Abstract: There is disclosed a method for integrating a vehicle stability enhancement system and rear wheel steering. The method includes inputting a vehicle speed and measured vehicle yaw rates. Determining a front and rear wheel steer angle. Calculating a desired yaw rate. Comparing the measured yaw rate with the desired yaw rate to determine a yaw error term. Applying a braking force to a wheel of a vehicle imparting a yaw moment based upon the magnitude of the error term calculated. The rear wheel steer angle is taken into account in calculating a desired yaw rate.

Abstract: There is disclosed a method for integrating a vehicle stability enhancement system and rear wheel steering. The method includes inputting a vehicle speed and measured vehicle yaw rates. Determining a front and rear wheel steer angle. Calculating a desired yaw rate. Comparing the measured yaw rate with the desired yaw rate to determine a yaw error term. Applying a braking force to a wheel of a vehicle imparting a yaw moment based upon the magnitude of the error term calculated. The rear wheel steer angle is taken into account in calculating a desired yaw rate.

Abstract: A method is disclosed for improving the estimate of vehicle yaw rate in the computer of the brake or traction control system of a vehicle, like a truck or sport utility vehicle, having a relatively high center of gravity and tending to roll during yaw. Yaw is typically estimated by sensing the speed of the non-driven wheels, determining the difference between the wheel velocities and dividing the difference by the track of the wheels. A table of correction factors correlated with vehicle speed is prepared and used to compensate for the effect of roll on yaw rate.

Abstract: A process is disclosed for use in a micro-processor managed brake control system that utilizes wheel speed sensors and a brake off/on switch when the system requires information as to whether the vehicle is experiencing hard braking. In accordance with the process, the average deceleration of the undriven wheels is estimated and the slip of each undriven wheel is estimated and the results are compared with predetermined values for these parameters over a suitable test period. At the conclusion of these tests, the data may be used in place of data from a brake pedal position sensor or to confirm the data from such a sensor.

Abstract: An improved vehicle yaw control that does not require a yaw sensor, wherein the validity of an estimate of vehicle yaw is determined and used to select an appropriate control methodology. The vehicle yaw is estimated based on the measured speeds of the un-driven wheels of the vehicle, and various other conditions are utilized to determine if the estimated yaw rate is valid for control purposes. When it is determined that the estimated yaw rate is valid, a closed-loop yaw rate feedback control strategy is employed, whereas in conditions under which it is determined that the estimated yaw rate is not valid, a different control strategy, such as an open-loop feed-forward control of vehicle yaw, is employed. The validity of the estimated yaw rate is judged based on a logical analysis of the measured wheel speed information, braking information, and steering wheel angle. The measured speeds of the un-driven wheels are used to compute an average un-driven wheel speed and an average un-driven wheel acceleration.

Abstract: An improved closed-loop vehicle yaw control in which a yaw rate limit based on measured lateral acceleration is used during transient steering maneuvers to dynamically limit a desired yaw rate derived from driver steering input. A preliminary yaw rate limit is computed based on the measured lateral acceleration, and a dynamic yaw rate limit having a proper phase relationship with the desired yaw rate is developed based on the relative magnitudes of the desired yaw rate and the preliminary yaw rate limit. A two-stage process is used to develop the dynamic yaw rate limit. A first stage yaw rate limit is determined according the lower in magnitude of the desired yaw rate and the preliminary yaw rate limit, and a second stage yaw rate limit (i.e., the dynamic yaw rate limit) is determined according to the relative magnitudes of (1) the desired yaw rate and the second stage yaw rate limit, and (2) the first stage yaw rate limit and the second stage yaw rate limit.

