Patent Publication Number: US-2023158845-A1

Title: Hitch assistance system with interface presenting simplified path image

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The design patent application is a continuation of and claims priority to U.S. Design patent application Ser. No. 16/196,487, filed on Nov. 20, 2018, entitled “HITCH SYSTEM WITH INTERFACE PRESENTING SIMPLIFIED PATH IMAGE”, the entire contents of each, including the original Appendix, are hereby incorporated by reference in their entirety. To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be revisited. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a vehicle hitch assistance system. In particular, the system provides presents a simplified travel path as a static image to a user, with such image being updated according to predetermined parameters. 
     BACKGROUND OF THE INVENTION 
     Hitching a trailer to a vehicle can be a difficult and time-consuming experience. In particular, aligning a vehicle hitch ball with the desired trailer hitch can, depending on the initial location of the trailer relative to the vehicle, require repeated forward and reverse driving coordinated with multiple steering maneuvers to appropriately position the vehicle. Further, through a significant portion of the driving needed for appropriate hitch ball alignment, the trailer hitch cannot be seen, and the hitch ball can, under ordinary circumstance, never actually be seen by the driver. This lack of sight lines requires inference of the positioning of the hitch ball and hitch based on experience with a particular vehicle and trailer, and can still require multiple instances of stopping and stepping out of the vehicle to confirm alignment or to note an appropriate correction for a subsequent set of maneuvers. Even further, the closeness of the hitch ball to the rear bumper of the vehicle means that any overshoot can cause a collision of the vehicle with the trailer. Accordingly, further advancements may be desired. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the disclosure, a vehicle hitching assistance system includes a controller acquiring image data from the vehicle and deriving a vehicle path to align a center of a hitch ball of the vehicle with a centerline of a trailer coupler within the image data. The controller also outputs a video image including a representation of a simplified path from the hitch ball to the coupler and outputs a steering signal to cause the vehicle to steer along the vehicle path. 
     Embodiments of the first aspect of the disclosure can include any one or a combination of the following features or aspects:
         the vehicle path includes a set of path segments defining respective curvatures in opposite directions, and the simplified path includes only one segment having a curvature in a single direction; the simplified path is selected from the path segments set based on a theoretical turn radius at the hitch ball;   the simplified path is derived as an arced path between a current hitch ball position and a current coupler position;   the arced path is defined by a backing trajectory of the hitch ball that is centered about a theoretical turn center of the vehicle for a theoretical constant turn radius;   the simplified path is derived as a straight line path between a current hitch ball position and a current coupler position;   the video image output by the controller further includes at least a portion of the image data with the representation of the simplified path overlaid on the image data, and the video image is output to a human-machine interface within the vehicle for display thereon;   the controller further derives the simplified path at an initial state and updates the simplified path at least one subsequent state, wherein the representation of the simplified path included in the video image corresponds with a most recent state;   the simplified path derived at the initial state is an arced path, and the simplified path derived at the at least one subsequent state is a straight line path;   wherein the controller acquires the image data from an imaging system included with the vehicle, the imaging system having at least one camera; and   the controller outputs the steering signal to a steering system included with the vehicle, and the controller derives the steering signal based on at least a maximum steering angle of the steering system.       

