考虑阀口误差的阀控非对称液压缸系统建模、仿真与试验

从解决比例阀控制非对称缸系统存在的超压问题入手,分析因加工误差引起的各阀口重叠量不一致这一非线性因素对系统性能的影响,建立考虑阀口误差的阀控非对称缸系统的非线性状态方程模型和键图模型.应用这两种非线性数学模型分析一实际非对称阀控制非对称缸系统的压力特性,与试验结果的对比分析验证了所建的非线性数学模型的正确性.仿真和试验研究揭示比例阀控制非对称缸系统的阀口误差对系统性能影响较大,往往是引起有杆腔压力超过供油压力的主要原因.通过大量仿真研究获得了阀口误差与系统超压之间的关系,研究表明适当提高比例阀阀口的加工精度有利于消除超压现象和提高系统的性能,进而建议将某些比例阀阀口误差控制在最大阀位移的0.5%以内.给出的两种非线性数学模型具有通用性,可用于对各类阀控缸系统进行系统仿真、设计和控制策略等方面的理论研究工作.

MODELING, SIMULATION AND EXPERIMENT ON VALVE CONTROLLED ASYMMETRY PISTON CONSIDERING VALVE PORT ERROR

In order to solve the hyper pressure problem in the proportional valve controlled asymmetric cylinder system,non- linear state equations model and bond graph model are built to analyze the system performance influenced by the nonlinear factor of the different valve port overlap value,which is caused by the machining error.These two models are used to analyze the pressure properties of a practical asymmetric valve con- trolled asymmetric cylinder system.The comparison of the outcomes between simulation and experiment proves the cor- rectness of these two models.The simulation and experiment indicate that the valve port error in the proportional valve con- trolled asymmetric cylinder system,which is the prime reason of the pressure on the rod side exceeding the pressure of hy- draulic power supply,has great influence on the system per- formance.The relation between the valve port error and hyper pressure in the system,which is derived from lots of simula- tions,indicates that improving the valve port machining preci- sion of the proportional valve is favorable to avoid the hyper pressure and improve the system performance.It's suggested that the valve port error of proportional valve should be within 0.5 percent of the maximum valve displacement.The two non- linear mathematic models presented are universal,which can be used on various valve controlled cylinder systems to simulate, design and research the control strategy.