# Patent

## Title
Guidance system for a vehicle reversing a trailer along an intended backing path

## Abstract

A guidance system for a vehicle reversing a trailer is provided. The system includes a display and a controller configured to generate a steering icon on the display. The steering icon recommends a steering direction and a steering magnitude related to a steering device of the vehicle in order to correct a deviation from an intended backing path.

## Background
FIELD OF THE INVENTION
The present invention generally relates to vehicle guidance systems, and more particularly, to guidance systems for assisting a driver of a vehicle in reversing a trailer along an intended backing path.
BACKGROUND OF THE INVENTION
Reversing a trailer, in a straight line for example, can be especially challenging. Even when the vehicle and trailer are properly aligned, a trailer may move off at an angle during a backing maneuver, thereby causing a deviation from an intended backing path. Thus, there is a need for a guidance system that assists a driver in reversing the trailer by providing easy to follow directions to correct deviations so that the vehicle and trailer can be returned along the intended backing path.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a guidance system for a vehicle reversing a trailer is provided. The system includes a display and a controller configured to generate a steering icon on the display. The steering icon recommends a steering direction and a steering magnitude related to a steering device of the vehicle in order to correct a deviation from an intended backing path.
According to another aspect of the present invention, a guidance system for a vehicle reversing a trailer is provided. The system includes a display and a controller configured to generate a steering icon on the display to recommend a steering direction and a steering magnitude related to a steering device of the vehicle to correct a deviation from an intended backing path. The steering direction and the steering magnitude are determined at least in part based on a hitch angle between the vehicle and the trailer.
According to yet another aspect of the present invention, a method of reversing a vehicle and trailer along an intended backing path is provided. The method includes the steps of measuring a hitch angle between the vehicle and trailer, determining whether the vehicle and trailer have deviated from the intended backing path based on the measured hitch angle, and making a steering direction and steering magnitude recommendation on a display of the vehicle to correct a deviation from the intended backing path.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic diagram of a guidance system to assist a driver of a vehicle with reversing a trailer attached to the vehicle, according to one embodiment;
FIG. 2 illustrates a steering icon on a vehicle display for generating recommendations related to a vehicle steering device, according to one embodiment;
FIG. 3 illustrates an exemplary backing maneuver in which a vehicle and trailer deviate from an intended backing path followed by a correction for returning the vehicle and trailer to the intended backing path, according to one embodiment; and
FIG. 4 is a flow diagram of a method for reversing a trailer attached to a vehicle along a straight backing path, according to one embodiment.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
For purposes of description herein, it is to be understood that the disclosed trailer backup assist system and the related methods may assume various alternative embodiments and orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. While various aspects of the trailer backup assist system and the related methods are described with reference to a particular illustrative embodiment, the disclosed invention is not limited to such embodiments, and additional modifications, applications, and embodiments may be implemented without departing from the disclosed invention. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.
Referring to FIG. 1, a guidance system 10 is shown according to one embodiment. The guidance system 10 is used to assist a driver of a vehicle 12 with reversing a trailer 14 attached to the vehicle 12. The guidance system 10 includes a display 16 disposed within the vehicle 12 and in view of the driver. The display 16 may be located in a center console, dashboard, heads up display, rearview mirror, or any other display bearing surface in the front passenger compartment of the vehicle 12. A controller 18 is communicatively coupled with the display 16 and includes a memory 19 having instructions 20 thereon that are executable by a processor 21 for generating visuals on the display 16. In the presently illustrated embodiment, the controller 18 is configured to generate a steering icon 22 on the display 16. As will be described in greater detail below, the steering icon 22 recommends a steering direction and a steering magnitude related to a steering device 23 of the vehicle 12 in order to correct a deviation from an intended backing path. The steering device 23 may include a steering wheel or other device in which the driver can manipulate to effectuate steering of the vehicle 12. The position and rate of return of the steering device 23 may be measured by a steering angle sensor 24. The steering angle sensor 24 outputs steering information 25 including the position and rate of return of the steering device 23 in degrees to the controller 18 so that the controller 18 can monitor the position of steering device 23 to check whether the recommendations made using the steering icon 22 have been adopted by the driver.
