Displacement servo system of asymmetric hydraulic cylinder exists the characteristics of cylinder's acting areas are dif-ferent and the system model is uncertain.These characteristics cause tremendous difficulty for high-precision displacement tracking con-trol of hydraulic cylinder.In this regard,a compound control strategy that was mainly based on velocity feedforward and supplemented by displacement feedback was proposed.A new flow model for servo valve using control current and pressure difference between inlet and outlet of servo valve as independent variable was designed.The hydraulic test circuit was designed according to this model,and the pa-rameters in the model were identified through the test results.The velocity feedforward control was calculated based on the flow model and the target displacement trajectory.Then,the displacement error feedback control was calculated based on PI control.Finally,the ve-locity feedforward and displacement feedback were superimposed as the drive voltage of the servo valve.The experiment results show the ratio of the maximum error of displacement tracking to the target displacement amplitude is 2.1％under the compound control strategy,which reduces significantly compared with PID control.The proposed control strategy provides a simple and effective method for asym-metric hydraulic cylinder displacement tracking control in productive practice.
关键词
复合控制/非对称液压缸/流量模型/位移伺服系统
Key words
compound control/asymmetric hydraulic cylinder/flow model/displacement servo system
维普
万方数据