Adaptive steering control for robustness to errors in estimated or user-supplied trailer parameters

• US 10,604,184 B2
• Filed: 08/31/2017
• Issued: 03/31/2020
• Est. Priority Date: 08/31/2017
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Mattern, Donald Jacob, Buss, Brian George, Raad, Joseph M., Daavettila, Tyler
• Primary Examiner(s): Lonsberry, Hunter B
• Assistant Examiner(s): Martinez Borrero, Luis A
• Application Number:
  US15/692,569
• Publication Number:
  US 20190061817A1
• Time in Patent Office: 943 Days
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence
• CPC Class Codes: B62D 15/0285 Parking performed automatically
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A system for assisting in reversing of a vehicle-trailer combination includes a vehicle steering system and a controller. The controller outputs a steering signal based on a control parameter to the steering system to maintain the trailer along a commanded backing path, determines an error between a measured behavior of a characteristic of the vehicle-trailer combination and a predicted behavior of the characteristic, and adjusts the control parameter based on the error.

Claims

1. A system for assisting in reversing of a vehicle-trailer combination, comprising:

a vehicle steering system including steered vehicle wheels;

a curvature input device outputting a commanded curvature of the vehicle-trailer combination based on a position of the device; and

a controller;

receiving the commanded curvature;

outputting a steering signal based on the commanded curvature and at least one kinematic parameter of the vehicle-trailer combination to the steering system to converge the vehicle-trailer combination to a backing path having the commanded curvature;

calculating a predicted steering angle for the steered vehicle wheels corresponding with the backing path having the commanded curvature;

measuring an actual steering angle for the steered vehicle wheels;

determining an error between the actual steering angle and the predicted steering angle; and

scaling the commanded curvature based on the error to output a scaled curvature.

2. The system of claim 1, wherein scaling the commanded curvature based on the error compensates for an inaccuracy the at least one kinematic parameter.

3. The system of claim 2, wherein the predicted steering angle is further based on the at least one kinematic parameter.

4. The system of claim 2, wherein at least one of the kinematic parameters is a dimension within the vehicle-trailer model that is one of input by a user or estimated by the system.

5. The system of claim 1, wherein:

the controller determines that the vehicle-trailer combination is in a steady-state condition before scaling the commanded curvature;

the scaled curvature is subsequently used in outputting the steering signal; and

scaling the commanded curvature based on the error converges the actual steering angle to the predicted steering angle.

6. The system of claim 1, wherein the controller scales the commanded curvature by a function of the error to converge the error to zero.

7. The system of claim 1, wherein:

the steering signal is further output based on a measurement of a hitch angle between a vehicle and a trailer in the vehicle-trailer combination; and

scaling the commanded curvature based on the error compensates for an inaccuracy of the measurement of the hitch angle.

8. A vehicle, comprising:

a steering system including steered vehicle wheels;

a curvature input device outputting a commanded curvature of the vehicle-trailer combination based on a position of the device; and

a controller;

receiving the commanded curvature;

outputting a steering signal based on the commanded curvature and at least one kinematic parameter to the steering system to converge a combination of the vehicle and a trailer articulably coupled with the vehicle to a backing path having the commanded curvature;

calculating a predicted hitch angle between the vehicle and the trailer corresponding with the backing path having the commanded curvature;

measuring an actual hitch angle between the vehicle and the trailer;

determining an error between the actual hitch angle and the predicted hitch angle; and

scaling the commanded curvature based on the error to output a scaled curvature.

9. The vehicle of claim 8, wherein:

the steering signal is further based on a plurality of kinematic parameters in a vehicle-trailer model; and

scaling the commanded curvature based on the error compensates for an inaccuracy in one or more of the kinematic parameters.

10. The vehicle of claim 9, wherein the predicted hitch angle is further based on the plurality of kinematic parameters in the vehicle-trailer model.

11. The vehicle of claim 9, wherein at least one of the kinematic parameters is a dimension within the vehicle-trailer model that is one of input by a user or estimated by the system.

12. The vehicle of claim 8, wherein the controller scalies the commanded curvature by a function of the error to converge the error to zero.

13. A method for assisting in reversing of a vehicle-trailer combination, comprising:

receiving an input of a commanded curvature of the vehicle-trailer combination from a curvature input device outputting the commanded curvature based on a position of the input device;

outputting a steering signal based on the commanded curvature and at least one kinematic parameter of the vehicle-trailer combination to a steering system of a vehicle in the vehicle-trailer combination to converge the vehicle-trailer combination to a backing path having the commanded curvature;

calculating a predicted steering angle for steered wheels of the steering system corresponding with the backing path having the commanded curvature;

measuring an actual steering angle for the steered vehicle wheels;

determining an error between the actual steering angle and the predicted steering angle; and

scaling the commanded curvature based on the error.

14. The method of claim 13, wherein the predicted steering angle is further based on at the least one kinematic parameter.

15. The method of claim 14, wherein at least one kinematic parameter is a dimension within the vehicle-trailer model that is one of input by a user or estimated by the system.

16. The method of claim 13, wherein the commanded curvature the commanded curvature is scaled by a function of the error and is subsequently used to output the steering signal to converge the error to zero.