Abstract: The energy-saving electrohydraulic flow matching (EFM) system opens up an opportunity to minimize valve losses by fully opening the control valves, but the controllability is lost under overrunning load conditions. To address this issue, this paper proposes a valve-based compensator to improve the controllability of the energy-saving EFM system. The valve-based compensator consists of a static compensator and a differential dynamic compensator based on load conditions. The energy efficiency, the stability performance, and the damping characteristic are analyzed under different control parameters. A parameter selection method is used to improve the efficiency, ensure the stability performance, and obtain good dynamic behavior. A test rig with a 2-t hydraulic excavator is built, and experimental tests are carried out to validate the proposed valve-based compensator. The experimental results indicate that the controllability of the EFM system is improved, and the characteristic of high energy efficiency is obtained by the proposed compensator.

基于阀补偿的电液流量匹配节能系统的动态性能改进

[1]Axin, M., 2013. Fluid Power Systems for Mobile Applications: with a Focus on Energy Efficiency and Dynamic Characteristics. Licentiate Thesis, Linköping University, Linköping, Sweden.

[2]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.

[3]Borghi, M., Zardin, B., Pintore, F., et al., 2014. Energy savings in the hydraulic circuit of agricultural tractors. Energy Procedia, 45:352-361.

[4]Cristofori, D., Vacca, A., Ariyur, K., 2012. A novel pressure-feedback based adaptive control method to damp instabilities in hydraulic machines. SAE International Journal on Commercial Vehicles, 5(2):586-596.

[5]Daher, N., Ivantysynova, M., 2015. Yaw stability control of articulated frame off-highway vehicles via displacement controlled steer-by-wire. Control Engineering Practice, 45:46-53.

[6]DeBoer, C.C., Yao, B., 2001. Velocity control of hydraulic cylinders with only pressure feedback. Proceedings of ASME International Mechanical Engineering Congress and Exposition.

[7]Du, C., Plummer, A., Johnston, N., 2016. Performance analysis of an energy-efficient variable supply pressure electro-hydraulic motion control system. Control Engineering Practice, 48:10-21.

[8]Ekoru, J.E., Pedro, J.O., 2013. Proportional-integral-derivative control of nonlinear half-car electro-hydraulic suspension systems. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 14(6):401-416.

[9]Finzel, R., Helduser, S., 2008. Energy-efficient electro-hydraulic control systems for mobile machinery/flow matching. Proceedings of the 6th International Fluid Power Conference.

[10]Garimella, P., Yao, B., 2002. Nonlinear adaptive robust observer for velocity estimation of hydraulic cylinders using pressure measurement only. Proceedings of ASME International Mechanical Engineering Congress and Exposition.

[11]Heikkilä, M., Linjama, M., 2013. Displacement control of a mobile crane using a digital hydraulic power management system. Mechatronics, 23(4):452-461.

[12]Heybroek, K., 2008. Saving Energy in Mobile Machinery Using Displacement Control Hydraulics: Concept Realization and Validation. PhD Thesis, Linköping University, Linköping, Sweden.

[13]Inderelst, M., Sgro, S., Murrenhoff, H., 2010. Energy recuperation in working hydraulics of excavators. The Bath/ASME Symposium on Fluid Power and Motion Control.

[14]Ketonen, M., Linjama, M., Huhtala, K., 2010. Retrofitting digital hydraulics–an analytical study. Proceedings of the 9th International Fluid Power Conference.

[15]Kim, D., Son, D.H., Jeon, D., 2012. Feed-system autotuning of a CNC machining center: rapid system identification and fine gain tuning based on optimal search. Precision Engineering, 36(2):339-348.

[16]Kogler, H., Scheidl, R., 2008. Two basic concepts of hydraulic switching converters. Proceedings of the 1st Workshop on Digital Fluid Power.

[17]Laamanen, M.S.A., Vilenius, M., 2003. Is it time for digital hydraulics? Proceedings of the 8th Scandinavian International Conference on Fluid Power.

[18]Lin, X., Pan, S., Wang, D., 2008. Dynamic simulation and optimal control strategy for a parallel hybrid hydraulic excavator. Journal of Zhejiang University-SCIENCE A, 9(5):624-632.

[19]Linjama, M., 2011. Digital fluid power: state of the art. Proceedings of the 12th Scandinavian International Conference on Fluid Power.

[20]Liu, W., 2011. Investigation into the Characteristics of Electrohydraulic Flow Matching Control Systems for Excavators. PhD Thesis, Zhejiang University, Hangzhou, China (in Chinese).

[21]Merrill, K.J., Holland, M.A., Lumkes, J.H., 2010. Efficiency analysis of a digital pump/motor as compared to a valve plate design. Proceedings of the 7th International Fluid Power Conference.

[22]Mettälä, K., Djurovic, M., Keuper, G., et al., 2007. Intelligent oil flow management with EFM: the potentials of electrohydraulic flow matching in tractor hydraulics. Proceedings of the 10th Scandinavian International Conference on Fluid Power, p.25-34.

[23]Minav, T.A., Laurila, L.I.E., Pyrhönen, J.J., 2013. Design and control of a closed-loop hydraulic energy-regenerative system. Automation in Construction, 30:144-150.

[24]Stelson, K.A., 2011. Saving the world’s energy with fluid power. Proceedings of the 8th JFPS Intentional Symposium on Fluid Power.

[25]Troxel, N.A., Yao, B., 2011. Hydraulic cylinder velocity control with energy recovery: a comparative simulation study. Proceedings of the ASME 2011 Dynamic Systems and Control Conference.

[26]Wang, T., Wang, Q., 2014. An energy-saving pressure-compensated hydraulic system with electrical approach. IEEE/ASME Transaction on Mechatronics, 19(2):570-578.

[27]Xu, B., Cheng, M., Yang, H., et al., 2015a. A hybrid displacement/pressure control scheme for an electrohydraulic flow matching system. IEEE/ASME Transaction on Mechatronics, 20(6):2771-2782.

[28]Xu, B., Sun, Y.H., Zhang, J.H., et al., 2015b. A new design method for the transition region of the valve plate for an axial piston pump. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 16(3):229-240.

[29]Xu, B., Ding, R.Q., Zhang, J.H., et al., 2015c. Pump/valves coordinate control of the independent metering system for mobile machinery. Automation in Construction, 57:98-111.

[30]Xu, B., Hu, M., Zhang, J.H., et al., 2016. Characteristics of volumetric losses and efficiency of axial piston pump with respect to displacement conditions. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 17(3):186-201.

[31]Yang, H.Y., Pan, M., 2015. Engineering research in fluid power: a review. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 16(6):427-442.

[32]Zaev, E., Rath, G., Kargl, H., et al., 2013. Energy efficient active vibration damping. Proceedings of the 13th Scandinavian International Conference on Fluid Power.