Vehicle speed control system

• US 9,701,308 B2
• Filed: 08/15/2013
• Issued: 07/11/2017
• 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: Fairgrieve, Andrew, Kelly, James, Woolliscroft, Daniel
• Primary Examiner(s): WONG, YUEN H
• Application Number:
  US14/421,942
• Publication Number:
  US 20150217769A1
• Time in Patent Office: 1,426 Days
• 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 10/11 Stepped gearings
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2520/30 Wheel torque
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels
• 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 vehicle speed control system for a vehicle having a plurality of wheels, the vehicle speed control system comprising: means for receiving a user input of a target speed at which the vehicle is intended to travel; and means for commanding application of torque to one or more wheels of the vehicle, wherein the system is configured such that when it is required to accelerate the vehicle to achieve the target speed and the system detects a wheel slip event, the system is operable temporarily to suspend further acceleration of the vehicle.

Claims

1. A vehicle speed control system for a vehicle having a plurality of wheels, the vehicle speed control system comprising:

an input device for receiving a user input of a target speed at which the vehicle is intended to travel; and

a vehicle controller for commanding application of torque to one or more wheels of the vehicle,

wherein the system is configured such that when the system is required to accelerate the vehicle to achieve the target speed and the system detects a wheel slip event, the system is operable to temporarily suspend further acceleration of the vehicle until the system lifts the suspension of further acceleration and, when the suspension of further acceleration is lifted, the system is operable automatically to inhibit slip by resuming acceleration at a rate limited to a rate of acceleration of the vehicle when the wheel slip event was detected.

2. The system as claimed in claim 1 configured automatically to lift the suspension of further acceleration of the vehicle once a prescribed one or more conditions are met.

3. The system as claimed in claim 1 wherein the prescribed one or more conditions are selected from amongst the conditions that the wheel slip event has ceased, that the vehicle has traveled a prescribed distance or for a prescribed time period since the wheel slip event involving the one or more wheels ceased, and that the vehicle has traveled a prescribed distance or for a prescribed time period since the wheel slip event involving one or more leading wheels ceased.

4. The system as claimed in claim 3 wherein the prescribed one or more conditions include the condition that the vehicle has traveled the prescribed distance since the wheel slip event involving the one or more leading wheels ceased, the prescribed distance corresponding to a distance between leading and following wheels of the vehicle, or that the vehicle has traveled for a prescribed time period since the wheel slip event involving the one or more leading wheels ceased, the prescribed time period corresponding to a time required for the following wheels to reach a position at which the wheel slip event involving the one or more leading wheels ceased.

5. The system as claimed in claim 1 configured to maintain a substantially constant speed when further acceleration is temporarily suspended.

6. The system as claimed in claim 5 wherein the substantially constant speed corresponds to the speed at which the vehicle was traveling when the wheel slip event was detected.

7. The system as claimed in claim 1 configured to resume acceleration at a prescribed rate.

8. The system as claimed in claim 7 wherein the prescribed rate corresponds to the rate of acceleration of the vehicle when the wheel slip event was detected.

9. The system as claimed in claim 1, comprising:

a vehicle speed sensor for determining a current speed at which the vehicle is traveling,

wherein the vehicle controller is configured to compare the current speed with the target speed and provide an output indicative of a difference between the current speed and the target speed; and

wherein the vehicle controller is configured to evaluate the torque to be applied to at least one of the vehicle wheels in dependence on the output.

10. The system as claimed in claim 9, operable to command application of torque to at least two wheels of the vehicle substantially simultaneously.

11. The system as claimed in claim 10, operable to command application of torque to at least four wheels of the vehicle substantially simultaneously.

12. The system as claimed in claim 9, further being operable to:

inhibit operation of the vehicle control system in an event that the current speed is determined to be in excess of a predetermined threshold speed.

13. The system as claimed in claim 12, wherein the predetermined threshold speed is between 25 and 35 kph.

14. The vehicle speed control system as claimed in claim 13, wherein the predetermined threshold speed is substantially 30 kph.

15. The system as claimed in claim 12, wherein the predetermined threshold speed is a first, lower threshold speed, the vehicle speed control system further being operable to:

compare the current vehicle speed with a second, higher threshold speed and, when the current vehicle speed is less than the second, higher threshold speed, hold the vehicle speed control system in a wait state and initiate vehicle speed control only once the current vehicle speed is reduced to below the first, lower threshold speed.

