A novel fuzzy controller to improve desired suspension performance

Semi-active suspension systems allow for adjusting the vehicle shock damping and hence improved suspension performance can be achieved over passive methods. This paper presents the design of a novel fuzzy control structure to concurrently improve ride comfort and road handling of vehicles with semi-active suspension system. A full car model with seven degrees of freedom is adopted that includes the vertical, roll, and pitch motions as well as the vertical motions of each wheel. Four decentralized fuzzy controllers are developed and applied to each individual damper in the vehicle suspension system. Mamdani's method is applied to infer the damping coefficient output from the fuzzy controller. To evaluate the performance of the proposed controller, numerical analyses were carried out on a real road bump. Moreover, results were compared with well-known and widely used controllers such as Skyhook. It is shown that the proposed fuzzy controller is capable of achieving enhanced ride comfort and road handling over other widely used control methods.