# Patent

## Title
System for determining hitch angle

## Abstract

A system for determining a hitch angle between a vehicle and trailer is provided. The system includes an imaging device disposed on the trailer. A first navigation system is disposed on-board the vehicle. A second navigation system is integrated with the imaging device. A controller determines the hitch angle based on data received from the first navigation system and the second navigation system.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This patent application is a continuation-in-part of U.S. patent application Ser. No. 14/313,310, which was filed on Jun. 24, 2014, entitled “TRAILER ANGLE DETECTION TARGET PLAUSIBILITY,” now U.S. Pat. No. 9,296,422, which is a continuation-in-part of U.S. patent application Ser. No. 14/301,919, which was filed on Jun. 11, 2014, entitled “TRAILER LENGTH ESTIMATION IN HITCH ANGLE APPLICATIONS,” now U.S. Pat. No. 9,335,163, which is a continuation-in-part of U.S. patent application Ser. No. 14/294,489, which was filed on Jun. 3, 2014, entitled “TRAILER LENGTH ESTIMATION IN HITCH ANGLE APPLICATIONS,” now U.S. Pat. No. 9,335,162, which is a continuation-in-part of U.S. patent application Ser. No. 14/289,888, which was filed on May 29, 2014, entitled “DISPLAY SYSTEM UTILIZING VEHICLE AND TRAILER DYNAMICS,” which is a continuation-in-part of U.S. patent application Ser. No. 14/256,427, which was filed on Apr. 18, 2014, entitled “CONTROL FOR TRAILER BACKUP ASSIST SYSTEM,” now U.S. Pat. No. 9,493,187. U.S. Pat. No. 9,335,162 is also a continuation-in-part of U.S. patent application Ser. No. 14/257,420 which was filed on Apr. 21, 2014, entitled “TRAJECTORY PLANNER FOR A TRAILER BACKUP ASSIST SYSTEM,” which is a continuation-in-part of U.S. patent application Ser. No. 14/256,427, which was filed on Apr. 18, 2014, entitled “CONTROL FOR TRAILER BACKUP ASSIST SYSTEM,” now U.S. Pat. No. 9,493,187, which is a continuation-in-part of U.S. patent application Ser. No. 14/249,781, which was filed on Apr. 10, 2014, entitled “SYSTEM AND METHOD FOR CALCULATING A HORIZONTAL CAMERA TO TARGET DISTANCE,” now U.S. Pat. No. 9,374,562, which is a continuation-in-part of U.S. patent application Ser. No. 14/188,213, which was filed on Feb. 24, 2014, entitled “SENSOR SYSTEM AND METHOD FOR MONITORING TRAILER HITCH ANGLE,” which is a continuation-in-part of U.S. patent application Ser. No. 13/847,508, which was filed on Mar. 20, 2013, entitled “HITCH ANGLE ESTIMATION.” U.S. patent application Ser. No. 14/188,213 is also a continuation-in-part of U.S. patent application Ser. No. 14/068,387, which was filed on Oct. 31, 2013, entitled “TRAILER MONITORING SYSTEM AND METHOD,” now U.S. Pat. No. 9,102,271, which is a continuation-in-part of U.S. patent application Ser. No. 14/059,835, which was filed on Oct. 22, 2013, entitled “TRAILER BACKUP ASSIST SYSTEM,” now U.S. Pat. No. 9,248,858, which is a continuation-in-part of U.S. patent application Ser. No. 13/443,743 which was filed on Apr. 10, 2012, entitled “DETECTION OF AND COUNTERMEASURES FOR JACKKNIFE ENABLING CONDITIONS DURING TRAILER BACKUP ASSIST,” now U.S. Pat. No. 8,825,328, which is a continuation-in-part of U.S. patent application Ser. No. 13/336,060, which was filed on Dec. 23, 2011, entitled “TRAILER PATH CURVATURE CONTROL FOR TRAILER BACKUP ASSIST,” now U.S. Pat. No. 8,909,426, which claims benefit from U.S. Provisional Patent Application No. 61/477,132, which was filed on Apr. 19, 2011, entitled “TRAILER BACKUP ASSIST CURVATURE CONTROL.” U.S. Pat. No. 9,374,562 is also a continuation-in-part of U.S. patent application Ser. No. 14/161,832, which was filed Jan. 23, 2014, entitled “SUPPLEMENTAL VEHICLE LIGHTING SYSTEM FOR VISION BASED TARGET DETECTION,” now U.S. Pat. No. 9,346,396, which is a continuation-in-part of U.S. patent application Ser. No. 14/059,835, which was filed on Oct. 22, 2013, entitled “TRAILER BACKUP ASSIST SYSTEM,” now U.S. Pat. No. 9,248,858. Furthermore, U.S. Pat. No. 9,374,562 is a continuation-in-part of U.S. application Ser. No. 14/201,130, which was filed on Mar. 7, 2014, entitled “SYSTEM AND METHOD OF CALIBRATING A TRAILER BACKUP ASSIST SYSTEM,” now U.S. Pat. No. 9,290,202, which is a continuation-in-part of U.S. patent application Ser. No. 14/068,387, which was filed on Oct. 31, 2013, entitled “TRAILER MONITORING SYSTEM AND METHOD,” now U.S. Pat. No. 9,102,271. The aforementioned related applications are hereby incorporated by reference in their entirety.


