Firefly Algorithm tuned Fuzzy Set-Point Weighted PID Controller for Antilock Braking Systems

Abstract

Antilock Braking Systems (ABSs) are brake controllers designed to maintain the wheel slip in desired level during braking and acceleration. Since the factors causing the wheel slip to change such as nature of road surface, vehicle mass etc are highly uncertain, the task of controlling it has been a challenging one. In this paper, a modified PID controller called Set-Point Weighted PID (SPWPID) Controller has been designed to control the wheel slip. First, a Genetic Algorithm (GA) based fuzzy inference system (GAFSPWPID) is developed to determine the value of the weight that multiplies the set-point for the proportional action, based on the current output error and its derivative. It makes the controller more adaptive to external disturbances. Then, the GA is replaced by Firefly Algorithm (FA). Minimization of Integral Square Error (ISE) has been taken as objective for both cases. The performance of proposed Firefly Algorithm tuned Fuzzy Set-Point Weighted PID (FAFSPWPID) Controller is compared with SPWPID and GAFSPWPID controllers. Also, the performance of proposed controller is assessed for different initial conditions. A comparison has also been made with the controllers presented earlier in literature. Simulation results show that the proposed FAFSPWPID Controller performs better in both set-point tracking and adaptive to external disturbances than the other controllers.