Hitch assist system

A hitch assist system is provided herein. The hitch assist system includes a sensing system configured to detect a hitch assembly and a coupler. A controller is configured to generate commands for maneuvering a vehicle along a first path or a second path. A user input device includes a display, the display configured to illustrate the first and second paths.

FIELD OF THE INVENTION

The present disclosure generally relates to autonomous and semi-autonomous vehicle systems, and more particularly, to hitch assist systems that facilitate the hitching of a vehicle to a trailer.

BACKGROUND OF THE INVENTION

The process of hitching a vehicle to a trailer can be difficult, especially to those lacking experience. Accordingly, there is a need for a system that simplifies the process by assisting a user in a simple yet intuitive manner.

SUMMARY OF THE INVENTION

According to some aspects of the present disclosure, a hitch assist system is provided herein. The hitch assist system includes a sensing system configured to detect a hitch assembly and a coupler. A controller is configured to generate commands for maneuvering a vehicle along a first path or a second path. A user input device includes a display. The display is configured to illustrate the first and second paths.

According to some aspects of the present disclosure, a hitch assist method is provided herein. The method includes determining an offset of a hitch ball relative to said coupler. The method also includes calculating a first path to align the hitch ball to said coupler, the first path having a positioning path and an alignment path. The method further includes maneuvering a vehicle a predefined distance along the positioning path at a first vehicle speed-setpoint. Lastly, the method includes aligning the hitch ball to said coupler along the alignment path at a second vehicle speed-setpoint, the second speed-setpoint less than the first vehicle speed-setpoint.

According to some aspects of the present disclosure, a hitch assist system is provided herein. The hitch assist system includes an imager for capturing one or more images of a hitch assembly and a coupler. A display generates an image patch based on the one or more images. A controller is configured to identify the hitch assembly, identify a coupler, and display an overlaid vehicle occupation zone on the display that extends through the hitch assembly, the vehicle occupation zone defining an area in which a vehicle travels to align the hitch assembly with the coupler.

DETAILED DESCRIPTION OF THE PREFERRED EXAMPLES

The following disclosure describes a hitch assist system for a vehicle. The hitch assist system may include a sensing system configured to detect a hitch assembly and/or a coupler of a trailer through one or more imagers and/or sensors. The hitch assist system further includes a controller configured to generate commands for maneuvering the vehicle along a positioning path and a subsequent alignment path, if desired and/or needed. The positioning path locates the hitch assembly proximate the coupler of the trailer. The alignment path may have one or more sequential corrections such that the hitch assembly is aligned with the coupler upon completion of the alignment path. The vehicle may move at a first speed-setpoint during the positioning path and a second speed-setpoint during the alignment path. The controller may further generate a vehicle occupation zone that illustrates an area through which the vehicle may move to align the hitch assembly with the coupler. Additionally, the controller may generate multiple paths that may align the hitch assembly with the coupler. A user may select a desired path from the plurality of generated paths.

Referring toFIGS. 1 and 2, reference numeral10designates a hitch assistance system (also referred to as a “hitch assist” system) for a vehicle12. In particular, the hitch assist system10includes a controller14acquiring position data of a coupler16of a trailer18and deriving a vehicle path20(FIG. 3) to align a hitch assembly22of the vehicle12with the coupler16. In some examples, the hitch assembly22may include a ball mount24supporting a hitch ball26. The hitch ball26may be fixed on the ball mount24that extends from the vehicle12and/or the hitch ball26may be fixed to a portion of the vehicle12, such as a bumper of the vehicle12. The ball mount24may couple with a receiver28that is fixed to the vehicle12.

As shown inFIG. 1, the vehicle12is exemplarily embodied as a pickup truck having a truck bed30that is accessible via a rotatable tailgate32. The hitch ball26may be received by a coupler16in the form of a coupler ball socket34that is provided at a terminal end portion of the coupler16. The trailer18is exemplarily embodied as a single axle trailer from which the coupler16extends longitudinally. It will be appreciated that additional examples of the trailer18may alternatively couple with the vehicle12to provide a pivoting connection, such as by connecting with a fifth wheel connector. It is also contemplated that additional examples of the trailer18may include more than one axle and may have various shapes and sizes configured for different loads and items, such as a box trailer or a flatbed trailer without departing from the teachings provided herein.

