Double Fuzzy Control with Compensating Factor for Electronic-hydraulic Servovalve-controlled System

To address the asymmetry problem caused by the asymmetry of the asymmetric cylinder when electronic-hydraulic servovalve-controlled system is working at symmetric motion state, a double fuzzy control method with compensating factor is proposed. Considering the electronic-hydraulic servovalve-controlled system with asymmetric cylinder, fuzzy controller with compensating factor is used to solve the asymmetry problem caused by the asymmetry of the asymmetric cylinder. Since the load force will vary in large range, the fuzzy PID controller is used to adapt the mutative load. The inputs of fuzzy PID controller and fuzzy controller with compensating factor are error and the differential of error which generated by tracking differentiator. The fuzzy PID controller output the coefficients of PID controller and the fuzzy controller with compensating factor output the compensating factor. An effective method to solve the asymmetry problem of the asymmetric cylinder is generated by combining compensating factor and the fuzzy PID controller. Simulations and experiments show that the proposed method has the ability to solve the asymmetry problem caused by the asymmetry of the asymmetric cylinder in electronic-hydraulic servovalve-controlled system, and has perfect control performance.