Design and control of electronic control suspension using a magneto-rheological shock absorber

Abstract

This paper investigates the design and control of electronic control suspension (ECS) equipped with a controllable magneto-rheological (MR) shock absorber and appropriate control strategy. In order to achieve this goal, a cylindrical-type MR fluid shock absorber which satisfies the design specification for Macpherson strut-type suspension for a middle-sized commercial passenger vehicle is designed using an optimization methodology. After experimentally evaluating the field-dependent characteristics of the manufactured MR shock absorber, a quarter-vehicle MR ECS system, consisting of sprung mass, spring, tyre, controller, and the MR shock absorber, is established in order to investigate the ride comfort and driving stability performance. On the basis of the governing equation of motion of the suspension system, five control strategies (soft, hard, comfort, sport, and optimal mode) are formulated. The proposed control strategies are then experimentally realized with the quarter-vehicle MR ECS system. Control performances such as vertical acceleration of the car body and tyre deflection are evaluated in both time and frequency domains under various road conditions. In addition, a comparative study of vehicle motion with a full-vehicle MR ECS system is undertaken to investigate inherent control characteristics, using computer simulation.