Research On Vehicle Semi-active Seat Suspension Based On Sliding Mode Variable Structure Control

Along with the rapidly development of science and technologies and the significant improvement of the people’s living standard, automobiles have gradually been popularized into family life. The consumers put forward higher requirements for ride comfort and performance of automobile. In the complicated vehicle vibration system, seat suspension system is one of the important factors that affect the occupants’dynamic comfort. Magnetorheological seat suspension system includes sensors, controller and actuators, etc. The controller plays an important role in the vibration reduction and intelligent degree of the whole system. So choosing an appropriate control strategy which is used in semi-active seat suspension based on magnetorheological damper is of great theoretical significance and practical value.This paper took the semi-active seat suspension based on MR damper as the research object, summarized the research situation of domestic and overseas suspension, especially the seat suspension, compared and analyzed different semi-active control strategies, and then selectd sliding mode variable structure control algorithm which was nonlinear control algorithm with a high degree of robustness. A three-DOF approximate sky-hook damping model was proposed as a reference model. Then we forced the tracking error dynamics between the reference model and the plant into an asymptotically stable sliding model. In the proposed controller, the parameters of the switching surface were determined by pole assignment method. The comparison of the vibration reduction effect among sliding mode control, PID control and passive system was carried out by numerical simulation. In order to prove the effectiveness of the controller mentioned in this paper, we analyzed its tracking performance and robustness. So it could provide the reliable theory basis for experimental study on the seat suspension vibration reduction using sliding mode control.This paper summarized the present development and utilization of MR damper, built the modified Bouc-Wen model, a three-DOF one-quarter vehicle seat suspension model, a five-DOF half vehicle seat suspension model and a ten-DOF whole vehicle seat suspension model.The MR damper polynomial inverse model was derived from the fitting positive model. So the active control algorithm could be applied into the semi-active control system. In view of the chattering phenomenon, we used RBF neural network to optimize the system and discuss the improvement degree of seat suspension performance.The experiment test was carried out to verify the validity of SMC controller designed in this paper by using the single-DOF seat suspension test system built by the studying team after the comparison between charts and figures.