Fuzzy sliding mode PID control applied to anti-lock braking system in smart vehicles

Antilock brake system (ABS) is one of important components in vehicles. Due to the highly nonlinear problems in vehicle dynamics, the nonlinear controller with robust performance is needed for antilock braking system. In comparison with conventional ABS models, the ABS model proposed in this paper includes the drag force from air and the resistance force from the wheel rolling friction, except for the adhesion force. Hence, the proposed ABS model matches the real situation well. A fuzzy sliding mode PID controller is proposed for the ABS control, to realize fuzzy PID control of the vehicle slip on an adaptive sliding surface. The simulations at different initial braking velocities, different vehicle mass and different road conditions are studied. The simulated results demonstrate that the proposed controller can quickly respond to the dynamic vehicle operation in the optimal slip range to maximize the adhesion force. Furthermore, the proposed controller has the advantages of fast convergence and high stability.