A New Approach of Antiskid Braking System (ABS) via Disk Pad Position Control (PPC) Method 02-14-01-0004

A classical antiskid brake system (ABS) is typically used to control the brake fluid pressure by creating repeated cycles of decreasing and increasing brake force to avoid wheel locking, causing the fluctuation of the brake hydraulic pressure and resulting in vibration during wheel rotation. This article proposes a new approach of skid control for ABS by controlling the disk pad position. This new approach involves using a modest control method to determine the optimal skid that allows the wheel to exert maximum friction force for decelerating the vehicle by shifting the brake pad position instead of modulating the brake fluid pressure. This pad position control (PPC) method works in a continuous manner. Therefore, no rapid changes are required in the brake pressure and wheel rotation speed. To identify the PPC braking performance, braking test simulations and experiments have been carried out. The optimal pad position was calculated by estimating the friction coefficient, in which the wheel skid was maintained in range. Different initial velocities and road conditions were used to study the braking behavior. Furthermore, the experimental results obtained using the PPC method, an ABS, and the conventional braking method in a braking test simulator were compared. Results show that the PPC method exhibited a suitable performance for wheel lock-up prevention. A significant reduction was obtained in the brake fluid oscillation and braking distance with the PPC method. Thus, the PPC method is a method suitable for controlling the wheel skid with limited vibration. This method is applicable to autonomous or electric cars because of the influence of voltage fluctuation on the motor-drive avoidance.