Adaptive discrete-time fuzzy sliding mode control for anti-lock braking systems

An adaptive discrete time fuzzy sliding mode controller is proposed for an anti-lock braking system (ABS). Due to strong uncertainties in car/brake environment, the presented controller aims to least depend on a mathematical model. The controller is designed based on a hybrid combination of variable structure control, direct adaptive fuzzy control and linear control. Two fuzzy approximators are used to estimate nonlinear functions of the plant. The sliding mode controller guarantees that states remain within a valid approximation region, hence obtaining globally and uniformly Lyapunov stability. Simulation results show that the approach gave good output tracking performance despite road uncertainties and disturbances.