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Axin, Mikael
Publications (10 of 13) Show all publications
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. (2015). Arbetshydraulik i mobila maskiner. In: : . Paper presented at Hydraulikdagarna 2015, 16-17 March, Linköping University, Linköping, Sweden.
Open this publication in new window or tab >>Arbetshydraulik i mobila maskiner
2015 (Swedish)Conference paper, Published paper (Refereed)
Abstract [sv]

I mobila maskiner finns en mängd olika systemtyper för arbetshydrauliken. Det vanligaste är fortfarande det kostnadseffektivaoch robusta öppet-centrum systemet med fast pump. Det ger operatören en mjuk styrning med hög dämpning. Ennackdel är dock den låga energieffektiviteten. Under de senaste decennierna har det lastkännande systemet blivit mer ochmer populärt. Energieffektiviteten i detta system är högre även om tryck och flöde varierar stort över tid och mellan olikafunktioner. En nackdel är dock att systemets dämpning är låg. Det finns ett antal olika systemtyper som kombinerar en mjukstyrning med relativt hög energieffektivitet. Nyckeln är att begränsa flödet genom det öppna centrumet i riktningsventilen.Detta kan göras med en variabel tryckstyrd pump som regleras så att öppet-centrum flödet hålls på en konstant nivå. Alternativetär en flödesstyrd pump som styrs direkt från operatörens joystickkommandon eller via flödet i det öppna centrumet. Iden här artikeln görs en jämförande analys av olika systemtyper för arbetshydrauliken i mobila maskiner. Fokus ligger påenergieffektivitet, dynamiska egenskaper och pumpreglering. En genomgång av mer avancerade systemtyper såsom individuellastrypställen och pumpstyrda aktuatorer har också gjorts.

Keywords
Mobila maskiner, arbetshydraulik, systemtyper, energieffektivitet, dynamik, reglering
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-116640 (URN)
Conference
Hydraulikdagarna 2015, 16-17 March, Linköping University, Linköping, Sweden
Available from: 2015-03-30 Created: 2015-03-30 Last updated: 2015-09-07Bibliographically approved
Axin, M. (2015). Mobile Working Hydraulic System Dynamics. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Mobile Working Hydraulic System Dynamics
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis deals with innovative working hydraulic systems for mobile machines. Flow control systems are studied as an alternative to load sensing. The fundamental difference 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 and there is no load pressure feedback causing stability issues. Experimental results show a reduced pump pressure margin and energy saving potential for a wheel loader application.

The damping contribution from the inlet and outlet orifice in directional valves is studied. Design rules are developed and verified by experiments.

A novel system architecture is proposed where flow control, load sensing 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. Experiments show that it is possible to avoid unnecessary energy losses while improving system response and increasing stability margins compared to load sensing. Static and dynamic differences between different control modes are also demonstrated experimentally.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015. p. 85
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1697
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-121070 (URN)10.3384/diss.diva-121070 (DOI)978-91-7685-971-1 (ISBN)
Public defence
2015-10-02, A35, A-huset, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2015-09-07 Created: 2015-09-04 Last updated: 2015-09-08Bibliographically 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
Axin, M. & Krus, P. (2013). Design Rules for High Damping in Mobile Hydraulic Systems. In: 13th Scandinavian International Conference on Fluid Power: . Paper presented at 13th Scandinavian International Conference on Fluid Power, June 3-5, 2013, Linköping, Sweden (pp. 13-20). Linköping University Electronic Press
Open this publication in new window or tab >>Design Rules for High Damping in Mobile Hydraulic Systems
2013 (English)In: 13th Scandinavian International Conference on Fluid Power, Linköping University Electronic Press, 2013, p. 13-20Conference paper, Published paper (Refereed)
Abstract [en]

This paper analyses the damping in pressure compensated closed centre mobile working hydraulic systems. Both rotational and linear loads are covered and the analysis applies to any type of pump controller. Only the outlet orifice in the directional valve will provide damping to a pressure compensated system. Design rules are proposed for how the system should be dimensioned in order to obtain a high damping. The volumes on each side of the load have a high impact on the damping. In case of a small volume on the inlet side, the damping becomes low. However, the most important thing is to design the outlet orifice area properly. There exists an optimal orifice dimension for maximized damping; both smaller and larger orifice areas give lower damping independently of the volumes. This paper presents a method to dimension the outlet orifice area and the load volumes in order to obtain a desired system damping. Experimental results, which confirm the theoretical expectations, are also presented. The conclusions are that it is possible to obtain a high damping contribution from the outlet orifice if the system is dimensioned correctly. However, the energy efficiency needs to be considered while improving the damping

Place, publisher, year, edition, pages
Linköping University Electronic Press, 2013
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 92
Keywords
Damping, compensator, outlet orifice, efficiency
National Category
Other Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-100122 (URN)10.3384/ecp1392a2 (DOI)978-91-7519-572-8 (ISBN)
Conference
13th Scandinavian International Conference on Fluid Power, June 3-5, 2013, Linköping, Sweden
Available from: 2013-10-28 Created: 2013-10-28 Last updated: 2018-01-23Bibliographically approved
Axin, M. (2013). Fluid Power Systems for Mobile Applications: with a Focus on Energy Efficiency and Dynamic Characteristics. (Licentiate dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Fluid Power Systems for Mobile Applications: with a Focus on Energy Efficiency and Dynamic Characteristics
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis studies an innovative working hydraulic system design for mobile applications. The purpose is to improve the energy efficiency and the dynamic characteristics compared to load sensing systems without increasing the complexity or adding additional components.

