Research On Vehicle Chassis Integrated Control Based On Joint Simulation

The active suspension and the direct yaw moment system can effectively improve the ride comfort and stability of the vehicle.Firstly,according to the structural characteristics of the two systems,seven degrees of freedom active suspension system model,four wheel road surface input model,tire model and brushless dc motor model were established.Considering active suspension system design is a multi-objective control problem,in order to coordinate different targets and make the whole performance optimal,active suspension comprehensive index LQR controller was designed.However,the functional requirements of active suspension in different working conditions are different,so the LQR controller which focuses on different functions was designed.In order to reduce the difficulty of manually selecting the weighted coefficient in the performance index function of LQR controller,by combining the advantages of genetic algorithm and simulated annealing algorithm,simulated annealing genetic algorithm was proposed for the LQR controller performance index function of the weighted coefficient optimization.Considering the two variables,yaw rate and centroid side slip,all of them will affect vehicle stability,this paper combined with the advantages of fuzzy control and sliding mode control,fuzzy sliding mode control was proposed.Then,the fuzzy sliding mode controller was designed with the two variables as the control target respectively.The layered integrated controller was designed.The lower controller consists of the active suspension and the direct pendulum moment controller.The upper controller is based on the idea of function allocation to coordinate the output of the lower controller through fuzzy control.Finally,the simulation analysis was carried out on the five operating conditions of straight line driving condition,braking condition,sinusoidal stagnation steering condition,double lane change condition and step steering condition.The simulation results show that the designed control strategy can effectively improve the ride comfort and stability of the vehicle.