Fuzzy sliding mode control of vehicle suspension systems

Suspension systems are one of the most important vehicle components and have become an attractive research and development area by automotive companies and researchers.The ultimate goal of this research is to develop an active suspension control algorithm to improve the ride comfort and performance of cars suspensions. For this purpose a new fuzzy sliding mode controller was applied to quarter and half car model. Sliding mode control is combined with two inputs-single output fuzzy logic controller to make a new control method which is called fuzzy sliding mode controller. Error and derivative error are inputs of fuzzy logic controller and the slope constant of the sliding surface of the sliding mode controller is the output of fuzzy logic controller. Fuzzy logic algorithm continuously updates the slope constant of the sliding surfaces of the sliding mode controller.Another goal of this research is the introduction of new approaches to the suspension gap problem in the quarter and half car model.It has been shown that the designed controller does not cause any problem in suspension gap limits in addition to improvement in the ride comfort.