Control method using trailer yaw rate measurements for trailer backup assist

Patent metadata

Field	Value
Publication number	US-2018111621-A1
Application number	US-201615331517-A
Country	US
Kind code	A1
Filing date	Oct 21, 2016
Priority date	Oct 21, 2016
Publication date	Apr 26, 2018
Grant date	—

Abstract

A system for assisting a vehicle in reversing a trailer includes a vehicle steering system, a vehicle sensor outputting a vehicle velocity and a trailer sensor outputting a trailer yaw rate. The system further includes a controller controlling the vehicle steering system in reversing the trailer to cause a control parameter based on the trailer yaw rate and the vehicle velocity to converge toward a predetermined value.

First claim

What is claimed is:

1 . A system for assisting a vehicle in reversing a trailer, comprising:
a vehicle steering system; a vehicle sensor outputting a vehicle velocity; a trailer sensor data including a trailer yaw rate; and a controller controlling the vehicle steering system in reversing the trailer to cause a control parameter based on the trailer yaw rate and the vehicle velocity to converge toward a predetermined value.

2 . The system of claim 1 , wherein:
the control parameter is a modified curvature of the vehicle reversing the trailer, determined as the trailer yaw rate divided by the vehicle velocity; and the predetermined value is a user-selected trailer curvature.

3 . The system of claim 1 , further including a curvature input device, wherein:
the controller determines the predetermined value as a function of a position of the curvature input device.

4 . The system of claim 3 , wherein the controller scales the position of the curvature input device when determining the predetermined value by a constant.

5 . The system of claim 1 , wherein the controller determines that the estimated trailer length is unavailable when either no estimate has been obtained or when an estimate is outside an acceptable accuracy range.

6 . The system of claim 1 , wherein:
the vehicle sensor further outputs a vehicle yaw rate; the controller further:
determines an estimated trailer length based on an estimated hitch angle, the vehicle yaw rate, the vehicle velocity, and the trailer yaw rate in view of a kinematic relationship;
controls the vehicle steering system in reversing the trailer to cause the control parameter based on the trailer yaw rate and the vehicle velocity to converge toward the predetermined value, until the estimated trailer length is determined; and
upon determining the estimated length of the trailer, controls the vehicle steering system in reversing the trailer to cause a curvature of the trailer based on a kinematic model of the vehicle and trailer combination including the estimated length of the trailer and an instantaneous hitch angle to converge toward a desired trailer curvature.

7 . The system of claim 1 , wherein the controller further controls the steering system to maintain a condition of the vehicle in reversing the trailer outside a jackknife condition.

8 . The system of claim 1 , further including a vehicle brake system, wherein the controller further controls the vehicle brake system to attempt to maintain the vehicle velocity below a limit that is a function of the modified curvature.

9 . The system of claim 1 , wherein the controller implements a control scheme including proportional and integral gains determined using an estimated maximum trailer length and an estimated minimum hitch offset.

10 . A vehicle, comprising:
a steering system; a sensor outputting a velocity of the vehicle; and a controller:
determining a trailer yaw rate based on data received from a trailer sensor coupled with the controller;
determining a control parameter of the vehicle based on the vehicle velocity and the trailer yaw rate; and
controlling the vehicle steering system to cause the control parameter to converge toward a predetermined value.

11 . The vehicle of claim 10 , wherein:
the control parameter is a modified curvature of the vehicle in reversing the trailer determined as the trailer yaw rate divided by the vehicle velocity.

12 . The vehicle of claim 10 , further including a curvature input device, wherein:
the controller determines the predetermined value as a function of a position of the curvature input device; and the controller scales the position of the curvature input device when determining the predetermined value by a constant.

13 . The vehicle of claim 10 , wherein the controller:
determines an estimated trailer length; determines that the estimated trailer length is unavailable when either no estimate has been obtained or when an estimate is outside an acceptable accuracy range; and controls the vehicle steering system to cause the control parameter to converge toward a predetermined value when the estimated trailer length is determined to be unavailable.

14 . The vehicle of claim 13 , wherein:
the sensor further outputs a vehicle yaw rate; the controller further:
determines the estimated length of the trailer based on an estimated hitch angle, the vehicle yaw rate, the vehicle speed, and the trailer yaw rate in view of a kinematic relationship of the vehicle in combination with the trailer; and
upon determining the estimated length of the trailer, controls the vehicle steering system in reversing the trailer to cause a curvature of the trailer based on a kinematic model including the estimated length of the trailer and an instantaneous hitch angle to converge toward a desired trailer curvature.

15 . The vehicle of claim 10 , wherein the controller further controls the steering system to maintain a condition of the vehicle in reversing the trailer outside a jackknife condition.

16 . A method for assisting a vehicle in reversing a trailer, comprising:
receiving a vehicle velocity signal; receiving a trailer yaw rate signal; and controlling a vehicle steering system by:
determining a control parameter of the vehicle reversing the trailer based on the vehicle velocity and the trailer yaw rate; and
causing the control parameter to converge toward a predetermined value.

17 . The method of claim 16 , further including:
receiving as an input from a curvature input device including a position of the input device; determining the predetermined value as a function of the position of the curvature input device scaled by a constant.

18 . The method of claim 16 , wherein:
the controller determines that an estimated trailer length is unavailable when either no estimate has been obtained or when an estimate is outside an acceptable accuracy range; and controls the vehicle steering system by determining a control parameter of the vehicle reversing the trailer based on the vehicle velocity and the trailer yaw rate when the estimated trailer length is unavailable.

19 . The method of claim 18 , further including:
receiving a vehicle yaw rate signal; determining an estimated length of the trailer based on an estimated hitch angle, the vehicle yaw rate, the vehicle velocity, and the trailer yaw rate in view of a kinematic relationship of the vehicle in combination with the trailer; and upon determining the estimated length of the trailer, controlling the vehicle steering system during reversing to cause the curvature of the trailer to converge toward a predetermined curvature.

20 . The method of claim 16 , wherein controlling the steering system further includes maintaining a condition of the vehicle in reversing the trailer outside a jackknife condition.

Assignees

• Ford Global Tech Llc

Inventors

• Buss Brian George

Classifications

• B62D13/06

  for backing a normally drawn trailer · CPC title

• B60W2520/14

  Yaw · CPC title

• B60W30/18036 Primary

  Reversing · CPC title

• B60W2520/22

  Articulation angle, e.g. between tractor and trailer · CPC title

• B60W2520/10

  Longitudinal speed · CPC title