Abstract:In order to improve the ride comfort and stability of one light bus with two level variable stiffness rear suspension, a virtual combined optimal model was composed of the multi objective immune system algorithm（MISA) program composition by MATLAB and a virtual dynamic optimal model of the light bus in Adams Car. The parameters of the front and rear suspension were reasonably optimized. To ensure the accuracy of the model, the tire mechanical characteristics were tested, then the Magic Formula tire model was obtained by parameter identification method. An optimal method for the light bus’s suspension systems was put forward. In the proposed method, the torsion stiffness of front torsion bar, the front and rear damping curve coefficients, the torsional stiffness of front and rear stabilizer bars and the two level stiffness of rear suspension were taken as the optimal antibodies(variables). The max lateral acceleration of steady static circular simulation, the yaw rate and roll angle of the body of slalom simulation, and the Z direction acceleration root mean square(RMS) of the frame on B class road(80 km·h-1) were selected as the optimal antigen target. By using MISA to conduct optimization, the optimized suspension parameters were obtained. Finally, the suspension samples were manufactured and the comparative trials of vehicle ride comfort, handling and stability and subjective evaluation test were respectively carried out in an automotive proving ground to evaluate the optimization results. The results show that the proposed optimization method can be used for improving the vehicle’s ride comfort and stability and it has become a development trend of automotive computer aided optimization(CAO) technology. Therefore, it will provide guiding significance for the virtual development and optimization of automotive chassis.
