Research of pneumatic braking force control on regenerative braking electric vehicle

Regenerative braking is one of the key means to increase the range of electric vehicle. Previously, a braking force distribution control strategy has already been made, including braking force distribution between front axle and rear axle, braking force distribution between pneumatic braking force and motor braking force. For pneumatic braking electric bus, the two key issues of regenerative braking are pneumatic braking force control and motor braking force control. Assuming that the motor braking force has been controlled ideally, this work focus on the control of pneumatic braking force. On the basis of traditional pneumatic braking system, sensors and some valves are added, high speed on-off valve for instance, to control the front and rear pneumatic braking force. High speed on-off valve can be controlled by single chip microcomputer directly, thus greatly improving the control accuracy and shorting the response time and overshoot of the braking system. In view of the problems of pneumatic braking control, the parameter self-tuning fuzzy PID control algorithm is adopted. This kind of controller can setting suitable PID parameters automatically with the requirements of process control on-line, so as to give full play to the function of PID and achieve better control quality. To verify the performance of the control system, this work built a hardware in the loop (HIL) simulation platform. The result of the HIL test shows that using the fuzzy adaptive PID algorithm can improve the performance of the pneumatic system. The system can track the input signal quickly and have higher steady-state accuracy, relative to the conventional PID control system.