Vehicle Hitch Assist System and Vehicle

Abstract

The present disclosure provides "Compensating for Trailer Coupler Height During Automatic Hitching Operations." A vehicle hitch assist system includes: a controller that: obtains position data of a trailer coupler; and derives a vehicle path for aligning a hitch ball of the vehicle with the coupler, the controller including compensating for a determined change in the position of the coupler in a direction of travel, the determined change in the position of the coupler in the direction of travel being related to a difference between a vertical position of the coupler in the position data and a height of the hitch ball.

Description

Technical Field

[0001] The present disclosure generally relates to a system for assisting in vehicle-trailer hitch operations. Specifically, the system compensates for horizontal movement of a coupler during lowering the coupler onto a hitch ball. Background Art

[0002] Hitching a trailer to a vehicle can be a difficult and time-consuming experience. Specifically, depending on the initial position of the trailer relative to the vehicle, aligning the vehicle's hitch ball with the desired trailer hitch may require repeated forward and reverse driving, coordinated with multiple steering maneuvers, to properly position the vehicle. Furthermore, the trailer hitch is out of sight throughout much of the driving required for proper hitch ball alignment, and under ordinary circumstances, the driver virtually never sees the hitch ball. This lack of visibility requires inferring the positioning of the hitch ball and hitch based on experience with the specific vehicle and trailer, and may still require multiple instances of stopping and getting out of the vehicle to confirm alignment or record appropriate corrections for a subsequent set of maneuvers. Furthermore, the proximity of the hitch ball to the vehicle's rear bumper means that any overshoot could result in a collision between the vehicle and trailer. Therefore, further development may be needed. Summary of the Invention

[0003] According to one aspect of the present disclosure, a vehicle hitch assist system includes a controller that: obtains position data of a coupler of a trailer; and derives a vehicle path for aligning a hitch ball of the vehicle with the coupler, which includes compensating for a determined change in the position of the coupler in the direction of travel, wherein the determined change in the position of the coupler in the direction of travel is related to a difference between a vertical position in the position data of the coupler and a height of the hitch ball.

[0004] Embodiments of the first aspect of the present invention may include any one or a combination of the following features:

[0005] • the system further comprising means for acquiring said data, said data comprising the position of said coupler of said trailer;

[0006] • said means for acquiring comprises one or more cameras mounted on said vehicle;

[0007] • the controller determines a variation in the position of the coupler in the vertical direction, the variation being used to align with the hitch ball of the vehicle;

[0008] • the direction of travel is in a plane substantially perpendicular to the vertical direction;

[0009] • the controller compensates for the change in the position of the coupler in the direction of travel based on the position data related to the vertical position of the coupler by correlating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation of the coupler about an axis;

[0010] • the axis is vertically aligned with the single axle of the trailer;

[0011] • correlating the change in position of the coupler in the vertical direction with the change in position of the coupler in the direction of travel as a rotation of the coupler about the axis is based on stored information including a distance between the coupler and the axis;

[0012] • the controller obtains the information including the distance between the coupler and the axis through user input;

[0013] • when the vehicle is coupled to the trailer, the controller estimates the distance between the coupler and the axis based on dynamics measured during travel; and

[0014] • The distance between the coupler and the axis is stored as a global estimate.

[0015] According to another aspect of the present disclosure, a vehicle includes a hitch ball mounted on an exterior of the vehicle and a controller. The controller: obtains position data of a coupler of a trailer; and derives a vehicle path for aligning the hitch ball with the coupler, which includes compensating for a determined change in the position of the coupler in a direction of travel, the determined change in the position of the coupler in the direction of travel being related to a difference between a vertical position in the position data of the coupler and a height of the hitch ball.

[0016] According to another aspect of the present disclosure, a method for assisting in coupling a vehicle to a trailer includes obtaining position data of a coupler of the trailer; and deriving a vehicle path for aligning a hitch ball of the vehicle with the coupler, which includes compensating for a determined change in the position of the coupler in a direction of travel, the determined change in the position of the coupler in the direction of travel being related to a difference between a vertical position in the position data of the coupler and a height of the hitch ball.

[0017] These and other aspects, objects, and features of the present disclosure will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the attached figure:

[0019] Figure 1 is a perspective view of the vehicle in an unhitched position relative to the trailer;

[0020] Figure 2 is a diagram of a system for facilitating alignment of a vehicle with a trailer in a position for hitching the trailer to the vehicle according to aspects of the present disclosure;

[0021] Figure 3 is a schematic top view of a vehicle during one step of a sequence for aligning the vehicle with a trailer;

[0022] Figure 4 is a side view schematic diagram illustrating the trajectory of a trailer coupler during pivoting of the trailer about a point;

[0023] Figure 5 is a side view showing the vehicle during a hitch operation, wherein the trailer requires the trailer coupler to move downward;

[0024] Figure 6 is a detail view showing the horizontal offset of the coupler position due to the coupler moving downward to engage the vehicle;

[0025] Figure 7 is a schematic top view of the vehicle during a subsequent step in the sequence of aligning the vehicle with the trailer;

[0026] Figure 8 Yes Figure 7 depiction of an image received from a vehicle camera during an alignment sequence step;

[0027] Figure 9 is a schematic top view of the vehicle during a subsequent step in the sequence of aligning the vehicle with the trailer;

[0028] Figure 10 is a top schematic view of the vehicle during a subsequent step in the sequence of aligning the vehicle with the trailer and illustrating the position of the vehicle's hitch ball at the end of the derived alignment path; and

[0029] Figure 11 is a flow chart depicting the steps in the alignment sequence. DETAILED DESCRIPTION

[0030] For the purpose of description herein, the terms "upper", "lower", "right", "left", "rear", "front", "vertical", "horizontal", "inner", "outer" and their derivatives shall refer to the upper and lower parts of the body. Figure 1However, it will be understood that the apparatus may adopt various alternative orientations unless expressly indicated to the contrary. It will also be understood that the specific apparatus and processes illustrated in the drawings and described in the following specification are merely exemplary embodiments of the inventive concepts defined in the appended claims. Accordingly, specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting unless the claims expressly state otherwise. Additionally, unless otherwise indicated, it will be understood that a discussion of a particular feature of a component extending in or along a given direction, etc., does not imply that the feature or component follows a straight line or axis in this direction, or that it extends only in this direction or in this plane without other directional components or deviations, unless otherwise indicated.