To ensure that the steering direction and steering magnitude recommendations are accurate, the controller 18 may communicate with a hitch angle detection device 26 of the vehicle 12. The hitch angle detection device 26 may include a camera 28 configured to image a rear-vehicle scene. The images taken by the camera 28 are analyzed by an image processor 30 that is configured to track the position of a target 32 within the captured images. The target 32 may be an existing structure of the trailer 14 or an object placed on the trailer 14 for the purpose of being detected by the image processor 30. By tracking the position of the target 32, the image processor 30 may calculate a hitch angle λ between the vehicle 12 and the trailer 14. Alternatively, the hitch angle λ may be determined through hitch angle sensors or any other means known in the art. As defined herein, the hitch angle λ corresponds to an angle between a longitudinal axis 34 of the vehicle and a longitudinal axis 36 of the trailer 14. Hitch angle information 38 is sent from the image processor 30 to the controller 18 and the controller 18 may make steering direction and/or steering magnitude recommendations based at least in part on the hitch angle information 38. The controller 18 may also receive positional information 40 related to the vehicle 12 from a global positioning system (GPS) receiver 42 disposed on the vehicle 12. Additionally, another GPS receiver 43 may be disposed on the trailer 14 to wirelessly communicate positional information 44 related to the trailer 14 to the controller 18. It is also contemplated that the controller 18 may take into account vehicle and trailer-related information to increase the accuracy of the recommendations. For example, the controller 18 may make steering direction and/or steering magnitude recommendations based on a wheelbase measurement 46 and a trailer length measurement 48 as both of these characteristics have an impact on the manner in which the vehicle 12 and trailer 14 behave when the steering device 23 is turned. The controller 18 may also take into account a speed 50 at which the vehicle 12 and trailer 14 are moving, which may be measured and inputted to the controller 18 via a speed sensor 52 of the vehicle 12. The wheelbase measurement 46 is defined herein as the distance between the front and rear axles 54, 56 of the vehicle 12 and may be retrieved from the memory 19 of the controller 18. The trailer length measurement 48 may be measured by a driver or other user and inputted to the controller 18 via a user-input device 58. The user-input device 58 may be part of display 16 or elsewhere located in the vehicle 12. Alternatively, the user-input device 58 may include a portable electronic device such as a smartphone, tablet, and the like.
Referring to FIG. 2, an exemplary embodiment of the steering icon 22 is shown generated on a display 16 of a center console 60. The display 16 may be a touchscreen display or other conventional display. For purposes of simplicity, only the steering icon 22 is shown on the display 16. However, it should be appreciated that other visuals may appear on the display 16 alongside the steering icon 22. That is, the steering icon 22 may share the display 16 with other visuals related or unrelated to the guidance system 10 described herein. The steering icon 22 includes a directional element 61 shown as arrows 62 and 64 and a magnitude element 66 that may be positioned between arrows 62 and 64 and corresponds to a numerical value measured in degrees. When a vehicle 12 and trailer 14 makes a deviation from an intended backing path, one of the arrows 62, 64 may illuminate to indicate whether to turn the steering device 23 in a counterclockwise or clockwise direction, respectively, whereas the magnitude element 66 indicates how far the steering device 23 should be turned in the recommended direction. For example, in the present embodiment, a recommendation is made to turn the steering device 23 forty-five degrees in a counterclockwise direction. To further assist the driver, the steering icon 22 may also include a relating element 68 to visually relate the current position of the steering device 23 to the recommended steering direction and steering magnitude. The relating element 68 is exemplarily shown in FIG. 2 as a steering wheel graphic that matches the steering device 23 and is configured to turn in accordance with the direction and magnitude specified by the directional element 61 and the magnitude element 66. As an additional feature, the speed at which the steering wheel graphic turns may function as a recommended speed for turning the steering device 23. The use of the relating element 68 provides another means with which to guide the driver back along the intended backing path. Once the driver has turned the steering device 23 in the recommended direction and magnitude, the driver may be notified through the illumination of a hold indicator 70 to maintain the steering device 23 in its current position. Alternatively, one or both of the directional and magnitude elements 61, 66 may make additional recommendations related to a new steering direction and steering magnitude, respectfully, for correcting any remaining deviation(s) from the intended backing path. The hold indicator 70 may be located in the center of the relating element 68 but may be elsewhere located on the display 16 if desired. It is also contemplated that any of the notifications and recommendations described herein may also be delivered to the driver through non-visual means such as auditory, haptic, and the like, provided the vehicle 12 is equipped with such functionality.