     According to another aspect of the disclosure, a vehicle includes a steering system and a controller. The controller acquires image data from the vehicle and derives a vehicle path to align a center of a hitch ball of the vehicle with a centerline of a trailer coupler within the image data. The controller further outputs a video image including a representation of a simplified path from the hitch ball to the coupler and outputs a steering signal to the steering system to steer along the vehicle path. 
     According to another aspect of the disclosure, a method for assisting a vehicle in hitching with a trailer includes acquiring image data from the vehicle, deriving a vehicle path to align a center of a hitch ball of the vehicle with a centerline of a trailer coupler within the image data, presenting a video image including a representation of a simplified path from the hitch ball to the coupler, and causing the vehicle to steer along the vehicle path. 
     According to another aspect of the disclosure, a vehicle hitching assistance system includes a human-machine interface including a video screen; and a controller acquiring image data from the vehicle. The controller further derives a vehicle path to align a hitch ball of the vehicle with a trailer coupler within the image data, the vehicle path including a set of path segments defining respective curvatures in opposite directions, outputs a video image, including a representation of a simplified path from the hitch ball to the coupler, to the video screen for display thereon, the simplified path including only one segment selected from the path segment set, and outputs a steering signal to cause the vehicle to steer along the vehicle path. 
     According to another aspect of the disclosure, a vehicle, includes a steering system, a human-machine interface including a video screen, a controller. The controller acquires image data from the vehicle, derives a vehicle path to align a hitch ball of the vehicle with a trailer coupler within the image data, derives a simplified path from the hitch ball to the coupler at an initial state, and outputs a video image, including a representation of a simplified path, to the video screen for display thereon. The controller further outputs a steering signal to the steering system to steer along the vehicle path and updates the simplified path in at least one subsequent state while steering along the vehicle path. The representation of the simplified path included in the video image corresponds with a most recent state, at least by having an updated curvature that is different from an initial curvature corresponding with the initial state. 
     According to another aspect of the disclosure, a method for assisting a vehicle in hitching with a trailer includes acquiring image data from the vehicle, deriving a vehicle path to align a hitch ball of the vehicle with a trailer coupler within the image data, deriving a simplified path from the hitch ball to the coupler at an initial state, and outputting a video image, including a representation of a simplified path, to the video screen for display thereon. The method further includes causing the vehicle to steer along the vehicle path and updating the simplified path in at least one subsequent state while causing the vehicle to steer along the vehicle path. The representation of the simplified path included in the video image corresponds with a most recent state, at least by having an updated curvature that is different from an initial curvature corresponding with the initial state. 
     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 perspective view of a vehicle in an unhitched position relative to a trailer; 
         FIG.  2    is a diagram of a system according to an aspect of the disclosure for assisting in aligning the vehicle with a trailer in a position for hitching the trailer to the vehicle by movement along a path, with a schematic depiction of a simplified path for presentation to a user; 
         FIG.  3    is an overhead schematic view of a vehicle during a step of the alignment sequence with the trailer; 
         FIG.  4    is a depiction of an image received from the vehicle camera during the alignment sequence step with a simplified vehicle path overlaid thereon; 
         FIG.  5    is an overhead schematic view depicting the geometry for determining a simplified path radius; 
         FIG.  6    is an overhead schematic view depicting the determination of the simplified vehicle path; 
         FIG.  7    is an overhead schematic view of the vehicle during a subsequent step of the alignment sequence with the trailer; 
         FIG.  8    is a depiction of an image received from a vehicle camera during the alignment sequence step of  FIG.  6   ; 
         FIG.  9    is an overhead schematic view of the vehicle during a subsequent step of the alignment sequence with the trailer; 
         FIG.  10    is an overhead schematic view of the vehicle during a subsequent step of the alignment sequence with the trailer and showing the position of a hitch ball of the vehicle at an end of a derived alignment path; 
         FIG.  11    is an overhead schematic view of an alternative simplified path; 
         FIG.  12    is an overhead schematic view of an alternative, multi-portion simplified path; 
         FIG.  13    is a depiction of an image received from the vehicle camera during an alignment sequence step with a first portion of the simplified vehicle path overlaid thereon; 
         FIG.  14    is a depiction of a subsequent image received from the vehicle camera during a further alignment sequence step with a second portion of the simplified vehicle path overlaid thereon; and 
         FIG.  15    is a flowchart depicting steps in the alignment sequence. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “interior,” “exterior,” and derivatives thereof shall relate to the device as oriented in  FIG.  1   . However, it is to be understood that the device may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawing, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless otherwise specified, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like does not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified. 
     Referring generally to  FIGS.  1 - 10   , reference numeral  10  designates a hitch assistance system (also referred to as a “hitch assist” system) for a vehicle  12 . The system  10  includes a controller  26  acquiring image data  55  from the vehicle  12  and deriving a vehicle path  32  to align a hitch ball  34  of the vehicle  12  with a trailer coupler  14  within the image data  55 . The controller  26  also outputs a video image  43  including a representation of a simplified path  86  from the hitch ball  34  to the coupler  14  and outputs a steering signal to cause the vehicle  12  to steer along the vehicle path  32 . 
     With respect to the general operation of the hitch assist system  10 , as illustrated in the system diagram of  FIG.  2   , system  10  includes various sensors and devices that obtain or otherwise provide vehicle status-related information. This information includes positioning information from a positioning system  22 , which may include a dead reckoning device  24  or, in addition or as an alternative, a global positioning system (GPS), to determine a coordinate location of the vehicle  12  based on the one or more locations of the devices within the positioning system  22 . In particular, the dead reckoning device  24  can establish and track the coordinate location of the vehicle  12  within a localized coordinate system  82  based at least on vehicle speed and steering angle S. Other vehicle information received by hitch assist system  10  may include a speed of the vehicle  12  from a speed sensor  56  and a yaw rate of the vehicle  12  from a yaw rate sensor  58 . It is contemplated that in additional embodiments, a proximity sensor  54  or an array thereof, and other vehicle sensors and devices may provide sensor signals or other information, such as sequential images of a trailer  16 , including the detected coupler  14 , that the controller  26  of the hitch assist system  10  may process with various routines to determine the height H and position of coupler  14 . 
