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Axin, M., Eriksson, B. & Krus, P. (2016). A Flexible Working Hydraulic System for Mobile Machines. International Journal of Fluid Power, 17(2), 79-89
Open this publication in new window or tab >>A Flexible Working Hydraulic System for Mobile Machines
2016 (English)In: International Journal of Fluid Power, ISSN 1439-9776, Vol. 17, no 2, p. 79-89Article in journal (Other academic) Published
Abstract [en]

This paper proposes a novel working hydraulic system architecture for mobile machines. Load sensing, flow control and open-centre are merged into a generalized system description. The proposed system is configurable and the operator can realize the characteristics of any of the standard systems without compromising energy efficiency. This can be done non-discretely on-the-fly. One electrically controlled variable displacement pump supplies the system and conventional closed-centre spool valves are used. The pump control strategies are explained in detail. Experimental results demonstrate one solution to the flow matching problem and the static and dynamic differences between different control modes.

Place, publisher, year, edition, pages
Taylor & Francis, 2016
Keywords
Mobile hydraulics, dynamics, energy efficiency, pump controller
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-121068 (URN)10.1080/14399776.2016.1141635 (DOI)
Available from: 2015-09-04 Created: 2015-09-04 Last updated: 2017-12-04Bibliographically approved
Axin, M., Eriksson, B. & Krus, P. (2014). A Hybrid of Pressure and Flow Control in Mobile Hydraulic Systems. In: Hubertus Murrenhoff (Ed.), 9th InternationalFluid Power Conference (IFK). Vol. 1. Aachen, Germany, 24-26 March 2014: . Paper presented at 9th International Fluid Power Conference (IFK), 24-26 March 2014, Aachen, Germany (pp. 190-201).
Open this publication in new window or tab >>A Hybrid of Pressure and Flow Control in Mobile Hydraulic Systems
2014 (English)In: 9th InternationalFluid Power Conference (IFK). Vol. 1. Aachen, Germany, 24-26 March 2014 / [ed] Hubertus Murrenhoff, 2014, p. 190-201Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a hybrid pump controller approach for mobile hydraulic systems, influenced by both pressure and flow. The controller is tuneable to be able to set the order of importance of the pressure and flow controller, respectively. It is thus possible to realize a load sensing system, a flow control system or a mix of the two. Using a low load pressure feedback gain and a high flow control gain, a system emerges with high energy efficiency, fast system response, high stability margins and no flow matching issues. In this paper, both theoretical studies and practical implementations demonstrate the capability of a hybrid pump control approach.

Keywords
Mobile hydraulics, pressure control, flow control, energy efficiency, dynamics
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-105794 (URN)978-3-9816480-0-3 (ISBN)
Conference
9th International Fluid Power Conference (IFK), 24-26 March 2014, Aachen, Germany
Available from: 2014-04-07 Created: 2014-04-07 Last updated: 2015-09-07Bibliographically approved
Axin, M., Eriksson, B. & Krus, P. (2014). Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics. In: 9th JFPS International Symposium on Fluid Power. Matsue, Japan, 28-31 October 2014: . Paper presented at 9th JFPS International Symposium on Fluid Power, Shimane, Japan, 28-31 October 2014 (pp. 452-459). The Japan Fluid Power System Society
Open this publication in new window or tab >>Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics
2014 (English)In: 9th JFPS International Symposium on Fluid Power. Matsue, Japan, 28-31 October 2014, The Japan Fluid Power System Society , 2014, p. 452-459Conference paper, Published paper (Other academic)
Abstract [en]

This paper presents a flexible and energy efficient system solution which mimics the behaviour of an open-centre system. An electro-hydraulic variable displacement pump and closed-centre valves are used. Instead of having a flow in the open-centre gallery, that flow is calculated using a pressure sensor and a valve model. The variable pump is then controlled in order to only deliver the flow that would go to the actual loads. It is also possible for the operator to decide how much load dependency there should be. The extreme case is not having any load dependency at all, resulting in a system where the pump displacement setting is controlled according to the sum of all requested load flows. It is thus possible to realize a system design with open-centre characteristics, a flow control system or something in between. Each operator can thereby get their optimal control characteristic while having high energy efficiency.

