The Research Of Vehicle Semi-active Suspension Control System Based On Magnetorheological Damper

With the improvement of the highway network and the popularity of the automobile, people’s demand for car’s comfort is becoming higher and higher.The suspension is an important element of connecting the wheels and the car body,its performance is directly related to the quality of the car.Traditional passive suspension is used the most widely now.Because its structure is simple, control scheme is mature, reliability is high, price is low.From the subjective point of view, people hope the car has the best ride comfort and stability at the same time, but the two performance of the passive suspension is contradictory, they could not be resolved at the same time.The active suspension is equipped with a force generator to replace the shock absorber in the traditional suspension, it can produce the corresponding damping force to adjust the body state according to different external disturbance,s it has good vibration reduction performance. But because of its high cost and high energy consumption, it can not be applied to most of consumers. Semi active suspension is between active suspension and passive suspension.lt adds an adjustable damping force on the basis of passive suspension,it can adjust the damping force according to different conditions of highway, and its energy efficiency is small, it has strong economic and practicality.Through magnetorheological damper to realize the semi-active control of vehicle suspension is a promising method.Magnetorheological damper responses fast, it can response in a very short period of time according to the change of current time to respond to achieve the stepless control of output damping force and the performance is safe and reliable. Therefore,this paper studies the working principle of MR damper and it is applied to the suspension system as an intelligent vibration damper to realize the control of vehicle suspension.In the actual control, need to establish magnetorheological inverse model and produce the desired damping force that required to control current. Due to the complexity of the structure many variables, nonlinearity of magnetorheological damper, it is difficult to obtain accurate inverse model. Therefore, this paper uses the function of the neural network that it can approximate any nonlinear characteristics, to establish inverse model of the magnetorheological damper and it solves the problem by of the back stepping current.In the paper, semi-active suspension system based on the magnetorheological damper is the research object. In order to improve the stability of the suspension system,the paper proposed magnetorheological damper replace conventional dampers to control the suspension and form the Control system of automobile semi active suspension based on magnetorheological damper.First, to fully reflect the vibration of car and to establish the half car suspension model and use the fuzzy PID to control suspension system,The fuzzy neural controller was designed to further make up for the insufficiency of fuzzy PID. The vertical acceleration of the body e and acceleration change rate ec as input of the controller, the desired damper F as the output of the controller. Finally, the simulation analysis was carried out on the suspension. Through simulation analysis of the suspension systerm the road input is white noise and deceleration to verify the model and the design of control algorithm is effective; Through simulation analysis of the same road grade different vehicle speed and road grade at same speed to illustrate the effect of vehicle speed and road grade to the performance of the car.