Active Control of Nonlinear 2-Degrees-of-Freedom Vehicle Suspension Under Stochastic Excitations

Abstract

The optimal suspension design is one of the basic problems in ride comfort analysis. In recent years considerable interest has been concentrated on the use of active vehicle suspension which can improve the comfort and safety during high-speed driving of the vehicle in comparison to the passive suspension system. Usually, both the active control and the vehicle suspension models were considered as linear ones. However, over the last ten years, there has been an increasing effort devoted to nonlinear models of vehicle suspensions under stochastic excitations, see for instance [7], [8]. The solution of the active optimal control was approximately obtained by using statistical linearization. The linearization coefficients were determined from the mean — square criterion. Since in the vibration analysis of stochastic systems in mechanical and structural engineering, a few linearization approaches were proposed, the objective of this paper is to compare them in application to the determination of active control. The detailed analysis was presented for three criteria of statistical linearization, namely the mean — square error of the displacement, equality of the second order moments of nonlinear and linearized elements, and the mean-square error of the potential energies.