With respect to the general operation of the hitch assist system10, as illustrated inFIG. 2, the hitch assist system10includes a sensing system46that includes various sensors and devices that obtain or otherwise provide vehicle status-related information. For example, in some instances, the sensing system46incorporates an imaging system36that includes one or more exterior imagers38,40,42,44, or any other vision-based device. The one or more imagers38,40,42,44each include an area-type image sensor, such as a CCD or a CMOS image sensor, and image-capturing optics that capture an image of an imaging field of view (e.g., fields of view50,52a,52b,FIG. 3) defined by the image-capturing optics. In some instances, the one or more imagers38,40,42,44may derive an image patch54(FIG. 13) from multiple image frames that may be shown on a display118as a combination of the actual image frames and/or a generated image based on the image frames. In various examples, the hitch assist system10may include any one or more of a center high-mount stop light (CHMSL) imager38, a rear imager40, a left-side side-view imager42, and/or a right-side side-view imager44, although other arrangements including additional or alternative imagers are possible without departing from the scope of the present disclosure.

In some examples, the imaging system36can include the rear imager40alone or can be configured such that the hitch assist system10defaults to utilization of the rear imager40in a vehicle12with the multiple exterior imagers38,40,42,44. In some instances, the various imagers38,40,42,44included in the imaging system36can be positioned to generally overlap in their respective fields of view, which in the depicted arrangement ofFIG. 5includes fields of view48,50,52a,52bto correspond with the CHMSL imager38, the rear imager40, and the side-view imagers42and44, respectively. In this manner, image data56from two or more of the imagers38,40,42,44can be combined in an image processing routine58, or in another dedicated image processor within the imaging system36, into a single image or image patch54. In an extension of such examples, the image data56can be used to derive stereoscopic image data56that can be used to reconstruct a three-dimensional scene of the area or areas within overlapped areas of the various fields of view48,50,52a,52b, including any objects (e.g., obstacles or the coupler16) therein.

With reference toFIG. 3, in some instances, the trailer18may be laterally offset from the vehicle12and outside of the field of view50of the rear imager40. In such instances, if the trailer18is disposed within the field of view52a,52bof any other imager38,42,44, the hitch assist system10may detect the trailer18through use of the alternative imagers38,42,44. In some examples, if the trailer18is not within the field of view50of the rear imager40, the user U may select the trailer18from an alternative imager38,42,44disposed on the vehicle12. In some instances, a user interface, such as a touchscreen116may be used to select a field of view48,50,52a,52bfrom the one or more imagers38,40,42,44that correlates to an area surrounding the vehicle12. From that field of view48,50,52a,52b, the user U may select the trailer18that they wish to align the hitch assembly22therewith.

In some examples, the use of two images including the same object can be used to determine a location of the object relative to the two imagers38,40,42, and/or44, given a known spatial relationship between the imagers38,40,42, and/or44through projective geometry of the imagers38,40,42, and/or44. In this respect, the image processing routine58can use known programming and/or functionality to identify an object within the image data56from the various imagers38,40,42,44within the imaging system36. The image processing routine58can include information related to the positioning of any of the imagers38,40,42,44present on the vehicle12or utilized by the hitch assist system10, including relative to a center62(FIG. 1) of the vehicle12. For example, the positions of the imagers38,40,42,44relative to the center62of the vehicle12and/or to each other can be used for object positioning calculations and to result in object position data relative to the center62of the vehicle12, or other features of the vehicle12, such as the hitch ball26(FIG. 1), with known positions relative to the center62of the vehicle12. Moreover, as the vehicle12is moved along the path20, the coupler16may enter and/or exit the field of view48,50,52a,52bof one or more of the imagers38,40,42,44. In such instances, the path20may have been already calculated such that a smooth transition between various fields of view48,50,52a,52bmay monitor the coupler16as the vehicle12approaches the coupler16. As the hitch assembly22approaches the coupler16, any imager38,40,42,44having a field of view48,50,52a,52bthat includes the coupler16therein may be used to monitor the coupler16.

With further reference toFIGS. 1 and 2, a proximity sensor64or an array thereof, and/or other vehicle sensors70, may provide sensor signals that the controller14of the hitch assist system10processes with various routines to determine various objects proximate the vehicle12, the trailer18, and/or the coupler16of the trailer18. The proximity sensor64may also be utilized to determine a height and position of the coupler16. The proximity sensor64may be configured as any type of sensor, such as an ultrasonic sensor, a radio detection and ranging (RADAR) sensor, a sound navigation and ranging (SONAR) sensor, a light detection and ranging (LIDAR) sensor, a vision-based sensor, and/or any other type of sensor known in the art.

