KEYWORDS: Anti-lock brake system, AFC strategy, fuzzy logic, PID controller
ABSTRACT: Antilock braking systems (ABS) are safety and control devices implemented in ground vehicles that prevent the wheel lock-up during panic braking. The existing ABS controls have the ability to regulate the level of pressure to optimally maintain the wheel slip within the vehicle stability range. However, the ABS shows strong nonlinear characteristics in which the vehicles equipped with the existing controllers can still have a tendency to oversteer and become unstable. In this paper, a new intelligent robust control method based on active force control (AFC) strategy is proposed via a simulation study. It is designed and implemented in a hybrid form by having the AFC loop directly cascaded in series with a fuzzy logic (FL) self-tuning proportional-integral-derivative (PID) control as the outermost loop position control for the effective overall performance. From the results, it is evident that FL-PID with AFC scheme shows faster and better response compared to the classic PID controller for the given loading and operating conditions. The incorporation of the AFC-based scheme into the ABS serves to provide enhanced performance that has great potentials to be implemented in real-time system.
