Abstract: An electrically controlled fluid displacement piston positioned in a bore modulates braking pressure at a wheel brake for antilock controlled braking by modulating the position of the piston in the bore. At a fully extended home position, a check valve is unseated by the piston to hydraulically couple the brake system master cylinder to the wheel brake. To minimize the occurrences of the condition where the check valve is opened during ABS controlled braking, the piston is initialized prior to entry into antilock controlled braking at a position away from the check valve resulting in a greater volume of fluid being trapped upon entry into antilock controlled braking when a hydraulic passage in parallel with the check valve is closed in response to a detected incipient wheel lock condition. This permits the antilock brake system to apply a controlled brake pressure greater than the pressure initially trapped in the closed system.

Abstract: A multi-phased electrically commutated brushless DC motor driven brake pressure modulator includes a pressure actuator the position of which is controlled by the motor to establish the desired brake pressure. The movement of the actuator is determined by monitoring the motor rotation as represented by the output of the rotor position sensors used in commutation of the motor windings. The position of the actuator is represented by a counter value which is incremented or decremented in response to the output of the rotor position sensors and the direction of motor rotation. The counter value is related to the actuator position by presetting the counter value when the actuator in a known position such as a mechanical limit position. The known position is established by causing the motor to rotate in a direction to position the actuator toward the limit position until further outputs of the rotor position sensor are not sensed indicating the actuator is at its mechanical limit position.

Abstract: A vehicle antilock control system provides for selectively enabling the rear wheels of a vehicle to free-wheel and thereby attain vehicle velocity to provide an accurate measure of the vehicle speed during antilock controlled braking.

Abstract: A traction control system (TC) pressure actuator is provided. The actuator includes a frame with a central bore fluidly exposed to a solenoid valve and to a vehicle wheel cylinder. A piston is slidably mounted within the bore having a contact surface and a first predetermined position within the bore. A power device is actuated by a controller. A cam moved by the power device has a ramp surface in contact with the piston contact surface. The position of the piston within the wheel cylinder is determined by the position of the cam.

Abstract: An automotive vehicle drum brake including a brake drum for connected to the vehicle wheel and a backing plate for connected to the vehicle. At least one brake shoe is and pivotally mounted with respect to the backing plate. A non-rotative nut mounted for linear motion with respect to said backing plate and has a pivotal connection with the brake shoe. A power screw is threadably engaged with the nut. An electric motor powers the power screw to turn the same to actuate the brakes. A parking brake mechanism is also provided by a coil spring which surrounds a drum which is connected with the power train from and including the electrical motor and the power screw. An actuator is provided to move the coil spring to an unwound position to allow the parking brake to release.

Abstract: An automotive vehicle drum brake is provided including a brake drum connected to a wheel. A backing plate is connected to the vehicle and at least one brake shoe is connected with the backing plate and is pivotally mounted with respect thereto. A non-rotative nut is mounted for linear motion with respect to the backing plate and is pivotally connected with respect to the brake shoe. A power screw is threadably engaged with the nut. The power screw is also mounted to the backing plate. An electric motor is torsionally connected with the power screw to turn the same to actuate the brakes.

Abstract: An integrated anti-lock braking system (ABS)/traction control (TC) braking system for a vehicle having a fluid activated brake for a wheel is provided the system in one embodiment includes a system controller for signaling the system to an ABS or TC mode, a master cylinder for delivering pressurized fluid to the wheel brake, an actuator with a longitudinal bore having a first stop. A hollow primary piston is slidably mounted within the longitudinal bore biased towards the first stop. The interior of the primary piston is fluidly connected with its exterior. A secondary piston is slidably mounted within the primary piston and movable in one direction to pressurize the wheel brake and movable in an opposite direction to relieve said wheel brake in response to the controller.

Abstract: 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.

Abstract: 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. The predetermined fraction provides for adaptive adjustment of the brake pressure if the identified brake pressure is in error until a pressure is applied that produces substantially the maximum possible braking effort.

Abstract: 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.

Abstract: A wheel lock control system is described which utilizes both independent and select low modes of wheel lock controlled braking. When braking on a surface in which the coefficients of friction between the two sides of the vehicle are substantially different or when the vehicle is undergoing severe steering maneuvers while braking, the wheel lock control system utilizes a select low mode of braking for the vehicle rear wheels so as to maintain vehicle stability. However, when the four wheels are being braked on a substantially uniform coefficient of friction surface, the wheel lock control system utilizes an independent mode of braking for each of the wheels of the vehicle so as to minimize the vehicle braking distance.

Abstract: 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 the identified pressure after an incipient wheel lockup condition is sensed. Constants in an expression estimating the braking effort are adaptively adjusted to compensate for changes in system parameters over time.

Abstract: A control for separately driven, potentially interfering wiper blades includes position sensors for each wiper blade and a memory which stores, for each pattern, numbers representing inner and outer wipe positions with acceleration, constant velocity and deceleration regions therebetween and a command velocity for the constant velocity regions. The memory further stores numbers defining a zone of potential blade interference and, for each position of each blade within this zone, a non-interference zone for the other blade. The control further includes closed loop velocity control apparatus responsive to the signals from the position sensors and the command velocity to maintain the command velocity in the constant velocity region, accelerate to the command velocity in the acceleration region and decelerate from the command velocity in the deceleration region.

Abstract: 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. The predetermined fraction provides for adaptive adjustment of the brake pressure if the identified brake pressure is in error until a pressure is applied that produces substantially the maximum possible braking effort.

Abstract: 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.

Abstract: A transistor bridge driver circuit having reduced operating losses, comprising a driver transistor connected to supply drive current to diagonally opposed bridge transistors and an auxiliary transistor effective when biased conductive to divert driver current away from one of the diagonally opposed bridge transistors. Switching losses are minimized because the bridge is operated in the one quadrant control mode and driver losses are minimized because one driver circuit controls the conduction of two diagonally opposed bridge transistors.

Abstract: The gain of a servomotor driven process control system is adaptively compensated for changes in the motor coulomb friction torque. The gain is manually adjusted at the time of installation. Thereafter, the minimum motor current occurring in a process cycle is identified, and the gain is automatically adjusted if the identified minimum motor current changes over time, indicating a change in the motor coulomb friction torque. As a result, the level of response stability achieved at the time of installation is maintained despite changes in the motor coulomb friction torque.

Abstract: An overcurrent circuit interrupts energization of the electric motor of a motor vehicle electric power steering system whenever the motor current exceeds an overcurrent limit, thereby defining an overcurrent duty cycle. When the overcurrent duty cycle reaches a value indicative of motor stalling, the overcurrent limit is reduced to protect the motor and its drive circuitry during prolonged motor stalling.

Abstract: 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. The predetermined fraction provides for adaptive adjustment of the brake pressure if the identified brake pressure is in error until a pressure is applied that produces substantially the maximum possible braking effort.

Abstract: 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.