FIELD OF THE INVENTION
The present invention generally relates to driver assist and active safety technologies in vehicles, and more particularly to systems for calculating a hitch angle between a vehicle and a trailer.
BACKGROUND OF THE INVENTION
Reversing a vehicle that is connected to a trailer is very challenging for many drivers. If a hitch angle between a tow vehicle and trailer becomes sufficiently large, a potential jackknife condition may result. Thus, there is a need for a system that accurately determines the hitch angle between the vehicle and the trailer.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a system for determining a hitch angle between a vehicle and trailer is provided. The system includes an imaging device disposed on the trailer. A first navigation system is disposed on-board the vehicle. A second navigation system is integrated with the imaging device. A controller determines the hitch angle based on data received from the first navigation system and the second navigation system.
According to another aspect of the present invention, a system for determining a hitch angle between a vehicle and trailer is provided. A first GPS receiver is disposed on-board the vehicle. A portable electronic device having a second GPS receiver is disposed on the trailer. A controller determines the hitch angle based on data received from the first receiver and the second receiver.
According to yet another aspect of the invention, a system for determining a hitch angle between a vehicle and trailer is provided. An imaging device is disposed on the trailer. At least one first inertial sensor is disposed on-board the vehicle. At least one second inertial sensor is integrated with the imagine device. A controller determines the hitch angle based on data received from the at least one inertial sensor and the at least one second inertial sensor.
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 is a schematic diagram illustrating imaging devices located on a vehicle or a trailer that is attached to the vehicle;
FIG. 2 illustrates an imaging device according to one embodiment;
FIG. 3 is a top plan view of the vehicle connected to the trailer demonstrating a plurality of fields of view corresponding to the imaging devices;
FIG. 4 is a block diagram of a controller in communication with the imaging devices and other equipment;
FIG. 5 is a diagram of an aerial view of the vehicle and the trailer displayed on a display located within the vehicle;
FIG. 6 illustrates a path input screen displayed on the display;
FIG. 7 illustrates a touch event being registered on the path input screen to input an intended backing path;
FIG. 8 illustrates an intended backing path crossing through an obstacle;
FIG. 9 illustrates a touch event that modifies the intended backing path;
FIG. 10 illustrates a path selection screen displaying suggested backing paths; and
FIG. 11 is a flow diagram for a method of inputting a backing path.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to a detailed design and some schematics may be exaggerated or minimized to show function overview. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.
Backing and maneuvering a trailer can be a difficult task due to challenges in vision and path prediction. Challenges may vary based on vehicle dimensions, trailer dimensions, and environmental conditions. With large trailers a field of view behind the trailer may be completely occluded. With smaller trailers, small changes in steering can cause a hitch angle between the vehicle tow and the trailer to inflect quickly. In view of these and other concerns, the following improvements provide various implementations to bolster the functionality of a trailer backup assist system.
Backing and maneuvering a trailer can be a difficult task due to challenges in vision and path prediction. Challenges may vary based on vehicle dimensions, trailer dimensions, and environmental conditions. With large trailers a field of view behind the trailer may be completely occluded. With smaller trailers, small changes in steering can cause a hitch angle between the vehicle tow and the trailer to inflect quickly. In view of these and other concerns, the following improvements provide various implementations to bolster the functionality of a trailer backup assist system.