Referring still toFIGS. 1 and 2, a positioning system66, which may include a dead reckoning device68or, in addition, or as an alternative, a global positioning system (GPS) that determines a coordinate location of the vehicle12. For example, the dead reckoning device68can establish and track the coordinate location of the vehicle12within a localized coordinate system based at least on vehicle speed and/or steering angle δ (FIG. 3). The controller14may also be operably coupled with various vehicle sensors70, such as a speed sensor72and a yaw rate sensor74. Additionally, the controller14may communicate with one or more gyroscopes76and accelerometers78to measure the position, orientation, direction, and/or speed of the vehicle12.

To enable autonomous or semi-autonomous control of the vehicle12, the controller14of the hitch assist system10may be further configured to communicate with a variety of vehicle systems. According to some examples, the controller14of the hitch assist system10may control a power assist steering system80of the vehicle12to operate the steered road wheels82of the vehicle12while the vehicle12moves along a vehicle path20. The power assist steering system80may be an electric power-assisted steering (EPAS) system that includes an electric steering motor84for turning the steered road wheels82to a steering angle δ based on a steering command generated by the controller14, whereby the steering angle δ may be sensed by a steering angle sensor86of the power assist steering system80and provided to the controller14. As described herein, the steering command may be provided for autonomously steering the vehicle12during a maneuver and may alternatively be provided manually via a rotational position (e.g., a steering wheel angle) of a steering wheel88(FIG. 3) or a steering input device90, which may be provided to enable a driver to control or otherwise modify the desired curvature of the path20of vehicle12. The steering input device90may be communicatively coupled to the controller14in a wired or wireless manner and provides the controller14with information defining the desired curvature of the path20of the vehicle12. In response, the controller14processes the information and generates corresponding steering commands that are supplied to the power assist steering system80of the vehicle12. In some examples, the steering input device90includes a rotatable knob92operable between a number of rotated positions that each provides an incremental change to the desired curvature of the path20of the vehicle12.

In some examples, the steering wheel88of the vehicle12may be mechanically coupled with the steered road wheels82of the vehicle12, such that the steering wheel88moves in concert with steered road wheels82via an internal torque, thereby preventing manual intervention with the steering wheel88during autonomous steering of the vehicle12. In such instances, the power assist steering system80may include a torque sensor94that senses torque (e.g., gripping and/or turning) on the steering wheel88that is not expected from the autonomous control of the steering wheel88and therefore is indicative of manual intervention by the driver. In some examples, the external torque applied to the steering wheel88may serve as a signal to the controller14that the driver has taken manual control and for the hitch assist system10to discontinue autonomous steering functionality.

The controller14of the hitch assist system10may also communicate with a vehicle brake control system96of the vehicle12to receive vehicle speed information such as individual wheel speeds of the vehicle12. Additionally or alternatively, vehicle speed information may be provided to the controller14by a powertrain control system98and/or the vehicle speed sensor72, among other conceivable means. The powertrain control system98may include a throttle100and a transmission system102. A gear selector104may be disposed within the transmission system102that controls the mode of operation of a vehicle transmission. In some examples, the controller14may provide braking commands to the vehicle brake control system96, thereby allowing the hitch assist system10to regulate the speed of the vehicle12during a maneuver of the vehicle12. It will be appreciated that the controller14may additionally or alternatively regulate the speed of the vehicle12via interaction with the powertrain control system98.

Through interaction with the power assist steering system80, the vehicle brake control system96, and/or the powertrain control system98of the vehicle12, the potential for unacceptable conditions can be reduced when the vehicle12is moving along the path20. Examples of unacceptable conditions include, but are not limited to, a vehicle over-speed condition, sensor failure, and the like. In such circumstances, the driver may be unaware of the failure until the unacceptable backup condition is imminent or already happening. Therefore, it is disclosed herein that the controller14of the hitch assist system10can generate an alert signal corresponding to a notification of an actual, impending, and/or anticipated unacceptable backup condition, and prior to driver intervention, generate a countermeasure to prevent such an unacceptable backup condition.

