Vehicle speed control system and method employing torque balancing

• US 9,776,634 B2
• Filed: 10/15/2013
• Issued: 10/03/2017
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Inventors: Kelly, James, Woolliscroft, Daniel, Fairgrieve, Andrew
• Primary Examiner(s): Nguyen, Nga X
• Application Number:
  US14/421,929
• Publication Number:
  US 20150217767A1
• Time in Patent Office: 1,449 Days
• Field of Search: 701 93, 701 96, 701121, 701 41, 701300
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60K 31/02 including electrically actuated servomechanism including an electric control system or a servomechanism in which the vehicle velocity affecting element is actuated electrically
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 2210/14 Rough roads, bad roads, gravel roads
• CPC Class Codes: B60T 2210/16 Off-road driving conditions
• CPC Class Codes: B60T 2220/04 Pedal travel sensor, stroke sensor; Sensing brake request
• CPC Class Codes: B60T 2260/06 Active Suspension System
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2552/35 Road bumpiness, e.g. potholes
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60Y 2200/20 Off-Road Vehicles
• CPC Class Codes: F16H 2061/0234 Adapting the ratios to special vehicle conditions
• CPC Class Codes: F16H 59/66 : Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/0213 : characterised by the method for generating shift signals

Abstract

A method for operating a speed control system of a vehicle having a plurality of wheels is provided. The method comprises receiving one or more electrical signals representative of vehicle-related information. The method further comprises determining, based on the one or more electrical signals representative of vehicle-related information, that one or more of the wheels of the vehicle have overcome an obstacle or are about to overcome an obstacle and that therefore a reduction in an applied drive torque to one or more of the wheels of the vehicle by a powertrain subsystem (applied drive torque) will be required to maintain the speed of the vehicle at a target set-speed of the speed control system. The method still further comprises automatically commanding the application of a retarding torque to one or more of the wheels of the vehicle to counteract the effect of an overrun condition in the powertrain subsystem from increasing the speed of the vehicle. A system for controlling the speed of a vehicle comprising an electronic control unit configured to perform the above-described methodology is also provided.

Claims

1. A method of operating a speed control system of a vehicle having a plurality of wheels, comprising:

receiving one or more electrical signals from one or more sensors, the electrical signals being representative of vehicle-related information;

maintaining a target set-speed while traversing an obstacle by increasing an applied drive torque to one or more of the wheels of the vehicle;

determining, based on the one or more electrical signals representative of vehicle-related information, that at least one of the wheels of the vehicle have overcome the obstacle or are about to overcome the obstacle and that therefore an overrun condition in a powertrain subsystem is likely to occur for which a reduction in an applied drive torque to the one or more of the wheels of the vehicle by a powertrain subsystem will be required to prevent the speed of the vehicle from exceeding the target set-speed of the speed control system; and

in response to determining that the at least one of the wheels of the vehicle have overcome or are about to overcome the obstacle, while maintaining positive powertrain torque to the wheels of the vehicle simultaneously automatically commanding the application of a retarding torque to one or more of the wheels of the vehicle to counteract the effect of the overrun condition in the powertrain subsystem from increasing the speed of the vehicle.

19. An electronic memory device carrying a computer-readable code that, when executed, is configured to control a vehicle having a plurality of wheels to carry out the method according to claim 1.

2. An electronic control unit (ECU) for controlling the speed of a vehicle having a plurality of wheels, the ECU configured to:

receive one or more electrical signals from one or more sensors, the electrical signals being representative of vehicle-related information;

maintain a target set-speed while traversing an obstacle by increasing an applied drive torque to one or more of the wheels of the vehicle;

determine, based on the one or more electrical signals representative of vehicle-related information, that at least one of the wheels of the vehicle have overcome the obstacle or are about to overcome the obstacle and that therefore an overrun condition in a powertrain subsystem is likely to occur so that a reduction in an applied drive torque to the one or more of the wheels of the vehicle by a powertrain subsystem will be required to prevent the speed of the vehicle from exceeding the target set-speed of the speed control system; and

in response to determining that the at least one wheels of the vehicle have overcome or are about to overcome the obstacle, while maintaining positive powertrain torque to the wheels of the vehicle simultaneously automatically command the application of a retarding torque to one or more of the wheels of the vehicle to counteract the effect of the overrun condition in the powertrain subsystem from increasing the speed of the vehicle.

3. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to automatically command the application of a retarding torque by automatically commanding the application of a retarding torque to one or of the more of the wheels of the vehicle to counteract the effect of the overrun condition in the powertrain subsystem so as to maintain the speed of the vehicle at a target set-speed.

4. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to automatically command the application of a retarding torque by automatically commanding the application of a retarding torque to temporarily reduce the speed of the vehicle below a target set-speed, and thereafter controlling the powertrain subsystem and the application of the retarding torque to resume the target set-speed.

5. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to determine that the at least one wheels of the vehicle have overcome or are about to overcome an obstacle by:

monitoring the one or more electrical signals representative of vehicle-related information to determine a requested reduction in the applied drive torque following a rise in the applied drive torque above a predetermined value or rate; and

determining that the at least one wheels of the vehicle have or are about to overcome an obstacle based at least in part on the requested reduction in the applied drive torque.

6. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to determine that one or more wheels of the vehicle have overcome or are about to overcome an obstacle by:

monitoring, using the one or more electrical signals representative of vehicle-related information, one or more operating parameters of the vehicle; and

determining that one or more wheels of the vehicle have or are about to overcome an obstacle based at least in part on the one or more monitored operating parameters of the vehicle.

7. The electronic control unit (ECU) of claim 6, wherein the ECU is configured to monitor, using the one or more electrical signals representative of vehicle-related information, the longitudinal acceleration of the vehicle, and to determine that one or more of the wheels of the vehicle have overcome or are about to overcome an obstacle when the longitudinal acceleration of the vehicle exceeds a predetermined acceleration profile.

8. The electronic control unit (ECU) of claim 6, wherein the ECU is configured to monitor, using the one or more electrical signals representative vehicle-related information, the speed of the vehicle, and to determine that one or more of the wheels of the vehicle have overcome or are about to overcome an obstacle when the speed of the vehicle exceeds a target set-speed.

9. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to determine that one or more wheels of the vehicle is overcoming the obstacle by:

monitoring, using the one or more electrical signals representative of vehicle-related information, one or more operating parameters of the vehicle;

sensing a change in the terrain the vehicle is traversing based at least in part on the monitored operating parameters of the vehicle; and

determining that one or more of the wheels of the vehicle have overcome or are about to overcome an obstacle based at least in part on the sensed terrain change.

10. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to determine that one or more wheels of the vehicle have overcome or are about to overcome an obstacle:

monitoring, using the one or more electrical signals representative of vehicle-related information, information relating to the terrain the vehicle is traversing;

sensing a change in the terrain the vehicle is traversing based at least in part on the monitored information relating to the terrain the vehicle is traversing; and

determining that one or more of the wheels of the vehicle have overcome or are about to overcome an obstacle based at least in part on the sensed terrain change.

11. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to automatically command the application of a retarding torque to the one or more wheels of the vehicle by automatically commanding an increase in a retarding torque being applied to the one or more wheels of the vehicle.

12. The electronic control unit (ECU) of claim 2, wherein the ECU is configured to automatically command the application of a retarding torque to the one or more wheels of the vehicle by automatically commanding one or both of the powertrain subsystem and a brake subsystem of the vehicle to apply a retarding torque to the one or more wheels of the vehicle.

13. The electronic control unit (ECU) of claim 12, arranged for a hybrid vehicle wherein the ECU is configured to automatically command the powertrain subsystem to apply the retarding torque by means of an electric machine.

14. The electronic control unit (ECU of claim 2, wherein prior to automatically commanding the application of a retarding torque to the one or more wheels of the vehicle, the ECU is further configured to cause the brake subsystem of the vehicle to be primed.

15. The electronic control unit (ECU) of claim 14, wherein the ECU is configured to cause the brake subsystem of the vehicle to be primed in response to a detected increase in drive torque in excess of a predetermined rate.

16. The electronic control unit (ECU) of claim 2, wherein in response to detecting that an overrun condition in the powertrain subsystem is likely to occur, the ECU is further configured to automatically command a reduction in the applied drive torque at the one or more wheels of the vehicle.

17. The electronic control unit (ECU) of claim 16, wherein the ECU is further configured to balance the reduction in the applied drive torque at one or more of the wheels of the vehicle with the application of the retarding torque to one or more of the wheels of the vehicle to counteract the effect of the overrun condition in the powertrain subsystem from increasing the speed of the vehicle.

18. A vehicle having a plurality of wheels and comprising an electronic control unit (ECU) for controlling the speed of a vehicle having a plurality of wheels, the ECU configured to:

receive one or more electrical signals representative of vehicle-related information;

maintain a target set-speed while traversing an obstacle by increasing an applied drive torque to one or more of the wheels of the vehicle;

determine, based on the one or more electrical signals representative of vehicle-related information, that at least one of the wheels of the vehicle have overcome the obstacle or are about to overcome the obstacle and that therefore an overrun condition in a powertrain subsystem is likely to occur so that a reduction in an applied drive torque to the one or more of the wheels of the vehicle by a powertrain subsystem will be required to prevent the speed of the vehicle from exceeding the target set-speed of the speed control system; and

in response to determining that the at least one wheels of the vehicle have overcome or are about to overcome the obstacle, while maintaining positive powertrain torque to the wheels of the vehicle simultaneously automatically command the application of a retarding torque to one or more of the wheels of the vehicle to counteract the effect of an overrun condition in the powertrain subsystem from increasing the speed of the vehicle.