The Application and Control Optimization of Electronic Park Brake in the Park Assist

In order to improve vehicle active safety, friction work of brake and jerk intensity are selected as the indexes to evaluate the brake process quality, the dynamic characteristics of transmission system composed by engine, hydraulic torque converter and drive shaft, are analyzed in the parking process. Based on the calculus of variations, by taking the rate of brake torque as the control variable, the weighted sum of the friction work and the square of control variables is served as the objective function which is proposed for the optimal process control. Through the solution of the optimization function with boundary constrains, the optimized vehicle speed curve used as the reference speed is obtained, the deviation between the reference speed and the actual speed acquired by wheel speed sensor is fed back to EPB (Electrical Park Brake), forming closed loop control. The simulation result on the platform (MATLAB /Simulink) exhibits that the vehicle securely parking within a certain time and distance. By means of the measuring the related parameters of the test car, the optimal speed curves of parking course are received. The test result verifies the feasibility of the control strategy.