Speed limiting comfort enhancement

• US 9,676,377 B2
• Filed: 06/17/2015
• Issued: 06/13/2017
• Est. Priority Date: 06/17/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hafner, Michael, Lavoie, Erick Michael
• Primary Examiner(s): LANG, MICHAEL DEAN
• Application Number:
  US14/741,614
• Publication Number:
  US 20160368467A1
• Time in Patent Office: 727 Days
• CPC Class Codes: B60D 1/245 for facilitating push back or parking of trailers
• CPC Class Codes: B60D 1/36 for facilitating connection, e.g. hitch catchers , visual guide means, signalling aids B60D1/465 takes precedence; vehicle signalling in general B60Q; optical arrangements specially adapted for viewing trailer-hitches B60R1/003
• CPC Class Codes: B60D 1/62 involving supply lines, electric circuits, or the like
• CPC Class Codes: B60T 2201/10 Automatic or semi-automatic parking aid systems
• CPC Class Codes: B60T 2230/08 Driving in reverse
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 8/1708 for lorries or tractor-trailer combinations
• CPC Class Codes: B60T 8/323 Systems specially adapted for tractor-trailer combinations
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: B62D 15/0285 Parking performed automatically

Abstract

A vehicle includes a steering system, a vehicle speed detector, a brake system, and a control system. The control system is coupled with steering system for implementing a backup mode for reversing a trailer including controlling the steering system to maintain the trailer along a path. The control system is further coupled with the speed detector and the brake system and selectively outputs a rate-limited brake torque demand to the brake system to maintain a vehicle speed below a threshold speed.

Claims

1. A vehicle, comprising:

a vehicle speed detector detecting a vehicle speed;

a brake system; and

a control system;

implementing a control mode including determining a threshold speed;

monitoring the vehicle speed and implementing a control scheme to derive and output an initial brake torque demand to maintain the vehicle speed below the threshold speed; and

applying a rate-limit operator to the initial brake torque demand to derive a rate-limited brake torque demand for output to the brake system.

2. The vehicle of claim 1, further comprising a steering system, wherein:

the control mode is a backup mode for reversing a trailer further including controlling the steering system to maintain the trailer along a path.

3. The vehicle of claim 1, wherein the control system includes:

a first controller coupled with the steering system and implementing the backup mode; and

a second controller coupled with the speed detector and the brake system and implementing the control scheme to derive and output the rate-limited brake torque demand to the brake system to maintain the vehicle speed below the threshold speed.

4. The vehicle of claim 3, wherein the second controller is a proportional-integral controller implementing the control scheme to derive and output the initial brake torque demand.

5. The vehicle of claim 3, wherein the control scheme is non-linear and uses a zero integral gain if the vehicle speed is below a reference speed that is less than the threshold speed.

6. The vehicle of claim 1, wherein the rate-limiting operator reduces a ramp up rate of the rate-limited brake torque demand compared to a ramp up rate of the initial brake torque demand.

7. The vehicle of claim 1, wherein the control system further adjusts the rate-limiting operator on receipt of a selection of a comfort mode.

8. The vehicle of claim 7, wherein:

the control scheme is a proportional-integral control scheme; and

the control system further adjusts at least one of a proportional gain and an integral gain of the proportional-integral control scheme based on receipt of the selection of the comfort mode.

9. A backup assist system for a vehicle reversing a trailer, comprising:

a steering module;

a brake module;

a vehicle speed detector detecting a vehicle speed; and

a controller;

implementing a backup mode including providing an output to the steering module to maintain the trailer along a path; and

attempting to maintain the vehicle speed below a threshold speed, derived using a parameter of the backup mode, by selectively outputting a rate-limited brake torque demand to the brake module.

10. The system of claim 9, wherein the controller:

includes a vehicle speed detector;

receives a vehicle speed signal from the vehicle speed detector; and

derives the rate-limited brake torque demand using;

a proportional-integral control scheme with the threshold speed and the vehicle speed signal as inputs and an initial brake torque as an output; and

a rate limiting operator with the initial brake torque as an input and the rate-limited brake torque as an output.

11. The system of claim 10, wherein the rate limiting operator reduces a ramp up rate of the initial brake torque demand.

12. The system of claim 10, wherein the controller further filters the threshold speed into the proportional-integral controller.

13. The system of claim 10, wherein the controller adjusts the rate limiting operator on receipt of a selection of a comfort mode.

14. A method for assisting reversing of a vehicle with a trailer, comprising:

controlling a steering angle of a vehicle steering system to maintain the trailer along a user-selected reversing curvature path;

monitoring a speed of the vehicle; and

attempting to maintain a vehicle speed below a threshold speed, derived based on a parameter used in controlling the steering angle, by selectively outputting a rate-limited brake torque demand to a brake module of the vehicle.

15. The method of claim 14, wherein the rate-limited brake torque demand is derived using:

a proportional-integral control scheme with the threshold speed and the vehicle speed as inputs and an initial brake torque as an output; and

a rate limiting operator with the initial brake torque as an input and the rate-limited brake torque as an output.

16. The method of claim 15, further including adjusting the rate limiting operator on receipt of a selection of a comfort mode.