APPLICATION OF FUZZY CONTROL: SAFE BRAKING IN AUTOMOBILE USING ABS CONTROL SYSTEM

Abstract

Antilock braking system (ABS) is a control system used in vehicle for avoiding wheel locking which may occur during panic braking or because of the low frictional road surface. ABS developed at starting stage was having four wheel sensors along with actuators and an Electronic Control Unit (ECU) which was nothing but the simple ON-OFF controller. Now a days ABS comes with a faster ECU which can handle more inputs from more sensors. Also modem controlling techniques are used to control wheel speed such as neural control technique, sliding mode control technique, fuzzy logic control technique etc. The main objective of this work is to control the brake wheel pressure by considering the vertical load on rear wheels. Since the rear wheels are more responsible for stability of vehicle. Also another goal of this work is to reduce the stopping distance while cornering along with improved lateral stability. The controlling technique used in this work is fuzzy logic with Mamdani's fuzzy inference method. There are three inputs for the fuzzy controller Yaw rate error, wheel slip and the vertical force on a wheel. The output of controller is brake pressure for rear wheels. Results for this controller with three different road conditions and two different steering inputs are compared with the traditional ABS. Three different road conditions used are high ,u , low u and split p road surfaces whereas the steering inputs used are J-turn test steering signal and sinusoidal steering signal. The simulation environment is created with the help of CarSim8 software and controlling is done with MATLAB & SIMULINK.