According to some examples, the controller14may communicate with one or more devices, including a vehicle alert system106, which may prompt visual, auditory, and tactile notifications and/or warnings. For instance, vehicle brake lights108and/or vehicle emergency flashers may provide a visual alert. A vehicle horn110and/or speaker112may provide an audible alert. Additionally, the controller14and/or vehicle alert system106may communicate with a human-machine interface (HMI)114of the vehicle12. The HMI114may include a touchscreen116such as a navigation and/or entertainment display118mounted within a cockpit module, an instrument cluster, and/or any other location within the vehicle12, which may be capable of displaying images54(FIG. 5), indicating the alert.

In some instances, the HMI114further includes a user-input device, which can be implemented by configuring the display118as a portion of the touchscreen116with circuitry120to receive an input corresponding with a location over the display118. Other forms of input, including one or more joysticks, digital input pads, or the like can be used in place of or in addition to touchscreen116.

Further, the hitch assist system10may communicate via wired and/or wireless communication with some instances of the HMI114and/or with one or more handheld or portable devices122(FIG. 1). The network may be one or more of various wired or wireless communication mechanisms, including any desired combination of wired (e.g., cable and fiber) and/or wireless (e.g., cellular, wireless, satellite, microwave, and radio frequency) communication mechanisms and any desired network topology (or topologies when multiple communication mechanisms are utilized). Exemplary wireless communication networks include a wireless transceiver (e.g., a BLUETOOTH module, a ZIGBEE transceiver, a Wi-Fi transceiver, an IrDA transceiver, an RFID transceiver, etc.), local area networks (LAN), and/or wide area networks (WAN), including the Internet, providing data communication services.

The portable device122may also include the display118for displaying one or more images and other information to a user U. For instance, the portable device122may display one or more images of the trailer18on the display118and may be further able to receive remote user inputs via touchscreen circuitry120. In addition, the portable device122may provide feedback information, such as visual, audible, and tactile alerts. It will be appreciated that the portable device122may be any one of a variety of computing devices and may include a processor and memory. For example, the portable device122may be a cell phone, mobile communication device, key fob, wearable device (e.g., fitness band, watch, glasses, jewelry, wallet), apparel (e.g., a tee shirt, gloves, shoes or other accessories), personal digital assistant, headphones and/or other devices that include capabilities for wireless communications and/or any wired communications protocols.

The controller14is configured with a microprocessor124and/or other analog and/or digital circuitry for processing one or more logic routines stored in a memory126. The logic routines may include one or more routines including the image processing/hitch detection routine58, a path derivation routine128, and an operating routine130. Information from the imager40or other components of the sensing system46can be supplied to the controller14via a communication network of the vehicle12, which can include a controller area network (CAN), a local interconnect network (LIN), or other protocols used in the automotive industry. It will be appreciated that the controller14may be a stand-alone dedicated controller or may be a shared controller integrated with the imager40or other component of the hitch assist system10in addition to any other conceivable onboard or off-board vehicle control systems.

The controller14may include any combination of software and/or processing circuitry suitable for controlling the various components of the hitch assist system10described herein including without limitation microprocessors, microcontrollers, application-specific integrated circuits, programmable gate arrays, and any other digital and/or analog components, as well as combinations of the foregoing, along with inputs and outputs for transceiving control signals, drive signals, power signals, sensor signals, and so forth. All such computing devices and environments are intended to fall within the meaning of the term “controller” or “processor” as used herein unless a different meaning is explicitly provided or otherwise clear from the context.

With further reference toFIGS. 2-6, the controller14may 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 system80for effecting the steering of the vehicle12to achieve a commanded path20of travel for alignment with the coupler16of the trailer18. It will further be appreciated that the image processing routine58may be carried out by a dedicated processor, for example, within a stand-alone imaging system36for the vehicle12that can output the results of its image processing to other components and systems of vehicle12, including the microprocessor124. 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 the image processing routine58).

