Non-linear optimal control of a semi-active vehicle suspension system

This paper considers the optimal control of a semi-active vehicle suspension system. Analysis is based on a simple fifth-order mathematical model of the ride dynamics of an automotive suspension. The quarter-vehicle model describes the vertical motions of the vehicle body mass and of a single wheel mass. Although the underlying equations are essentially linear, significant nonlinear effects arises from the dissipative nature of the control actuator, and the inclusion of displacement limiting criteria for the control of suspension and tyre deflections. Optimal suspension control is considered under both free and forced motion of the suspension. New results are given concerning the ability of semi-active suspension to make use of road-surface preview information.