     As further shown in  FIG.  2   , one embodiment of the hitch assist system  10  is in communication with the steering system  20  of vehicle  12 , which may be a power assist steering system  20  including an electric steering motor  74  to operate the steered wheels  76  ( FIG.  1   ) of the vehicle  12  for moving the vehicle  12  in such a manner that the vehicle yaw changes with the vehicle velocity and the steering angle S. In the illustrated embodiment, the power assist steering system  20  is an electric power-assisted steering (“EPAS”) system including electric steering motor  74  for turning the steered wheels  76  to a steering angle δ based on a steering command, whereby the steering angle δ may be sensed by a steering angle sensor  78  of the power assist steering system  20 . The steering command may be provided by the hitch assist system  10  for autonomously steering during a trailer hitch alignment maneuver and may alternatively be provided manually via a rotational position (e.g., steering wheel angle) of a steering wheel of vehicle  12 . However, in the illustrated embodiment, the steering wheel of the vehicle  12  is mechanically coupled with the steered wheels  76  of the vehicle  12 , such that the steering wheel moves in concert with steered wheels  76 , preventing manual intervention with the steering wheel during autonomous steering. More specifically, a torque sensor  80  is provided on the power assist steering system  20  that senses torque on the steering wheel that is not expected from autonomous control of the steering wheel and therefore indicative of manual intervention, whereby the hitch assist system  10  may alert the driver to discontinue manual intervention with the steering wheel and/or discontinue autonomous steering. In alternative embodiments, some vehicles have a power assist steering system  20  that allows a steering wheel to be partially decoupled from movement of the steered wheels  76  of such a vehicle. 
     With continued reference to  FIG.  2   , the power assist steering system  20  provides the controller  26  of the hitch assist system  10  with information relating to a rotational position of steered wheels  76  of the vehicle  12 , including a steering angle δ. The controller  26  in the illustrated embodiment processes the current steering angle, in addition to other vehicle  12  conditions to guide the vehicle  12  along the desired path  32  ( FIG.  3   ). It is conceivable that the hitch assist system  10 , in additional embodiments, may be an integrated component of the power assist steering system  20 . For example, the power assist steering system  20  may include a hitch assist algorithm for generating vehicle steering information and commands as a function of all or a portion of information received from the imaging system  18 , the power assist steering system  20 , a vehicle brake control system  70 , a powertrain control system  72  (which includes throttle  73 , and the transmission system  92  with gear selector  94 ), and other vehicle sensors and devices, as well as a human-machine interface  40 , as discussed further below. 
     As also illustrated in  FIG.  2   , the vehicle brake control system  70  may also communicate with the controller  26  to provide the hitch assist system  10  with braking information, such as vehicle wheel speed, and to receive braking commands from the controller  26 . For instance, vehicle speed information can be determined from individual wheel speeds as monitored by the brake control system  70 . Vehicle speed may also be determined from the powertrain control system  72 , the speed sensor  56 , and the positioning system  22 , among other conceivable means. In some embodiments, individual wheel speeds can also be used to determine a vehicle yaw rate {dot over (γ)}, which can be provided to the hitch assist system  10  in the alternative or in addition to the vehicle yaw rate sensor  58 . The hitch assist system  10  can, 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 backing of the trailer  16 . For example, the hitch assist system  10 , in some embodiments, may regulate speed of the vehicle  12  during alignment of the vehicle  12  with the coupler  14  of trailer  16 , which can reduce the potential for a collision with trailer  16 , and can bring vehicle  12  to a complete stop at a determined endpoint  35  of path  32 . It is disclosed herein that the hitch assist system  10  can additionally or alternatively issue an alert signal corresponding to a notification of an actual, impending, and/or anticipated collision with a portion of trailer  16 . The powertrain control system  72 , as shown in the embodiment illustrated in  FIG.  2   , may also interact with the hitch assist system  10  for regulating speed and acceleration of the vehicle  12  during partial or autonomous alignment with trailer  16 . As mentioned above, regulation of the speed of the vehicle  12  may be advantageous to prevent collision with trailer  16 . 
     Additionally, the hitch assist system  10  may communicate with human-machine interface (“HMI”)  40  for the vehicle  12 . The HMI  40  may include a vehicle display  44 , such as a center-stack mounted navigation or entertainment display ( FIG.  1   ). HMI  40  further includes an input device, which can be implemented by configuring display  44  as a portion of a touchscreen  42  with circuitry  46  to receive an input corresponding with a location over display  44 . Other forms of input, including one or more joysticks, digital input pads, or the like can be used in place or in addition to touchscreen  42 . Further, the hitch assist system  10  may communicate via wireless communication with another embodiment of the HMI  40 , such as with one or more handheld or portable devices  96  ( FIG.  1   ), including one or more smartphones. The portable device  96  may also include the display  44  for displaying one or more images and other information to a user. For instance, the portable device  96  may display one or more images of the trailer  16  on the display  44  and may be further able to receive remote user inputs via touchscreen circuitry  46 . In addition, the portable device  96  may provide feedback information, such as visual, audible, and tactile alerts. 
     Still referring to the embodiment shown in  FIG.  2   , the controller  26  is configured with a microprocessor  60  to process logic and routines stored in memory  62  that receive information from the above-described sensors and vehicle systems, including the imaging system  18 , the power assist 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 as a function of all or a portion of the information received. Thereafter, the vehicle steering information and commands may be provided to the power assist steering system  20  for affecting steering of the vehicle  12  to achieve a commanded path  32  ( FIG.  3   ) of travel for alignment with the coupler  14  of trailer  16 . The controller  26  may include the microprocessor  60  and/or other analog and/or digital circuitry for processing one or more routines. Also, the controller  26  may include the memory  62  for storing one or more routines, including an image processing  64  routine and/or hitch detection routine, a path derivation routine  66 , and an operating routine  68 . It should be appreciated that the controller  26  may be a stand-alone dedicated controller or may be a shared controller integrated with other control functions, such as integrated with a vehicle sensor system, the power assist steering system  20 , and other conceivable onboard or off-board vehicle control systems. It should further be appreciated that the image processing routine  64  may be carried out by a dedicated processor, for example, within a stand-alone imaging system for vehicle  12  that can output the results of its image processing to other components and systems of vehicle  12 , including microprocessor  60 . Further, any system, computer, processor, or the like that completes image processing functionality, such as that described herein, may be referred to herein as an “image processor” regardless of other functionality it may also implement (including simultaneously with executing image processing routine  64 ). 