As shown in FIG. 1, the imaging devices C1-C5 may be arranged in various locations such that each field of view of the imaging devices C1-C5 is configured to capture a significantly different area of the operating environment 14. Each of the imaging devices C1-C5 may include any form of imaging device configured to capture image data such as, but not limited to, charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) image sensors. Although five imaging devices C1-C5 are discussed in reference to FIG. 1, the number of imaging devices may vary based on the particular operating specifications of the particular imaging devices implemented and the proportions and/or exterior profiles of a particular vehicle and trailer. For example, large vehicle and trailer combinations may require additional imaging devices to capture image data corresponding to a larger operating environment. The imaging devices may also vary in viewing angle and range of a field of view corresponding to a particular vehicle and trailer combination.
The imaging devices C1, C3, C4, and C5 are disposed on the vehicle 10, each oriented to have a field of view directed towards a substantially different region of the operating environment 14. Imaging device C1 is disposed centrally on a rear portion 16 (e.g. a tailgate) of the vehicle 10 and may employ object detection to monitor the position of a target 18 disposed on the trailer 12 so that a hitch angle γ between the vehicle 10 and the trailer 12 can be determined. As used herein, the hitch angle γ is defined as the angle between a longitudinal centerline axis 20 of the vehicle 10 and the longitudinal centerline axis 22 of the trailer 12. In addition to imaging device C1, or alternatively thereto, imaging device C1′ may be disposed centrally on a rear facing portion 24 of the vehicle 10 proximate a roof portion 26.
Imaging device C3 is disposed centrally on a front facing portion 28 of the vehicle 10 proximate a front grill portion 30. In addition to imaging device C3, or alternatively thereto, imaging device C3′ may be disposed centrally on a front facing portion 32 of the vehicle proximate the roof portion 26. Imaging devices C1 (and/or C1′) and C3 (and/or C3′) are oriented such that the corresponding fields of view encompass substantially the entire operating environment 14 in the aft and fore directions relative to the vehicle 10.
Imaging devices C4 and C5 are disposed on a passenger side 34 and a driver side 36, respectively, and are configured to capture image data corresponding to the operating environment 14 to the sides of the vehicle 10. In some implementations, imaging device C4 is disposed proximate a passenger side mirror 38 and imaging device C5 is disposed proximate a driver side mirror 40. Imaging devices C4 and C5, in combination with imaging devices C1 and C3, are configured to capture image data corresponding to approximately the entire operating environment 14 surrounding the vehicle 10. However, when the vehicle is towing the trailer 12, the trailer 12 may occlude a large portion of a rearward facing field of view from the vehicle 10.
Imaging device C2 may be configure to operate in combination with the imaging devices C1 and C3-C5 to provide a combined field of view of the operating environment 14 surrounding the vehicle 10 and the trailer 12. Imaging device C2 may be disposed on a rear structure 42 of the trailer 12. Imaging device C2 may be located centrally in an upper portion 44 of the trailer 12 and have a rearward facing field of view relative to the trailer 12. Imaging device C2 can be variously located depending on trailer type and trailer geometry. In various implementations, the imaging device C2 may have a substantially rearward facing field of view configured to capture image data corresponding to the operating environment 14 that may be occluded from imaging devices C1 and C3-C5 by the trailer 12.
Referring to FIG. 2, imaging device C2 is shown according to one implementation as a portable electronic device 46 with a built in camera 48 and corresponding image capture setting. Portable electronic device 46 may correspond to a smart device such as, but not limited to, a smart phone or a tablet. As shown, the portable electronic device 46 is provided in a housing 50 coupled to the rear structure 42 of the trailer 12. The housing 50 may be constructed from a transparent rigid material (e.g. plastic) to enable the portable electronic device 46 to accurately capture image data rearward of the trailer 12. The portable electronic device 46 can be supported within the housing 50 via a cradle 52 and/or other support mechanism and may be powered via a corresponding charging cord 54 that is electrically coupled to an electrical system of the trailer 12. The portable electronic device 46 may have an integrated navigational system 56 that includes a GPS receiver 58 for assisted GPS functionality and/or one or more integrated inertial sensors 60, which may include tri-axial gyroscopes, tri-axial accelerometers, tri-axial magnetometers, barometers, the like, or combination thereof. Image data from the camera 48 along with data from the GPS receiver 58 and/or the inertial sensors 60 may be communicated to a vehicle system via wired or wireless (e.g. Bluetooth®) connections. While one implementation of imaging device C2 has been described herein as being a portable electronic device 46, it should not be seen as limiting. Further, it should be appreciated that imaging devices C1 and C3-C5 may also be implemented as portable electronic devices, but are not limited thereto.
