Delphi Technologies, Inc.

Gm Global Technolgoy Operations, Inc.

Scott Wilson Badenoch

David Andrew Shal

Raymond Kurt Schubert

Albert Victor Fratini

Karen Marie Connair

Eldon Gerrald Leaphart

Scott A Stacey

Albert Victor Fratini, Jr

Todd A Belvo

Harold David Hamilton

A variable power steering system for a motor vehicle is responsive to an activity signal from a vehicle stability enhancement (VSE) system and a lateral surface coefficient of friction estimator to modify steering assist in an amount dependent on the estimated surface coefficient when the vehicle stability enhancement system is active. The modification is phased in and out with slew limiting in steps also determined by the estimated lateral surface coefficient, with both the maximum modification and the step size varying inversely with lateral surface coefficient. The system preferably determines offset current values for the VSE system and estimated lateral acceleration, as well as for any other vehicle traction limit handling systems such as anti-lock braking (ABS) or traction control (TCS) and chooses the greatest in magnitude as a road surface adaptation offset current for addition to a vehicle speed offset current to provide a total current signal for the modification.

Adaptive variable effort power steering system

A motor vehicle has a body supported on a front pair of wheels and a rear pair of wheels with front suspension apparatus providing controllable vertical wheel constraint and roll stiffness and a rear pair of wheels with rear suspension apparatus providing controllable vertical wheel constraint and rear roll stiffness. Responsive to a commanded vehicle acceleration or braking, the driven wheel (acceleration) or front (braking) suspension apparatus is briefly altered to provide optimal tire patch traction for the one of the pair of wheels. The alteration may be further responsive to vehicle speed and/or lateral acceleration. The controllable part of the suspension apparatus may be dampers, springs or anti-sway apparatus such as torsion bars. If anti-sway apparatus, the front and/or rear roll stiffness may be controlled to promote oversteer at low vehicle speed and understeer at high vehicle speed.

Motor vehicle dynamic control

A rear wheel steering control determines, when desired and actual lateral accelerations of a vehicle have the same direction, an instantaneous dynamic yaw center on a vehicle longitudinal axis in response to the measured vehicle speed. It further determines a cornering radius and an instantaneous Ackerman center as a point at the outer end of the cornering radius extended outward perpendicular to the vehicle longitudinal axis from the instantaneous Ackerman center. The control then directs a rear wheel of the vehicle to be perpendicular to a line connecting the instantaneous Ackerman center to the center of the wheel. The dynamic yaw center, and thus the instantaneous Ackerman center, is preferably shifted rearward with increasing vehicle speed to shift vehicle steering in a direction from oversteer at very low speeds for greater ease of steering in parking maneuvers to understeer for vehicle stability in high speed driving conditions. The method and apparatus preferably include a reverse lock routine to control the rear wheels when the desired and actual lateral accelerations of the vehicle have opposing directions, to control the vehicle in a four wheel drift; and the reverse lock routine may further adjust suspension damping.

Rear steering control with longitudinal shift in Ackerman center

A vehicle suspension control includes a vehicle body control responsive to body/wheel velocity at the corners of the vehicle body to derive a demand force command for dampers at each corner of the vehicle body for vehicle body control and applies each of the derived demand force commands to its respective damper only when a comparison of the direction of the demand force command with the sensed relative velocity of the damper indicates that a force corresponding to the demand force command can be effectively exerted by the damper. But the suspension control also includes a vehicle stability control responsive to an indicated vehicle lateral acceleration in a turn to determine, independently of the vehicle body control, a stability compression damping command for the suspension dampers on the side of the vehicle opposite the direction of the lateral acceleration and a stability rebound damping command for the suspension dampers on the side of the vehicle in the direction of the lateral acceleration. While the lateral acceleration is sensed, the vehicle stability control applies the stability compression damping command to the suspension dampers on the side of the vehicle opposite the direction of the lateral acceleration and the stability rebound damping command to the suspension dampers on the side of the vehicle in the direction of the lateral acceleration, without regard for the direction of demand force for any of the suspension dampers. The resulting stiffening of the suspension on the outside of the turning vehicle in compression and on the inside of the turning vehicle during rebound helps keep the tires of the vehicle firmly in contact with the road surface in spite of road surface irregularities.

Vehicle suspension control with stability in turn enhancement

A vehicle suspension system is responsive to an active brake signal from a brake system indicating the application of a greater braking force to one front corner brake than to the other front corner brake to affect vehicle yaw rate. The vehicle suspension system determines the relative velocities of the front corner suspension adjacent the front corner brake receiving the greater braking force and the diagonally opposed rear corner suspension and further determines a compression damping command for the front corner suspension and a rebound damping command for the rear corner suspension. While the active brake signal is present, the suspension control applies the compression damping command for the front corner suspension when its relative velocity indicates that it is in compression. While the active brake signal is present, the suspension control also applies the rebound damping command for the rear corner suspension when its relative indicates that it is in rebound.

Vehicle suspension control with compensation for yaw correcting active brake control

In a vehicle with four corner suspensions, wherein during a transient turning maneuver, a body of the vehicle tends to compress two of the corner suspensions on a first side of the vehicle and expand two of the corner suspensions on a second side of the vehicle, wherein road inputs cause random compression and rebound of the four corner suspensions, a suspension control method comprising the steps of: sensing vehicle speed; monitoring steering wheel velocity; responsive to the vehicle speed and the steering wheel velocity, determining a signal indicative of a transient turning maneuver of the vehicle; responsive to the signal, determining compression damping commands for the two corner suspensions on the first side of the vehicle; responsive to the signal, determining rebound damping commands for the two corner suspensions on the second side of the vehicle; monitoring relative velocity of each corner suspension; applying the compression damping commands for the two corner suspensions on the first side of the vehicle when the relative velocities for those two corner suspensions indicate that they are in compression and terminating the compression damping commands for the two corner suspensions on the first side of the vehicle during the random rebounds of those two corner suspensions caused by the road inputs; and applying the rebound damping commands for the two corner suspensions on the second side of the vehicle when the relative velocities for those two corner suspensions indicate that they are in rebound and terminating the rebound damping commands for the two corner suspensions on the first side of the vehicle during the random compressions of those two corner suspensions caused by the road inputs.

Vehicle suspension control system and method

A method of controlling a vehicle suspension system comprising the steps of: determining a relative velocity between a wheel and the corner of a vehicle body; determining responsive to the relative velocity, according to a non-linear passive function, a raw wheel demand force; determining an average vertical velocity of the wheel; determining, responsive to the average vertical velocity of the wheel, a first scaling factor; multiplying the first scaling factor by the raw wheel demand force to determine a scaled wheel demand force; and controlling the vehicle suspension system responsive to the scaled wheel demand force.

Growing community of inventors

Farmington Hills, MI, United States of America

Scott Wilson Badenoch