Direct and Indirect Stable Adaptive Control for Suspension Systems with MR Damper

The paper is concerned with stable adaptive schemes for semi-active control of suspension systems, which can deal with uncertainties in a nonlinear model of MR damper. To compensate for unknown nonlinear hysteresis dynamics of the MR damper, an adaptive inverse controller is implemented by indirect and direct methods. In the indirect method, on-line identification of a forward model of MR damper is executed. The direct method updates the inverse controller directly. Then a linear control scheme is designed and applied to the nonlinearly compensated system to give the desired damping force by taking into account the passivity of the MR damper. The effectiveness of the proposed adaptive semiactive control scheme is validated and the stability of the obtained total adaptive system is analyzed.