[0031] See overall Figures 1 to 11 , reference numeral 10 denotes a hitch assistance system (also referred to as a "hitch assist" system) for a vehicle 12. Specifically, the hitch assistance system 10 includes a controller 26 that obtains position data of a coupler 14 of a trailer 16 and derives a vehicle path 32 for aligning a hitch ball 34 of the vehicle 12 with the coupler 14. Deriving the vehicle path 32 includes compensating for changes in a position 28 of the coupler 14 in the direction of travel that are related to a difference between the vertical position 28 of the coupler 14 in the position data and the height of the hitch ball 34.

[0032] Relative to Figure 2 The overall operation of the hitch assist system 10 is illustrated in the system diagram of FIG. The system 10 includes various sensors and devices that obtain or otherwise provide information related to the vehicle's state. This information includes positioning information from a positioning system 22, which may include a dead reckoning device 24 (or, in addition or alternatively, a global positioning system (GPS)) for determining the coordinate position of the vehicle 12 based on one or more positions of devices within the positioning system 22. Specifically, the dead reckoning device 24 may establish and track the coordinate position of the vehicle 12 within a local coordinate system 82 based on at least the vehicle's speed and steering angle δ. Other vehicle information received by the hitch assist system 10 may include the speed of the vehicle 12 from a speed sensor 56 and the yaw rate of the vehicle 12 from a yaw rate sensor 58. It is contemplated that in other embodiments, the proximity sensor 54 or array thereof and other vehicle sensors and devices may provide sensor signals or other information, such as a sequential image of the trailer 16 including the detected coupler 14, which the controller 26 of the hitch assist system 10 may process using various procedures to determine the height H and position of the coupler 14 (e.g., based on the distance Dh and angle α h ).

[0033] like Figure 2 As further shown in FIG. 1 , one embodiment of the hitch assist system 10 communicates with the steering system 20 of the vehicle 12, which may be a power steering system 20 including an electric steering motor 74 for operating the steering wheels 76 ( Figure 1 ), thereby causing the vehicle 12 to move in such a manner that the vehicle yaw varies with vehicle speed and steering angle δ. In the illustrated embodiment, the power-assisted steering system 20 is an electric power-assisted steering (EPAS) system that includes an electric steering motor 74 for turning a steering wheel 76 to a steering angle δ based on a steering command, whereby the steering angle δ can be sensed by a steering angle sensor 78 of the power-assisted steering system 20. The steering command 69 can be provided by the hitch assist system 10 for autonomous steering during a trailer hitch alignment maneuver and can alternatively be provided manually via a rotational position (e.g., steering wheel angle) of the steering wheel of the vehicle 12. However, in the illustrated embodiment, the steering wheel of the vehicle 12 is mechanically coupled to the steering wheel 76 of the vehicle 12 such that the steering wheel moves in unison with the steering wheel 76, thereby preventing manual intervention via the steering wheel during autonomous steering. More specifically, a torque sensor 80 is provided on the power-assisted steering system 20. The torque sensor 80 senses torque on the steering wheel that is not expected to be from autonomous control of the steering wheel and therefore indicates manual intervention, whereby the hitch assist system 10 can warn the driver to stop manual intervention with the steering wheel and / or stop automatic steering. In alternative embodiments, some vehicles have power-assisted steering systems 20 that allow the steering wheel to be partially decoupled from the movement of the steering wheels 76 of such vehicles.

[0034] Continue to refer Figure 2 , the power steering system 20 provides information related to the rotational position of the steered wheels 76 of the vehicle 12, including the steering angle δ, to the controller 26 of the hitch assist system 10. In addition to other vehicle 12 conditions, the controller 26 in the illustrated embodiment processes the current steering angle to follow the desired path 32 ( Figure 3) guides the vehicle 12. It is contemplated that, in further embodiments, the hitch assist system 10 may be an integrated component of the power steering system 20. For example, the power steering system 20 may include a hitch assist algorithm for generating vehicle steering information and commands based on all or a portion of information received from the imaging system 18, the power steering system 20, the vehicle braking control system 70, the powertrain control system 72, and other vehicle sensors and devices, and the human-machine interface 40, as discussed further below.

[0035] Also like Figure 2 As shown in FIG, the vehicle brake control system 70 can also communicate with the controller 26 to provide braking information (such as vehicle wheel speed) to the hitch assist system 10 and receive braking commands from the controller 26. For example, vehicle speed information can be determined based on the speed of individual wheels monitored by the brake control system 70. Vehicle speed can also be determined based on other conceivable devices such as the powertrain control system 72, the speed sensor 56, and the positioning system 22. In some embodiments, the speed of individual wheels can also be used to determine the vehicle yaw rate. , as an alternative to or in addition to the vehicle yaw rate sensor 58, the determined vehicle yaw rate may be provided to the hitch assist system 10. The hitch assist system 10 may further provide vehicle braking information to the brake control system 70 for allowing the hitch assist system 10 to control braking of the vehicle 12 during reverse of the trailer 16. For example, in some embodiments, the hitch assist system 10 may adjust the speed of the vehicle 12 during alignment of the vehicle 12 with the coupler 14 of the trailer 16, which may reduce the likelihood of a collision with the trailer 16 and may cause the vehicle 12 to come to a complete stop at the determined endpoint 35 of the path 32. It is disclosed herein that the hitch assist system 10 may additionally or alternatively issue an alert signal corresponding to notification of an actual, impending, and / or anticipated collision with a portion of the trailer 16. As Figure 2 In the illustrated embodiment, the powertrain control system 72 may also interact with the hitch assist system 10 to regulate the speed and acceleration of the vehicle 12 during partial or autonomous alignment with the trailer 16. As described above, regulating the speed of the vehicle 12 may be beneficial in preventing a collision with the trailer 16.

