Multi-objective control for uncertain nonlinear active suspension systems

Abstract Performance requirements for vehicle active suspensions include: (a) ride comfort, which means to isolate the body as far as possible from road-induced shocks and vibrations to provide comfort for passengers; (b) road holding, which requires to suppress the hop of the wheels for the uninterrupted contact between wheels and road; and (c) suspension movement limitation, which is restricted by the mechanical structure. In view of such situations, plus the parametric uncertainties, this paper suggests a constrained adaptive backstepping control scheme for active suspensions to achieve the multi-objective control, such that the resulting closed-loop systems can improve ride comfort and at the same time satisfy the performance constraints in the presence of parametric uncertainties. Compared with the classic Quadratic Lyapunov Function (QLF), the barrier Lyapunov function employed in this paper can achieve a less conservatism in controller design. Finally, a design example is shown to illustrate the effectiveness of the proposed control law, where different initial state values are considered in order to verify the proposed approach in detail.