CONTROL SYSTEM FOR A VEHICLE SUSPENSION

• US 20160023530A1
• Filed: 01/14/2014
• Published: 01/28/2016
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Inventors: GUEST, Philip
• Granted Patent: US 9,908,379 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 17/0165 to an external condition, e.g. rough road surface, side wind
• CPC Class Codes: B60G 17/017 characterised by their use when the vehicle is stationary, e.g. during loading, engine start-up or switch-off
• CPC Class Codes: B60G 17/019 characterised by the type of sensor or the arrangement thereof B60G17/01941 takes precedence
• CPC Class Codes: B60G 2300/07 Off-road vehicles
• CPC Class Codes: B60G 2400/252 vertical

Abstract

The present application relates to a control system (49) for controlling a motor vehicle suspension (3). The suspension (3) has a plurality of adjustable height suspension units (19, 21, 23, 25) and a suspension control means (53) is provided to control the suspension units (19, 21, 23, 25). The control system (49) has a receiver for receiving height data form height sensors (41, 43, 45, 47) to provide height measurements for each suspension unit (19, 21, 23, 25). A suspension modelling means is provided for modelling the height of each suspension unit (19, 21, 23, 25). The control system (49) is configured to detect an unrequested suspension height change when the difference between the modelled height and the measured height of one or more suspension units (19, 21, 23, 25) exceeds a threshold. The present application also relates to a motor vehicle; and a method of detecting an unrequested suspension height change.

Claims

1. A control system for a motor vehicle suspension having a plurality of adjustable height suspension units, the control system comprising:

suspension control means for controlling the suspension units;

a receiver for receiving a measured height signal for each suspension unit; and

a suspension modelling means for modelling the height of each suspension unit;

wherein the control system is configured to detect an unrequested suspension height change when the difference between the modelled height and the measured height of one or more suspension units exceeds a first threshold.

3. A control system as claimed in claim 1, wherein the suspension control means is selectively operable to control said suspension units in a self-levelling mode;

and the control system is configured to inhibit said self-levelling mode when said unrequested suspension height change is detected for at least one, two, three or four of said suspension units.

4. A control system as claimed in claim 3, wherein the control system is configured to inhibit said self-levelling mode for each suspension unit when the unrequested suspension height change is detected;

or to inhibit said self-levelling mode only for the suspension unit(s) at which the unrequested suspension height change is detected.

5. A control system as claimed in claim 3, wherein the control system is configured to enable the self-levelling mode when the difference between the modelled height and the measured height decreases below a second threshold for at least one, two, three or four of said suspension units.

6. A control system as claimed in claim 1 configured to receive traction information for a driven wheel associated with one or more of said suspension units.

7. A control system as claimed in claim 5, wherein the suspension control means is configured to increase the height of one or more of said suspension units in response to a detected reduction in traction at the associated wheel in combination with the detection of an unrequested suspension height change in said suspension unit.

8. A control system as claimed in claim 1, wherein the first threshold is predefined.

9. A control system as claimed in claim 1, wherein the first threshold is variable in dependence on a calculated confidence in the modelled height of said one or more suspension units.

10. A control system as claimed in claim 1, wherein the suspension modelling means is configured to model the height of each said suspension unit in dependence on data relating to one or more of the following:

longitudinal vehicle acceleration;

lateral vehicle acceleration;

vertical vehicle acceleration;

vehicle pitch;

vehicle roll;

vehicle speed;

height measurement data for one or more of said suspension units;

wheel drive torque(s); and

wheel braking torque(s).

11. A control system as claimed in claim 1, wherein the control system is configured to pass either the modelled height of each said suspension unit;

or an offset between the modelled height and the measured height for each said suspension unit through a first filter to calculate a first running average over a first time period.

12. A control system as claimed in claim 11, wherein the control system is configured to pass said offset between the modelled height and the measured height for each said suspension unit through a second filter to calculate a second running average over a second time period, the first time period being longer than the second time period.

13. A control system as claimed in claim 12, wherein the control system is configured to calculate the difference between the modelled height and the measured height of said one or more suspension units based on the first and second running averages.

14. A control system as claimed in claim 12, wherein the control system stores the first running average of one or more of said suspension units as a reference value.

15. A control system as claimed in claim 14, wherein the control system stores the first running average at the time when the calculated difference becomes equal to or greater than the first threshold.

16. A control system as claimed in claim 14, wherein the control system is configured to detect a requested suspension height change when the calculated difference between the second running average and the stored reference value for at least one, two, three or four of said suspension units is less than a second threshold.

17. A control system as claimed in claim 1 configured to detect when a motor vehicle is wading, wherein:

said suspension control means comprises a suspension controller operable to control said plurality of adjustable height suspension units in a self-levelling mode; and

said first threshold comprises a wading detection threshold; and

a difference between the modelled height and the measured height of one or more suspension units exceeding a wading detection threshold being indicative of vehicle wading.

18. A control system as claimed in claim 1 configured for detecting a vehicle belly out event, the control system comprising:

said suspension control means comprises a suspension controller;

said receiver is further for receiving traction information for a driven wheel associated with each suspension unit; and

the control system being configured to detect an unrequested suspension height change indicative of a belly out event when said difference between the modelled height and the measured height of one or more suspension units exceeds a belly out detection threshold;

wherein, in dependence on the detection of said unrequested suspension height change at a suspension unit in combination with a detected reduction in traction at the driven wheel associated with that suspension unit, the suspension controller is configured to increase the height of said suspension unit.

19. A vehicle comprising a control system as claimed in claim 1.

2. (canceled)

20. A method of detecting an unrequested suspension height change, the method comprising:

measuring the height of a vehicle suspension unit;

modelling the height of said vehicle suspension unit; and

calculating a difference between the modelled height and the measured height of said vehicle suspension unit; and

identifying an unrequested suspension height change when the calculated difference exceeds a first threshold.

21-23. -23. (canceled)