[0036] Additionally, the hitch assist system 10 may communicate with a human-machine interface (HMI) 40 of the vehicle 12. The HMI 40 may include a vehicle display 44, such as a center-stack mounted navigation or entertainment display ( Figure 1). The HMI 40 also includes an input device, which can be implemented by configuring the display 44 as part of a touch screen 42 with circuitry 46 to receive input corresponding to a location on the display 44. Other forms of input (including one or more joysticks, numeric input pads, etc.) can be used instead of or in addition to the touch screen 42. In addition, the hitch assist system 10 can communicate with another embodiment of the HMI 40 via wireless communication, such as with one or more handheld or portable devices 96 (including one or more smart phones) ( Figure 1 ) communications. The portable device 96 may also include a display 44 for displaying one or more images and other information to a user. For example, the portable device 96 may display one or more images of the trailer 16 on the display 44 and may further be capable of receiving remote user input via the touch screen circuit 46. In addition, the portable device 96 may provide feedback information, such as visual, audible, and tactile alerts.

[0037] Still see Figure 2 In the embodiment shown in FIG, the controller 26 is configured with a microprocessor 60 for processing logic and programming stored in a memory 62 that receives information from the aforementioned sensors and vehicle systems, including the imaging system 18, the power steering system 20, the vehicle brake control system 70, the powertrain control system 72, and other vehicle sensors and devices. The controller 26 may generate vehicle steering information and commands based on all or a portion of the received information. The vehicle steering information and commands may then be provided to the power steering system 20 for influencing the steering of the vehicle 12 to achieve the commanded path of travel 32 ( FIG, 2 ) for alignment with the coupler 14 of the trailer 16. Figure 3 ). The controller 26 may include a microprocessor 60 and / or other analog and / or digital circuitry for processing one or more programs. In addition, the controller 26 may include a memory 62 for storing one or more programs, including an image processing program and / or a hitch detection program 64, a path derivation program 66, and an operating program 68. It should be understood that the controller 26 can be a stand-alone dedicated controller, or it can be a shared controller integrated with other control functions, such as with the vehicle sensor system, the power steering system 20, and other conceivable on-board or off-board vehicle control systems. It should be further understood that the image processing program 64 can be implemented by a dedicated processor (including the microprocessor 60) within a stand-alone imaging system of the vehicle 12 that can output the results of its image processing to other components and systems of the vehicle 12. In addition, regardless of what other functions any system, computer, processor, etc. that performs image processing functions, such as those described herein, may also perform (including simultaneously with the execution of the image processing program 64), it may be referred to herein as an "image processor."

[0038] The system 10 may also include an imaging system 18 that includes one or more external cameras. In the example shown, the external cameras include a rear camera 48, a center high-mount stop light (CMHSL) camera 50, and side-view cameras 52a and 52b, although other arrangements including additional or alternative cameras are possible. In one example, the imaging system 18 may include only the rear camera 48, or may be configured so that the system 10 utilizes only the rear camera 48 in a vehicle having multiple external cameras. In another example, the various cameras 48, 50, 52a, 52b included in the imaging system 18 may be positioned so that their respective fields of view substantially overlap. In the depicted arrangement, the respective fields of view include fields of view 49, 51, 53a, and 53b to correspond to the rear camera 48, the center high-mount stop light (CMHSL) camera 50, and the side-view cameras 52a and 52b, respectively. In this manner, image data 55 from two or more cameras can be combined into a single image in the image processing program 64 or in another dedicated image processor within the imaging system 18. In an extension of this example, the image data 55 can be used to derive stereo image data that can be used to reconstruct a three-dimensional scene of one or more areas within the overlapping regions of the various fields of view 49, 51, 53a, 53b, including any objects therein (e.g., obstacles or couplers 14). In one embodiment, two images comprising the same object can be used to determine the location of the object relative to the two image sources, given the known spatial relationship between the image sources. In this regard, the image processing program 64 can use known programming and / or functionality to identify objects within the image data 55 from the various cameras 48, 50, 52a, and 52b within the imaging system 18. In either example, the image processing program 64 can include information related to the positioning of any camera 48, 50, 52a, and 52b present on the vehicle 12 or used by the system 10, including relative to the center 36 ( Figure 1 ) ) related information, such as so that the positions of cameras 48, 50, 52a, and 52b relative to center 36 and / or each other can be used in object location calculations and to generate information relative to center 36 of vehicle 12 or other features of vehicle 12 (such as hitch ball 34 ( Figure 1 ) ) object position data.

[0039] As discussed further below, the height H of the hitch ball 34 b (or the vertical component of the data including the position) can be compared with the determined height H of the coupler 14 cIn conjunction therewith, the hitch ball 34 is used to determine a desired endpoint 35 of the vehicle path 32 for proper alignment between the hitch ball 34 and the coupler 14 when the coupler 14 is lowered to a position flush with (and therefore engaged with) the hitch ball 34 .

