Gm Global Technolgoy Operations, Inc.

Paul D Agarwal

Alexander Kade

Robert J Hammersmith

Thomas A Radomski

Roger D Fruechte

A wheel lock control system is described for a wheel braking system that includes a motor driven actuator for applying controlled hydraulic brake pressure to the wheel brake that is determined by motor current. The motor current corresponding to the brake pressure producing the maximum possible braking effort during each brake pressure application is identified and a value related thereto is reapplied to the motor after an incipient wheel lockup condition is sensed.

DC torque motor actuated anti-lock brake controller

A brake control system is described that prevents a wheel lockup condition by identifying the brake pressure that produces the maximum possible braking effort during each brake pressure application period and applying a predetermined fraction of the identified pressure after an incipient wheel lockup condition is sensed. One criteria for sensing an incipient wheel lockup condition is the decrease in the braking effort from the maximum possible braking effort by a predetermined amount as wheel slip increases from a critical slip value.

Anti-lock brake control system

A brake system actuator which is actuated to increase pressure delivered to a wheel brake through a drive transfer mechanism powered by a variable torque electric motor, the actuator piston being retracted by a substantially constant torque spiral spring which is preloaded to drive transfer means in the opposite direction when the motor is deenergized. This is particularly useful in a brake actuator which is a component of a vehicle wheel brake and wheel anti-lock control system.

Brake system actuator with a return spring

A vehicle brake and wheel anti-lock control system in which an electronically controlled actuator normally provides brake pressure for the vehicle wheel brakes and also acts as a modulator to vary the brake actuating pressures for wheel anti-lock control. The actuator is so arranged that a master cylinder may be used to provide actuating pressure to the wheel brakes, the pressure passing through the actuator pressurizing chamber, if for any reason the actuator does not perform as needed to provide brake actuating pressure to stop the vehicle.

Actuating mechanism in a vehicle wheel brake and anti-lock brake control

The torque gain of an electric motor assisted power steering system is modified as a function of the estimated level of road load friction such that the relationship between the operator exerted steering torque and the resulting rate of steer is substantially insensitive to a reduction in the level of road load. The road load is estimated as a function of the operator exerted steering torque, the torque assist provided by the electric motor, and the resulting steer rate.

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Troy, MI, United States of America

Paul D Agarwal