Research On ESP Control System Of A Heavy-duty Based On Multi-objective PID

In recent years, with the rapid development of China’s automobile industry, the amount of heavy-duty vehicles continues to grow. However, the road traffic accidents have happened more frequently. Heavy-duty vehicles have big load, length and high center of gravity and often encounter complex conditions that will cause instability phenomena, such as the car skidding, drifting and rollover. Heavy-duty vehicles with ESP can effectively reduce the occurrence of this phenomenon, but the research of ESP control is still in the initial stage in China. The key technology of ESP is still monopolized by foreign countries and the installation rate of ESP is still low. So, the research of ESP control theory for heavy-duty vehicles has important realistic significance to enhance the market competitiveness of the automobile industry and protect people’s lives and property safety.For a three axis heavy-duty vehicle, this dissertation built a seven DOF dynamics model and Dugoff nonlinear-tire model in MATLAB/Simulink, proved the correctness of the models in the typical driving conditions, and analyzed the effects of the initial vehicle speed, steering wheel angle, vehicle load and road adhesion coefficient on cornering stability. And then, this dissertation designed two kinds of ESP control system based on yaw rate and sideslip angle as control variable, which are the multi-objective PID coordinated control and multi-objective PID weighted control. The simulation results show that the weighted control is better than coordinated control. Taking longitudinal vehicle speed, yaw rate, sideslip angle and lateral acceleration as assessment index, the multi-objective PID weighted control was used to analyze the influences of the initial vehicle speed, steering wheel angle,vehicle load and road adhesion coefficient on control effect.In addition, the heavy-duty vehicle full-body model was built in ADAMS/Car,including front and rear suspension, steering subsystem, tire subsystem, braking subsystem, steering subsystem, power transmission subsystem, driving chamber subsystem, the container and chassis subsystem. The ADAMS vehicle model wascompared with the 7-DOF model built in MATLAB/Simulink. Based on the co-simulation of ADAMS-MATLAB, the multi-objective PID coordinated control and multi-objective PID weighted control was designed, and the vehicle longitudinal velocity, lateral acceleration, yaw rate and sideslip angle were calculated under step condition and single lane condition. The results show that both the two control methods can reduce the value of control target and effectively improve the driving stability, and multi-objective PID weighted control is more effective.Research of this dissertation not only present a valuable control strategy for ESP design of heavy-duty vehicle, but also provide the basis of theoretical analysis for the engineering applications in the future.