Abstract
Anti-lock Braking System (ABS) is a safety device for preventing wheel-locking in a sudden braking. It consists of hydraulic modulator, ECU and wheel speed sensors. The hydraulic modulators are classified into two types; sot-flow type and sol-sol type. In this paper, the hydraulic modulator is composed of one solenoid valve with 3way-2position. The braking friction force described by function of slip ratio can obtained maximum value if slip ratio cartbe maintained from 0.1 to 0.3. Consequently, slip ratio is controlled by PWM and SMC based on vehicle dynamics in the same way a two-level control scheme.
