Principle of Weight Dynamic Change Fuzzy-PID Integrated Control for the Displacement Ratio of Multi-range HMCVT

A weight dynamic change fuzzy-PID integrated control principle for the displacement ratio of multi-range hydro-mechanical continuously variable transmission (HMCVT) is presented, which enhances the control precision of transmission ratio by improves the dynamic characteristics of displacement ratio of variable pump-motor system. The weight dynamic change Fuzzy-PID integrated controller automatically adjusts the weight value according to the error of displacement ratio. When the error is larger, the fuzzy control is strengthened to improve the response speed; when the error is smaller, the PID control is strengthened to decrease the steady-state error. Bench test showed that this control method can improve the rapidity and accuracy, decrease dynamic tracking error for the control of transmission ratio of HMCVT.