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  • 1.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Parker Hannifin, Borås, Sweden.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    A Flexible Working Hydraulic System for Mobile Machines2016Ingår i: International Journal of Fluid Power, ISSN 1439-9776, Vol. 17, nr 2, s. 79-89Artikel i tidskrift (Övrigt vetenskapligt)
    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.

  • 2.
    Axin, Mikael
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Arbetshydraulik i mobila maskiner2015Konferensbidrag (Refereegranskat)
    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.

  • 3.
    Axin, Mikael
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Mobile Working Hydraulic System Dynamics2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

    Delarbeten
    1. Flow versus pressure control of pumps in mobile hydraulic systems
    Öppna denna publikation i ny flik eller fönster >>Flow versus pressure control of pumps in mobile hydraulic systems
    2014 (Engelska)Ingår i: Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, ISSN 0959-6518, E-ISSN 2041-3041, Vol. 228, nr 4, s. 245-256Artikel i tidskrift (Refereegranskat) 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.

    Ort, förlag, år, upplaga, sidor
    Sage Publications, 2014
    Nyckelord
    Hydraulics, flow control, load-sensing, mobile systems, energy efficiency, dynamic characteristics, compensators
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-105796 (URN)10.1177/0959651813512820 (DOI)000333799100005 ()
    Tillgänglig från: 2014-04-07 Skapad: 2014-04-07 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    2. Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems
    Öppna denna publikation i ny flik eller fönster >>Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems
    2011 (Engelska)Ingår i: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: Volume 2 / [ed] Harri Sairiala & Kari T. Koskinen, 2011, s. 223-238Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Nyckelord
    Flow control, load sensing, dynamic analysis, stability, damping
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-68636 (URN)978-952-15-2519-3 (ISBN)
    Konferens
    The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, May 18-20, 2011 Tampere, Finland
    Tillgänglig från: 2011-05-25 Skapad: 2011-05-25 Senast uppdaterad: 2015-09-07
    3. Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification
    Öppna denna publikation i ny flik eller fönster >>Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification
    2012 (Engelska)Ingår i: 8th International Fluid Power Conference Dresden: "Fluid Power Drives!", 2012, Vol. 1, s. 579-591Konferensbidrag, Enbart muntlig presentation (Övrigt vetenskapligt)
    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.

    Nyckelord
    Damping, compensator, outlet orifice, efficiency
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-76878 (URN)
    Konferens
    8th International Fluid Power Conference, March 26 - 28, 2012, Dresden
    Tillgänglig från: 2012-04-23 Skapad: 2012-04-23 Senast uppdaterad: 2015-09-07
    4. A Hybrid of Pressure and Flow Control in Mobile Hydraulic Systems
    Öppna denna publikation i ny flik eller fönster >>A Hybrid of Pressure and Flow Control in Mobile Hydraulic Systems
    2014 (Engelska)Ingår i: 9th InternationalFluid Power Conference (IFK). Vol. 1. Aachen, Germany, 24-26 March 2014 / [ed] Hubertus Murrenhoff, 2014, s. 190-201Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Nyckelord
    Mobile hydraulics, pressure control, flow control, energy efficiency, dynamics
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-105794 (URN)978-3-9816480-0-3 (ISBN)
    Konferens
    9th International Fluid Power Conference (IFK), 24-26 March 2014, Aachen, Germany
    Tillgänglig från: 2014-04-07 Skapad: 2014-04-07 Senast uppdaterad: 2015-09-07Bibliografiskt granskad
    5. Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics
    Öppna denna publikation i ny flik eller fönster >>Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics
    2014 (Engelska)Ingår i: 9th JFPS International Symposium on Fluid Power. Matsue, Japan, 28-31 October 2014, The Japan Fluid Power System Society , 2014, s. 452-459Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
    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.

    Ort, förlag, år, upplaga, sidor
    The Japan Fluid Power System Society, 2014
    Nyckelord
    Mobile hydraulics, energy efficiency, dynamics, damping
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-111819 (URN)4-931070-10-8 (ISBN)
    Konferens
    9th JFPS International Symposium on Fluid Power, Shimane, Japan, 28-31 October 2014
    Tillgänglig från: 2014-11-04 Skapad: 2014-11-04 Senast uppdaterad: 2016-05-17Bibliografiskt granskad
    6. A Flexible Working Hydraulic System for Mobile Machines
    Öppna denna publikation i ny flik eller fönster >>A Flexible Working Hydraulic System for Mobile Machines
    2016 (Engelska)Ingår i: International Journal of Fluid Power, ISSN 1439-9776, Vol. 17, nr 2, s. 79-89Artikel i tidskrift (Övrigt vetenskapligt) 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.

    Ort, förlag, år, upplaga, sidor
    Taylor & Francis, 2016
    Nyckelord
    Mobile hydraulics, dynamics, energy efficiency, pump controller
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-121068 (URN)10.1080/14399776.2016.1141635 (DOI)
    Tillgänglig från: 2015-09-04 Skapad: 2015-09-04 Senast uppdaterad: 2017-12-04Bibliografiskt granskad
  • 4.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    A Hybrid of Pressure and Flow Control in Mobile Hydraulic Systems2014Ingår i: 9th InternationalFluid Power Conference (IFK). Vol. 1. Aachen, Germany, 24-26 March 2014 / [ed] Hubertus Murrenhoff, 2014, s. 190-201Konferensbidrag (Refereegranskat)
    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.

