Control design of an active suspension system for a quarter-car model with hysteresis

Authors' research is devoted to develop new and effective methods to design control strategies for nonlinear mechanical systems. In this paper the system examined is a road vehicle whose vertical motion is excited by the road roughness. The goal of the investigation is to design optimal control laws for active suspension systems of road vehicles in order to mitigate vibrations caused by the road roughness. The road vehicle has been idealised with a quarter-car model whereas the suspension system has been schematised using the Bouc-Wen hysteresis model. A control actuator has been interposed between the sprung mass and the unsprung mass in order to reduce the road-induced vibrations. The control action has been obtained using optimal control theory and it has been calculated numerically using a combination of the iterative adjoint-based control optimization method with the linear-quadratic-Gaussian regulation algorithm. Simulations show that the designed control law significantly reduces the vibrations caused by the road profile.