Place, publisher, year, edition, pages
The Japan Fluid Power System Society, 2014
Keywords
Mobile hydraulics, energy efficiency, dynamics, damping
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-111819 (URN)4-931070-10-8 (ISBN)
Conference
9th JFPS International Symposium on Fluid Power, Shimane, Japan, 28-31 October 2014
Available from: 2014-11-04 Created: 2014-11-04 Last updated: 2016-05-17Bibliographically approved
Axin, M., Eriksson, B. & Krus, P. (2014). Flow versus pressure control of pumps in mobile hydraulic systems. Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, 228(4), 245-256
Open this publication in new window or tab >>Flow versus pressure control of pumps in mobile hydraulic systems
2014 (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. 228, no 4, p. 245-256Article in journal (Refereed) Published
Abstract [en]

This work studies an innovative working hydraulic system design for mobile applications, referred to as flow control. The fundamental difference compared to load-sensing systems is that the pump is controlled based on the operator’s command signals rather than feedback signals from the loads. This control approach enables higher energy efficiency since the pressure difference between pump and load is given by the system resistance rather than a prescribed pump pressure margin. Furthermore, load-sensing systems suffer from poor dynamic characteristics since the pump is operated in a closed-loop control mode. This might result in an oscillatory behaviour. Flow control systems have no stability issues attached to the load pressure feedback since there is none. This allows the pump to be designed to meet the response requirements without considering system stability. Pressure compensators are key components in flow control systems. This study addresses the flow matching problem which occurs when using traditional compensators in combination with a flow-controlled pump. Flow sharing pressure compensators solve this problem since the pump flow will be distributed between all active functions. Simulation results and measurements on a wheel loader application demonstrate the energy-saving potentials and the dynamic improvements for the flow control system.

Place, publisher, year, edition, pages
Sage Publications, 2014
Keywords
Hydraulics, flow control, load-sensing, mobile systems, energy efficiency, dynamic characteristics, compensators
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-105796 (URN)10.1177/0959651813512820 (DOI)000333799100005 ()
Available from: 2014-04-07 Created: 2014-04-07 Last updated: 2017-12-05Bibliographically approved
Krus, P., Braun, R., Nordin, P. & Eriksson, B. (2012). Aircraft System Simulation for Preliminary Design. In: Professor I Grant (Ed.), ICAS 2012 CD-ROM PROCEEDINGS: . Paper presented at 28th International Congress of the Aeronautical Sciences, Brisbane, Australia, 23 - 28 September, 2012 (pp. Art.nr. ICAS2012-1.9.3). Optimage Ltd
Open this publication in new window or tab >>Aircraft System Simulation for Preliminary Design
2012 (English)In: ICAS 2012 CD-ROM PROCEEDINGS / [ed] Professor I Grant, Optimage Ltd , 2012, p. Art.nr. ICAS2012-1.9.3-Conference paper, Published paper (Other academic)
Abstract [en]

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

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

Place, publisher, year, edition, pages
Optimage Ltd, 2012
Keywords
aircraft conceptual design, sy stem modeling, mission simulation
National Category
Software Engineering
Identifiers
urn:nbn:se:liu:diva-121484 (URN)978-0-9565333-1-9 (ISBN)
Conference
28th International Congress of the Aeronautical Sciences, Brisbane, Australia, 23 - 28 September, 2012
Funder
VINNOVA
Available from: 2015-09-22 Created: 2015-09-22 Last updated: 2018-01-11Bibliographically approved
Ericson, L., Eriksson, B., Dell'Amico, A. & Krus, P. (2011). An Electric Hydraulic Hybrid Light Vehicle with Energy Recovery. In: 52nd National Conference on Fluid Power: . Paper presented at 52nd National Conference on Fluid Power, Las Vegas, Nevada, USA, Mars 23-25, 2011 (pp. 741-749). Las
Open this publication in new window or tab >>An Electric Hydraulic Hybrid Light Vehicle with Energy Recovery
2011 (English)In: 52nd National Conference on Fluid Power, Las, 2011, p. 741-749Conference paper, Published paper (Refereed)
Abstract [en]

A three wheeled electric hydraulic hybrid vehicle with tiltingbody was built and tested at Linköping University as a partof a student project. The goal of the student project wasto design and fabricate an environmentally friendly vehicleto enter the Formula ATA Electric & Hybrid Italy 2009 competition.The design of the vehicle was based on the rulesand requirements of the competition. The vehicle was alsoprepared for a hydraulic recovery system which was laterimplemented on the vehicle. Hydraulic motor/pump unitsare used to brake and recover energy and to provide additionalboost during acceleration. The energy recovery storageis hydraulic gas accumulators, while the primary propulsionsystem is electrical with Li-Fe batteries. Gas accumulatorshave very high power density superior to electricalbatteries.In this paper, the design of the hydraulic recovery system isdescribed along with simulation and experimental results.The concept shows high potential and the tests show a20 % recovery of the kinetic energy by the hydraulic systemfor a given cycle.