[0040] The image processing program 64 may be specifically programmed or otherwise configured to locate the coupler 14 within the image data 55. In one example, the image processing program 64 may identify the coupler 14 within the image data 55 based on stored or otherwise known visual characteristics of the coupler 14 (or, in general, the hitch). In another embodiment, a marker in the form of a sticker or the like may be attached to the trailer 16 in a specific position relative to the coupler 14 in a manner similar to that described in commonly assigned U.S. Patent No. 9,102,271, the entire disclosure of which is incorporated herein by reference. In such an embodiment, the image processing program 64 may be programmed to recognize the characteristics of the marker for the location in the image data 55 and the location of the coupler 14 relative to the marker, so that the position 28 of the coupler 14 can be determined based on the marker's location. Additionally or alternatively, the controller 26 may seek confirmation of the determined coupler 14 via a prompt on the touch screen 42. If the determination of the coupler 14 is not confirmed, additional image processing may be provided, or the touch screen 42 or another input may be used to allow the user to move the depicted location 28 of the coupler 14 on the touch screen 42 to facilitate user adjustment of the location 28 of the coupler 14, which the controller 26 uses to adjust the determination of the location 28 of the coupler 14 relative to the vehicle 12 based on the use of the image data 55 described above. Alternatively, the user may visually determine the location 28 of the coupler 14 within the image presented on the HMI 40 and may provide a touch input to the coupler 14 in a manner similar to that described in co-pending, commonly assigned U.S. patent application Ser. No. 15 / 583,014, the entire disclosure of which is incorporated herein by reference. The image processing program 64 may then associate the location of the touch input with the coordinate system 82 applied to the image 30.

[0041] like Figure 3As shown, image processing program 64 and operating program 68 can be used in conjunction with each other to determine a path 32 along which hitch assist system 10 can guide vehicle 12 to align hitch ball 34 with coupler 14 of trailer 16. In the example shown, the initial position of vehicle 12 relative to trailer 16 can be such that coupler 14 is located only within field of view 53a of side camera 52a, with vehicle 12 positioned laterally from trailer 16 but coupler 14 nearly longitudinally aligned with hitch ball 34. In this manner, upon activation of hitch assist system 10, such as by user input on touch screen 42, image processing program 64 can identify coupler 14 within image data 55 of camera 52a and use image data 55 to estimate position 28 of coupler 14 relative to hitch ball 34, including determining distance D from coupler 14 by receiving focal length information within image data 55, according to one of the examples described above (or a combination of both examples) or by other known means. c and the angle α of the offset between the coupler 14 and the longitudinal axis of the vehicle 12 c This information can then be used based on the position 28 of the coupler 14 within the field of view of the image data 55 to determine or estimate the height H of the coupler 14. c When the coupler 14 is positioned D c , α c Once determined and optionally confirmed by the user, the controller 26 may control at least the vehicle steering system 20 to control movement of the vehicle 12 along the desired path 32 to align the vehicle hitch ball 34 with the coupler 14 .

[0042] In another reference Figure 2 Continue to refer to Figure 3 In one example, the position D of the coupler 14 has been estimated as described above. c , α c The controller 26 may execute the path derivation program 66 to determine the vehicle path 32 so as to align the vehicle hitch ball 34 with the coupler 14. Specifically, the controller 26 may store various characteristics of the vehicle 12 in the memory 62, including the wheelbase W, the distance from the rear axle to the hitch ball 34 (referred to herein as the drawbar length L), and the steerable wheel 76 rotatable delta. 最大 As shown, the wheelbase W and the current steering angle δ can be used to determine the corresponding turning radius ρ of the vehicle 12 according to the following equation:

[0043] (1)

[0044] Where the wheelbase W is fixed, and the steering angle δ can be controlled by the controller 26 through communication with the steering system 20, as described above. In this way, when the maximum steering angle δ is known 最大 When ρ is the minimum possible value of the turning radius最小 Identified as:

[0045] (2)

[0046] The path derivation program 66 may be programmed to derive the vehicle path 32 to align the known position of the vehicle hitch ball 34 with the estimated position 28 of the coupler 14, taking into account the determined minimum turning radius p. 最小 , to allow path 32 to use the least space and the least maneuvering. In this way, path derivation program 66 can use the position of vehicle 12 (which can be based on the center 36 of vehicle 12, the position along the rear axle, the position of dead reckoning device 24, or another known position on coordinate system 82) to determine the lateral distance from coupler 14 and the forward or rearward distance from coupler 14 and derive path 32 that achieves the desired lateral and forward-rearward movement of vehicle 12 within the constraints of steering system 20. The derivation of path 32 further considers the position of hitch ball 34 relative to the tracking position of vehicle 12 based on length L (which can correspond to the center of mass 36 of vehicle 12, the position of a global positioning system (GPS) receiver, or another designated known area) to determine the desired position of vehicle 12 to align hitch ball 34 with coupler 14.

[0047] As described above, the path derivation program 66 can determine the endpoint 35 of the path 32 to achieve alignment between the hitch ball 34 and the coupler 14. In this manner, as Figures 4 to 6 As shown, the position 28 of the coupler 14 is in a direction referred to herein as the "direction of travel," which is a direction generally parallel to the ground on which the vehicle 12 is positioned (ie, perpendicular to the vertical direction). Figures 4 to 6In the illustrated single-axle trailer 16, as the coupler 14 rotates about axis 84, the coupler 14 can move horizontally toward and away from axis 84. In this manner, the horizontal and vertical motions of the coupler 14 are directional components of the overall rotational motion of the coupler 14 about axis 84 and along a trajectory 86, which, as shown, takes the form of an arcuate path about axis 84. Consequently, when the vehicle 12 is backed toward the trailer 16 to the endpoint 35 of the vehicle path 32 that results in the hitch ball 34 being vertically aligned with the coupler 14, the raised position 28 of the coupler 14 will result in misalignment between the coupler 14 and the hitch ball 34 when the coupler 14 is lowered into a position horizontally aligned with the hitch ball 34. Because this horizontal alignment is required to receive the hitch ball 34 within the coupler 14 in order to couple the vehicle 12 to the trailer 16, this misalignment is undesirable. In this manner, hitch assist system 10 may compensate for horizontal movement Δx of coupler 14 in the direction of travel away from axis 84 by determining the vertical movement Δy of coupler 14 that would be required to receive hitch ball 34 within coupler 14 .