Referring to FIG. 3, a top plan view of the vehicle 10 connected to the trailer 12 is shown demonstrating a plurality of fields of view of imaging devices C1-C5. In the illustrated embodiment, imaging device C1 is shown having field of view 62, imaging device C2 is shown having field of view 64, imaging device C3 is shown having field of view 66, imaging device C4 is shown having field of view 68, and imaging device C5 is shown having field of view 70. In this implementation, each of fields of view 62, 64, and 66 include a horizontal viewing angle of approximately 170 degrees or greater and each of corresponding imaging devices C1, C2, and C3 are configured to capture image data corresponding to the fore and aft directions relative to the vehicle 10 and the trailer 12. Imaging devices C4 and C5 are configured to capture image data corresponding to the operating area to each side of the vehicle 10 and the trailer 12 and have corresponding fields of view 68 and 70 that may include viewing angles of approximately 170 degrees or greater. As shown, field of view 68 may form an overlapping portion 72 with field of view 66 and an overlapping portion 74 with field of view 62. Similarly, field of view 70 may also form an overlapping portion 76 with field of view 66 and an overlapping portion 78 with field of view 62. While not shown, each of fields of view 62, 68, and 70 may further form overlapping portions with field of view 64. The overlapping portions may be combined in some implementations to form an expanded view or an aerial view of the vehicle 10 and the trailer 12. The imaging devices C1-C5 are configured to capture image data corresponding to objects and terrain in the surrounding operating environment 14 of the vehicle 10 and the trailer 12.
In the various implementations discussed herein, each of the fields of view 62-70 may be combined in any combination to form various expanded fields of view and corresponding viewing angles based on operating states and relative orientations of the vehicle 10 and the trailer 12. The operating states and relative orientations of the vehicle 10 and the trailer 12 may be determined from the heading of the vehicle 10, the velocity of the vehicle 10, the steering angle δ, and the hitch angle γ between the vehicle 10 and the trailer 12. In some implementations, the fields of view 62-70 may also be combined to form a composite aerial view or bird's eye view of the vehicle 10 and the trailer 12. Information related to the operating state and orientation of the vehicle 10 relative to the trailer 12 may also be utilized to generate a simulated aerial view of the vehicle 10 and the trailer 12 demonstrating the hitch angle γ about point 80.
The various views of the vehicle 10 and the trailer 12, as discussed herein, may be generated and displayed by a controller on the display 13 such that an operator of the vehicle 10 may view the information corresponding to the vehicle 10, the trailer 12, and the surrounding operating environment 14. The display 13 may be implemented in the vehicle 10 as a center stack monitor, rear view display mirror, gauge cluster monitor, a heads-up display, or any other device configured to present the image data processed from the imaging devices C1-C5. The image data from the imaging devices C1-C5 may be raw image data, lens corrected camera image data, composite image data, or any other form of image data captured by the imaging devices C1-C5 or any other form of imaging device.
Referring to FIG. 4, a block diagram of a controller 82 is shown. The controller 82 may be combined or in communication with a trailer backup assist system. The controller 82 may receive and process image data from imaging devices C1-C5 to generate a variety of views for display on display 13. Display 13 may include a plurality of user inputs 84 to enable the controller 82 to receive selections from an operator of the vehicle 10. Display 13 may also include a screen 86 for showing one or more views, which may be selected by the operator and/or autonomously generated. According to one implementation, the screen 86 can be configured as a touch screen for registering one or more touch events. The screen 86 may employ resistive sensing, capacitive sensing, surface acoustic wave sensing, or any other sensing means capable of registering a single or multi-touch event for allowing an operator to input a variety of user commands related to trailer backup assist functionality.
The controller 82 may also be in communication with a first navigational system 88 that includes a GPS device 90, a compass 92, and one or more inertial sensors 94, each of which can be equipment already on-board the vehicle 10. The GPS device 90 can include GPS receiver 91 and is operable to determine a global position and location of the vehicle 10 and communicate the position and location to the controller 82. The compass 92 can be operable to determine the heading direction of the vehicle 10 relative to a geographic compass direction and communicate the heading direction to the controller 82. The inertial sensors 94 can be operable to determine the motion and rotation of the vehicle 10. They may include one or more motion sensors 96 (e.g. an accelerometer) and rotation sensors 98 (e.g. a gyroscope).
