Sliding Mode Observation and Control for Semiactive Vehicle Suspensions

Abstract

This thesis investigates the application of robust, nonlinear observation and control strategies,namely sliding mode observation and control (SMOC), to semiactive vehicle suspensions using amodel reference approach. The vehicle suspension models include realistic nonlinearities in thespring and magnetorheological (MR) damper elements, and the nonlinear reference models incorpo-rateskyhook damping. Since full state measurement is difficult to achieve in practice, a sliding modeobserver (SMO) that requires only suspension deflection as a measured input is developed. The per-formanceand robustness of sliding mode control (SMC), SMO, and SMOC is demonstrated throughcomprehensive computer simulations and compared to popular alternatives. The results of thesesimulations reveal the benefits of sliding mode observation and control for improved ride quality,and should be directly transferable to commercial semiactive vehicle suspension implementations.