Position control of an electric clutch actuator

A nonlinear-feedforward-feedback controller is designed for an electric clutch actuator, which adopts ball screw as the speed reduction mechanism. Ball screw has high transmission efficiency. However, it does not self-lock. Moreover, the nonlinear friction force, load force, and the nonlinear characteristics of the motor drive circuit increase the difficulty of the position control of the actuator. The designed controller contains two parts: the feedforward controller designed by differential flatness which can deal with the systems nonlinearities, and the feedback controller designed by PID method which guarantees system stability. Simulation result shows that, compared with pure PID controller, the designed controller provides better performance especially in the case of small displacement adjusting.