Pressure control apparatus for adjusting brake pressure in a vehicle

Abstract

A pressure control apparatus for adjusting the brake pressure in a braking system of a vehicle comprises a reservoir in which a pressure fluid is stored, an outlet through which the pressure fluid is discharged, at least one brake cylinder of the braking system, inlet and outlet valves through which the pressure fluid is supplied to and discharged from the brake cylinder, and a digital controller which controls the opening and closing of the inlet and outlet valves to minimize the deviation between an actual value and a command variable. The digital controller comprises individual controllers associated with the inlet and outlet valves. The individual controllers operate in accordance with a changeable PIDD.sup.2 control formula. The digital control further comprises a three-stage controller connected downstream of the individual controllers and adjustable low pass filters for the inlet and outlet valves. A pressure phase detector determines the current pressure phase to be set (i.e., increase, maintain or decrease) based on the command variable, and adjusts the operation of the individual controllers, the three-stage controller, and the low pass filters based on the current pressure phase.

Dependencies are inferred from the claim text.