SKID CONTROL SYSTEM

A skid control system for a vehicle having two or more wheels and the respective brakes for the wheels, includes two or more skid control circuits, each of which includes a wheel speed sensor for providing an output signal representative of the speed of the wheel or the mean speed of the wheels, an approximate vehicle speed generator for providing an output signal representative of the approximate speed of the vehicle on the basis of the output signal of the wheel speed sensor, a slip signal generator receiving the output signal of the wheel speed sensor, an acceleration/deceleration signal generator receiving the output signal of the wheel speed sensor, a valve control circuit receiving the outputs of the slip signal generator and acceleration/deceleration signal generator, and electromagnetic inlet and outlet valves receiving the output of the valve control circuit. The maximum of the outputs of the approximate vehicle speed generators of the skid control circuits is supplied to the respective slip signal generators, two predetermined amounts are set in the respective slip signal generators, and a slip signal for relieving the brake to the wheel is generated from the slip signal generator, when the speed of the corresponding wheel becomes lower by more than either of the two predetermined amounts than the maximum output of the approximate vehicle speed generators. The larger of the two predetermined amounts is selected in the respective slip signal generators, until skid signals representative of the skid condition of the wheels occur in all of the skid control circuits, or in the slip signal generator of any one of the skid control circuits, until a skid signal or skid signals representative of the skid condition of the wheel or wheels occurs in the other of the skid control circuits.