     System  10  can also incorporate an imaging system  18  that includes one or more exterior cameras, which in the illustrated examples include rear camera  48 , center high-mount stop light (CMHSL) camera  50 , and side-view cameras  52   a  and  52   b , although other arrangements including additional or alternative cameras are possible. In one example, imaging system  18  can include rear camera  48  alone or can be configured such that system  10  utilizes only rear camera  48  in a vehicle with multiple exterior cameras. In another example, the various cameras  48 ,  50 ,  52   a ,  52   b  included in imaging system  18  can be positioned to generally overlap in their respective fields of view, which may correspond with rear camera  48 , center high-mount stop light (CMHSL) camera  50 , and side-view cameras  52   a  and  52   b , respectively. In this manner, image data  55  from two or more of the cameras can be combined in image processing routine  64 , or in another dedicated image processor within imaging system  18 , into a single image. In an extension of such an example, the image data  55  can be used to derive stereoscopic image data that can be used to reconstruct a three-dimensional scene of the area or areas within overlapped areas of the various fields of view of the various cameras including any objects (obstacles or coupler  14 , for example) therein. In an embodiment, the use of two images including the same object can be used to determine a location of the object relative to the two image sources, given a known spatial relationship between the image sources. In this respect, the image processing routine  64  can use known programming and/or functionality to identify an object within image data  55  from the various cameras  48 ,  50 ,  52   a , and  52   b  within imaging system  18 . In either example, the image processing routine  64  can include information related to the positioning of any cameras  48 ,  50 ,  52   a , and  52   b  present on vehicle  12  or utilized by system  10 , including relative to the center  36  ( FIG.  1   ) of vehicle  12 , for example such that the positions of cameras  48 ,  50 ,  52   a , and  52   b  relative to center  36  and/or to each other can be used for object positioning calculations and to result in object position data relative to the center  36  of vehicle  12 , for example, or other features of vehicle  12 , such as hitch ball  34  ( FIG.  1   ), with known positions relative to center  36 . 
     The image processing routine  64  can be specifically programmed or otherwise configured to locate coupler  14  within image data  55 . In one example, the image processing routine  64  can first attempt to identify any trailers  16  within the image data  55 , which can be done based on stored or otherwise known visual characteristics of trailer  16 , of an number of different types, sizes or configurations of trailers compatible with system  10 , or trailers in general. When a trailer  16  is identified, system  10  can seek confirmation from the user that the identification of the trailer  16  is accurate and is the correct trailer for which to complete an automated hitching operation. After the trailer  16  is identified, controller  26  may then identify the coupler  14  of that trailer  16  within the image data  55  based, similarly, on stored or otherwise known visual characteristics of coupler  14  or couplers in general. In another embodiment, a marker in the form of a sticker or the like may be affixed with trailer  16  in a specified position relative to coupler  14  in a manner similar to that which is described in commonly-assigned U.S. Pat. No. 9,102,271, the entire disclosure of which is incorporated by reference herein. In such an embodiment, image processing routine  64  may be programmed with identifying characteristics of the marker for location in image data  55 , as well as the positioning of coupler  14  relative to such a marker so that the location  28  of coupler  14  can be determined based on the marker location. Additionally or alternatively, controller  26  may seek confirmation of the determined coupler  14 . If the coupler  14  determination is not confirmed, further image processing may be provided, or user-adjustment of the position  28  of coupler  14  may be facilitated, either using touchscreen  42  or another input to allow the user to move the depicted position  28  of coupler  14  on touchscreen  42 , which controller  26  uses to adjust the determination of position  28  of coupler  14  with respect to vehicle  12  based on the above-described use of image data  55 . 
     As shown in  FIG.  3   , the image processing routine  64  and operating routine  68  may be used in conjunction with each other to determine the path  32  along which hitch assist system  10  can guide vehicle  12  to align hitch ball  34  and coupler  14  of trailer  16 . Upon initiation of hitch assist system  10 , such as by user input on touchscreen  42 , for example, image processing routine  64  can identify coupler  14  within the image data  55  and at least attempt to estimate the position  28  of coupler  14  relative to hitch ball  34  using the image data  55  in accordance with one of the examples discussed above to determine a distance D c  to coupler  14  and an angle α c  of offset between a line connecting hitch ball  34  and coupler  14  and the longitudinal axis of vehicle  12 . Image processing routine  64  can also be configured to identify the trailer  16  overall and can use the image data of trailer  16 , alone or in combination with the image data of coupler  14 , to determine the orientation or heading  17  of trailer  16 . In this manner the path  32  can further be derived to align vehicle  12  with respect to trailer  16  with the longitudinal axis  13  of vehicle  12  within a predetermined angular range of the heading  17  of trailer  16 . Notably, such alignment may not require that the longitudinal axis  13  of vehicle  12  is parallel or collinear with the heading  17  of trailer  16 , but may simply be within a range that generally allows connection of hitch ball  34  with coupler  14  without collision between vehicle  12  and trailer  16  and may, further allow immediate controlled backing of trailer  16  using vehicle  12 . In this manner, the angular range may be such that the alignment of vehicle  12  with trailer  16  at the end of the operating routine  68  is such that the angle between longitudinal axis  13  and heading  17  is less than the jackknife angle between the vehicle  12  and trailer  16  when coupled or a reasonable estimate thereof. In one example, the angular range may be such that longitudinal axis  13  is within about 30° from collinear with heading  17  in either direction. When collected, the position information can then be used in light of the position  28  of coupler  14  within the field of view of the image data  55  to determine or estimate the height H c  of coupler  14 . Once the positioning D c , α c  of coupler  14  has been determined and, optionally, confirmed by the user, controller  26  can take control of at least the vehicle steering system  20  to control the movement of vehicle  12  along the desired path  32  to align the vehicle hitch ball  34  with coupler  14 , as discussed further below. 
     Continuing with reference to  FIG.  3    with additional reference to  FIG.  2   , controller  26 , having estimated the positioning D c , α c  of coupler  14 , as discussed above, can, in one example, execute path derivation routine  66  to determine vehicle path  32  to align the vehicle hitch ball  34  with coupler  14 . In particular, controller  26  can have stored in memory  62  various characteristics of vehicle  12 , including the wheelbase W, the distance from the rear axle to the hitch ball  34 , which is referred to herein as L, as well as the maximum angle to which the steered wheels  76  can be turned δ max . As shown, the wheelbase W and the current steering angle δ can be used to determine a corresponding turning radius ρ for vehicle  12  according to the equation: 
     
