This paper presents comprehensive theoretical and experimental exploration on control performance of magnetorheological (MR) suspension system under various road conditions. MR dampers with monotube structure are designed and installed on front and rear vehicle suspensions. The response time of MR damper force is experimentally determined. Meanwhile, a feasible inverse model is constructed to portray the behavior of the MR dampers based on data obtained from experimental testing with random displacement and current as inputs. Three representative control strategy, i.e., Skyhook control, Linear Quadratic Regular (LQR) control and Fuzzy Logical control, are adopted to reduce the vertical response of sprung and unsprung mass, as well as the roll and pitch angles. The superiority of fuzzy logical control lays in without the restriction of the precise vehicle dynamic parameters and the inherent robustness for the nonlinearity and uncertainty. To be practical, the required feedback signals are relative velocity of MR dampers, the vertical velocity at vehicle mass center, and the angular velocity of roll and pitch which are convenient to collect by commercial sensors like displacement sensor and IMU. To verify the feasibility of the system, a passenger vehicle which suspension equipped with four MR dampers was tested on various representative road profiles like the resonance road, the square pit road, and the waveform path. The experiment results indicate the better performance of ride comfort and body attitude of vehicle can be achieved by the proposed MR suspension system. Especially, due to the robustness in coping with the inherent nonlinearity and uncertainty of real vehicle, the fuzzy logical control was demonstrated that is able to achieve satisfactory performance at various complex road test profiles.
 

Control algorithm,magnetorheological damper,vehicle