The controller 82 may further be in communication with a second navigational system 100, which can include a GPS receiver 102 and one or more inertial sensors 104. According to one implementation, GPS receiver 102 is integrated with imaging device C2. Optionally, inertial sensors 104 may also be integrated with imaging device C2, which can be configured as the portable electronic device 46 shown in FIG. 2. However, it should be appreciated that imaging device C2 can be implemented as a dedicated piece of equipment that is fixed to the trailer 12. Further, GPS receiver 102 and inertial sensors 104 can be provided elsewhere on the trailer 12 and may be incorporated with other equipment and/or structures on the trailer 12.
GPS receiver 102 may be operable to determine a global position and location of the trailer 12 and communicate the position and location to the controller 82. Inertial sensors 104 may be operable to determine the motion and rotation of the trailer 12 and can include any sensor configurations described herein. By providing a navigational system 100 on the trailer 12, the hitch angle γ between the vehicle 10 and the trailer 12 can be determined without the need for image based target recognition. This would also eliminate the need for an operator to attach a target (e.g. target 18) on the trailer 12 or perform vehicle/trailer measurements related to setting up an image based target detection system.
In one implementation, the controller 82 can calculate the hitch angle γ by comparing the vehicle position to the trailer position using vehicle position data received from GPS receiver 91 and trailer position data received from GPS receiver 102. In another implementation, the controller 82 may include a hitch angle detection module 106 configured to alternate between receiving vehicle position data outputted from GPS receiver 91 and trailer position data outputted from GPS receiver 102. The hitch angle detection module 106 can include a Kalman filter 108 for smoothing and extrapolating a vehicle position and a trailer position from the vehicle position data and the trailer position data and subsequently computing a hitch angle γ based on the extrapolated vehicle position and the extrapolated trailer position. In yet another implementation, the controller 82 may calculate the hitch angle γ based on data received from the inertial sensors 94 associated with the vehicle 10 and the inertial sensors 104 associated with the trailer 12. For instance, inertial sensors 94 and 104 can provide the controller 82 with data related to an instantaneous vehicle direction and an instantaneous trailer direction, respectively, which the controller 82 can use to calculate the hitch angle γ. In yet another implementation, the controller 82 may utilize position data for the vehicle 10 as a reference to compute differential position biases for the trailer 12 and vice versa. Doing so may result in more accurate relative position calculations between the vehicle 10 and the trailer 12, thereby resulting in more precise hitch angle γ calculations. It should be appreciated that each of the abovementioned implementations can be combined or performed separately.
As is further shown in FIG. 4, the controller 82 can be configured to communicate with one or more vehicle systems, shown as powertrain system 110, steering system 112, brake system 114, and a gear selection device (PRDNL) 116. Jointly, the powertrain system 110, steering system 112, brake system 114, and gear selection device 116 may cooperate to control the vehicle 10 and the trailer 12 during a backing procedure. According to one implementation, the controller 82 may send instructions to any one of the powertrain system 110, steering system 112, brake system 114, and gear selection device 116 based on input received from a steering input apparatus 118, which may include information defining a path of travel of the vehicle 10 and the trailer 12. The steering input apparatus 118 can be configured as a rotatable device (e.g. knob, steering wheel) that allows an operator of the vehicle 10 to steer the vehicle 10 during a backing maneuver.
The controller 82 may include a memory 120 coupled to one or more processors 122 for executing instructions 124 stored in the memory 120. The memory 120 and instructions 124 together define an example of a non-transient processor-readable medium. The controller 82 may further include a plurality of modules for combining the image data received from the imaging devices C1-C5 with satellite image data (e.g. from GPS device 90) to form various composite views of the operating environment 14 surrounding the vehicle 10 and the trailer 12. The plurality of modules may include a distortion correction module 126, a view conversion module 128, an image trimming/scaling module 130, an image reference identification module 132, and an image compositor 134.
To generate a composite view combining imaging data corresponding to two or more of the image devices C1-C5, the controller 82 may receive image data from the imaging devices C1-C5 and correct any distortion in the image data with the distortion correction module 126. Distortion in the image data may be the result of lens distortion, viewpoint correction, or any other form of distortion common in imaging devices. The view conversion module 128 may the convert a viewpoint of the image data. A viewpoint correction may correspond to altering the orientation of a perspective of the image data corresponding to a field of view of an imaging device. For example, the image data may be adjusted from a side view to an aerial view. The image data from each of the two or more imaging devices may then be trimmed and scaled by the image trimming/scaling module 130 and combined in the image compositor 134. The composite image data output by the compositor 134 may form an expanded field of view, an aerial view, or any combination of the image data received from the imaging devices C1-C5.