       
         
           
             
               
                 
                   
                     ρ 
                     = 
                     
                       1 
                       
                         W 
                         ⁢ 
                             
                         tan 
                         ⁢ 
                             
                         δ 
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     in which the wheelbase W is fixed and the steering angle δ can be controlled by controller  26  by communication with steering system  20 , as discussed above. In this manner, when the maximum steering angle δ max  is known, the smallest possible value for the turning radius μ min  is determined as: 
     
       
         
           
             
               
                 
                   
                     ρ 
                     min 
                   
                   = 
                   
                     
                       1 
                       
                         W 
                         ⁢ 
                             
                         tan 
                         ⁢ 
                             
                         
                           δ 
                           max 
                         
                       
                     
                     . 
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     Path derivation routine  66  can be programmed to derive vehicle path  32  to align a known location of the vehicle hitch ball  34  with the estimated position  28  of coupler  14  that may take into account the determined minimum turning radius ρ min  to allow path  32  to use the minimum amount of space and maneuvers. In this manner, path derivation routine  66  can determine both a lateral distance to the coupler  14  and a rearward distance to coupler  14  and derive a path  32  that achieves the needed lateral and forward-backward movement of vehicle hitch ball  34  within the limitations of steering system  20 . The derivation of path  32  further takes into account the positioning of hitch ball  34 , based on length L, relative to the tracked location of vehicle  12  (which may correspond with the center  36  of mass of vehicle  12 , the location of a GPS receiver, or another specified, known area) to determine the needed positioning of vehicle  12  to align hitch ball  34  with coupler  14  and to appropriately locate the frame of reference for the above-discussed calculations. It is noted that hitch assist system  10  can compensate for horizontal movement Δx of coupler  14  in a driving direction away from axle  84  by determining the movement of coupler  14  in the vertical direction Δy that will be needed to receive hitch ball  34  within coupler  14 . Such functionality is discussed further in co-pending, commonly-assigned U.S. patent application Ser. Nos. 14/736,391 and 16/038,462, the entire disclosures of which are hereby incorporated by reference herein. In further aspects, path derivation routine  66  can operate to achieve alignment of the vehicle axis  13  with the trailer heading  17  within a predetermined range (as discussed above) and/or to avoid any obstacles detected by image processing routine  64 . Still further, the path  32  derived by path derivation routine  66  may take into account the initial position of the steered wheels  76  (i.e. an initial steering angle δ) by initially including movement of the vehicle  12  in the direction dictated by the initial position of the steered wheels  76  and only changing the steering angle δ as needed once rearward movement of vehicle  12  has been initiated (as discussed below). Operation according to this or a similar scheme may make use of the system less alarming to the driver by removing the need to initially adjust the steering angle S. 
     As discussed above, once the desired path  32  has been determined, controller  26  is then allowed to at least control the steering system  20  of vehicle  12  with the powertrain control system  72  and the brake control system  70  (whether controlled by the driver or by controller  26 , as discussed below) controlling the velocity (forward or rearward) of vehicle  12 . In this manner, controller  26  can receive data regarding the position of vehicle  12  during movement thereof from positioning system  22  while controlling steering system  20 , as needed to maintain vehicle  12  along path  32 . In particular, the path  32 , having been determined based on the vehicle  12  and the geometry of steering system  20 , can adjust the steering angle δ, as dictated by path  32 , depending on the position of vehicle  12  there along. It is additionally noted that in an embodiment, the path  32  may comprise a progression of steering angle δ adjustment that is dependent on the tracked vehicle position. 
     As illustrated in  FIG.  3   , vehicle path  32  can be determined to achieve the needed lateral and rearward movement within the smallest area possible and/or with the lowest number of maneuvers, while, optionally avoiding obstacles or achieving a desired alignment between vehicle axis  13  and trailer heading  17 . In the illustrated example of  FIG.  3   , path  32  can include three portions  33  defined by steering of wheels  76  in different directions to collectively traverse the needed lateral movement of vehicle  12  to bring hitch ball  34  into alignment with coupler  14 . It is noted that variations in the depicted path  32  may be used. It is further noted that the estimates for the positioning D c , α c  of coupler  14  may become more accurate as vehicle  12  traverses path  32 , including to position vehicle  12  in front of trailer  16  and as vehicle  12  approaches coupler  14 . Accordingly, such estimates can be continuously derived and used to update path derivation routine  66 , if necessary, in the determination of the adjusted endpoint  35  for path  32 , as discussed above. In a similar manner, the path  32 , as derived using the position and orientation data acquired from smartphone  96 , can be fine-tuned once the image processing routine  64  can identify coupler  14  in the image data  55 , with continued updates for path  32  being similarly derived as the image data  55  becomes increasingly clear during the approach toward trailer  16 . It is further noted that, until such a determination can be made, the dead reckoning device  24  can be used to track the location of vehicle  12  in its movement along path  32  toward the initially-derived endpoint  35 . 
     In one aspect, it may be desired to communicate to the driver that system  10  has identified the coupler  14  of the trailer  16  and that path derivation routine  66  has been completed successfully with an indication of the general direction of the path and the final position of hitch ball  34  included at the end of the derived path. It may also be desired to provide some level of visual tracking for user as vehicle  12  traverses the path  32 , as discussed further below. As shown in  FIG.  3   , such communication may be made using the display  44  associated with the vehicle human machine interface (“HMI”)  40  within vehicle  12 . In one aspect, system  10  can be programmed or otherwise configured to output a graphical representation of the path as an overlay on a video image  43  presented on HMI  40  that includes image data  55  with the path image being correlated with the known field of view and image characteristics of camera  48 , for example, to place the path image in the perspective of the portion of the video image  43  based on image data  55  such that the path image appears extending rearward of hitch ball  34  to the location of coupler  14 . In this manner, the ability of system  10  to project a path image that reflects the actual path  32  in a dynamic manner, including a path  32  with multiple portions  33  of varying characteristics may be dependent on the configuration and processing capability of system  10 . In particular, the capability to dynamically display a complex path  32  and to accurately correlate the movement of vehicle  12  along the actual path  32  with the displayed path may require system  10  to include a dedicated graphical processing unit (“GPU”) or other processing capability that may not otherwise be included with or needed in connection with system  10 . Further, such capability and the related hardware may increase the overall power consumption of system  10 , which may have an undesired negative impact on the fuel consumption of the subject vehicle  12 . The inclusion of such hardware or other system capability and/or the decreased efficiency resulting from such path display capability may outweigh the benefits from displaying a complex dynamic path on HMI  40 . In this manner, system  10  may be configured, instead, to display a simplified path  86  on HMI in the form of static image that can be updated at acceptable intervals. 
     As shown in  FIGS.  3  and  4    the simplified path  86  can be a single arc-shaped segment extending from the hitch ball  35  to the coupler  14 . In one aspect the simplified path  86  can represent a possible actual path to align hitch ball  35  with coupler  14  in that the simplified path  86  can link the known position of hitch ball  35  with the detected position of coupler  14 . Referring to  FIG.  5   , the theoretical radius r path  of the arc-shaped segment can be determined as follows: 
     
       
         
           
             
               
                 
                   
                     
                       r 
                       path 
                     
                     = 
                     
                       
                         
                           ρ 
                           2 
                         
                         + 
                         
                           L 
                           2 
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       where 
                       : 
                           
                       ρ 
                     
                     = 
                     
                       
                         
                           x 
                           cp 
                           2 
                         
                         + 
                         
                           2 
                           ⁢ 
                           
                             x 
                             cp 
                           
                           ⁢ 
                           L 
                         
                         + 
                         
                           y 
                           cp 
                           2 
                         
                       
                       
                         2 
                         ⁢ 
                         
                           y 
                           cp 
                         
                       
                     
                   
                   , 
                   and 
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
         
         
           
             (x cp ,y cp ) represents the detected position of coupler  14 .
 
In this manner, if system  10  were to cause vehicle  12  to navigate a path  32  corresponding with the simplified path  86 , the simplified path  86  could be presented on display  40  and adjusted only in length to track coupler  14  within the image  43  as the position thereof changes with movement of vehicle  12 . In such an implementation, it may, nevertheless, be beneficial to not update the depiction of simplified path  86  dynamically (i.e. in real time) but to, instead, maintain a static depiction of the simplified path  86  for an interval and to only update the depiction of simplified path  86  periodically, as doing so may save computing power and lower the requirements of system  10  and/or the power consumption of system  10  and the related vehicle  12 .
 
           
         
       
    