In some examples, the image processing routine58can be programmed or otherwise configured to locate the coupler16within the image data56. In some instances, the image processing routine58can identify the coupler16within the image data56based on stored or otherwise known visual characteristics of the coupler16or hitches in general. In some instances, a marker in the form of a sticker or the like may be affixed with trailer18in a specified position relative to coupler16in a manner similar to that which is described in commonly assigned U.S. Pat. No. 9,102,271, entitled “TRAILER MONITORING SYSTEM AND METHOD,” the entire disclosure of which is incorporated by reference herein. In such examples, the image processing routine58may be programmed with identifying characteristics of the marker for location in the image data56, as well as the positioning of the coupler16relative to such a marker so that the location of the coupler16can be determined based on the marker location. Additionally or alternatively, the controller14may seek confirmation that the recognized coupler16is the one desired by the user U, via a prompt on the touchscreen116and/or the portable device122. If the coupler16determination is not confirmed, further image processing may be provided, or user-adjustment of the position134of the coupler16may be facilitated, either using the touchscreen116or another input to allow the user to move the depicted position134of the coupler16on the touchscreen116, which the controller14uses to adjust the determination of the position134of the coupler16with respect to the vehicle12based on the above-described use of the image data56. Alternatively, the user can visually determine the position134of the coupler16within an image presented on HMI114and can provide a touch input in a manner similar to that which is described in co-pending, commonly-assigned U.S. patent application Ser. No. 15/583,014, filed May 1, 2017, and entitled “SYSTEM TO AUTOMATE HITCHING A TRAILER,” the entire disclosure of which is incorporated by reference herein.

As shown inFIGS. 3-6, in some exemplary instances of the hitch assist system10, the image processing routine58and operating routine130may be used in conjunction with each other to determine the path20along which the hitch assist system10can guide the vehicle12to align the hitch ball26and the coupler16of the trailer18. As provided in more detail below, the path20may include a positioning path142and an alignment path144(FIGS. 7 and 8). Accordingly, the positioning path142may terminate at an initial endpoint132and the alignment path144may terminate at a final endpoint140. In some circumstances, the initial and final endpoints132,140may be the same location.

In the example shown, an initial position of the vehicle12relative to the trailer18may be such that the coupler16is in the field of view52aof the side imager42, with the vehicle12being positioned latitudinally from the trailer18but with the coupler16being almost longitudinally aligned with the hitch ball26. In this manner, upon initiation of the hitch assist system10, such as by user input on the touchscreen116, for example, the image processing routine58can identify the coupler16within the image data56of the imager42and estimate the position134of the coupler16relative to the hitch ball26using the image data56in accordance with the examples discussed above or by other known means, including by receiving focal length information within image data56to determine a distance Dcto the coupler16and an angle αcof offset between the coupler16and the longitudinal axis174(FIG. 13) of the vehicle12. Once the positioning Dc, αcof the coupler16has been determined and, optionally, confirmed by the user, the controller14can take control of at least the vehicle steering system80to control the movement of the vehicle12along the desired path20to align the vehicle hitch ball26with the coupler16.

Continuing with reference toFIG. 3, the controller14(FIG. 2), having estimated the positioning Dc, αcof the coupler16, as discussed above, can, in some examples, execute the path derivation routine128to determine the vehicle path20to align the vehicle hitch ball26with the coupler16. The controller14can store various characteristics of vehicle12, including a wheelbase W, a distance D from the rear axle to the hitch ball26, which is referred to herein as the drawbar length, as well as a maximum angle to which the steered wheels82can be turned δmax. As shown, the wheelbase W and the current steering angle δ can be used to determine a corresponding turning radius ρ for the vehicle12according to the equation:

ρ=1W⁢⁢tan⁢⁢δ,(1)
in which the wheelbase W is fixed and the steering angle δ can be controlled by the controller14by communication with the steering system80, as discussed above. In this manner, when the maximum steering angle δmaxis known, the smallest possible value for the turning radius ρminis determined as:

The path derivation routine128can be programmed to derive the vehicle path20to align a known location of the vehicle hitch ball26with the estimated position134of the coupler16that takes into account the determined minimum turning radius μmin, which may allow the path20to use the minimum amount of space and maneuvers. In this manner, the path derivation routine128can use the position of the vehicle12, which can be based on the center62of the vehicle12, a location along the rear axle, the location of the dead reckoning device68, or another known location on the coordinate system, to determine both a lateral distance to the coupler16and a forward or rearward distance to coupler16and derive the path20that achieves lateral and/or forward-backward movement of the vehicle12within the limitations of the steering system80. The derivation of the path20further takes into account the positioning of the hitch ball26relative to the tracked location of vehicle12(which may correspond with the center62of mass of the vehicle12, the location of a GPS receiver, or another specified, known area) to determine the needed positioning of the vehicle12to align the hitch ball26with the coupler16.