Place, publisher, year, edition, pages
Las: , 2011
Series
52nd National Conference on Fluid Power ; 52
Keywords
Hybrid Vehicle, Fluid Power, Hydraulic
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-67481 (URN)0-942220-49-8 (ISBN)
Conference
52nd National Conference on Fluid Power, Las Vegas, Nevada, USA, Mars 23-25, 2011
Available from: 2011-04-14 Created: 2011-04-14 Last updated: 2017-12-20
Axin, M., Eriksson, B., Palmberg, J.-O. & Krus, P. (2011). Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems. In: Harri Sairiala & Kari T. Koskinen (Ed.), The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: Volume 2. Paper presented at The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, May 18-20, 2011 Tampere, Finland (pp. 223-238).
Open this publication in new window or tab >>Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems
2011 (English)In: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: Volume 2 / [ed] Harri Sairiala & Kari T. Koskinen, 2011, p. 223-238Conference paper, Published paper (Refereed)
Abstract [en]

Interest has increased in flow controlled systems in the field of mobile fluid power. The capital distinction between traditional load-sensing (LS) systems and flow controlled systems is that the pump is controlled based on the operator’s total flow demand rather than maintaining a certain pressure margin over the maximum load pressure. One of the main advantages of flow controlled systems is the absence of the feedback of the highest load pressure to the pump controller. In this paper, a dynamic analysis is performed where flow controlled and LS systems are compared. It is shown how instability can occur in LS systems due to the pump controller and proven that no such instability properties are present in flow controlled systems. A drawback with one type of flow controlled system is that the highest load dynamically will disturb the lighter loads. This paper shows a novel way to optimize the damping in such systems by controlling the opening position of the directional valve independently of the flow. The mentioned disturbance between the highest load to the others can thereby be reduced.

Keywords
Flow control, load sensing, dynamic analysis, stability, damping
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-68636 (URN)978-952-15-2519-3 (ISBN)
Conference
The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, May 18-20, 2011 Tampere, Finland
Available from: 2011-05-25 Created: 2011-05-25 Last updated: 2015-09-07
Braun, R., Nordin, P., Eriksson, B. & Krus, P. (2011). High Performance System Simulation Using Multiple Processor Cores. In: Harri Sairiala & Kari T. Koskinen (Ed.), The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: . Paper presented at The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, 18th–20th May, Tampere, Finland.
Open this publication in new window or tab >>High Performance System Simulation Using Multiple Processor Cores
2011 (English)In: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11 / [ed] Harri Sairiala & Kari T. Koskinen, 2011Conference paper, Published paper (Refereed)
Abstract [en]

Future research and development will depend on high-speed simulations, especially for large and complex systems. Rapid prototyping, optimization and real-time simulations require  simulation tools that can take full advantage of  computer hardware.  Recent developments  in the computer market indicate  a change in focus from increasing the speed of processor cores towards increasing the number of cores in each processor. HOPSAN is a simulation tool for fluid power and mechatronics, developed at Linköping University. It  is based upon the transmission line  modeling  (TLM)  technique. This method is very suitable for taking advantage of multi-core  processors.  This paper presents  the  implementation  of multi-core support in the next generation of HOPSAN. The concept is to divide the  model  into equally sized  groups of  independent components,  to make it possible to  simulate  them  in separate threads. Reducing overhead costs and finding an effective sorting algorithm constitute  critical steps for maximizing the benefits.  Experimental results show  a significant reduction in simulation time. Improvement of algorithms in combination with a continuous increase in the number of processor cores can potentially  lead to further  increases  in simulation performance. 

Keywords
Multi-core, simulation, transmission line element method, transmission line modelling, fluid power, system simulation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-68373 (URN)978-952-15-2517-9 (ISBN)978-952-15-2520-9 (ISBN)978-952-15-3273-3 (ISBN)
Conference
The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, 18th–20th May, Tampere, Finland
Available from: 2011-05-23 Created: 2011-05-23 Last updated: 2016-04-07
Eriksson, B. & Palmberg, J.-O. (2011). Individual Metering Fluid Power Systems: Challenges and Opportunities. Paper presented at Proceedings of the Sixth International Fluid Power Conference, IFK’08, March 31 - April 2, Dresden, Gemany. Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, 225(12), 196-211
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
Eriksson, B., Nordin, P. & Krus, P. (2010). Hopsan NG, A C++ Implementation using the TLM Simulation Technique. In: sko Juuso (Ed.), SIMS 2010 Proceedings, The 51st Conference on Simulation and Modelling, 14-15 October 2010 Oulu, Finland: . Paper presented at Conference of Scandinavian Simulation Society, sims’10, 14th–15th October, Oulu, Finland. Oulu, Finland
Open this publication in new window or tab >>Hopsan NG, A C++ Implementation using the TLM Simulation Technique
2010 (English)In: SIMS 2010 Proceedings, The 51st Conference on Simulation and Modelling, 14-15 October 2010 Oulu, Finland / [ed] sko Juuso, 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)9789525183429 (ISBN)
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: 2018-10-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6371-1390

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