A rotary magnetorheological (MR) damper for a semi-active suspension was developed, laboratory tested. The working principle and features of the rotary MR damper was outlined and its theoretical model was developed. Full optimization of the magnetic design was accomplished with the help of magnetic finite element software ANSYS in the limited space. The parameters of the MR damper’s theoretical model were identified by a series of harmonic loading tests. It is demonstrated that the damping capacity of this MR damper is a function of strain amplitude and field strength, and it is feasible to use for the life application in terms of force characteristics.

Considering nonlinear characteristics of springiness and damping element, the quarter-car suspension nonlinear dynamic model is established with ADAMS. The simulation model of suspension established, and the simulation curve of nonlinear suspension is gotten by using the numerical simulation methods. The target parameters of the piecewise linear three stage control mode of the shock absorber are studied under the different random road excitation, it would provide the theoretical basic for the nonlinear damping matching of the vehicle suspension system.

A hydro-pneumatic balanced suspension is proposed based on the structural features of general hydro-pneumatic suspension and balanced suspension. Two types of suspensions mathematics models are built and differential equations of motion are derived with Lagrange-Equation. Performance of the two suspensions is simulated with the software of MATLAB. The results show that ride performance of vehicles is improved using hydro-pneumatic balanced suspension. Therefore, hydro-pneumatic balanced suspension is more suitable for multi-spindled vehicles.

In order to analyze the performance of a certain FSAE racing car with rear wing at different attack angles by virtual prototyping technology. The multi-body model of a FSAE racing car which takes non-linear factors into consideration was built by applying ADAMS/Car. The correctness of the model is verified by comparison with the actual experiment result. By the simulation of the air resistance and lift characteristics of the rear wing, a feasible method to building the aerodynamic characteristics of the rear wing in multi-body model was proposed. Based on these, the crosswind stability of FSAE racing car with rear wing at different attack angles was analyzed, the result shows that the effect of crosswind is reduced with the increase of the attack angle of the rear wing.

A new control method used in the semi-active suspension is studied. The force generated by the semi-active damper can be divided into two parts, one is the uncontrollable force, and the other is the controllable force. In order to make the sprung mass have the ideal isolation effect, the controllable force should be equal to the sum of the uncontrollable force and the force generated by the suspension spring. But the controllable force is limited by many constraints. Therefore, the control strategy can be concluded. The simulation results show that the ride comfort and handling stability are both improved by the control method.