16. The system as claimed in claim 15 wherein the second, higher threshold speed corresponds to a speed above which the speed control system is cancelled, wherein when the vehicle speed subsequently falls below the second, higher threshold speed the system does not assume the wait state.

17. The system as claimed in claim 12, comprising a cruise control system which is operable to maintain vehicle speed at speeds above the predetermined threshold speed.

18. The system as claimed in claim 17, wherein the cruise control system is operable to suspend operation of the system on receiving the slip detection output signal.

19. The system as claimed in claim 1, comprising:

sensors for detecting a nature of terrain over which the vehicle is traveling;

the system being operable to determine for determining whether the target speed is appropriate for the nature of the terrain over which the vehicle is traveling; and

maintain the vehicle at the target speed by commanding application of torque to the at least one of the plurality of wheels only when the target speed is determined to be appropriate.

20. A system for a vehicle having a plurality of wheels, the vehicle control system comprising:

a powertrain and a brake system controller for applying torque to at least one of the plurality of wheels;

a traction control system controller for detecting a wheel slip event between any one or more of the plurality of the wheels and ground over which the vehicle is traveling when the vehicle is in motion and for providing a slip detection output signal in the wheel slip event; and

an input device for receiving a user input of a target speed at which the vehicle is intended to travel,

wherein the system is configured such that when the system is required to accelerate the vehicle to achieve the target speed and the system detects the wheel slip event, the system is operable to temporarily suspend further acceleration of the vehicle until the wheel slip event is no longer detected, and when the wheel slip event is no longer detected, the system is operable automatically to inhibit slip by resuming acceleration at a rate limited to a rate of acceleration of the vehicle when the wheel slip event was detected.

21. A vehicle speed control system for a vehicle having a plurality of wheels, the vehicle speed control system comprising:

an input device for receiving a user input of a target speed at which the vehicle is intended to travel; and

a vehicle controller for commanding application of torque to one or more wheels of the plurality of wheels of the vehicle,

wherein the system is configured such that when the system is required to accelerate the vehicle to achieve the target speed and a wheel slip event is detected, the system is operable to temporarily maintain the vehicle speed at a value substantially equal to that at which the vehicle was traveling until the system lifts a suspension of further acceleration and, when the suspension of further acceleration is lifted, the system is operable automatically to inhibit slip by resuming acceleration at a rate limited to a rate of acceleration of the vehicle when the wheel slip event was detected.

22. A vehicle, comprising:

a vehicle speed control system, the vehicle speed control system including;

an input device for receiving a user input of a target speed at which the vehicle is intended to travel; and

a vehicle controller for commanding application of torque to one or more wheels of the vehicle,

wherein the system is configured such that when the system is required to accelerate the vehicle to achieve the target speed and the system detects a wheel slip event, the system is operable to temporarily suspend further acceleration of the vehicle until the system lifts the suspension of further acceleration and, when the suspension of further acceleration is lifted, the system is operable automatically to inhibit slip by resuming acceleration at a rate limited to a rate of acceleration of the vehicle when the wheel slip event was detected.

23. A method of controlling a speed of a vehicle having a plurality of wheels, the method comprising:

applying torque to at least one of the plurality of wheels;

detecting, by a vehicle controller, a wheel slip event between any one or more of the plurality of wheels and a ground over which the vehicle is traveling when the vehicle is in motion and providing a slip detection output signal in the wheel slip event;

receiving a user input of a target speed at which the vehicle is intended to travel; and

accelerating, by the vehicle controller, the vehicle to achieve the target speed,

whereby in an event that the wheel slip event is detected, the method comprises suspending temporarily further acceleration of the vehicle until the wheel slip event is no longer detected; and

when the wheel slip event is no longer detected, inhibiting slip by lifting the suspension and automatically resuming acceleration at a rate limited to a rate of acceleration of the vehicle when the wheel slip event was detected.

24. The method as claimed in claim 23 wherein the step of resuming acceleration comprises resuming acceleration at a rate corresponding to a rate of acceleration of the vehicle when the wheel slip event was first detected.