This paper focuses on performance evaluation of several outer loop controller designs employed in a quarter car suspension featuring a magnetorheological fluid damper. A Magne-Ride damper was employed and its behaviour was investigated in the form of force-displacement and force-velocity characteristics. The non-linear hysteretic behaviour of the damper was modelled using a sixth order polynomial model. Force tracking control was performed to check the force tracking ability of the damper using a PI control. The governing equations of motions were formulated and integrated with skyhook control. Skyhook policy was then adapted in the development of a fuzzy logic control to enhance the ride performance. The performance of fuzzy logic control was compared with the on-off and continuous skyhook control in time domain. The results show that skyhook algorithm-based fuzzy logic control gives better performances than its counterparts.

This paper presents modelling and force tracking control of a non-linear hydraulic actuator applied in a quarter-car active suspension system. The controller structure of the active suspension system was decomposed into two loops namely outer loop and inner loop controllers. Outer loop controller is used to calculate the optimum target force to reject the effects of road disturbances, while, the inner loop controller is used to keep the actual force close to this desired force. The results of the study show that the inner loop controller is able to track well the target force ranging from sinusoidal to random functions of target force. The performance of outer loop controller also shows significant improvement in terms of body acceleration, body displacement and suspension displacement as compared to the passive suspension system