[0048] As described above, the hitch assist system 10 may provide image data 55 to the image processing program 64, which may be used by the image processing program 64 (via the process described above or via other available processes) to determine the height H of the hitch ball 34. b (ie, the vertical component of the data including the position 28 of the coupler 14). In addition, the hitch assist system 10 may determine the height H of the hitch ball 34. b stored in memory 62 or may be determined in other ways. In one example, during an initial setup procedure of the hitch assist system 10, a user may be prompted to install the hitch ball 34 by assembling a ball mount including the hitch ball 34 with a receiver positioned on the rear of the vehicle 12. The user may then be asked to measure the height H of the hitch ball 34. b (such as measuring its top or center) and inputting that measurement into the memory 62, for example, via the HMI 40. In this way, a plurality of different height measurements of a plurality of hitch balls 34 used in conjunction with a particular vehicle 12 may be stored in the memory 62 and may be selected by the user. In another example, the hitch ball 34 may be located within the field of view 49 of the rear camera 48, as shown in FIG. Figure 8 As shown, the image data 55 can be processed in real time or on an on-demand basis to determine the height H of the hitch ball 34. b .

[0049] like Figure 6 As shown, the vertical component of the position 28 of the coupler 14 is used to determine the desired position 38 for placing the hitch ball 34. dThe strategy of aligning the endpoint 35 of the vehicle path 32 with the coupler 14 involves calculating an actual or approximate trajectory 86 of the coupler 14 moving about the axis 84. The endpoint 35 is then derived as described above or otherwise to place the hitch ball 34 at the desired location 38 on the trajectory 86. d In fact, this solution is achieved by determining the height H of the coupler 14. c The height H of the hook ball 34 b The difference between the vertical distance Δy and the horizontal distance Δx of the movement of the coupler 14 in the direction of travel resulting from the vertical distance Δy is then used to correlate the vertical distance Δy with the horizontal distance Δx of the movement of the coupler 14 in the direction of travel resulting from the vertical distance Δy. Figure 3 ), this horizontal distance Δx may be directly input into the path derivation routine 66 as its desired endpoint 35 or may be applied as an offset to the endpoint 35 derived from the initially determined position 28 of the coupler 14.

[0050] Continue to refer Figure 6 By assuming that the coupling 14 is around the height H of the hitch ball 34 bBy pivoting at the same height as point 87, a roughly accurate estimation of trajectory 86 can be made in a simplified manner. In this manner, the height of axle 84 need not be known. In this manner, trajectory 86 can be determined as an arc having a radius corresponding to the drawbar length L of trailer 16, which is the horizontal distance between coupler 14 and pivot point 87, with such an arc centered on pivot point 87. Therefore, hitch assist system 10 must utilize some value of drawbar length L. In one implementation, drawbar length L can be a constant value stored in memory 62 that generally corresponds to an average value of typical trailer lengths determined for use with a particular type of vehicle 12, which provides an acceptable calculation of trajectory 86. In another implementation, a set of different drawbar lengths L can be stored in memory 62 and can correspond to different average lengths for various trailer types (e.g., boats, utilities, recreational vehicles, etc.), which can be selected by the user or determined by image processing program 64. Furthermore, various related vehicle systems (including various implementations of the trailer back-up assist system) can provide a simplified user interface for controlling the vehicle 12 during backing of the trailer 16, such as those described in U.S. Patent Application No. 14 / 736,391, the entire disclosure of which is incorporated herein by reference. The hitch assist system 10 can be included in a vehicle having such additional systems or related capabilities such that a value of the drawbar length L obtained by operating the trailer back-up assist system can be used by the hitch assist system 10 to determine the trajectory 86. In one specific aspect, the hitch assist system 10 can include one or more of the above-described average drawbar lengths L stored in the memory 62 as a default setting, thereby allowing the hitch assist system 10 to operate without requiring an input or derived measurement of the drawbar length L, while allowing the use of an input or available specific value.

[0051] Given a specific value of the drawbar length L, the hitch assist system 10 may use the determined vertical component of the position 28 of the coupler 14 (corresponding to the height H of the coupler 14). c ) and the height H of the hook ball 34 b The value of the vertical movement Δy of the coupler 14 is derived for determining the adjustment offset Δx of the end point 35 of the path 32. Figures 4 to 6 In the case shown in FIG. 1 , it can be assumed that the trailer pivot point 87 is at the same height as the hitch ball 34, that the floor 89 of the trailer 16 is parallel to the ground when the trailer 16 is coupled to the vehicle 12, and that the coupler 14 does not raise or lower independently of the rest of the trailer 16 (and is only raised by rotating about the pivot point 87), the following equation can be used to determine the adjustment offset Δx:

[0052] (3)

[0053] In situations where none of the above assumptions can be made, such as when the geometry of the actual trailer 16 differs from the geometry involved in the assumptions, the endpoint 35 of the path 32 derived using the determined offset Δx may not be accurate enough to align the coupler 14 with the hitch ball 34 as the coupler 14 is lowered toward the hitch ball 34. The hitch assist system 10 can be configured to allow compensation for such variations. For example, equation (3) can be modified to allow input of the height of the shaft 84 so that the trajectory 86 can be positioned about the shaft 84 to compensate for the pivot point 87 not being horizontally aligned with the hitch ball 34. Further, when the coupler 14 and the hitch ball 34 are engaged, any difference between the hitch ball 34 and the pivot point 87 can be used to determine a non-zero angle of the floor 89. Alternatively, a measurement of this angle can be input and used in a modified version of equation (3) and the height of the pivot point 87 determined.

