Vehicle roll control

• US 6,588,769 B2
• Filed: 03/27/2001
• Issued: 07/08/2003
• Est. Priority Date: 09/29/1998
• Status: Expired due to Term

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Land Rover (TATA Motors Limited)
• Inventors: Burdock, William
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): ROYAL, PAUL
• Application Number:
  US09/806,256
• Publication Number:
  US 20030094774A1
• Time in Patent Office: 833 Days
• Field of Search: 280/5.58, 280/5.51, 280/5.511, 280/124.106, 280/124.107
• US Class Current: 280/5.508
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/0165 to an external condition, e.g. rough road surface, side wind
• CPC Class Codes: B60G 17/01908 Acceleration or inclination sensors characterised by the use of gyroscopes B60G21/08
• CPC Class Codes: B60G 21/0553 adjustable
• CPC Class Codes: B60G 2202/135 Stabiliser bar and/or tube
• CPC Class Codes: B60G 2400/10 Acceleration; Deceleration
• CPC Class Codes: B60G 2400/1042 using at least two sensors
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/821 Uneven, rough road sensing affecting vehicle body vibration
• CPC Class Codes: B60G 2400/91 Frequency
• CPC Class Codes: B60G 2500/20 Spring action or springs
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/60 Signal noise suppression; Electronic filtering means
• CPC Class Codes: B60G 2600/602 high pass
• CPC Class Codes: B60G 2600/604 low pass
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/162 Reducing road induced vibrations
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/912 Attitude Control; levelling control
• CPC Class Codes: B60G 2800/915 Suspension load distribution

Abstract

A vehicle roll control system uses two accelerometers (38, 40) on the vehicle to detect body roll and then filters out higher frequency roll movements as indicative of a rough road surface. The system also monitors vehicle speed, and increases roll stiffness in response to measured increase in vehicle speed, but decreases roll stiffness in response to detected rough road surfaces.

Claims

1. An apparatus for detecting the roughness of a surface over which a vehicle, having sprung part and a roll axis, is traveling, the apparatus comprising:

a pair of accelerometers located on the sprung part at different distances from the roll axis, for measuring roll movements of the vehicle, filtering means for detecting high frequency roll movements, and a controller arranged to measure the roughness by measuring the level of the high frequency roll movements.

2. The apparatus according to claim 1, wherein the accelerometers are vertically spaced and each accelerometer is arranged to detect acceleration in a direction which is lateral to the vehicle.

3. The apparatus according to claim 1, wherein the controller mechanism is arranged to monitor the measured acceleration from each of the accelerometers, and to produce a roll signal dependent on the difference between the two measured accelerations, the roll signal being indicative of instantaneous vehicle roll.

4. The apparatus according to claim 3, wherein the difference is an integral over time of the instantaneous difference between the measured accelerations.

5. The apparatus according to claim 3, wherein the difference between respective integrals over time of the two measured accelerations.

6. The vehicle suspension system comprising an apparatus according to claim 1, for detecting surface roughness wherein the controller is arranged to control the roll stiffness of the vehicle, and is arranged to reduce the roll stiffness of the vehicle in response to the detection of increased surface roughness.

7. The system according to claim 6, further comprising vehicle speed sensor wherein the controller is arranged to increase the roll stiffness in response to increasing vehicle speed.

8. A vehicle suspension system comprising roll control means for controlling the roll stiffness of the vehicle, roughness measuring means for measuring the roughness of the surface over which the vehicle is traveling, vehicle speed measuring means for measuring the speed of the vehicle characterized in that the roll control means is arranged to increase the roll stiffness if the vehicle speed increases but to decrease the roll stiffness of the roughness of the surface over which the vehicle is traveling increases.