Optimization Based Sliding Mode Control in Active Suspensions: Design and Hardware-in-the-Loop Assessment

The paper presents an optimization based sliding mode controller designed to provide the correct amount of force to the actuator of an active suspension system in order to guarantee ride comfort. First, the description of the mechanics of the active suspension system is provided. Then, the mathematical state space form of the quarter-car active suspension model is introduced. A Sliding Mode Control controller is designed to properly manage the active force production. The parameters of the proposed controller are tuned, relying on an optimization procedure, so as to improve the quality of the ride, in particular in terms of ride comfort, road holding and suspension deflection. First, the performance of the controlled active suspension are assessed in simulation using the formulated quarter-car mode. Then, the proposed optimized sliding mode controller is tested on an experimentally validated full-car model of a Range Rover Evoque in a Hardware-in-the-Loop (HiL) test rig available at the Automotive Engineering Department of TU Ilmenau, also comparing its performance with those obtained by using a standard PID controller. The HiL test rig is equipped with an active electromechanical suspension system. Simulation and HiL test results confirm that the proposed SMC controller provides better ride quality than the standard PID controller, which corroborates its suitableness for practical implementation.