     When presenting static overlay depiction of simplified path  86 , system  10  can be programmed or otherwise configured to determine when the depiction should be updated based in a change in state of the hitch-ball coupler relationship. In one aspect, such an update can be dictated by monitoring the theoretical radius of the path with respect to the radius of the currently depicted path. In another aspect, such an update can be made at regular time intervals during the backing of vehicle  12  under the control of system  10 . In another aspect, the updating of the simplified path  86  depiction can be dictated by monitoring the position of coupler  14  in the depicted image  43  with respect to the currently depicted endpoint  87  of the simplified path  86 . As shown in  FIG.  4   , the endpoint  35  can correspond with the initial position of coupler  14  when the particular depiction is determined and displayed and can be depicted as a circle around the detected coupler  14 . As shown, the circle at endpoint  87  can be somewhat larger than the coupler  14  such that a level of visual tolerance is established. In this respect, the depiction of simplified path  86  can be updated when coupler  14  is determined to have moved out of the circle at endpoint  87  (or outside of an additional buffer area surrounding the circle). In some aspects, such a tolerance may correspond with between 1 and 3 feet of vehicle  12  travel along the ground plane  30  and, which depending on the speed of vehicle, can take between one second and three seconds. The size of the depicted circle at endpoint  87  and any tolerance or buffer therearound can be adjusted to correspondingly adjust the approximate time interval for updating the static overlay of simplified path  86 . 
     In one implementation, the simplified path  86  can be determined by an algorithm stored in the memory  62  accessible by microprocessor  60 . The algorithm can be operable to determine when the static overlay depictions of the simplified path  86  are desired, according to adjustable criteria, and can generate such depictions when it is determined that they are to be displayed or updated. The algorithm may determine when each overlay is displayed based on the actual planned vehicle path  32  for the autonomous maneuver, including in advance or in real-time as vehicle  12  backs along path  32  during execution of operating routine  68 . The overlays can be based on a mathematically-derived simplified path  86  that generally communicates aspects of the planned path  32  of the vehicle  12  to the user. 
     As shown in  FIGS.  5  and  6   , the arced path of the simplified path  86  may be defined by the following equations, where x and y are points on the normalized path: 
         x=−x   c  cos(−α)+ y   c  sin(−α)+ x   c   (5)
 
         y=−x   c  sin(−α)− y   c  cos(−α)+ y   c ,  (6)
 
     where:
         x c ,y c  is a coordinate representing the turn center for a given position of coupler  14 ;   ρ represents the distance between the center of the rear axle and the turn center for the detected position of coupler  14  (x cp ,y cp ) (as discussed above with respect to  FIG.  3   );   L represents the distance between the center of the rear axle and a point (P On ) defined along the center line of the vehicle and coincident with hitch ball  34 , coordinate (0,0); and   α represents the angle between the hitch ball  34  (P On ) and any point (P On+1 ) on the simplified path  86  with respect to the turn center (x c ,y c ).
 
Therefore, by increasing a from 0° to a predetermined angle (i.e., 60°) at a predetermined interval (i.e., 2°), a number of points can be generated using Equations (5) and (6) to represent the simplified path  86 .
       

     In this manner, the turn center for a left turn can be described as x c =−L and y c =−ρ and can be described as x c =−L and y c =ρ for a right turn using a frame of reference centered at hitch ball  34  and with its x-axis aligned with the vehicle  12  longitudinal axis  13 . As further shown in  FIGS.  5  and  6   , the simplified path  86  represents the path that would be traversed by the hitch ball  34  of vehicle  12 . Notably, the length L, as well as the wheelbase W, which affect the positioning of the turn center for the determined steering angle are configurable based on the various vehicle parameters and can be stored in memory  62 . Using equation (5) and (6), a set of arcs with different turn radius and therefore different turn center (x c ,y c ) are stored in the memory. During the hitching maneuver, depending on the trailer coupler position (x cp ,y cp ) and calculated turn radius r path  using Equation (3), a stored arc which has a radius closest to r path  will be retrieved as the simplified path  86 . 
     Returning to the example of  FIG.  3   , the use of the above scheme in depicting simplified path  86  in place of an actual path  32  including multiple segments  33  in varying directions, including some such segments  33  that do not extend directly toward coupler  14  can result in the simplified path  86  that is determined with coupler  14  in a particular position becoming unaligned with coupler  14  during backing of vehicle  12  along path  32 . As discussed above, during such backing, the end circle  87  of the depicted simplified path  86  will move away from the location in image  43  that corresponds with coupler  14 . Additionally, in situations similar to what is depicted in  FIG.  3   , the simplified path  86  will also move laterally away from an aligned position with the coupler  14 . In this manner, a subsequent iteration of the portion of the algorithm that determines the geometry of simplified path  86  may result in a different arc shape being generated in light of the change in relative position of coupler  14  to vehicle  12 , as well as the theoretical turn radius used in the subsequent determination of the turning center (x c ,y c ) used to determine the subsequent static simplified path  86 . 
     The schematic depiction of  FIG.  6    shows the changing simplified path projection for position n+1 and n+2 of the vehicle during an autonomous maneuver, for example, corresponding with a position of vehicle  12  relative to coupler  14  that is farther away than at n+1 such that the simplified path  86  corresponding with n+1 may be presented as an overlay of the video image  43  until system  10  determines that the simplified path  86  is no longer an accurate enough simplification for the given positioning (e.g., difference between R On+2  and R On+1  exceeds certain margin), whereupon the simplified path  86  corresponding with n+2 can replace the prior simplified path image  86 . This simplified path  86  presentation and refreshing can occur as needed until hitch ball  34  is aligned with coupler  14 . As can be seen in  FIG.  4   , the simplified path  86 , derived according to the above algorithm can be presented as a still images overlaid on to the image  43  presented on HMI  40  using the image data  55  from camera  48 , for example. In this manner, the geometry of simplified path  86  can be translated into an image thereof that corresponds with or otherwise appears to be visually in place within the particular image  43 . In this manner, algorithm within system  10  can map the arced path geometry of simplified path  86  into the three-dimensional space presented in the two-dimensional image  43 . That is, the coordinate system from  FIGS.  5  and  6    within which simplified path  86  lies is mapped into the perspective view of image  43 , which may be based on the known characteristics of camera  48  and any manipulations applied to the image data  55  to present it on screen  42 . Such characteristics can include the focal length and field of view of camera  48  with any perspective correction and/or cropping carried out in presenting the image on screen  42 . Further, the mapped coordinates can be placed within image  43  such that the depicted plane visually coincides with the height of hitch ball  34  and such that the origin P On  is visually aligned with hitch ball  34 . In this manner, the visual overlay depiction of simplified path  86  will extend rearward from the depiction of hitch ball  34  within image  43  in an arc that extends in proper perspective to the general location of coupler  14 , which may be positioned within or close to endpoint circle  87 . 
     Turning now to  FIGS.  7 - 10   , once the trailer  16  and coupler  14  have been identified, and system  10  determines the path  32  to align hitch ball  34  with the coupler  14  (with the initial simplified path  86  being determined and presented in the image  43  on screen  42 ), the operating routine  68  may continue to guide vehicle  12  to move hitch ball  34  toward the desired position  38   d  relative to coupler  14  for coupler  14  to engage with hitch ball  34  when coupler  14  is lowered into horizontal alignment therewith. In the example discussed above, image processing routine  64  continuously monitors the positioning D c ,α c  of coupler  14 , constantly or once available, during execution of operating routine  68 , with continued movement of vehicle  12  along path  32 , as shown in  FIG.  7   . As discussed above, as system  10  delays for a predetermined time or distance interval or, in another example, determines that the movement of vehicle  12  has placed coupler  14  out of a visually-acceptable proximity to simplified path  86 , including with respect to the depicted endpoint circle  87 , the simplified path  86  may be updated or otherwise re-calculated. As shown in  FIGS.  7  and  8   , such an update may result in a different simplified path  86  being derived with different characteristics, including the radius, arc length, etc. that can replace the prior image (i.e. from  FIG.  4   ) with a new image of simplified path  86  that similarly extends from hitch ball  34  to within an acceptable range of coupler  14  in the image  43  presented on screen  42 , as shown in  FIG.  8   . This process can be repeated, as called for by system  10  according to the criteria for simplified path  86  re-calculation, as vehicle  12  moves closer to trailer  16 , as shown in  FIG.  9   , for example, until vehicle  12  reaches the desired position in which hitch ball  34  is aligned with coupler  14 , as shown in  FIG.  10   . 
     As shown in  FIGS.  11 - 14   , a simplified path  86  according to the principles described above can be determined and represented in alternative forms. In one aspect, shown in  FIG.  11   , the simplified path  86  may be depicted as a straight line extending from hitch ball  34  to coupler  14 , with system  10  providing an overlay of the straight line simplified path  86  on HMI  40  in a similar manner to that which is shown in  FIGS.  4  and  8   . In this manner, a plurality of straight line simplified path  86  images can be generated or otherwise created in advance in a manner that correlates with the positioning of hitch ball  34  within image  43  and the field of view from the camera (e.g. rear camera  48 ) from which the image data  55  is obtained. The stored simplified path  86  images can correspond with incremental positions of vehicle  12  with respect to coupler  14  and/or trailer  16  through a range of such positions. For example, as discussed above, the actual path  32  for vehicle  12  in approaching trailer  16  is limited by the minimum turning radius Amin, as it relates to the maximum steering angle max of vehicle  12  by Equation (2), above. In this manner, the limits of the range of possible coupler angles α c  between the longitudinal axis  13  of vehicle  12  and coupler  14  is defined by the equation: 
     
