直接泵控系统比阀控系统具有很大节能优势和应用前景，但泵控差动缸现有技术都不理想，采用非对称泵平衡差动缸不对称流量是一种有效的解决方案。基于非对称定量泵，提出一种非对称变量泵VAPP （Variable-displacement asymmetric axial piston pump）。采用伺服比例阀和与斜盘固定连接的角位移传感器组成闭环控制方式对VAPP斜盘倾角进行控制，实现VAPP的变量输出。仿真和试验表明，VAPP通过变量机构控制斜盘倾角，B口和T口的油液流量均随着斜盘角度的增大而增大，响应速度也加快。当出油口有工作压力，其流量脉动随着斜盘倾角的增大明显减小，但柱塞腔压力依旧随着斜盘倾角的增大而增大。当配流窗口B、T加载压力相等时，B口的流量脉动周期比T口的长，流量波峰比T口波峰高；T口流量脉动比B口流量脉动大，T口应该连接在低压油箱或者蓄能器上，以免影响VAPP的性能。
The variable displacement control has a great energy-saving advantages and application prospects than that valve control. But variable displacement control differential cylinder is not ideal for existing technologies. Using asymmetric pump-controlled asymmetric cylinder strategy to balance the unequal volumetric flow through a single rod cylinder in closed-circuit is an effective method. However, the asymmetric axial piston pump had been presented is fixed displacement. In this paper, variable-displacement asymmetric axial piston pumps (VAPP) is researched. The VAPP variable-displacement output is implemented by controlled the swash plate angle with angle feedback control loop, which is composed through servo proportional valve and angular displacement sensor fixed to connected to the swash plate. Experiments are carried to verify theoretical results. Both the simulation and Experiments results showed that Swash plate angle is controlled by variable mechanism; when swash plate angle increased, oil flow of port B and T are increased and response speed accelerate also. When the discharge ports have load pressure, the flow ripple significantly reduced with the increase of swash plate angle, but the cylinder pressure still increases with the increase of swash plate Angle. The flow ripple cycle of port B is longer than that port T and peak flow is higher than that port T when port B load pressure equals to port T. At same time port T should connection to the low pressure sides or oil tank, to avoid affecting the performance of VAPP.
[1] 权龙. 泵控缸电液技术研究现状存在问题及创新解决方案[J]. 机械工程学报,2008,44(11):87-92. QUAN Long. Current state,problems and the innovative solution of electro-hydraulic technology of pump controlled cylinder[J]. Journal of Mechanical Engineering,2008,44(11):87-92.
[2] LAWRENCE P D,SALCUDEAN S E,SEPEHRI N,et al. Coordinated and Force-Feedback Control of Hydraulic Excavators[C]//4th International Symposium on Experimental Robotics,June 30-July 2,1995,Stanford,California. San Francisco:ISER,1995:1-8.
[3] RAHMFELD R,IVANTYSYNOVA M,WEBER J. Displacement controlled wheel loader -a simple and clever solution[C]//Proceedings of the 4th international fluid power conference,March 24-26,2004,Dresden,Germany,2004:183-196.
[4] RAHMFELD R,IVANTYSYNOVA M. Energy saving hydraulic actuators for mobile machines[C]//Proceedings of 1st Bratislavian Fluid Power Symposium,June 2-3,1998,Casta-Pila,Slovakia,1998:47-58.
[5] HEYBROEK K,LARSSON J,PALMBERG JO. Open Circuit Solution for Pump Controlled Actuators[C]//Proceedings of 4th FPNI PhD Symposium,2006,Sarasota,Florida,USA,2006:27-40.
[6] WANG L K,BOOK W J,HUGGINS J D. A hydraulic circuit for single rod cylinders[J]. J. Dyn. Syst. Meas. Control,2012,134:1-11.
[7] WILLIAMSON C,IVANTYSYNOVA M. Pump mode prediction for four-quadrant velocity control of valve less hydraulic actuators[C]//Proceedings of the 7th JFPS International Symposium on Fluid Power,September 15-18,2008,Toyama. 2008:323-328.
[8] 张晓刚,权龙,杨阳,等. 并联型三配流窗口轴向柱塞泵特性理论分析及试验研究[J]. 机械工程学报,2011,47(14):151-157. ZHANG Xiaogang,QUAN Long,YANG Yang,et al. Theoretical analysis and experimental research on characteristics of parallel three assignment windows axial piston pump[J]. Journal of Mechanical Engineering,2011,47(14):151-157.
[9] ZHANG Xiaogang,QUAN Long,YANG Yang,et al. Output characteristics of a series three-port axial piston pump[J]. Chinese Journal of Mechanical Engineering,2012,25(3):498-505.
[10] HUANG Jiahai,ZHAO Hu,QUAN Long,et al. Development of an asymmetric axial piston pump for displacement-controlled system[J]. Proc. IMechE. Part C:J. Mechanical Engineering Science,2014,228(8):1418-1430.
[11] HUANG Jiahai,YAN Zheng,QUAN Long. Characteristics of delivery pressure in the axial piston pump with combination of variable displacement and variable speed[J]. Proc IMechE Part I:J Systems and Control Engineering,2015,229(7):599-613.
