An electronically controlled air suspension system has been introduced to improve the ride performance of a vehicle. A fuzzy controller is designed on the basis of fuzzy logic control strategy which is applied to control the air suspension system. The vibration reduction of a coach with the suspension system is achieved by controlling the stiffness of the air spring and the damping of a switchable damper. A nonlinear dynamic model of a half-vehicle is used to simulate traditional air suspension and the one with fuzzy controller for ride performance respectively on road input. The results indicate that implementing a control strategy can improve the ride performance of the coach on the condition of normal road.

Considering the influence factors of material nonlinearity ,geometric nonlinearity and etc.of air spring with auxiliary chamber in numerical calculations, implement method of airbag nonlinear characteristic ,gas unit, connecting pipe were defined. Finite element model was established in ABAQUS,and vertical characteristic simulation was carried out ,and the results shows that, system static stiffness reduces when increasing in the volume of the auxiliary chamber, but the change in stiffness is not is obvious when the volume increases to a certain degree, and static stiffness also reduces when initial pressure reducing. Simulation results are verified through characteristic test,and both are in good consistency.

Taking the full-vehicle eight-freedom dynamic model of a type of bus as the simulation object , a new optimal control method is introduced. This method is based on the genetic algorithm, and the full-vehicle optimal control model is built in the MatLab. The weight matrix of the optimal control is optimized through the genetic algorithm; then the outcome is compared with the artificially-set optimal control simulation, which shows that the genetic-algorithm based optimal control presents better performance, thereby creating a smoother ride and improving the steering stability of the vehicle.