A Fuzzy PID Cascade Control System of a Hydro-viscous Drive Speed Regulating Start

The effect of hydro-viscous drive speed regulating start depends both on reasonable structural design and appropriate control strategy. But the control system used at present cannot completely satisfy practical requirements. In order to resolve the problem, a fuzzy PID cascade control system is presented based on cascade control theory in this paper. In auxiliary control loop a PID controller is used to adjust the proportional relief valve, in main control loop a fuzzy PID controller is used to control the system. The fuzzy PID cascade control system was simulated by using Matlab software. The results show that the system can meet the actual demands quite well. To verify correctness of theoretical analysis, a test-bed of hydro-viscous drive speed regulating start was built and the experiments were carried out. The results prove the feasibility of the fuzzy PID cascade control system. Different from the simulation, in experiments, the output speed lags behind the given speed to a large extent because of the static friction force of the system. It is inevitable. More attention should be paid to this case in design of the control system.