Abstract: In order to realize the cooperative optimization of ride comfort and handling stability, the suspension system of a tractor semitrailer is taken as the research object. The maximum acceleration in z direction above the seat cushion under pulse input and the amplitude of yaw rate under angle step input are taken as the objectives. The leaf spring stiffness of front or rear suspension, the saddle stiffness of front or rear suspension and the damping coefficient are selected as the design variables. what’s more,based on objective function, the improved NSGA -Ⅱ genetic algorithm is used to optimize and match the design variables. Finally, the optimal parameters are imported into the pre established vehicle simulation model of ADAMS/CAR software for simulation test analysis, which deepens the application of genetic algorithm in the multi-objective optimization of semi suspension tractor. The results show that the ride comfort and handling stability after optimization are improved effectively. The research also provides an effective matching method for studying the ride comfort and handling stability of vehicles.

Key words: handling stability, genetic algorithm, multiobjective optimization, ride comfort