In some implementations, the relative location of the image data received from the two or more imaging devices may further be aligned by the image reference identification module 132. The image reference identification module 132 may be operable to detect and identify objects in the image data received from each of the imaging devices C1-C5 and utilize objects in different fields of view to align and accurately combine the image data. The image compositor 134 may further be able to identify occluded and/or missing image data and request satellite image data or other feature data from the GPS device 90 to further supplement and enhance the composite image data. The resulting enhanced composite image data may then be output to the screen 86 for display to the operator of the vehicle 10.
Referring to FIG. 5, an aerial view of the vehicle 10 and the trailer 12 is displayed on the screen 86 of display 13. A vehicle model 136 of the vehicle 10 and a trailer model 138 of the trailer 12 may be incorporated into the aerial view by the controller 82 as sample image data and/or rendered graphics. The sample image data may include stock images of the vehicle 10 and a library of trailer images that may be incorporated in the aerial view to demonstrate the proportions and position of the vehicle 10 relative to the trailer 12. In some implementations, the vehicle operator may input the dimensions of the trailer 12 from the vehicle operator via the user inputs 84 of display 13. The controller 82 may also be operable to estimate the dimensions of the trailer 12 based on known relationships of the positions of each of the imaging devices C1-C5. For example, the controller 82 may be operable to detect the trailer 12 in the image data with the image reference identification module 132. Based on the known relationships of the positions of the imaging devices C1-C5 and the corresponding fields of view 62-70, the controller 82 may be operable to determine the proportions, approximate dimensions, and shape of the trailer 12 to generate the trailer model 138.
The controller 82 may further utilize the hitch angle γ to process and compare image data of the trailer 12 in different positions relative to the vehicle 10 to gain additional image data to determine the proportions, approximate dimensions, and shape of the trailer 12. The hitch angle γ may further be utilized by the controller 82 to display the trailer model 138 relative to the vehicle model 136 at the corresponding hitch angle γ. By demonstrating the vehicle model 136 and the trailer model 138, the controller 82 may provide useful information to the operator of the vehicle 10. In some implementations, a graphic outline simulating the trailer 12 may also be included in the image data displayed on the screen 86 for a reference to the operator of the vehicle 10 to demonstrate the position of the trailer model 138 relative to the vehicle model 136 and an operating environment model 140. Based on the determined proportions, approximate dimensions, and shape of the trailer 12, the controller 82 may automatically select a trailer graphic or a stock image of a trailer model 138 from a library of trailer images or graphics via memory 120.
A plurality of environmental features 142 may also be displayed on the screen 86 by the controller 82. The environmental features 142 may be incorporated in the image data displayed on the screen 86 to demonstrate a location of the environmental features 142 relative to the vehicle model 136 and the trailer model 138. The locations of the environmental features 142 may be extrapolated from the composite image data captured by the imaging devices C1-C5 by the image reference identification module 132 of the controller 82. Each of the environmental features 142 may be identified based on one or more feature identification algorithms configured to identify various natural and man-made features that may obstruct the path of the vehicle 10 and the trailer 12. Additionally or alternatively, sensors and/or radar may be used for detecting environmental features that may be in the path of the vehicle 10 and the trailer 12.
The environmental features 142 may be identified and incorporated in the aerial view based on image data, satellite image data, and any other data corresponding to the position and heading of the vehicle 10. Based on the position and heading of the vehicle 10, the environmental features 142 may be added to the composite image data and located on the screen 86 relative to the vehicle model 136 and the trailer model 138 by utilizing global positions of each of the environmental features 142. The location of the environmental features 142 may be determined by the controller 82 from the GPS device 90 and the compass 92. By enhancing the aerial view with satellite image data, the controller 82 may provide additional information that may be used in addition to the information identified from the imaging devices C1-C5. In some implementations, satellite image data may further be utilized by the controller 82 to provide information corresponding to a region that may be occluded from the fields of view 62-70 of the imaging devices C1-C5.