  • 5.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics2014Ingår i: 9th JFPS International Symposium on Fluid Power. Matsue, Japan, 28-31 October 2014, The Japan Fluid Power System Society , 2014, s. 452-459Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 6.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Flow versus pressure control of pumps in mobile hydraulic systems2014Ingår i: Proceedings of the Institution of mechanical engineers. Part I, journal of systems and control engineering, ISSN 0959-6518, E-ISSN 2041-3041, Vol. 228, nr 4, s. 245-256Artikel i tidskrift (Refereegranskat)
    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.

  • 7.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Design Rules for High Damping in Mobile Hydraulic Systems2013Ingår i: 13th Scandinavian International Conference on Fluid Power, Linköping University Electronic Press, 2013, s. 13-20Konferensbidrag (Refereegranskat)
    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

  • 8.
    Axin, Mikael
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Fluid Power Systems for Mobile Applications: with a Focus on Energy Efficiency and Dynamic Characteristics2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

    Delarbeten
    1. Energy Efficient Load Adapting System Without Load Sensing: Design and Evaluation
    Öppna denna publikation i ny flik eller fönster >>Energy Efficient Load Adapting System Without Load Sensing: Design and Evaluation
    2009 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Ort, förlag, år, upplaga, sidor
    Linköping: , 2009
    Nyckelord
    fluid power, mobile systems, LS systems, pre compensation, energy efficiency, flow sharing
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-52691 (URN)
    Konferens
    11th Scandinavian International Conference on Fluid Power, SICFP'09, June 2-4, Linköping, Sweden
    Tillgänglig från: 2010-01-08 Skapad: 2010-01-08 Senast uppdaterad: 2015-08-31Bibliografiskt granskad
    2. Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems
    Öppna denna publikation i ny flik eller fönster >>Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems
    2011 (Engelska)Ingår i: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: Volume 2 / [ed] Harri Sairiala & Kari T. Koskinen, 2011, s. 223-238Konferensbidrag, Publicerat paper (Refereegranskat)
    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.

    Nyckelord
    Flow control, load sensing, dynamic analysis, stability, damping
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-68636 (URN)978-952-15-2519-3 (ISBN)
    Konferens
    The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11, May 18-20, 2011 Tampere, Finland
    Tillgänglig från: 2011-05-25 Skapad: 2011-05-25 Senast uppdaterad: 2015-09-07
    3. Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification
    Öppna denna publikation i ny flik eller fönster >>Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification
    2012 (Engelska)Ingår i: 8th International Fluid Power Conference Dresden: "Fluid Power Drives!", 2012, Vol. 1, s. 579-591Konferensbidrag, Enbart muntlig presentation (Övrigt vetenskapligt)
    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.

    Nyckelord
    Damping, compensator, outlet orifice, efficiency
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-76878 (URN)
    Konferens
    8th International Fluid Power Conference, March 26 - 28, 2012, Dresden
    Tillgänglig från: 2012-04-23 Skapad: 2012-04-23 Senast uppdaterad: 2015-09-07
  • 9.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Palmberg, Jan-Ove
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Optimized Damping in Cylinder Drives Using the Meter-out Orifice: Design and Experimental Verification2012Ingår i: 8th International Fluid Power Conference Dresden: "Fluid Power Drives!", 2012, Vol. 1, s. 579-591Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 10.
    Axin, Mikael
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Ökad dämpning genom rätt design av utloppsstrypningen2012Ingår i: Hydraulikdagarna 2012, Linköping, 2012Konferensbidrag (Refereegranskat)
    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.

  • 11.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Palmberg, Jan-Ove
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska högskolan.
    Dynamic Analysis of Single Pump, Flow Controlled Mobile Systems2011Ingår i: The Twelfth Scandinavian International Conference on Fluid Power, SICFP'11: Volume 2 / [ed] Harri Sairiala & Kari T. Koskinen, 2011, s. 223-238Konferensbidrag (Refereegranskat)
    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.

  • 12.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Braun, Robert
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Dell'Amico, Alessandro
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Nordin, Peter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Pettersson, Karl
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Staack, Ingo
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Krus, Petter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Next Generation Simulation Software using Transmission Line Elements2010Ingår i: Fluid Power and Motion Control / [ed] Dr D N Johnston and Professor A R Plummer, Centre for Power Transmission and Motion Control , 2010, s. 265-276Konferensbidrag (Refereegranskat)
    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.

  • 13.
    Axin, Mikael
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Palmberg, Jan-Ove
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluid och mekanisk systemteknik. Linköpings universitet, Tekniska högskolan.
    Energy Efficient Load Adapting System Without Load Sensing: Design and Evaluation2009Konferensbidrag (Refereegranskat)
    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.

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