The system analysed in this thesis is 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. High power savings are possible especially at medium flow rates.

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.

Pressure compensators are key components in flow control systems. This thesis addresses the flow matching problem which occurs when using conventional 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. A novel control approach where the directional valve is controlled without affecting the cylinder velocity with the objective of optimizing the damping is proposed.

In this research, both theoretical studies and practical implementations demonstrate the capability of flow control systems. Experiments show a reduced pump pressure margin and energy saving possibilities in a short loading cycle for a wheel loader application.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. p. 59
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1595
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-92578 (URN)LIU-TEK-LIC-2013:29 (Local ID)978-91-7519-600-8 (ISBN)LIU-TEK-LIC-2013:29 (Archive number)LIU-TEK-LIC-2013:29 (OAI)
Presentation
2013-05-17, ACAS, A-huset, Campus Valla, Linköpings universitet, Linköping, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2013-05-22 Created: 2013-05-13 Last updated: 2013-06-25Bibliographically approved
Axin, M., Palmberg, J.-O. & Krus, P. (2012). Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification. In: 8th International Fluid Power Conference Dresden: "Fluid Power Drives!". Paper presented at 8th International Fluid Power Conference, March 26 - 28, 2012, Dresden (pp. 579-591). , 1
Open this publication in new window or tab >>Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification
2012 (English)In: 8th International Fluid Power Conference Dresden: "Fluid Power Drives!", 2012, Vol. 1, p. 579-591Conference paper, Oral presentation only (Other academic)
Abstract [en]

This paper analyses the damping of a flow controlled cylinder with a mass load and an outlet orifice. By using linear models, a mathematical expression for the damping is derived. It is shown that the volumes on each side of the piston have a high impact on the damping. In case of a small volume on the inlet side, the damping becomes low. However, the most important thing is to design the outlet orifice area properly. There exists an optimal orifice dimension; both smaller and larger orifice areas give low damping independently of the size of the volumes. In this paper a design is proposed of the outlet orifice area that optimizes the damping of the system. Experimental results which confirm the theoretical expectations are also presented. The conclusions are that without an outlet orifice, the hydraulic system will not contribute with any damping at all. Furthermore, large dead volumes in the cylinder will increase the damping, but at the expense of the system’s efficiency.

Keywords
Damping, compensator, outlet orifice, efficiency
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-76878 (URN)
Conference
8th International Fluid Power Conference, March 26 - 28, 2012, Dresden
Available from: 2012-04-23 Created: 2012-04-23 Last updated: 2015-09-07
Axin, M. (2012). Ökad dämpning genom rätt design av utloppsstrypningen. In: Hydraulikdagarna 2012. Paper presented at Hydraulikdagarna 2012. Linköping
Open this publication in new window or tab >>Ökad dämpning genom rätt design av utloppsstrypningen
2012 (Swedish)In: Hydraulikdagarna 2012, Linköping, 2012Conference paper, Oral presentation only (Refereed)
Abstract [sv]

Svängningar är ett vanligt förekommande problem i hydrauliska system. Den här artikeln analyserar dämpningen i ett system bestående av en tryckkompenserad ventil, en cylinder samt en last. Genom att designa utloppsstrypningen i ventilen på ett bra sätt kan en hög dämpning erhållas. Resultaten som presenteras i den här artikeln kan ligga till grund vid systemdimensionering för att erhålla önskad dämpning i tryckkompenserade hydraulsystem. Volymerna på respektive sida av cylinderkolven har stor inverkan på dämpningen. Om inloppsvolymen är liten blir dämpningen låg. Det absolut viktigaste är dock att designa utloppsstrypningen på ett bra sätt. En optimal öppningsarea existerar; både mindre och större area ger lägre dämpning. I den här artikeln föreslås en design av utloppsstrypningen som optimerar dämpningen i det mest ogynnsamma fallet samtidigt som förlusterna över strypningen hålls relativt små. Experimentella resultat som bekräftar de teoretiska förväntningarna presenteras också.

Place, publisher, year, edition, pages
Linköping: , 2012
Keywords
Dämpning, utloppsstrypning, experimentella resultat, förlustanalys
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-76882 (URN)
Conference
Hydraulikdagarna 2012
Available from: 2012-06-13 Created: 2012-04-23 Last updated: 2012-06-13Bibliographically approved
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