The screen 86 of display 13 may be configured as a touchscreen of any type such as a resistive type, capacitive type, surface acoustic type, infrared type, and optical type. The plurality of user inputs 84 may be implemented as soft keys and provide options for the operator of the vehicle 10 to alter a view displayed by the controller 82. The soft keys may allow the operator of the vehicle 10 to view the operating environment 140 and select a view corresponding to each of the imaging devices C1-C5, a combination of the imaging devices C1-C5, or the composite aerial view. The soft keys may further provide an option for a manual mode to manually control the view displayed on the screen 86 or an automatic mode to automatically control the view displayed on the screen 86.
While the composite aerial view is selected, an operator of the vehicle 10 may touch soft key 144 to enter a path input mode. When the path input mode is activated, the controller 82 may prompt the display 13 to display a path input screen 145 as shown in FIG. 6. The path input screen 145 can correspond to a “zoomed out” aerial view of the aerial view shown in FIG. 5. Additionally, the zoomed out aerial view may show other environmental features 142 that were not shown in the previous aerial view. By providing a zoom feature, the operator of the vehicle 10 is afforded a greater view of the operating environment. However, it is contemplated that the operator may decrease the amount of zoom should the operator desire a magnified view. The amount of zoom may be adjusted automatically or manually via zoom out key 146 and zoom in key 148. It is also contemplated that the vehicle model 136 and the trailer model 138 may be initially located at the center of the screen 86 by default. An operator may later adjust the screen center by touching the edit center soft key 150 and then dragging the aerial view in a desired direction. Once the aerial view is located in the desired position, the operator may touch the edit center soft key 150 to lock the new aerial view in place. The controller 82 may fit the new aerial view to the screen 86 and analyze image data and/or satellite image data to display any new environmental features 142 arising therefrom.
According to one implementation, the screen 86 is configured to register a touch event that inputs an intended backing path for the vehicle 10 and the trailer 12. Before the intended backing path can be inputted, certain prerequisite conditions may be required. For instance, it may be required for the gear selection device 116 of the vehicle 10 to be in either a park or a reverse position and that the vehicle 10 and the trailer 12 be aligned with one another. To input an intended backing path, the operator of the vehicle 10 may touch the new path soft key 151 and then trace the intended backing path on the screen 86. At any point, the operator may touch the exit soft key 153 to exit the path input mode.
An intended backing path 152 is exemplarily shown in FIG. 7. The intended backing path 152 may be traced (e.g. using finger) from the rear of the trailer model 138 and terminates at a final position 154 selected by the operator. Once traced, the intended backing path 152 is represented as an overlay on the screen 86. The intended backing path 152 may be curved, straight, or a combination thereof. Preferably, the intended backing path 152 is traced to avoid obstacles displayed on the screen 86, which may include environmental features 142 and any objects that would impede the vehicle 10 and trailer 12 from being backed along the intended backing path 152. The obstructions can be natural and/or man-made and may be detected using one or a combination of imaging devices C1-C5 in addition to satellite image data. It is also contemplated that sensors and/or radar may be employed for object detection.
When the intended backing path 152 has been traced, the operator may touch soft key 156 to accept the intended backing path 152 or otherwise touch soft key 158 to trace a new one. While the intended backing path 152 is being traced or afterwards, the controller 82 may determine if any unacceptable path conditions are present. An unacceptable path condition may arise if any traced portions of the intended backing path 152 would result in a hitch angle γ between the vehicle 10 and the trailer 12 exceeding a maximum hitch angle γ, thereby creating a possible jackknife condition. Another unacceptable path condition may arise if one or more obstacles block the intended backing path 152. If one or more unacceptable path conditions arise, the controller 82 may generate a warning to the operator indicating that the intended backing path 152 requires revision or that a new intended backing path needs to be inputted. The warning may be of any type intended to stimulate the senses of an operator and may include warnings that are visual, auditory, tactile, or a combination thereof
In FIG. 8, an intended backing path 152 is exemplarily shown crossing through an obstacle 160. As shown, the intended backing path 152 has various traced portions corresponding to unobstructed portions 162 and an obstructed portion 164. To alert the operator of the unacceptable path condition, the controller 82 may display the unobstructed portions 162 of the intended backing path 152 in a first color (e.g. green) and display the obstructed portion 164 in a second color (e.g. red) that is visually distinguishable from the first color. In response to the unacceptable path condition, another touch event may be performed to modify the intended backing path 152.
