Patent ID: 6928356

Claim:
An antiskid control system for a four-wheel-drive vehicle, comprising: a master cylinder generating a braking hydraulic pressure; a braking cylinder attached to each wheel of the four-wheel-drive vehicle, the braking cylinder generating a braking force by receiving the braking hydraulic pressure; a switch control valve disposed between the master cylinder and the braking cylinder, the switch control valve switching between a pressure decreasing control condition of decreasing the hydraulic pressure of the braking cylinder and a pressure increasing control condition of increasing the hydraulic pressure; a wheel speed detector attached to each wheel, the wheel speed detector detecting a wheel speed of each wheel and outputting a wheel speed indicative signal; and a control unit coupled to the switch control valve and the wheel speed detector, the control unit being arranged, to calculate a target control speed on the basis of the wheel speed of each wheel, to calculate a wheel acceleration of each wheel from the wheel speed, to set the switch control valve at the pressure decreasing control condition when the wheel speed reaches the target control speed, to set the switch control valve at the pressure increasing control condition when the wheel acceleration is outside of a range from zero to a predetermined positive value after the switch control valve is set at the pressure decreasing control condition, to calculate a difference between an average of the wheel accelerations of front wheels and an average of the wheel acceleration of rear wheels, to determine that a driveline vibration is generated when the difference is greater than a vibration determination threshold, and to execute a vibration convergence control for converging the driveline vibration when the driveline vibration is generated, wherein the vibration determination threshold includes a vibration determination starting threshold for determining a starting point of the vibration convergence control and a vibration determination terminating threshold for determining a terminating point of the vibration convergence control.