Simulation Researches On Control Methods Of Vehicular Active Suspension

From the economic point of view,currently passive suspension system is still used by all kinds of middle-grade and low-grade vehicles.The main drawback of passive suspension is that its stiffness and damping can only be designed according to specific road conditions.The matching of stiffness and damping,and damping performance can not be changed with the change of road conditions which reduces the adaptability and ride comfort of vehicles under different road surfaces,and can not meet the people's requirements to vehicle dynamics performance.Active suspension can effectively avoid the above drawbacks and control the ride comfort of vehicles by using the input of external energy.The main control method is that the control force acting on the bodywork is automatically adjusted by using the bodywork's feedback signals so that the vehicle can adapt to different road conditions,which has strong road adaptability.The active suspension as future development tendency of vehicle suspension system has attracted many scholars.For giving full play to the vibration damping performance of the active suspension systems of vehicles,the control technologies are the key,and appropriate control strategies and corresponding controllers need to be designed.In this paper,a dynamic model of a quarter-bodywork active suspension system was established.The control methods of the vehicle vibration were studied by three control strategies.They are PID control,fuzzy control and fuzzy PID control based on genetic algorithm optimization.The PID controller,the fuzzy controller and the fuzzy PID controller for active suspension system were designed,and the vertical vibration acceleration of bodywork was taken as the main evaluation indexes of suspension performance.In Matlab environment,a Simulink simulation model for realizing these control strategies is constructed.Genetic algorithm was focused on research,and the genetic algorithm and fuzzy PID control strategy were combined and applied to the vibration control algorithm design of active suspension.The fuzzy rules used by fuzzy PID controller were optimized.Through simulation researches,the vehicle body acceleration signal,suspension stroke and tire dynamic load characteristics are obtained and compared before and after the control.Simulation results demostrated that active suspensions can reduce the vibration acceleration of bodywork under the three control strategies and the control effect of Fuzzy-PID control that is optimized by genetic algorithm is the best.Compared with passive suspension,the active suspension with fuzzy-PID control can significantly suppress thevibration of the bodywork and improve the ride comfort of vehicle.Furthermore,the comparisions of PID control strategy and fuzzy control strategy showed the active suspension with fuzzy-PID control can make the acceleration change gentle,so the control performance is more superior.