       
         
           
             
               
                 
                   
                     
                       ❘ 
                       &#34;\[LeftBracketingBar]&#34; 
                     
                     
                       ∝ 
                       c 
                     
                     
                       ❘ 
                       &#34;\[RightBracketingBar]&#34; 
                     
                   
                   ≤ 
                   
                     
                       tan 
                       
                         - 
                         1 
                       
                     
                     ⁢ 
                     
                       L 
                       
                         ρ 
                         min 
                       
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
           
         
       
     
     In general, the range of possible coupler angles α c  may be within about 15° (in either direction) of longitudinal axis  13  of vehicle  12 . Accordingly, a set of correlated straight line images can be stored for every degree (i.e. in 1° increments) throughout the range determined by Equation (7). Additionally, a plurality of such sets can be stored for given increments (e.g. 1′ to 5′) of the acceptable coupler distances D c  for which system  10  can locate coupler  14  and back vehicle  12  into alignment between hitch ball  34  and coupler  14 . With such sets/subsets of graphical straight line simplified paths  86  stored in memory  82 , system  10  can cause the presentation of the appropriate one of such images for overlay on the image  43  presented on HMI  40  for the detected coupler  14  location D c ,α c  and can change the overlay image, as needed while the coupler  14  and its location D c ,α c  are tracked during operation of operating routine  68 . 
     Turning to  FIGS.  12 - 14   , another example of an alternative simplified backing path  86  that can be presented graphically on image  43  is shown. In the example of  FIG.  11   , the backing path  86  is initially presented in the form of an arc  86   a  defined about a turn center x c ,y c  that corresponds with the turn center determined using Equations (5) and (6), discussed above, when the given steering angle δ is at the maximum steering angle max for the given vehicle  12 . For such a steering angle δ max , the radius ρ, as determined using Equation (2) will, again, be the minimum radius ρ min  for vehicle  12  and results in simplified path  86  having a radius r path  defined by the equation: 
         r   path =√{square root over ( L   2 +ρ min   2 .)}  (8)
 
     As shown, the initially-presented arc for simplified backing path  86  does not extend the full distance D c  between hitch ball  35  and coupler  14 , but rather extends through an angle α max  that corresponds with the distance along the arced simplified path  86  that vehicle  12  would have to traverse to align vehicle  12  for straight backing toward coupler  14 . As shown in  FIG.  12   , this angle αmax is defined by the equation: 
     
       
         
           
             
               
                 
                   
                     α 
                     max 
                   
                   = 
                   
                     
                       
                         sin 
                         
                           - 
                           1 
                         
                       
                       ⁢ 
                       
                         
                           ρ 
                           min 
                         
                         
                           
                             
                               
                                 ( 
                                 
                                   
                                     x 
                                     c 
                                   
                                   - 
                                   
                                     x 
                                     cp 
                                   
                                 
                                 ) 
                               
                               2 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   
                                     y 
                                     c 
                                   
                                   - 
                                   
                                     y 
                                     cp 
                                   
                                 
                                 ) 
                               
                               2 
                             
                           
                         
                       
                     
                     - 
                     
                       
                         tan 
                         
                           - 
                           1 
                         
                       
                       ⁢ 
                       
                         
                           
                             
                               ❘ 
                               &#34;\[LeftBracketingBar]&#34; 
                             
                             
                               
                                 y 
                                 c 
                               
                               - 
                               
                                 y 
                                 cp 
                               
                             
                             
                               ❘ 
                               &#34;\[RightBracketingBar]&#34; 
                             
                           
                           
                             
                               ❘ 
                               &#34;\[LeftBracketingBar]&#34; 
                             
                             
                               
                                 x 
                                 c 
                               
                               - 
                               
                                 x 
                                 cp 
                               
                             
                             
                               ❘ 
                               &#34;\[RightBracketingBar]&#34; 
                             
                           
                         
                         . 
                       
