Shift Force Optimization and Trajectory Tracking Control for a Novel Gearshift System Equipped With Electromagnetic Linear Actuators

Electromagnetic linear actuators (ELAs) are used to engage gears in an electric automated manual transmission. The structure is simplified due to the elimination of intermediate mechanisms. An ELA can provide 1500 N of electromagnetic force to drive the synchronizer mechanisms. Additionally, the dynamic characteristics of the actuator are remarkable, improving the performance of shifting gears. To achieve balanceable and comprehensive gearshift performance including shift time, friction work, and degrees of jerk, Pontryagin's minimum principle is employed to optimize the friction torque, and current feed-forward active disturbance rejection control is proposed to track the optimized shift force. Moreover, a double closed-loop controller based on active disturbance rejection control is used to achieve fast and stable displacement control. Comparative simulations and experiments are carried out, and the results indicate that the proposed tracking method can implement the optimal shift force well and can integrate the optimal shift indices, including shift time, degrees of jerk, and friction work. Combined with the proposed control method, the superiority and feasibility of the novel direct-drive electromagnetic gearshift system are validated.