Designing an Optimal Proportional-Integral Sliding Surface for a Quarter Car Active Suspension System with Suspension Components Possessing Uncertain Constants and Nonlinear Characteristics

In this paper, design of a controller for a quarter car active suspension system have been done with the focus on sliding mode strategy. Suspension components, including spring and shock-absorber have nonlinear characteristics with uncertain constants, but they have defined bound. To simplify the controller designing, feedback-linearization is proposed, then with using the optimal strategy, we obtain a proportional - integral sliding surface and a controller for meeting the sliding condition has been proposed. The design process is in a such way that not only, guarantees asymptotic stability of the suspension system in the presence of parametric uncertainties, but also the designer can supply his slightly trade-off between convenience of passengers and controllability of car, with setting some parameters.