                     
                   
                 
               
               
                 
                   ( 
                   9 
                   ) 
                 
               
             
           
         
       
     
     where the coordinate (x cp ,y cp ) is defined at the coupler  14  location. 
     As shown in  FIG.  14   , the arced simplified path  86   a  may be determined based on the initial position D c ,α c  of coupler  14  relative to vehicle  12  and is presented as a correlated graphical overlay of the arced simplified path  86  on HMI  40  in a similar manner to that which is described above. Similar to the variation of path  86  discussed with respect to  FIG.  11   , arced paths  86  of varying lengths within a useable distance D c  range of such arced paths  86  corresponding with the maximum steering angle δ max  of vehicle  12  can be stored in memory  62  for presentation, as needed on HMI  42 . In an example, the length of path  86   a , after being initially determined or selected to correspond with the determined angle α max  and ending at point  87   a , can be decreased according to the correlation with the image  43  presented on HMI  40  in increments of, for example, every 0.2 meters or the like until vehicle  12  has rotated (whether directly or not, as the actual path  32  may vary from the simplified path  86   a ) through the angle α max  or traversed a distance generally equal to the length of the arced simplified path  86   a , as initially determined. Accordingly, path images corresponding with such length increments at the above-determined radius r path  may be stored in memory  62  for presentation on HMI  40 . 
     As also shown in  FIG.  11   , once vehicle  12 ′ is in a position where the longitudinal axis  13  of vehicle  12  is aligned within a predetermined threshold (e.g. within about 5°) of an aligned position with respect to coupler  14 , the simplified path  86  can transition to a straight line simplified path portion  86   b  that can extend rearward from hitch ball  34 ′ to the general area of coupler  14 . In a similar manner to the arced simplified path portion  86   a , the straight line simplified path portion  86   b  can be presented on HMI  40  in a correlated manner with image  43 , as shown in  FIG.  13   , and may decrease in the depicted length with, for example, every 0.2 meters traversed by vehicle  12  toward coupler  14 . In one example, the simplified path image  86   b  can be removed from image  43  when the hitch ball  34  is within 1 meter or the like from coupler  14 . 
     Turning now to  FIG.  15   , a flowchart showing steps in one operating scheme  200  for using hitch assist system  10  to align a vehicle hitch ball  34  with a trailer coupler  14  is shown. In particular, in step  202 , the hitch assist system  10  is initiated. Once the hitch assist system  10  is initiated  202 , controller  26  can use imaging system  18  to scan the viewable scene using any or all available cameras  48 ,  50 ,  52   a ,  52   b  (step  204 ). The scene scan (step  204 ) can be used to then identify  206  the trailer  16  and coupler  14 , which may be confirmed by the user. If the coupler  14  can be identified (step  208 ) in the image data  55 , the height H c  distance D c , and offset angle α c  of coupler  14 , as identified in step  206 , can then be determined using the available image data  55  (step  206 ) as discussed above, including using image processing routine  64 . As discussed above, image processing routine  64  can be programmed or otherwise configured to identify coupler  14  of trailer  16  within image data  55  (step  206 ). In this manner, after the results of the initial scene scan (step  204 ) are analyzed, controller  26  can determine if coupler  14  has been confirmed by the user (such as by way of HMI  40 ). If coupler  14  has not been confirmed or if a determined coupler  14  has been rejected, the scene scan (step  204 ) can be continued, including while instructing driver to move vehicle  12  to better align with trailer  16 , including by positioning the trailer  16  and/or coupler  14  until coupler  14  is identified. 
     When coupler  14  has been identified and confirmed, the path derivation routine  66  can be used to determine the vehicle path  32  to align hitch ball  34  with coupler  14  in step  210 . In this manner, the positioning D h , α h  of coupler  14  is extracted from the image data  55  and used to place the coupler  14  within the stored data relating the image coordinates with the real-world coordinates of the area surrounding vehicle  12 . In doing so, controller  26  uses path derivation routine  66  to determine path  32  to align hitch ball  34  with the predicted position  28  of coupler  14  to an engaging position over hitch ball  34 , as described above with respect to  FIGS.  1 - 9   . Once the actual planned path  32  has been derived, path derivation routine  66  can also derive the simplified path  86  (step  212 ) and present the simplified path on display  42  (step  214 ), as discussed above with respect to  FIGS.  3 - 6   ,  FIGS.  13  and  14   , or as would otherwise be understood based on the above description. 
     Once the path  32  and simplified path  86  have been derived, hitch assist system  10  can ask the user U to relinquish control of at least the steering wheel of vehicle  12  (and, optionally, the throttle  73  and brake, in the implementation of hitch assist system  10  described above wherein controller  26  assumes control of powertrain control system  72  and brake control system  70  during execution of operating routine  68 ). When it has been confirmed that user U is not attempting to control steering system  20  (for example, using torque sensor  80 , as discussed above), controller  26  begins to move vehicle  12  along the determined path  32 . Hitch assist system  10  then controls steering system  20  (step  216 ) to maintain vehicle  12  along path  32  as either user U or controller  26  controls the velocity of vehicle  12  using powertrain control system  72  and braking control system  70 . As discussed above, controller  26  can control at least steering system  20 , while tracking the position D c , α c  of coupler  14  to back vehicle  12  and can continue such backing until it has been determined that the desired position has been reached (step  218 ). As vehicle  12  reverses under control of system  10 , the tracked position of coupler  14  can be compared with the simplified path  86  derived in step  212  to determine if the coupler  14  is within an acceptable range of the simplified path  86 , including the end circle  87  thereof (step  220 ). If the coupler  14  is still within the desired range of simplified path  86 , system  10  continues navigating vehicle  12  along path  32  (step  216 ). If coupler  14  is not within the desired range of simplified path  86 , a new simplified path can be generated (step  212 ) and presented on the image  43  on screen  42  (step  214 ). As discussed above, at time or distance interval can be used in a similar method in place of the described range monitoring. 
     When vehicle  12  reaches a position (as determined in step  220 ), wherein the vehicle  12  hitch ball  34  reaches the desired position  38   d  for the desired alignment with coupler  14 , at which point operating routine  68  can end (step  222 ), either by controlling brake system  70  to cause vehicle  12  to stop (which can be done progressively as vehicle  12  approaches such a point), or by issuing a command to the user to stop vehicle  12  (which can also be done progressively or by a countdown as vehicle  12  approaches the desired location) before deactivating hitch assist system  10  (step  222 ). Vehicle  12  can then be driven normally with system  10  remains idle until a reactivation input (step  224 ) is received, at which point the above-described method restarts at the scanning step  204 . 
     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.