Simultaneous optimization design of vehicle chassis integrated control system based on particle swarm optimization algorithm

With the application of active control technology in vehicle, the performances of vehicle such as riding comfort, active safety and handling stability were greatly improved in recent years. However, most of these control systems were aimed to improve individual performance of vehicle respectively. In fact, the improvement of the overall vehicle dynamics performance not only depends on the cooperative work among these various control subsystems but also depends on the coupling interferences of the mechanical structure and control system of vehicle in the running process. In order to remove the coupling interferences between the mechanical structure and control system of vehicle chassis system and to further enhance the overall performance of vehicle, the method of simultaneous optimization of mechanical structure and controller parameters of vehicle chassis system based on Particle Swarm Optimization Algorithm is presented in this paper. According to the fundamental principle of vehicle dynamics, a half car mode of active suspension system and anti-lock braking systems established at first. Then the linear quadratic gauss controller of the active suspension system and sliding mode controller of anti-lock braking system are designed. Taking controllers designed for active suspension system and anti-lock braking system as bottom controllers, the upper coordinated control logic of the systems is put forward and the upper PID coordinated controller is designed on the basis of analyzing the coupling conflict between active suspension system and anti-lock braking system. Finally, a Particle Swarm Optimization Algorithm was adopted for simultaneous optimization of mechanical structure and controller parameters of vehicle chassis integrated control system, because the traditional design method of a vehicle system is always to design control parameters following structure parameters and it can not obtain the global optimal performances for the system. In order to verify the effectiveness of the algorithm, the simultaneous optimization program is developed based on Particle Swarm Optimization Algorithm in MATLAB environment while the mechanical structure and control parameters of chassis control system are set as optimization variables and the overall vehicle dynamics performance is set as objective function. Simulation result shows that the pitching angular acceleration of vehicle is reduced and vehicle riding comfort performance is improved after optimized. Braking distance and dynamic load of front and rear wheels of vehicle are also reduced significantly which indicating vehicle active safety is improved dramatically. The vehicle road test was also carried out based on integrated controller is development of anti-lock braking system and active suspension system using ARM7 when vehicle speed is 40 km/h under braking condition. The road test also shows that the dynamic load of front and rear wheels of vehicle are reduced by 34.20% and 34.10%, braking time and braking distance of vehicle were reduced by 2.31% and 4.50% respectively, the response of vehicle pitching angular acceleration at braking condition is decreased by 15.10% after optimized, and both vehicle active safety and riding comfort are improved at different levels.. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.