Referring to FIG. 3, an exemplary backing maneuver is shown with further reference to the guidance system 10 and steering icon 22 described in FIGS. 1 and 2, respectfully. The backing maneuver illustrates several instances of a vehicle 12 and trailer 14 being reversed toward a final parking spot 72. The backing maneuver begins at instance A, where the vehicle 12 and trailer 14 are in a substantially straight alignment. In the illustrated example, a straight backing maneuver is intended in the trailer heading specified by arrow 74. As the vehicle 12 and trailer 14 are reversed along path 76, the vehicle 12 and trailer 14 begin to deviate at instance B along path 78. As the vehicle 12 and trailer 14 begin to deviate, the controller 18 determines a steering direction and steering magnitude recommendation for correcting the deviation. The steering direction and steering magnitude recommendation may be displayed to the driver by the steering icon 22 generated on the display 16 of the vehicle 12. The steering direction and steering magnitude recommendation may be determined as a function of hitch angle information, global positioning information, vehicle and trailer-related properties, vehicle and trailer speed, or a combination thereof. In the illustrated embodiment, a first steering direction and steering magnitude recommendation may be made to the driver of the vehicle 12 at instance C prompting the driver to turn the steering device 23 (e.g., steering wheel) in a clockwise direction at a determined magnitude, which may be specified in degrees as described herein. The magnitude may depend on various factors such as, but not limited to, the speed in which the vehicle 12 and trailer 14 are traveling, vehicle 12 and trailer 14 related dimensions and properties, etc. At instance D, a second steering direction and steering magnitude recommendation may be made to the driver of the vehicle 12 prompting the driver to turn the steering device 23 in a counterclockwise direction at another determined magnitude to cause the vehicle 12 and trailer 14 to eventually straighten out along path 82. Once in a straight alignment on path 82, the driver may be notified hold indicator 70 to hold the steering device 23 in its current position so that the trailer 14 may be reversed along the desired heading to the final parking spot 72 (instance E). As the vehicle 12 and trailer 14 move toward the final parking spot 72 along path 82, the controller 18 may continue checking for deviations and the appropriate corrections can be made if necessary. While the intended backing path described above corresponds to a straight backing maneuver, it should be appreciated that steering direction and steering magnitude recommendations may also be made in instances where a driver is attempting a backing maneuver along a curved path. Furthermore, it is contemplated that steering direction and steering magnitude recommendations may also be made in instances where the vehicle 12 and trailer 14 are travelling in a forward direction.
Referring to FIG. 4, a flow diagram of a method 84 for reversing a trailer 14 attached to a vehicle 12 along a straight backing path is shown according to one embodiment. The vehicle 12 is equipped with the guidance system 10 described herein and the method 84 may be executed by the controller 18 of the guidance system 10. For purposes of understanding, certain steps of the method 84 will be described with continued reference to elements appearing in FIGS. 1 and 2.
As shown in step 86, the controller 18 receives a straight backing request inputted by a driver or other user via the user-input device 58. In response, the controller 18 checks whether or not the vehicle 12 and trailer 14 are aligned at step 88 based on trailer angle information 38 received from the hitch angle detection device 26. If the vehicle 12 and trailer 14 are misaligned, the driver of the vehicle 12 may be instructed to pull the vehicle forward (step 90) in the desired heading until the vehicle 12 and trailer 14 are oriented in a straight alignment relative one another. Once it is determined that the vehicle 12 and trailer 14 are in a straight alignment (e.g., hitch angle λ equals approximately 0), the driver is instructed to place the vehicle 12 in reverse and apply gas to the vehicle 12 (step 92). As the vehicle 12 and trailer 14 begin to reverse, the controller 18 may determine a trailer heading at step 94. The determination of the trailer heading may be achieved through global positioning information or by other acceptable means. As the reversing of the trailer 14 continues, the controller 18 repeatedly checks for any deviation (step 96) from the trailer heading determined in step 94 based on hitch angle information 38 supplied by the hitch angle detection device 26. If the controller 18 finds that deviation has occurred, the controller 18 determines one or more steering direction and steering magnitude recommendations to be displayed on the display 16 of the vehicle 12 to correct the deviation (step 98). The steering direction and steering magnitude recommendation(s) may be determined according to any of the methods described herein. Should the driver of vehicle 12 decide to follow the steering direction and steering magnitude recommendations, the vehicle 12 and trailer 14 will be returned along the intended trailer heading.
It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.

