Adaptive braking system with special control for slippery surfaces

Abstract

An adaptive braking system for a vehicle having fluid pressure operated brakes includes a skid detecting circuit for generating a signal when an incipient skidding condition is detected, a pressure command generator which is responsive to the skid detecting signal for generating a pressure command signal proportional to the optimum fluid pressure level in the vehicle's brakes, and a duty cycle translator responsive to the pressure command signal to actuate the brake pressure modulator. Of course, since the pressure level in the vehicle brakes cannot drop below zero, the value of the pressure command signal generated by the pressure command generator cannot drop below a predetermined level. If the skid detecting circuit continues to generate a signal indicating an incipient skidding condition after the pressure command signal is at its lowest level, the subsequent brake pressure increase which is normally initiated upon termination of the skid detecting signal is delayed for a time period which is a function of the time period in which the skid detecting signal was generated after the value of the pressure command signal had dropped to the lowest permissible level.