[0054] As described above, once the desired path 32 including the endpoint 35 has been determined, the controller 26 is then allowed to control the steering system 20 of the vehicle 12 using at least the powertrain control system 72 and the brake control system 70 (whether controlled by the driver or by the controller 26, as described below) to control the speed (forward or reverse) of the vehicle 12. In this way, the controller 26 can receive data from the positioning system 22 regarding the position of the vehicle 12 during its movement, while controlling the steering system 20 as needed to keep the vehicle 12 along the path 32. Specifically, the path 32, which has been determined based on the geometry of the vehicle 12 and the steering system 20, can be adjusted based on the position of the vehicle 12 along the path. It should also be noted that in one embodiment, the path 32 can include a progression of adjustments to the steering angle δ that depends on the tracked vehicle position.

[0055] like Figure 3 As shown, such as when the trailer 16 is positioned laterally to the side of the vehicle 12, the initial positioning of the trailer 16 relative to the vehicle 12 can be such that forward movement of the vehicle 12 is required within the desired vehicle path 32. In this manner, the path 32 can include various portions 33 requiring forward travel or reverse travel by the vehicle 12 separated by inflection points 90 at which the vehicle 12 must transition between such forward travel and such reverse travel. In one embodiment, the path derivation program 66 can be configured to include a straight reverse portion 33 of a defined distance prior to reaching the point at which the hitch ball 34 aligns with the position 28 of the coupler 14. The remaining portion 33 can be determined to achieve the desired lateral and forward / rearward movement within the smallest area possible and / or utilizing a minimum number of total segments 33 or inflection points 90. In Figure 3In the example shown, the path 32 may include two portions 33 that together traverse the lateral movement required by the vehicle 12 while providing a straight backing motion to bring the hitch ball 34 into the offset alignment described above with the coupler 14, one of the portions 33 including a right turn direction at a maximum steering angle δ. 最大 The forward direction is to be driven, and the other direction includes turning left with a maximum steering angle δ 最大 Then, a single turning point 90 is included where the vehicle 12 transitions from forward travel to reverse travel, followed by the aforementioned straight backward reverse portion 33. It should be noted that variations of the depicted path 32 may be used, including variations having a maximum steering angle δ of less than δ. 最大 A single forward travel portion 33 of rightward steering angle δ is followed by a turning point 90 and a maximum leftward steering angle δ 最大 The reverse portion 33 of travel may be combined with a shorter straight reverse portion 33, wherein further paths 32 may exist. In another example, the system 10 may be configured to operate with the vehicle 12 only when in reverse, in which case the system 10 may prompt the driver, as needed, to steer the vehicle 12 to position the trailer 16 within a specified area relative to the vehicle 12 (including behind it) so that the path derivation program 66 may determine a vehicle path 32 that includes only reverse travel. Such instructions may further prompt the driver to position the vehicle 12 relative to the trailer 16 to compensate for other limitations of the system 10, including a specific distance for identifying the coupler 14, a minimum offset angle α, and a minimum distance for identifying the coupler 14. c It should be further noted that the positioning D of the coupler 14 c , α c The estimates may become more accurate as vehicle 12 traverses path 32, including positioning vehicle 12 in front of trailer 16 and as vehicle 12 approaches coupler 14. Thus, such estimates may be continuously derived and used to update path derivation program 66 as needed when determining the adjusted endpoint 35 of path 32, as described above.

[0056] Now turn Figures 7 to 10 , the operating procedure 68 may continue to guide the vehicle 12 until the hitch ball 34 is in the desired position 38 relative to the coupler 14 d , so that when the coupler 14 is lowered into horizontal alignment with the hitch ball 34, the coupler 14 engages the hitch ball 34. In the example discussed above, the image processing program 64 performs the following operations during the execution of the operating program 68 (including when the coupler 14 continues to move along the path 33 as the vehicle 12 continues to move, such as Figure 7 ) into a clearer view of the rear camera 48 (as shown) Figure 8 As shown)) continuously monitors the position D of the coupler 14 c , α cAs described above, the position of the vehicle 12 may also be monitored by the dead reckoning device 24, wherein the position 28 of the coupler 14 is continuously updated and input into the path derivation program 66, in such situations (including when the vehicle moves closer to the trailer 16 (e.g. Figure 9 ), the path 32 and / or the endpoint 35 may be improved or should be updated (because of an improved height H due to, for example, a closer resolution or additional image data 55). c , distance D c Or the offset angle α c Further, the coupler 14 may be assumed to be stationary, such that the position of the vehicle 12 may be tracked by continuing to track the coupler 14, eliminating the need to use the dead reckoning device 24. In a similar manner, a modified variation of the operating procedure 68 may be performed through a predetermined sequence of maneuvers involving steering at or below the maximum steering angle δ. 最大 The vehicle 12 is turned by an angle of , while tracking the position D of the coupler 14 c , α c To converge the known relative position of the hitch ball 34 to its desired position 38d relative to the tracking position 28 of the coupler 14, as described above and as Figure 10 shown.

