Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Peter J Spadafora

Kevin Gerard Leppek

Martin A Hogan

Alan J Lee

Philip Mark Headley

Jill Gosma Hersberger

A motor speed controller for an antilock brake system motor driven brake pressure modulator controls the speed during the pressure ramping phase of an antilock brake pressure control cycle by commanding periods of dynamic braking of the motor while the motor current is being controlled to ramp the pressure.

Antilock brake system motor speed control

The current to the motor of a motor driven pressure modulator of an antilock brake system is controlled at a high value in response to a sensed incipient wheel lock condition so as to rapidly release the brake pressure for a calibrated time period that is a function of wheel parameters to reduce brake pressure by an amount determined to effect a recovery from the incipient wheel lock condition under normal antilock controlled braking. After the calibrated time period, the motor is braked so as to quickly halt its rotation and therefore the rapid pressure reduction by applying a motor brake current to the motor by controlling the motor current in the pressure apply direction. The duration of this rapid reduction of brake pressure and therefore the amount of pressure reduction is independent of a sensed recovery condition of the wheel and is based solely on an open loop calibration value determined to effect wheel recovery from the incipient wheel lock condition.

Antilock brake system with step-down release control

The period of an initial apply motor current in each apply phase of an antilock brake pressure cycle in a motor driven pressure modulator antilock braking system is adaptively controlled following a sensed recovery from an incipient wheel lockup condition to establish substantially a steady state condition relationship between current and pressure before motor current is ramped to ramp brake pressure. The period of the initial apply motor current is made a function of the amount of pressure decrease during a prior release phase portion of the antilock brake cycle to account for the greater increase in brake pressure to the initial reapply value.

Antilock brake system with motor current control of the pressure

A schedule of brake pressure ramp rates is provided in a vehicle antilock brake controller as a function of predetermined wheel parameters. The ramp rates associated with the specific values of the wheel parameters are filtered by limiting the changes in ramp rate to a next higher ramp rate from the schedule of rates when the ramp rate called for by the wheel parameters is greater than the present ramp rate and to a next lower ramp rate from the schedule of rates when the ramp rate called for by the wheel parameters is less than the present ramp rate.

Antilock brake controller with brake mode filter

The motor current in a vehicle antilock brake system motor driven pressure modulator is increased in stepwise fashion to ramp the brake pressure in the apply phase of an antilock braking cycle. At the beginning of each current step as the motor current is increased in stepwise fashion, the motor torque is increased momentarily at least by an amount to assure that the static friction of the pressure modulator is overcome and that motor rotation is initiated. The motor torque is increased to a value to initiate motor rotation at the beginning of each current step by momentarily increasing the motor current to a value greater than the current step value by a predetermined amount that assures that the increase of motor torque exceeds the static friction of the pressure modulator.

Antilock brake system with motor current control

An anti-lock braking control system is described in which the braking pressure cycle is filtered by limiting the minimum time period of each brake pressure cycle. The period from the time a brake pressure release phase is initiated until the next brake pressure release phase is called for is timed. If the time is less than a predetermined value, the brake pressure is held constant until the minimum time period has expired.

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Howald, Luxembourg

Peter J Spadafora