Integrated control of direct yaw moment control and active suspension system for 4wd vehicles
This paper presents an integrated control of DYC (direct yaw moment control system) and ASS (active suspension system) for 4WD (four-wheel drive) vehicles. In order to improve the comprehensive performance of 4WD vehicles, a ten degree of freedom nonlinear vehicle dynamics model is established and the torque distribution characteristic of an inter-wheel torque distribution device is analyzed. Based on the two degree of freedom linear vehicle model, the direct yaw moment controller with distribution of driving force is designed by means of sliding mode variable structure control. The active suspension system controller with a double-loop control structure is designed on the basis of its dynamics model. According to the analysis of the influence of the suspension on the vehicle steering performance, the integrated control of direct yaw moment control system and active suspension system is studied. The simulation of step steering condition and single lane change condition of vehicle is carried out using MATLAB/Simulink software. The simulation results show that the integrated control system can obviously improve vehicle riding comfort and handling stability much more than the individual control.