Anti-skid system for a vehicle

摘要

An improved anti-skid system for a vehicle which effectively utilizes an approximated slip ratio between vehicle or body velocity and wheel velocity to generate a brake release signal for a brake release valve but without actually utilizing a vehicle or body velocity detector. Storage apparatus is used to store a reference signal representing vehicle velocity but actually corresponding to a present or just past maximum value of wheel velocity. Control apparatus is then utilized for removing energy from the storage apparatus at a controlled predetermined rate chosen to approximate the expected vehicle deceleration (but without using an actual vehicle or body deceleration detector) such that the reference signal (capacitor voltage) will continue to accurately represent approximate vehicle velocities even during periods of deceleration. Various exemplary embodiments are described for the control apparatus which may be used to hold the discharge rate constant, to change it from a first low rate to a second high rate during brake release (for compensating inherent time lags in the vehicle brake system) and/or to continuously change the rate in an inverse dependency upon wheel deceleration to even more closely approximate actual vehicle deceleration under variable road conditions. Other features of the improved system may be used to result in rapid oscillatory brake releases as a transition both before and after a more prolonged brake release period to provide for smoother operation of the anti-skid system. Spurious influences of any A.C. ripple components on the detected wheel velocity signal may also be substantially eliminated by using some of the features of this system.