AN OPTIMAL DESIGN METHOD AND EXPERIMENTAL TEST OF MAGNETORHEOLOGICAL FLUID SHOCK ABSORBER FOR MINI-BUS SUSPENSION SYSTEM

摘要

Magnetorheological (MR) fluids exhibit controllable rheological behavior in the presence of magnetic field. In order to develop automotive semi-active suspension system, which consists of passive spring and active shock absorber with adjustable damping force for different road conditions and automobile running conditions, some design methods of MR fluid shock absorber have received considerable attention in recent years. In this paper, nonlinear magnetic behaviors of soft magnetic material and MR fluid have been coupled to the non-Newtonian fluid mechanics. To minimize the power consumption and inductive time constant and to maximize the control ratio of the MR fluid shock absorber, objective function with bus MR fluid shock absorber has been designed and fabricated at Chongqing University according to the optimal design method. The performances of MR fluid shock absorber have been tested from sine excitation with frequency 1.97Hz, maximum piston velocity 0.3m/s and maximum displacement 25mm in The National Center for Test and Supervision of Coach Quality of China in the light of requirements of Chang' an mini-bus suspension system. The experimental results demonstrate that damping force offered by MR fluid shock absorber can be controlled by application of magnetic field (current) to meet the requirements of ride comfort and driving safety of mini-bus, control ratio of the MR fluid shock absorber is larger than that of previous MR fluid shock absorber, the power consumption is less than 5 watts. Research on dynamic response of MRF shock absorber is under way.