Coordinated Compensation Between Active and Semi-Active Actuators for Suspension Control System

Abstract

This paper presents coordinated compensation schemes between active and semi-active actuators in suspension control system. Generally in active suspension systems, active actuators have been adopted to generate a control force calculated by a controller. However, active actuators adopted in actual vehicles have physical constraints such as maximum force, bandwidth and force-velocity limitation. On the other hand, a semi-active actuator can be a good alternative to active one in view of maximum force and bandwidth despite it cannot generate an active control force. However, the performance of semi-active actuators is limited by half of active ones. Hence, it is necessary to compensate the control force of semi-active actuators by active ones. In this paper, it is assumed that a vehicle has both of active and semi-active actuators. A control force needed to enhance ride comfort is generated by linear quadratic regulator (LQR). The controller is designed with 2-DOF quarter-car model and applied into 7-DOF full-car one. To generate the control force with active and semi-active actuators, several coordinated compensation schemes are proposed. A simulation on a simulation package show that the proposed coordinated compensation schemes are effective in reducing the control force of the active actuator over the wider range of frequencies.