According to one implementation shown in FIG. 9, the operator may manipulate the obstructed portion 164 of the intended backing path 152 by dragging the obstructed portion 164 away from the obstacle 160. It is contemplated that the operator may drag any area of the obstructed portion 164 in any direction. While this occurs, the controller 82 may automatically adjust the curvature of the modified intended backing path 166 as needed to ensure allowable hitch angles y and/or avoid any other potential obstacles. If no unacceptable backing conditions arise from the modified intended backing path 166, soft key 168 may become available to allow the operator to accept the modified intended backing path 166. Otherwise, the operator may touch soft key 170 to exit back to the path input screen 145. Additionally or alternatively, the controller 82 may automatically generate one or more possible backing paths A, B, as shown in FIG. 10, and the operator may be given the option of selecting one of the suggested backing paths A, B via a corresponding soft key 172, 174.
Once a backing path has been entered via soft key 168, the controller 82 may extrapolate GPS coordinates for all points along the backing path. The controller 82 may work in conjunction with the GPS device 90 and send instructions to the powertrain system 110, steering system 112, and/or brake system 114 to back the vehicle 10 and the trailer 12 along the inputted backing path. Depending on which systems 110, 112, 114 are employed, the backing maneuver may be completely autonomous or require some actions on the part of the operator of the vehicle 10. While the vehicle 10 and the trailer 12 are backing along the backing path, the operator may adjust the path curvature using the steering input apparatus 118 and/or performing another touch event on the screen 86 (e.g. dragging a traced portion of the backing path). The final resulting backing path may be saved to the GPS device 90 or other location, either manually or automatically. Additionally, the GPS coordinates along with the orientation of the vehicle 10 and trailer 12 may also be saved to the GPS device 90 and/or other location. In this manner, an operator performing repetitive backing maneuvers can simply retrieve and order a saved backing path to be performed instead of having to manually input the backing path each time. Similarly, when an operator pulls of a parking spot, the corresponding pull out path may also be saved accordingly and may be subsequently or concurrently displayed as an overlay on the screen 86. It should be appreciated that an operator may input a pull out path via one or more touch events in a similar way to inputting a backing path, as described herein. Furthermore, saved backing and/or pull out paths may be offered as suggested paths when applicable.
Referring now to FIG. 11, a method 175 for inputting a backing path is shown. The method may be implemented using the controller 82 and other equipment described herein and shown in FIGS. 4-10. More specifically, the method can be embodied as instructions 124 stored in memory 120 and executable by processor 122. The method 175 may begin at step 176, which includes generating an aerial view of a vehicle 10 and a trailer 12 based on at least one of image data and satellite image data. Step 178 includes displaying the aerial view on a display 13 having a touch screen 86. Step 180 includes registering a touch event on the touch screen 86 that inputs an intended backing path for the vehicle 10 and the trailer 12. Step 182 includes determining whether an unacceptable path condition is present. If an unacceptable path condition exits, step 184 includes modifying the intended backing path to overcome the unacceptable path condition or selecting a backing path from one or more suggested backing paths to overcome the unacceptable path condition. Step 186 includes backing the vehicle 10 and the trailer 12 along either the intended backing path or the backing path selected in step 184.
The systems and methods described herein may offer improvements to the functionality of a trailer backup assist system. Though the systems and methods were described and illustrated herein as being implemented on a specific vehicle and trailer, it should be appreciated that the systems and methods described herein may be utilized with any vehicle and trailer combination in accordance with the disclosure.
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 system for determining a hitch angle between a vehicle and a trailer, comprising:
a first GPS receiver disposed on-board the vehicle;
a portable electronic device having a second GPS receiver and disposed on-board the trailer; and
a controller for determining a hitch angle based on data received from the first and second GPS receivers and comprising a hitch angle detection module configured to alternate between receiving data from the first and second GPS receivers.

2. The system of claim 1, wherein the portable electronic device is coupled to a rear structure of the trailer and is disposed to capture image data rearward of the trailer.

3. The system of claim 1, wherein the portable electronic device comprises one of a smart phone and a tablet.

4. The system of claim 1, wherein the first GPS receiver is operable to determine a vehicle position and the second GPS receiver is operable to determine a trailer position.

5. The system of claim 4, wherein the controller calculates the hitch angle by comparing the vehicle position to the trailer position.

6. The system of claim 1, wherein the hitch angle detection module comprises a Kalman filter for extrapolating a vehicle position and a trailer position from the data and subsequently computing the hitch angle based on the extrapolated vehicle position and the extrapolated trailer position.