METHOD AND APPARATUS FOR ANTI-SKID BRAKE CONTROL OF AN AUTOMOTIVE VEHICLE

Disclosed is a method and apparatus for controlling application and release of brake pressure in automotive vehicle brakes in order to prevent the vehicle from skidding. The system has a component for determining the coefficient of friction between the road surface and a tire tread, operative to determine that coefficient as a function of the wheel acceleration, wheel load and brake torque. Additionally there is provided a circuit for detecting a peak of the friction coefficient during a control cycle, as well as circuitry for determining wheel r.p.m. and for determining target wheel r.p.m. The latter function is performed on the detected wheel r.p.m. responsively to detection of the peak of the friction coefficient. Additionally, a control device is provided for controlling applying and releasing of fluid pressure to wheel cylinders for skid controlling the rate of wheel deceleration. The target wheel r.p.m. determining circuit determines a deceleration coefficient of wheel r.p.m. based on the difference of wheel r.p.m. between the time of detecting the peak of the friction coefficient and the time of detecting the immediately preceding peak, and the length of the interval between detecting the peaks. The circuit determines the target wheel r.p.m. by subtracting a time varying amount, obtained as a function of the determined deceleration coefficient, from the wheel r.p.m. determined at the time of detecting of the peak of the friction coefficient.