[0057] Now turn Figure 11 , a flow chart illustrating the steps involved in aligning the vehicle hitch ball 34 with the trailer coupler 14 using the hitch assist system 10. Specifically, in step 110, the hitch assist system 10 is activated. In one example, the hitch assist system 10 can be activated at any point when the coupler 14 is within the field of view 49, 51, 53a, 53b of at least one camera 48, 50, 52a, 52b within the imaging system 18. Thus, when the hitch assist system 10 is activated, the controller 26 can use the imaging system 18 to scan the visible scene using any or all available cameras 48, 50, 52a, 52b (step 112). The scene scan (step 112) can then be used to identify the coupler 14 and, optionally, the associated trailer, which can be confirmed by the user (step 118). The height H of the coupler 14 identified in step 116 can then be determined using the available image data 55 (including, as described above, using the image processing program 64). c , distance D c and the offset angle α c(Step 120). As described above, the image processing program 64 may be programmed or otherwise configured to identify the coupler 14 of the trailer 16 within the image data 55 (Step 116). In this manner, after analyzing the results (Steps 114-118) of the initial scene scan (Step 112), the controller 26 may determine in Step 120 whether the user has confirmed the coupler 14 (such as via the HMI 40). If the coupler 14 has not been confirmed or if the determined coupler 14 has been rejected, the scene scan (Step 112) may continue (including when instructing the driver to move the vehicle 12 to better align with the trailer 16) until the coupler 14 is identified. When the coupler 14 has been identified and confirmed, the path derivation program 66 may be used to determine in Step 122 the vehicle path 32 used to align the hitch ball 34 with the coupler 14. In this manner, the positioning D of the coupler 14 is determined. h , α h The controller 26 uses the path derivation routine 66 to determine the path 32 so as to align the hitch ball 34 with the predicted position 28 of the coupler 14 when the coupler 14 is lowered to the engaged position over the hitch ball 34 as required, as shown above with respect to the vehicle 12. Figures 3 to 10 As stated.

[0058] Once the path 32 has been derived, the hitch assist system 10 may request that the user U relinquish control of at least the steering wheel of the vehicle 12 (and optionally, in the aforementioned implementation of the hitch assist system 10 where the controller 26 is responsible for controlling the powertrain control system 72 and the brake control system 70 during execution of the operating procedure 68, the throttle 73 and actuators) (step 124). Once it has been confirmed (e.g., using the torque sensor 80, as described above) that the user U is not attempting to control the steering system 20, the controller 26 begins moving the vehicle 12 along the determined path 32. In systems 10 that include forward travel and / or gear shifting capabilities, the system 10 may determine whether the transmission system 92 is in the correct gear and, if necessary, cause the transmission system 92 to shift to the desired gear or prompt the user U to shift to the desired gear (step 126). The hitch assist system 10 then controls the steering system 20 (step 128) to maintain the vehicle 12 along the path 32 while the user U or the controller 26 controls the speed of the vehicle 12 using the powertrain control system 72 and the brake control system 70. If the vehicle 12 reaches a path 32 that includes both forward and reverse travel (such as Figure 3 If the inflection point 90 in the path shown in FIG) is reached, additional transformations or prompts for transformations may be implemented. As described above, the controller 26 or the user may track the position D of the coupler 14. c , αc (Step 130) Controlling at least the steering system 20 until the vehicle 12 reaches the endpoint 35 where the vehicle 12 hitch ball 34 reaches the desired position 38 for desired alignment with the coupler 14 d At that point, the operational routine 68 may end (step 132) by controlling the braking system 70 to bring the vehicle 12 to a stop (which may occur gradually as the vehicle 12 approaches this point) or by issuing a command to the user to bring the vehicle 12 to a stop prior to deactivating the hitch assist system 10 (which may also occur gradually or by a countdown as the vehicle 12 approaches the desired position).

[0059] It will be understood that changes and modifications can be made to the foregoing constructions without departing from the concepts of the present disclosure, and it will be further understood that such concepts are intended to be encompassed by the following claims unless such claims expressly indicate otherwise in their language.

[0060] For purposes of this disclosure, the term "coupled" (in all its forms, couple, coupling, coupled, etc.) generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary or movable in nature. Such joining may be achieved by integrating the two components (electrical or mechanical) and any additional intermediate members into a single integral body with one another or with the two components. Unless otherwise specified, such joining may be permanent in nature or may be removable or releasable.

[0061] It is also important to note that the structure and arrangement of the elements of the present disclosure as shown in the exemplary embodiments are illustrative only. While this disclosure describes only a few embodiments of the present innovation in detail, those skilled in the art who review the contents of this disclosure will readily appreciate that numerous modifications (e.g., variations in the size, dimensions, structure, shape, and proportions of various elements, parameter values, mounting arrangements, material usage, color, orientation, etc.) may be made without materially departing from the novel teachings and advantages of the subject matter described. For example, elements shown as integrally formed may be constructed from multiple parts, or elements shown as multiple parts may be integrally formed, the operation of interfaces may be reversed or otherwise varied, the structure and / or components of the system, or the length or width of connectors or other elements may be varied, and the nature or number of adjustment positions provided between elements may be varied. It should be noted that the elements and / or components of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability in any variety of colors, textures, and combinations. Therefore, all such modifications are intended to be included within the scope of the present innovation. Other substitutions, modifications, changes, and omissions may be made to the design, operation, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovation.

[0062] It should be understood that any described process or steps in a described process can be combined with other disclosed processes or steps to form structures within the scope of the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and should not be construed as limiting.

[0063] According to the present invention, a vehicle hitch assist system is provided, which has a controller, which: obtains position data of a coupler of a trailer; and derives a vehicle path for aligning a hitch ball of the vehicle with the coupler, which includes compensating for a determined change in the position of the coupler in the travel direction, wherein the determined change in the position of the coupler in the travel direction is related to the difference between the vertical position in the position data of the coupler and the height of the hitch ball.

