Design of an active suspension system for a quarter-car road vehicle model using model reference control

Abstract

The use of skyhook damping for reduction of the vibration in the suspension systems is well documented. The drawback is that it is not practically feasible to obtain the equivalent of a reference point in the sky. The alternative method of using a damper between the sprung mass (the vehicle hull) and the unsprung mass (the wheel assembly) leads to a deterioration in the performance of the unsprung mass. In this paper a new method is proposed that tries to overcome the limitation of the practical skyhook damping method by the use of the model reference control (MRC) method, where the control input is utilized to achieve near-ideal skyhook sprung mass performance in a practical skyhook damping set-up. The MRC method is also applied to a quarter-car suspension model, where the control input is used to achieve the response of a system with damping and stiffness values different from those of the actual system. This allows for variation of the system constants as dictated by dynamic response needs. The proposed methods are applied on a typical quarter-car suspension system and the necessary time and frequency domain simulations are carried out to validate the theoretical predictions.