## Claims

1. A guidance system for a vehicle reversing a trailer, comprising:
a display; and
a controller configured to generate a steering icon on the display, wherein the steering icon recommends a steering direction and a steering magnitude related to a steering device of the vehicle in order to correct a deviation from an intended backing path.

2. The guidance system of claim 1, wherein the intended backing path comprises a straight backing path.

3. The guidance system of claim 1, wherein the controller determines the steering direction and the steering magnitude based on a measured hitch angle between the vehicle and the trailer.

4. The guidance system of claim 1, wherein the steering icon comprises a directional element indicating a direction in which to turn the steering device.

5. The guidance system of claim 4, wherein the directional element comprises a first arrow for indicating a counterclockwise turn of the steering device and a second arrow for indicating a clockwise turn of the steering device.

6. The guidance system of claim 4, wherein the steering icon further comprises a magnitude element indicating how far to turn the steering device in the direction indicated by the directional element.

7. The guidance system of claim 6, wherein the magnitude element comprises a numerical value measured in degrees.

8. The guidance system of claim 1, wherein the steering icon comprises a relating element to visually relate a current position of the steering device to the recommended steering direction and steering magnitude.

9. The guidance system of claim 1, wherein the steering icon comprises a hold indicator for instructing a driver of the vehicle to maintain the steering device at its current position.

10. A guidance system for a vehicle reversing a trailer, comprising:
a display; and
a controller configured to generate a steering icon on the display to recommend a steering direction and a steering magnitude related to a steering device of the vehicle to correct a deviation from an intended backing path, wherein the steering direction and the steering magnitude are determined at least in part based on a hitch angle between the vehicle and the trailer.

11. The guidance system of claim 10, wherein the intended backing path comprises a straight backing path.

12. The guidance system of claim 10, wherein the steering icon comprises a directional element indicating a direction in which to turn the steering device.

13. The guidance system of claim 12, wherein the directional element comprises a first arrow for indicating a counterclockwise turn of the steering device and a second arrow for indicating a clockwise turn of the steering device.

14. The guidance system of claim 12, wherein the steering icon further comprises a magnitude element indicating how far to turn the steering device in the direction indicated by the directional element.

15. The guidance system of claim 14, wherein the magnitude element comprises a numerical value measured in degrees.

16. The guidance system of claim 10, wherein the steering icon comprises a relating element to visually relate a current position of the steering device to the recommended steering direction and steering magnitude.

17. The guidance system of claim 10, wherein the steering icon comprises a hold indicator for instructing a driver of the vehicle to maintain the steering device at its current position.

18. A method of reversing a vehicle and trailer along an intended backing path, comprising the steps of:
measuring a hitch angle between the vehicle and trailer;
determining whether the vehicle and trailer have deviated from the intended backing path based on the measured hitch angle; and
making a steering direction and steering magnitude recommendation on a display of the vehicle to correct a deviation from the intended backing path.

19. The method of claim 18, wherein the intended backing path comprises a straight backing path.

20. The method of claim 18, wherein the step of making a steering direction and steering magnitude recommendation further comprises the step of instructing a driver of the vehicle to maintain a steering device of the vehicle in its current position.