Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Kevin Gerard Leppek

Allen John Walenty

David Alan Thatcher

Alexander Kade

Martin A Hogan

Peter J Spadafora

Robert J Hammersmith

Alan J Lee

Dennis J Ricker

Thomas H Gardner

James J Kowalik

Paul D Wilkey

Alex Kade

Naila Mikhaeil-Boules

Scott R Kloess

Calvin E Wolf

Alfred Russell Robertson

John Andrew Weber

An improved ABS control method incorporates entry criteria for initiating ABS control based on brake pedal position and rate of depression, adaptively adjusted by a reference pedal position corresponding to a predefined vehicle deceleration. A periodically-updated characterization of the relationship between brake pedal position and vehicle deceleration is used to establish the reference brake pedal position, and when insipient wheel lock is detected, the initiation of ABS control is delayed by an entry delay period that decreases with increasing rate of pedal depression and with the degree to which the pedal position exceeds the reference pedal position. In this way, the entry conditions are predicated primarily on the manner of brake pedal depression, with adaptive adjustment for variations in braking effectiveness.

Anti-lock brake control method having adaptive entry criteria

An improved anti-lock control method for a vehicle brake system identifies various factors that degrade the effectiveness of the brake system and adaptively adjusts a brake apply rate during anti-lock brake control to compensate for the identified degradation so that the optimal tractive force during anti-lock brake control is more nearly realized. The identified factors include fading due to brake heating, hydraulic leakage, mis-adjusted and non-releasing rear brakes, brake wear and excessive vehicle weight.

Adaptive compensation method for an anti-lock brake control

Apparatus and methods are provided for controlling movement of an automobile in a pitched position. The apparatus has an attitude sensor that is configured to determine a pitch of the automobile and a speed sensor that is configured to determine a speed of the automobile. In addition, the apparatus has a braking mechanism that is configured to inhibit movement of the automobile and a controller that is configured to control the braking mechanism. The controller is configured to receive the pitch and the speed determined by the attitude sensor and the speed sensor, respectively, and control the braking mechanism based at least in part upon an evaluation of the pitch and the speed in order to inhibit movement of the automobile in the pitched position.

Methods and apparatus for inhibiting movement of an automobile in a pitched position

A method and apparatus for operating a vehicle anti-lock braking system includes a brake pedal and a brake modulator that reduces braking pressure by an initial pressure reduction after detecting insipient wheel lock. Vehicle deceleration is measured as a function of brake pedal position. A first table is updated with the vehicle deceleration and the brake pedal position. A coefficient of friction of a road surface is estimated based on the first table. A slip target for at least one wheel is estimated and is based on an estimated maximum slip of the at least one wheel before losing traction minus an estimated potential for vehicle rollover. A deceleration target for at least one wheel is estimated and is based on an estimated maximum deceleration of the at least one wheel before losing traction minus the estimated potential for vehicle rollover.

Anti-lock braking system controller for adjusting slip thresholds on inclines

A vehicle anti-lock braking system includes a brake pedal and a brake modulator. The brake system reduces braking pressure by an initial pressure reduction after detecting insipient wheel lock. Vehicle deceleration is measured as a function of brake pedal position. A first table is updated with the vehicle deceleration and the brake pedal position. A coefficient of friction of a road surface is estimated based on the first table. Wheel slip and deceleration target thresholds are determined based on the coefficient of friction. The wheel slip and deceleration target thresholds are used to populate a command table for the anti-lock braking system. Brake heat, brake torque, vehicle weight and grade are estimated. Release and apply pressures are calculated from an adjusted coefficient of friction, a coefficient of friction and the grade.

Method for determining optimal ABS slip and deceleration thresholds

An improved anti-lock rear brake yaw control method utilizes a measure of braking intensity to regulate both the initiation of yaw control and the anti-lock braking control parameters once yaw control is initiated. The brake torque and the rate of brake pedal depression provide measures of braking intensity, and are used to develop variable slip and deceleration thresholds to which the rear wheel differential slip and deceleration are compared. The variable thresholds permit initiation of yaw control at relatively low levels of differential wheel slip or deceleration during panic braking, while requiring higher levels of differential wheel slip or deceleration to initiate yaw control during moderate braking. Once yaw control is initiated, the slip and deceleration thresholds are utilized to adaptively adjust the slip and deceleration targets, so that the targets are set in accordance with the slip and deceleration of the rear wheel with the lowest coefficient of friction during panic braking, and at higher levels during moderate braking.

Anti-lock brake yaw control method

An improved anti-lock brake control method in which the brake pressure reduction initiated upon detection of insipient wheel lock is adaptively determined based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration. The brake torque and vehicle weight are estimated based on the characterization data, corrected for variation in brake heating, and used to compute the surface coefficient of friction, which in turn, is used to schedule the initial anti-lock brake pressure reduction for optimal braking system performance.

