Research On Semi-Active Vehicle Seat Suspension Based On Magneto-Rheological Damper

With the rapid development of national economy, automobiles have became an indispensable means of transportation, Meanwhile, people have made greater demands on the comfort and security of automobiles.The seat suspension system is a critical component of car which can affect the safety and ride comfort of the automotive.It is important approach to make the seat suspension have real-time control function according to the road surface conditions and the automobile motion state of, which can effectively improve seat comfort and security. But the semi-active seat suspension systems, which consist of passive springs and active dampers with adjustable damping force for different road conditions and running conditions, are the most popular suspension form and gets extensive attention of the academe and industry due to the active seat suspension's high cost and passive suspension's limited performances. It is a key using about semi-active seat suspensions that should have real-time damper. Practice proved, that magneto-rheological (MR) damper can carry out the transition between Newton fluid and semi-solid statesunder external magnetic field, can provide damp power which can be controlled, and has some advantages such as simple structure, little power requirement etc, easy to be used on semi-active control actually.This dissertation, which is based on studying status, has established a human-seat-vehicle seven-DOF model and a semi-active seat suspension system based on magneto-rheological (MR) damper. The following four subjects are mainly studied in this dissertation.(1) Based on summarizing the present situation and development of the magneto-rheological damper. The dissertation has built up modified Bouc-Wen model and improved double arch secant hysteresis model of magneto-rheological damper. Additionally it has validated two models by simulating and choosed the Bouc-Wen model at last.(2) A human-seat-vehicle seven-DOF model and the random roughness of road surface input model has been presented to apply to this semi-active seat suspension system with magneto-rheological (MR) damper. What's more, it has indicated that the random roughness of road surface input can commendably simuliate the real road surface input by simulating.(3) Using the seat suspension system with magneto-rheological (MR) damper by making use of the human-seat-vehicle seven-DOF model, Bouc-Wen model, the random roughness of road surface input model.the dissertation has designed the PID controller, the expert PID controller, the fuzzy controller for this-system.(4) With the Matlab/Simulink software, the dissertation has a completed simulating analysis between semi-active seat suspension and passive seat suspension. The simulation results indicate that the semi-active seat suspension is better than passive seat suspension in restraining the vertical vibration of body and enhancing the comfort of the seat.