Fuzzy Sliding Mode Controller for Slip Control of Antilock Brake Systems

Anti-lock braking system is designed to optimize braking procedure while maintaining automobile steerability through controlling wheels slip. However, due to nonlinearity and uncertainty of ABS structure, designing the controller for wheel slip encounters so many problems which necessitate a robust control system. In this paper a hybrid controller is proposed for ABS to address this issue. The designed controller is a combination of sliding mode control and fuzzy control. In fact, the fuzzy system determines switching factor of sliding mode controller proportional to automobile speed employing fuzzy rules. In this way, it would be able to avoid braking command fluctuations in lower speeds. Simulations are performed in ¼ model of automobile in MATLAB environment. The simulation results revealed the capability of proposed system to maintain slip ratio in optimal value as well as avoiding braking fluctuations in low speeds.