Process and circuit arrangement for controlling the slip when braking a road vehicle

Claim 1

A process for improving control during braking of a road vehicle by controlling the slip in the presence of different adhesive values on the right and left sides of the vehicle, wherein means are provided for detecting the rotational behavior of the vehicle wheels and the vehicular velocity to provide derived measured values in signal form and wherein the said signals are logically combined and processed and wherein, upon the instabilization of a wheel including the occurrence of a lock-up tendency, the signals independently control the braking force at said respective instable front wheel is kept at least constant and upon change in signal is thereafter reincreased, said process comprising the steps of evaluating the rotational behavior of the wheels (VR, VL, HR, HL) and the vehicular deceleration according to predetermined criteria manifesting the possibility of danger due to yawing moments which are capable of impairing the driving stability of the vehicle and wherein, when a predetermined yawing moment threshold value or a corresponding measured value is reached, restricting any further increase of the yawing moment by limiting the braking force, by keeping the braking force constant, or if the yawing moment continues by reducing said braking force, and by diminishing the degree of increase of the braking force at the front wheel which has a better contact with the road surface and further wherein the same said braking force is applied to the rear wheels (HR, HL) of the vehicle, wherein control of said braking force is a function of the slip signal of the rear wheel having a worse contact with the road surface, and wherein the deceleration (v HRh ) of the rear wheel with a better contact with the road surface is evaluated as a measure of the vehicular deceleration when ascertaining the criteria for determining the yawing moment.