[0064] According to one embodiment, the above invention is further characterized by means for acquiring said position data of said coupler of said trailer.

[0065] According to one embodiment, said means for acquiring comprises one or more cameras mounted on said vehicle.

[0066] According to one embodiment, the controller determines a variation in the position of the coupler in a vertical direction, the variation being used to align with the hitch ball of the vehicle.

[0067] According to one embodiment, the driving direction is in a plane substantially perpendicular to the vertical direction.

[0068] According to one embodiment, the controller compensates for the change in the position of the coupler in the direction of travel based on the position data associated with the vertical position of the coupler by associating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation of the coupler around an axis.

[0069] According to one embodiment, the axis is vertically aligned with a single axle of the trailer.

[0070] According to one embodiment, correlating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation of the coupler around the axis is based on stored information including the distance between the coupler and the axis.

[0071] According to one embodiment, the controller obtains the information including the distance between the coupler and the axis through user input.

[0072] According to one embodiment, when the vehicle is coupled to the trailer, the controller estimates the distance between the coupler and the axis based on dynamics measured during travel.

[0073] According to one embodiment, the distance between the coupler and the axis is stored as a global estimate.

[0074] According to the present invention, a vehicle is provided having: a hitch ball mounted on the exterior of the vehicle; and a controller, which: obtains position data of a coupler of a trailer; and derives a vehicle path for aligning the hitch ball with the coupler, which includes compensating for determined changes in the position of the coupler in the direction of travel, the determined changes in the position of the coupler in the direction of travel being related to the difference between the vertical position in the position data of the coupler and the height of the hitch ball.

[0075] According to one embodiment, the above invention is further characterized by: a steering system; and a braking system; wherein: the controller further controls the steering system to guide the vehicle along the path and controls the braking system to stop the vehicle at the end of the vehicle path, thereby compensating for the determined change in the vertical position of the coupler in the travel direction, and the determined change in the vertical position of the coupler in the travel direction is related to the difference between the vertical position in the position data of the coupler and the height of the hitch ball.

[0076] According to one embodiment, the above invention is further characterized by: an imaging system, wherein the imaging system includes one or more cameras mounted on the vehicle; wherein the controller obtains the position data of the coupler by processing data received from the imaging system.

[0077] According to one embodiment, the controller determines a variation in the position of the coupler in the vertical direction, the variation being used for alignment with the hitch ball of the vehicle.

[0078] According to one embodiment, the controller compensates for the change in the position of the coupler in the travel direction based on the position data related to the vertical position of the coupler by correlating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the travel direction as a rotation of the coupler around an axis.

[0079] According to the present invention, a method for assisting in the coupling of a vehicle to a trailer comprises obtaining position data of a coupler of the trailer; and deriving a vehicle path for aligning a hitch ball of the vehicle with the coupler, which comprises compensating for a determined change in the position of the coupler in the direction of travel, the determined change in the position of the coupler in the direction of travel being related to a difference between a vertical position in the position data of the coupler and a height of the hitch ball.

[0080] According to one embodiment, the above invention is further characterized by: controlling the vehicle steering system to guide the vehicle along the path; and controlling the vehicle braking system to stop the vehicle at the end of the vehicle path, thereby compensating for the determined change in the position of the coupler in the travel direction, and the determined change in the position of the coupler in the travel direction is related to the difference between the vertical position in the position data of the coupler and the height of the hitch ball.

[0081] According to one embodiment, the above invention is further characterized in that: the position data of the coupler is obtained by processing data received from a vehicle imaging system; wherein: deriving the vehicle path also includes determining a variable of the position of the coupler in the vertical direction, which is used to align with the hitch ball of the vehicle.

[0082] According to one embodiment, compensating for the change in the position of the coupler in the direction of travel based on the position data related to the vertical position of the coupler includes associating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation of the coupler around an axis.

Claims

1. A vehicle hitch assist system, comprising: Braking system; as well as a controller, the controller: obtaining position data of a coupling of a trailer; deriving a vehicle path for aligning a hitch ball of the vehicle with the coupler, comprising compensating for a determined change in the position of the coupler in the direction of travel based on the position data associated with the vertical position of the coupler by correlating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation about an axis, and The braking system is controlled to stop the vehicle at an end of the vehicle path.

2. The system of claim 1, further comprising means for acquiring the position data of the coupler of the trailer.

3. The system of claim 2, wherein the means for acquiring comprises one or more cameras mounted on the vehicle.

4. The system of claim 1 wherein the controller determines a variation in the position of the coupler in a vertical direction for alignment with the hitch ball of the vehicle.

5. The system of claim 4, wherein the direction of travel is in a plane substantially perpendicular to the vertical direction.

6. The system of claim 1, wherein the axis is vertically aligned with a single axle of the trailer.

7. The system of claim 1 , wherein correlating the change in the position of the coupler in the vertical direction with the change in the position of the coupler in the direction of travel as a rotation of the coupler about the axis is based on stored information including the distance between the coupler and the axis.

8. The system of claim 7, wherein the controller obtains the information including the distance between the coupler and the axis through user input.

9. The system of claim 7, wherein the controller estimates the distance between the coupler and the axis based on dynamics measured during travel when the vehicle is coupled to the trailer.

10. The system of claim 7, wherein the distance between the coupler and the axis is stored as a global estimate.

11. A vehicle comprising: Braking system; a hitch ball mounted on the exterior of the vehicle; as well as A system as claimed in any one of the preceding claims 1 to 10.

12. The vehicle of claim 11, further comprising: Steering system; as well as in: The controller further controls the steering system to guide the vehicle along the path.

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