Abstract: 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.

Abstract: 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.

Abstract: 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 diff

Abstract: An electric braking system controls the vehicle brake torque based on the pressure applied by the vehicle operator to the vehicle brake pedal and a moving vehicle brake system gain to provide normal power assisted braking while the vehicle is moving. The deviation of the vehicle braking condition from a level incline and lowest vehicle weight (LVW) is determined based upon a determined percent difference between the actual vehicle deceleration while the vehicle is being braked to a stop and an expected deceleration that would result from the total brake torque, a level road surface, and the vehicle weight at LVW. The expected deceleration is determined by determining the total vehicle brake torque represented by the sum of the brake torques applied by the individual wheel brakes and dividing by the LVW of the vehicle.

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 braking system is provided which, in a preferred embodiment, includes a master cylinder having a bore with first and second diameters, a first piston slidably mounted within the master cylinder having a first periphery sealed with the bore first diameter and a second periphery sealed with the bore second diameter, the first piston establishing within the master cylinder bore a first pressure chamber between the first and second sealed peripheries and a second pressure chamber between the first piston second sealed periphery and the bore closed end, the first piston also having a central bore exposed to the second pressure chamber, first and second fluid lines joining the first and second pressure chambers with the wheel brake, a second piston slidably sealably inserted within the first piston bore, the second piston having a flange and having limiting displacement away from the bore closed end, a spring captured between the first piston and the second piston flange, a pressure sensor to determine the pressu

Abstract: The left and right rear brake systems of a vehicle each are controlled by a respective electric torque motor. A rear wheel braking system controls the current to each of the torque motors so that each rear wheel is controlled to a speed having a predetermined relationship to the corresponding front wheel. The relationship between the motor currents when each wheel speed has been established at the predetermined relationship is used to determine a bias current value used to equalize the gains of the left and right rear brake systems.

Abstract: 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.

Abstract: A brake system for the rear wheels of a vehicle applies brake pressure to each rear wheel so as to establish the rear wheel speed at a predetermined relationship to the speed of the front wheel on the same side of the vehicle. The brake pressure applied to each of the front and rear wheels is limited by antilock controlled braking in response to a sensed incipient lockup condition of the wheel. When a front wheel first enters into an antilock controlled braking, in response to an incipient wheel lockup condition, the brake pressure to the rear wheel on the same side of the vehicle is rapidly increased to induce an incipient wheel lockup condition thereby inducing antilock controlled braking of the rear wheel.

Abstract: In an antilock braking system, when wheel parameters including slip represent an incipient wheel lockup condition normally calling for a release of brake pressure during a pressure apply mode of an antilock braking cycle and the duration of the pressure apply mode is less than a predetermined threshold representing an abnormal rapid cycling of the brake pressure, the wheel slip threshold representing an incipient wheel lockup condition is increased, the rate of increase in brake pressure during the brake pressure apply mode is set to a high level and the pressure apply mode is continued during which the wheel brake pressure is ramped at the increased rate. These steps are repeated while the wheel parameters represent an incipient wheel lockup condition normally calling for a release of brake pressure until the time of the pressure apply mode equals the predetermined threshold representing a normal brake pressure cycling period.

Abstract: A vehicle wheel anti-lock braking system (ABS) is provided including a master cylinder and a wheel brake. A controller cognizant of the rotational condition of the wheel provides a signal when the wheel condition is within preset parameters. An actuator frame is also provided having a bore fluidly communicating with the wheel brake. A piston is mounted within the bore for providing a variable control volume in communication with the wheel brake and for modulating the pressure therein. A reversible motor reciprocally powers the piston. The motor has a rotor with a connected disc. A friction surface is provided for engagement with the disc to lock the position of the piston. A plunger is also provided to urge the friction surface into engagement with the disc. An electromagnetic core, responsive to a signal by the controller, moves the plunger to a position allowing cessation of engagement between the friction surface and the disc thereby allowing rotation of the motor and movement of the piston.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A vehicle wheel anti-lock braking system (ABS) is provided including a master cylinder and a wheel brake. An ABS controller cognizant of the rotational condition of the wheel provide a signal when the wheel condition is within preset parameters. An isolation valve responsive to close upon an activation signal given by said controller prevents fluid communication between the master cylinder and the wheel brake. An actuator frame is also provided having a bore fluidly communicating with the wheel brake. A piston is mounted within the bore for providing a variable control volume in communication with said wheel brake for and modulating the pressure therein. A reversible motor reciprocally powers piston. The motor has a rotor with a connected disc. A friction surface is provided for engagement with the disc to lock the position of the piston. A plunger is also provided to urge said friction surface into engagement with said disc.

Abstract: A brake control system is described that maximizes the braking efficiency of an under-damped actuator, such as a motor-driven linear screw. When an incipient lock condition is detected, the system determines the optimal brake pressure, relieves brake pressure and measures the duration of the pressure release. When the wheel is approaching recovery, but has not yet substantially recovered, the system holds brake pressure constant at a value calculated to represent the amount of pressure remaining at the wheel brake. This calculated hold value is based upon the measured optimal pressure and the measured release duration, and allows the wheel to continue to reaccelerate towards recovery while preventing unnecessary pressure relief. Once the wheel recovers, the system reapplies brake pressure to a substantial fraction of the optimal pressure without over-exciting the actuator and over-shooting the desired pressure.

Abstract: A brake control system is described that maximizes vehicle braking efficiency by first determining, and then cycling wheel brake pressure and consequently wheel slip about, the critical slip value for the road surface. As each road surface has unique tractive characteristics, the amount of brake pressure required to produce critical wheel slip, and hence maximum brake force, varies for different coefficient of friction road surfaces. This invention determines the coefficient of friction for the operating surface and adjusts the system slip threshold to accurately mimic the actual critical slip value for the road surface. The invention then applies and releases wheel brake pressure so as to cycle wheel slip about this critical slip value.

Abstract: A brake control system is described that maximizes vehicle braking efficiency by maximizing the amount of time spent cycling pressure at or near the optimal pressure for the road surface. Upon detecting an incipient wheel lock condition, the system measures the optimal pressure for the road surface and relieves pressure. Once wheel recovery is sensed, the system reapplies pressure to a significant fraction of the optimal pressure and increases pressure gradually from that point. If a change to a higher coefficient surface occurs while the system is modulating brake pressure, the system detects that surface transition and rapidly increases brake pressure to quickly arrive at the new optimal pressure.