Vehicle roll control

• US 6,752,401 B2
• Filed: 04/11/2003
• Issued: 06/22/2004
• 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:
  US10/412,797
• Publication Number:
  US 20030189300A1
• Time in Patent Office: 438 Days
• Field of Search: 280/5.508, 280/5.51, 280/5.54, 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. A vehicle suspension system comprising a roll controller for controlling the roll stiffness of the vehicle, a roughness sensing system for measuring the roughness of a surface over which the vehicle is traveling, and a vehicle speed sensor for measuring the speed of the vehicle wherein the roll controller is arranged to combine the outputs from the roughness sensing system and the speed sensor to produce an integral over time which will increase in response to an increase in road roughness but decrease in response to increasing vehicle speed, and to increase the roll stiffness of the vehicle in response to a decrease in the integral, but decrease the roll stiffness in response to an increase in the integral.

2. The system according to claim 1 wherein the roughness sensing system comprises at least one accelerometer.

3. The system according to claim 2 for a vehicle having a sprung part and a roll axis, wherein the roughness sensing system comprises a pair of accelerometers located on the sprung part at different distances from the roll axis.

4. The system according to claim 3 wherein the accelerometers are vertically spaced and each accelerometer is arranged to detect acceleration in a direction which is lateral to the vehicle.

5. The system according to claim 1 wherein the controller includes a low gain amplifier and a high gain amplifier and is arranged to receive a vehicle speed signal from the speed sensor and input it to each of the amplifiers, and is arranged to use the output from the low gain amplifier to produce the integral if the vehicle speed is below a predetermined speed, and to use the output from the high gain amplifier to produce the integral of the vehicle speed is above the predetermined speed.

6. A vehicle suspension system comprising roll control means for controlling the roll stiffness of the vehicle, roughness sensing means for measuring the roughness of a surface over which the vehicle is travelling, and a vehicle speed sensing means for measuring the speed of the vehicle wherein the roll controller means is arranged to combine the outputs from the roughness sensing means and the speed sensing means to produce an integral over time which will increase in response to an increase in mad roughness but decrease in response to increasing road speed, and to increase the roll stiffness of the vehicle in response to a decrease in the integral, but decrease the roll stiffness in response to an increase in the integral.

7. A vehicle suspension system comprising a roll controller for controlling the roll stiffness of the vehicle, a roughness sensing system for measuring the roughness of a surface over which the vehicle is traveling, and a vehicle speed sensor for measuring the speed of the vehicle wherein the roll controller is arranged to combine the outputs from the roughness sensing system and the speed sensor to produce an integral over time which will vary in a first manner in response to an increase in road roughness and vary in a second manner in response to increasing road speed, and to decrease the roll stiffness in response to variations in the first manner in the integral, but increase the roll stiffness of the vehicle in response to variations in the second manner in the integral.