Anti-lock brake control method having adaptive initial brake pressure reduction

A brake system control method for use in a vehicle in which wheel speed normalization factors are iteratively updated, comprising the steps of: monitoring a plurality of wheel speed signals from a plurality of wheel speed sensors; determining for each wheel a wheel acceleration responsive to the wheel speed signal; determining an acceleration dead band for each wheel, wherein the acceleration dead band is proportional to a measure of vehicle acceleration; comparing the wheel acceleration to the dead band; and if the magnitude of the wheel acceleration is greater than the magnitude of the dead band, inhibiting update of the normalization factors.

Brake system control in which update of wheel speed normalization factors is selectively inhibited

An improved anti-lock brake control method adaptively determines exit criteria for terminating anti-lock brake control based on rate of brake pedal release and estimates of the brake torque and road surface coefficient of friction. The brake torque and road surface coefficient of friction are estimated based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration.

Anti-lock brake control method having adaptive exit criteria

An improved method of diagnosing conditions of a vehicle braking system that degrade the braking effectiveness informs the driver of the condition so that repair or adjustment can be timely made. The relationship between brake pedal position and vehicle deceleration is determined during a calibration interval to construct a calibration table of brake effectiveness, and then periodically over the life of the braking system to develop a current brake effectiveness table. Braking system abnormalities that impair the braking effectiveness are diagnosed by analyzing the table values.

Method of diagnosing a vehicle brake system using brake pedal position and vehicle deceleration

A control for an automatic shifting power transmission employs an algorithm to determine the proper gear ratio during vehicle deceleration. The algorithm establishes downshift grade requirements based on the brake pressure and speed threshold targets based on brake pressure. A grade average is calculated from the operating parameters of acceleration, engine braking, aerodynamic drag, rolling resistance and brake torque deceleration. If the grade average is within downshifting range and the speed target is met, the control commands a downshift to the next lower gear ratio. The downshift grade requirements decrease as brake pressure increases and speed targets increase as brake pressure increases.

Adaptive brake compensation for grade braking

An adaptive brake control method, for a motor vehicle with first and second front vehicle wheels and third and fourth rear vehicle wheels, is achieved according to the steps of: receiving an operator input brake command; responsive to a brake command function stored in memory and the operator input brake command, developing a rear brake position command; outputting the rear brake position command to a rear brake actuator; monitoring the first and second front wheel speeds and the third and fourth rear wheel speeds; responsive to the monitored first and second front wheel speeds and the monitored third and fourth rear wheel speeds, updating the brake command function stored in memory, wherein the brake position command table is adaptively updated and a front to rear brake proportioning of the vehicle is adaptively controlled to minimize a difference between the front and rear wheel speeds during braking.

Method for proportionally controlling the brakes of a vehicle based on

A method of brake control, comprising the steps of: determining a deceleration of a vehicle; measuring a first wheel rotational velocity of a front wheel of the vehicle; measuring a second wheel rotational velocity of a rear wheel of the vehicle; determining a front wheel normalization value responsive to the deceleration and a front tire deformation constant; determining a rear wheel normalization value responsive to the deceleration and a rear tire deformation constant; determining a front normalized wheel rotational velocity responsive to the front wheel normalization value and the first wheel rotational velocity, wherein the front normalized wheel rotational velocity is responsive to a front tire deformation that occurs during a braking maneuver of the vehicle; determining a rear normalized wheel rotational velocity responsive to the rear wheel normalization value and the second wheel rotational velocity, wherein the rear normalized wheel rotational velocity is responsive to a rear tire deformation that occurs during a braking maneuver of the vehicle; subtracting the front normalized wheel rotational velocity from the rear normalized wheel rotational velocity to determine a difference; and adjusting front to rear brake proportioning responsive to the difference, wherein front to rear brake proportioning is responsive to tire deformation that occurs during a braking maneuver.

Electrohydraulic braking applied to a plurality of automotive vehicle braking channels operates to drive brake pressure modulator position toward a position corresponding to a braking input and corrected for channel to channel braking variations and vehicle deceleration error. A function for adapting the braking input to a position command is provided for each channel and is periodically adapted in accord with a difference between the channel's brake pressure modulator position error and a desired position error.

Electrohydraulic braking system

A regenerative and friction brake blend control method for use in a vehicle with at least one positionable hydraulic brake actuator for achieving friction braking and an electric propulsion motor with regenerative braking capability wherein an amount of regenerative braking achieved is indicated by a signal, wherein the method comprises the steps of determining a hydraulic actuator position command indicating a desired vehicle braking, determining responsive the hydraulic actuator position command a regenerative braking command, commanding the electric propulsion motor to regeneratively brake the vehicle responsive to the regenerative braking command, receiving the signal indicative of regenerative braking achieved, converting the signal indicative of regenerative braking achieved to an actuator position reduction signal, subtracting the actuator position reduction signal from the hydraulic actuator position command to determine a difference command, and commanding the hydraulic actuator according to the difference command, wherein the hydraulic actuator and the regenerative braking together achieve the desired vehicle braking.

Growing community of inventors

Rochester Hills, MI, United States of America

Kevin Gerard Leppek