Vehicle suspension control with stability in turn enhancement

• US 6,219,602 B1
• Filed: 03/27/2000
• Issued: 04/17/2001
• Est. Priority Date: 04/01/1999
• Status: Expired due to Fees

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Fratini, Albert Victor Jr., Shal, David Andrew, Badenoch, Scott Wilson, Schubert, Raymond Kurt, Leaphart, Eldon Gerrald, Connair, Karen Marie
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Beaulieu, Yonel
• Application Number:
  US09/535,702
• Time in Patent Office: 386 Days
• Field of Search: 701/37, 701/38, 701/48, 701/73, 701/91, 280/5.5, 280/5.502, 280/5.506, 280/5.507, 280/5.512, 280/5.515, 180/41, 180/197
• US Class Current: 701/37
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/202 Piston speed; Relative velocity between vehicle body and wheel
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2600/184 Semi-Active control means
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 2800/912 Attitude Control; levelling control
• CPC Class Codes: B60G 2800/9122 ARS - Anti-Roll System Control

Abstract

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.

Claims

1. A method of controlling suspension dampers at the four corners of the body of a motor vehicle having steering apparatus and further having a wheel coupled to each of the suspension dampers, the method comprising the steps:

determining a relative velocity of each of the suspension dampers and deriving from the determined relative velocities a demand force command for each of the dampers;

applying each of the derived demand force commands to its respective damper if and only if 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;

sensing a vehicle lateral acceleration indicating parameter;

responsive to the sensed vehicle lateral acceleration indicating parameter, determining a stability compression damping command for the suspension dampers on the side of the vehicle opposite the direction of indicated vehicle lateral acceleration and a stability rebound damping command for the suspension dampers on the side of the vehicle in the direction of indicated vehicle lateral acceleration;

while the vehicle lateral acceleration indicating parameter is sensed, applying the stability compression damping command to the suspension dampers on the side of the vehicle opposite the direction of indicated vehicle lateral acceleration and the stability rebound damping command to the suspension dampers on the side of the vehicle in the direction of indicated vehicle lateral acceleration, without regard for the direction of demand force for any of the suspension dampers.

2. A method according to claim 1 wherein the vehicle lateral acceleration indicating parameter is a measured lateral acceleration.

3. The method of controlling suspension dampers of claim 2 further comprising:

sensing a steering angle of the steering apparatus;

sensing a vehicle speed;

deriving a calculated lateral acceleration value from the sensed steering angle of the steering apparatus and the sensed vehicle speed;

deriving a combined lateral acceleration value having a magnitude component derived from the larger magnitude of the measured lateral acceleration and the calculated lateral acceleration value and having a direction component the same as that of the measured lateral acceleration; and

deriving at least one of the stability compression damping command and the stability rebound damping command from the derived combined lateral acceleration value.

4. A method according to claim 1 wherein the vehicle lateral acceleration indicating parameter is a steering angle of the steering apparatus.

5. A suspension control for a vehicle body having steering apparatus and a suspension system having suspension dampers at the four corners of the body and a wheel coupled to each of the suspension dampers, the control comprising:

means for determining a relative velocity of each of the suspension dampers and deriving from the determined relative velocities a demand force command for each of the dampers;

means for applying each of the derived demand force commands to its respective damper if and only if 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;

means for sensing a vehicle lateral acceleration indicating parameter;

means for determining a stability compression damping command for the suspension dampers on the side of the vehicle opposite the direction of indicated vehicle lateral acceleration and a stability rebound damping command for the suspension dampers on the side of the vehicle in the direction of indicated vehicle lateral acceleration; and

means effective, while the lateral acceleration is sensed, for applying the stability compression damping command to the suspension dampers on the side of the vehicle opposite the direction of indicated vehicle lateral acceleration and the stability rebound damping command to the suspension dampers on the side of the vehicle in the direction of indicated vehicle lateral acceleration, without regard for the direction of demand force for any of the suspension dampers.

6. A suspension control according to claim 5 wherein the means for sensing a vehicle lateral acceleration indicating parameter is a lateral acceleration sensor providing a measured lateral acceleration signal.

7. A suspension control according to of claim 6 further comprising:

a steering angle sensor providing a steering angle signal;

a vehicle speed sensor providing a vehicle speed signal;

means for deriving a calculated lateral acceleration value from the steering angle signal and the vehicle speed signal;

means for deriving a combined lateral acceleration value having a magnitude component derived from the larger magnitude of the measured lateral acceleration and the calculated lateral acceleration value and having a direction component the same as that of the measured lateral acceleration; and

deriving at least one of the stability compression damping command and the stability rebound damping command from the combined lateral acceleration value.

8. A suspension control according to claim 5 wherein the means for sensing a vehicle lateral acceleration indicating parameter is a steering angle sensor providing a steering angle signal.

9. A method of controlling suspension dampers at the four corners of the body of a motor vehicle having steering apparatus and further having a wheel coupled to each of the suspension dampers, the method comprising the steps:

determining a relative velocity of each of the suspension dampers and deriving from the determined relative velocities a demand force command for each of the dampers;

applying each of the derived demand force commands to its respective damper if and only if 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;

sensing a direction and a magnitude of vehicle lateral acceleration;

sensing a steering angle of the steering apparatus;

sensing a vehicle speed;

from the sensed steering angle of the steering apparatus and sensed vehicle speed, deriving an estimated vehicle lateral acceleration magnitude;

responsive to the larger of the estimated vehicle lateral acceleration magnitude and the sensed magnitude of vehicle lateral acceleration, determining a stability compression damping command for the suspension dampers on the side of the vehicle opposite the sensed direction of vehicle lateral acceleration and a stability rebound damping command for the suspension dampers on the side of the vehicle in the sensed direction of vehicle lateral acceleration; and

applying the stability compression damping command to the suspension dampers on the side of the vehicle opposite the sensed direction of vehicle lateral acceleration and the stability rebound damping command to the suspension dampers on the side of the vehicle in the sensed direction of vehicle lateral acceleration, without regard for the direction of demand force for any of the suspension dampers.

10. A method of controlling suspension dampers at the four corners of the body of a motor vehicle having steering apparatus and further having a wheel coupled to each of the suspension dampers, the method comprising the steps:

determining a relative velocity of each of the suspension dampers and deriving from the determined relative velocities a demand force command for each of the dampers;

applying each of the derived demand force commands to its respective damper if and only if 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;

sensing a vehicle lateral acceleration indicating parameter;

deriving a direction of vehicle lateral acceleration from the sensed vehicle lateral acceleration indicating parameter;

determining a stability compression damping command for the suspension dampers on the side of the vehicle opposite the direction of vehicle lateral acceleration and a stability rebound damping command for the suspension dampers on the side of the vehicle in the direction of vehicle lateral acceleration; and

applying the stability compression damping command to the suspension dampers on the side of the vehicle opposite the direction of vehicle lateral acceleration and the stability rebound damping command to the suspension dampers on the side of the vehicle in the direction of vehicle lateral acceleration, without regard for the direction of demand force for any of the suspension dampers.

11. A method according to claim 10 wherein the vehicle lateral acceleration indicating parameter is a measured lateral acceleration.

12. A method according to claim 10 wherein the vehicle lateral acceleration indicating parameter is a steering angle of the steering apparatus.