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A detailed multi-body dynamic model of a passenger car was modeled using ADAMS/Car and then checked by the ride comfort and handling stability test results in this paper. The performance criterion for ride comfort evaluation was defined as the overall weighted acceleration root mean square (RMS) value of car body floor, while the roll angle and lateral acceleration of car body were considered as evaluation indicators for handling stability performance. Simultaneously, spring stiffness and shock absorber damping coefficients of the front and rear suspensions were taken as the design variables (also called factors), which were considered at three levels. On this basis, a L9 orthogonal array was employed to perform the ride and handling simulations.

For the roll vibration problem of a Truck, a 4-DOF roll vibration model of its front suspension system was built. According to dynamics theory, the complex modal vibration modes of the model were all obtained. At the same time, the frequency response functions of frame roll angle acceleration, the relative dynamic load of wheel and the suspension dynamic deflection were respectively presented. Then their characteristics were respectively researched. In the process of characteristic analysis, a new system parameter was proposed, which is the space ratio of the space between suspensions of left and right sides and the wheel track of the front axle (space ratio in short). At last, the influence of system parameters on the vibration transmission property was also reserached, which included the natural frequency of the frame, the damping ratio, the stiffness ratio, the mass ratio, the rotational inertia ratio and the space ratio.

This paper sets up a simplified dynamic model for simulating the yaw/roll stability of heavy tractor-semitrailer using Matlab/Simulink. A linear quadratic regulator (LQR) based on partial-state feedback controller is used to optimize the roll stability of the vehicle. The control objective for optimizing roll stability is to be reducing the lateral load transfer rate while keeping the suspension angle less than the maximum allowable angle. The simulation result shows that the LQR controller is effective in the active roll stability control of the heavy tractor-semitrailer.