Application of the Improved Variable Arguments PID in Asymmetric Hydraulic Cylinder Electro-hydraulic Servo System

When asymmetric hydraulic cylinder electro-hydraulic servo system has positive and inverse kinematics, the flow rate required by the system and various motion parameters are very different. That makes the asymmetry for static and dynamic characteristics of both directions. This structure on the asymmetry of the system has the characteristics of nonlinear, time-varying and gain asymmetry, which bring great difficulty in system control. According to control deviation, PID controller with variable arguments changes the three PID control arguments online by nonlinear function, which overcomes the negative influence of motion control from the asymmetry positive and negative kinematics of the system. Experimental results show that asymmetric hydraulic cylinder electro-hydraulic servo system controlled by the PID controller with variable arguments has good control performance, small differences in forward and reverse movement characteristics, can satisfy the general symmetry of control requirements.