Abstract: A brake system control method, comprising the steps of: measuring a longitudinal speed and steering angle of the vehicle; specifying an un-damped natural frequency and a damping ratio for a linear reference model of said vehicle; determining a first gain parameter relating a desired value of steady state lateral velocity to the vehicle steering angle; computing a desired lateral velocity as a function of said first gain parameter, the measured longitudinal speed, the measured steering angle, and the specified un-damped natural frequency and damping ratio; determining a second gain parameter relating a desired value of steady state yaw rate to the vehicle steering angle; computing a desired yaw rate as a function of said second gain parameter, the measured longitudinal speed and steering angle, and the specified un-damped natural frequency and damping ratio; measuring a lateral acceleration and yaw rate of said vehicle, and forming a yaw rate command for said vehicle based at least part in a first deviation be

Abstract: An improved low cost vehicle yaw rate control that is compensated for road bank angle using readily available information, such as steering angle, vehicle speed, and the speeds of the un-driven vehicle wheels. The control is founded on the recognition that, under linear operating conditions on a banked surface, the difference between the desired yaw rate and the actual or estimated yaw rate yields a yaw rate offset that will compensate for the bank angle, and the product of yaw rate and vehicle speed corresponds substantially to lateral acceleration. The yaw rate offset is used to compensate the yaw control when the steering angle, the yaw rate--vehicle speed product and yaw rate error are indicative of operation on a banked road. The compensation is deactivated when the steering angle, the yaw rate--vehicle speed product and yaw rate error are not indicative of operation on a banked road.

Abstract: An improved active brake control for carrying out a desired wheel speed differential for enhanced vehicle lateral stability while maintaining suitable front-to-rear brake pressure proportioning. During driver braking, the target speeds for the wheels of the driven axle during active brake control are determined as a combined function of the wheel speeds of the un-driven axle and the desired wheel speed differential. Specifically, the target speeds for the driven wheels are determined according to the measured speeds of the corresponding un-driven wheels, and one of the target speeds is reduced to reflect the desired wheel speed differential. If the desired wheel speed differential is designed to produce a clockwise yaw moment, the target speed for the driven wheel on the right-hand side of the vehicle is reduced; if the differential is designed to produce a counter-clockwise yaw moment, the target speed for the driven wheel on the left-hand side of the vehicle is reduced.

Abstract: An improved active brake control in which differential braking is used in a feed-forward control to develop vehicle yaw in response to a desired yaw value determined as a function of steering wheel position and vehicle speed. The desired yaw rate value is used to develop a derivative yaw component and a proportional yaw component, which are summed to form a feed-forward yaw command for differential braking. Both proportional and derivative components have limited control authority determined by dead-band and saturation thresholds, and the proportional term is subjected to a diminishing integrator which reduces the yaw command as the desired yaw rate value approaches steady-state.

Abstract: A brake system control for use in a vehicle with wheels, wheel brakes and a body, comprising the steps of: measuring a plurality of vehicle parameters; responsive to the measured parameters, determining at least a vehicle yaw rate, a vehicle slip angle, a desired yaw rate and a desired slip angle; responsive to the measured parameters, estimating a coefficient of adhesion between the vehicle wheels and a road surface; implementing a control responsive to the vehicle yaw rate and the desired yaw rate with a first authority and responsive to the vehicle slip angle and the desired slip angle with a second authority, wherein the first authority increases as the estimated coefficient of adhesion increases and decreases as the estimated coefficient of adhesion decreases; and controlling the wheel brakes responsive to the control to reduce a first difference between the vehicle yaw rate and the desired yaw rate and to reduce a second difference between the vehicle slip angle and the desired slip angle.

Abstract: In a vehicle with a first operating mode in which all vehicle wheels have substantially no lateral movement on a road surface and a second operating mode in which at least some of the vehicle wheels have lateral movement on the road surface, and with an actuator capable of affecting vehicle yaw rate, a vehicle yaw rate control method comprising the steps of: measuring an actual vehicle yaw rate; measuring vehicle steering wheel position; in the second mode of operation, determining a desired yaw rate command linearly responsive to the measured steering wheel position; wherein the actuator is controlled to minimize a difference between the measured vehicle yaw rate and the desired vehicle yaw rate.