005-09-26 Created: 2005-09-26 Last updated: 2011-09-06Bibliographically approved
    2. Dynamic Simulation of Construction Machinery: Towards an Operator Model
    Open this publication in new window or tab >>Dynamic Simulation of Construction Machinery: Towards an Operator Model
    2005 (English)In: Proceedings from the IFPE 2005 Technical Conference, 2005, p. 429-438Conference paper, Published paper (Other academic)
    Abstract [en]

    In dynamic simulation of complete wheel loaders, one interesting aspect, specific for the working task, is the momentary power distribution between drive train and hydraulics, which is balanced by the operator. This paper presents the initial results to a simulation model of a human operator. Rather than letting the operator model follow a predefined path with control inputs at given points, it follows a collection of general rules that together describe the machine's working cycle in a generic way. The advantage of this is that the working task description and the operator model itself are independent of the machine's technical parameters. Complete sub-system characteristics can thus be changed without compromising the relevance and validity of the simulation. Ultimately, this can be used to assess a machine's total performance, fuel efficiency and operability already in the concept phase of the product development process.

    Keywords
    Simulation, construction machinery
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13369 (URN)
    Conference
    International Fluid Power Exhibition 2005 Technical Conference, March 16-18, Las Vegas, USA
    Available from: 2005-09-26 Created: 2005-09-26 Last updated: 2011-09-06Bibliographically approved
    3. An Event-driven Operator Model for Dynamic Simulation of Construction Machinery
    Open this publication in new window or tab >>An Event-driven Operator Model for Dynamic Simulation of Construction Machinery
    2005 (English)In: Proceedings form the Ninth Scandinavian International Conference on Fluid Power, Linköping, Sweden, 2005Conference paper, Published paper (Other academic)
    Abstract [en]

    Prediction and optimisation of a wheel loader's dynamic behaviour is a challenge due to tightly coupled, non-linear subsystems of different technical domains. Furthermore, a simulation regarding performance, efficiency, and operability cannot be limited to the machine itself, but has to include operator, environment, and work task. This paper presents some results of our approach to an event-driven simulation model of a human operator. Describing the task and the operator model independently of the machine's technical parameters, gives the possibility to change whole sub-system characteristics without compromising the relevance and validity of the simulation.

    Keywords
    Discrete simulation, continuous simulation, complex systems, operator model, driver model
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13370 (URN)
    Conference
    The Ninth Scandinavian International Conference on Fluid Power, Linköping, Sweden, June 1–3
    Available from: 2005-09-26 Created: 2005-09-26 Last updated: 2011-09-06Bibliographically approved
    4. Anläggningsmaskiner: Hydrauliksystem i multidomäna miljöer
    Open this publication in new window or tab >>Anläggningsmaskiner: Hydrauliksystem i multidomäna miljöer
    2003 (English)Conference paper, Published paper (Other academic)
    Abstract [sv]

    I hjullastare och liknande maskiner konkurrerar arbetshydrauliken och drivlinan om dieselmotorns vridmoment. Balansen mellan dessa tre  system präglas av en hög dynamik, vilket är en avgörande skillnad mot vad som är fallet i person- och lastbilar. Bedömning av hur väl denna balans kan upprätthållas och kontrolleras är huvudpunkten i förarens subjektiva bedömning av en maskins körbarhet.

    I artikeln diskuteras möjligheter till en objektiv kvantifiering av körbarhet. En mätmetod presenteras samt nya sätt att visualisera denna så viktiga balans mellan maskinens delsystem.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2003
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13371 (URN)
    Conference
    Hydraulikdagar 2003, Linköping, Sweden, June 3–4
    Available from: 2009-12-10 Created: 2009-02-11 Last updated: 2011-08-31Bibliographically approved
  • 50.
    Filla, Reno
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Ericsson, Allan
    Volvo Wheel Loaders AB.
    Palmberg, Jan-Ove
    Linköping University, Department of Management and Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    Dynamic Simulation of Construction Machinery: Towards an Operator Model2005In: Proceedings from the IFPE 2005 Technical Conference, 2005, p. 429-438Conference paper (Other academic)
    Abstract [en]

    In dynamic simulation of complete wheel loaders, one interesting aspect, specific for the working task, is the momentary power distribution between drive train and hydraulics, which is balanced by the operator. This paper presents the initial results to a simulation model of a human operator. Rather than letting the operator model follow a predefined path with control inputs at given points, it follows a collection of general rules that together describe the machine's working cycle in a generic way. The advantage of this is that the working task description and the operator model itself are independent of the machine's technical parameters. Complete sub-system characteristics can thus be changed without compromising the relevance and validity of the simulation. Ultimately, this can be used to assess a machine's total performance, fuel efficiency and operability already in the concept phase of the product development process.

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