Semi-active control of an integrated full-car suspension with seat suspension and driver body model using ER dampers

Abstract

In this paper, an integrated vehicle semi-active suspension control system that includes a full-car suspension model (7 Degree-Of-Freedom (DOF)), a seat suspension model (2 DOF) and a driver body model (4 DOF) is developed. A H∞ static output feedback controller which only uses measurable variables as feedback signals is designed to improve vehicle ride comfort performance in terms of driver head acceleration under constraints of actuator saturation, suspension deflection limitation and road holding capability. The controller design conditions, which are expressed as Linear Matrix Inequalities (LMIs) are derived by dealing with each control input separately under a common Lyapunov function, so that a feasible solution can be found for the integrated high order system that has five control inputs and ten control outputs; each control input may require different feedback signals and have different saturation limitations. Furthermore, a semiactive control strategy is applied to implement the proposed control system using electrorheological (ER) dampers. Numerical simulations are used to evaluate the improvement of ride comfort performance in terms of driver head acceleration responses under typical road disturbances.