Design of a Fuzzy Controller for Independent Control of Front Wheels Steering Angles

In this study a novel control strategy for independent control of front wheels’ steering angles, using fuzzy logic control, has been developed. For this purpose at first the appropriate vehicle dynamic models have been introduced. A simplified two-degree-of-freedom model is considered as the reference model and then a comprehensive eight-degree-of-freedom model is developed as the simulation tool. In the next step, the comprehensive control system has been designed. The control system based on the yaw rate error of the actual vehicle comparing to the predefined reference model, the actual vehicle side slip angle and also lateral acceleration of the actual vehicle, calculates the correction steering angles of the front inner and outer wheels. Finally, a sophisticated precise numerical simulation is performed. In order to ponder the performance of the proposed controller, an optimal control system as an active steering control (ASC) has been used for comparison. The simulation results show considerable improvement in handling and stability of the vehicle compared to the conventional non-controlled system and also a vehicle equipped with an optimal controller ASC.