Method, circuit, and apparatus for anti-skid brake control in motor vehicles

An anti-skid control apparatus for an automobile, which comprises:

• sensor means for producing outputs corresponding respectively to respective rotating speeds of a plurality of vehicle wheels;
• a simulative vehicle speed producing circuit to detect simulatively the wheel speed from the outputs of said sensor means, thereby to produce a simulative vehicle speed signal;
• a wheel speed detecting circuit to derive a speed signal of a wheel to be controlled from said outputs of said sensor means;
• a deceleration calculating circuit to calculate the deceleration of the wheel to be controlled;
• a comparing logical circuit to compare said simulative vehicle speed signal with said wheel speed signal thereby to calculate a slip ratio and to discriminate between a predetermined slip range and other slip ranges;
• and
• control means for increasing braking hydraulic pressure when said slip ratio is above said predetermined slip range to bring said slip ratio within said predetermined slip range, for increasing or decreasing the braking hydraulic pressure in response to acceleration or deceleration of the wheel when said slip ratio is within said predetermined slip range, and for decreasing the braking hydraulic pressure to bring said slip ratio within said predetermined slip range when said slip ratio is below said predetermined slip range.