Once the desired path20, including the initial endpoint132, has been determined, the controller14may at least control the steering system80of the vehicle12with the powertrain control system98and the brake control system96(whether controlled by the driver or by the controller14) controlling the speed (forward or rearward) of the vehicle12. In this manner, the controller14can receive data regarding the position of the vehicle12during movement thereof from the positioning system66while controlling the steering system80to maintain the vehicle12along the path20. The path20, having been determined based on the vehicle12and the geometry of steering system80, can adjust the steering angle δ, as dictated by the path20, depending on the position of the vehicle12therealong. It is additionally noted that in some examples, the path20may comprise a progression of steering angle δ adjustments that are dependent on the tracked vehicle position. Moreover, in some instances, each correction may include a single steering angle δ adjustment during that correction.

As illustrated inFIG. 3, the initial positioning of the trailer18relative to the vehicle12may be such that forward movement of vehicle12is needed for the desired vehicle path20, such as when the trailer18is latitudinally offset to the side of vehicle12. In this manner, the path20may include various segments136of forward driving and/or rearward driving of the vehicle12separated by inflection points138at which the vehicle12transitions between forward and rearward movement. As used herein, “inflection points” are any point along the vehicle path20in which a vehicle condition is changed. The vehicle conditions include, but are not limited to, a change in speed, a change in steering angle δ, a change in vehicle direction, and/or any other possible vehicle condition that may be adjusted. For example, if a vehicle speed is altered, an inflection point138may be at the location where the speed was altered. In some examples, the path derivation routine128can be configured to include a straight backing segment136for a defined distance before reaching the point at which the hitch ball26is aligned with the position134of the coupler16. The remaining segments136can be determined to achieve the lateral and forward/backward movement within the smallest area possible and/or with the lowest number of overall segments136or inflection points138. In the illustrated example ofFIG. 3, the path20can include two segments136that collectively traverse the lateral movement of the vehicle12, while providing a segment136of straight, rearward backing to bring the hitch ball26into an offset position134of the coupler16, one of which includes forward driving with a maximum steering angle δmaxin the rightward-turning direction and the other including forward driving with a maximum steering angle δmaxin the leftward-turning direction. Subsequently, a single inflection point138is included in which the vehicle12transitions from forward driving to rearward driving followed by the previously-mentioned straight rearward backing segment136. It is noted that variations in the depicted path20may be used, including a variation with a single forward-driving segment136at a rightward steering angle δ less than the maximum steering angle δmax, followed by an inflection point138and a rearward driving segment136at a maximum leftward steering angle δmaxwith a shorter straight backing segment136, with still further paths20being possible.

In some instances, the hitch assist system10may be configured to operate with the vehicle12in reverse only, in which case the hitch assist system10can prompt the driver to drive vehicle12, as needed, to position the trailer18in a designated area relative to the vehicle12, including to the rear thereof so that path derivation routine128can determine a vehicle path20that includes rearward driving. Such instructions can further prompt the driver to position the vehicle12relative to the trailer18to compensate for other limitations of the hitch assist system10, including a particular distance for identification of the coupler16, a minimum offset angle αc, or the like. It is further noted that the estimates for the positioning Dc, αcof the coupler16may become more accurate as the vehicle12traverses the path20, including to position the vehicle12in front of the trailer18and as the vehicle12approaches the coupler16. Accordingly, such estimates can be derived and used to update the path derivation routine128, if desired, in the determination of the adjusted initial endpoint132for the path20.

Referring toFIGS. 5 and 6, a strategy for determining an initial endpoint132for the vehicle path20that places hitch ball26in a projected position for alignment with the coupler16given the vertical component of the position134of the coupler16involves calculating the actual or an approximate trajectory for movement of the coupler16while lowering the coupler16onto the hitch ball26. The initial endpoint132is then derived, as discussed above or otherwise, to place hitch ball26at the desired location140on that trajectory. In effect, such a scheme is implemented by determining the difference between the height of the coupler16and the height of the hitch ball26, which represents the vertical distance by which coupler16will be lowered to engage with hitch ball26. The determined trajectory is then used to relate the vertical distance with a corresponding horizontal distance Δx of coupler16movement in the driving direction that results from the vertical distance. This horizontal distance Δx can be input into the path derivation routine128as the desired initial endpoint132thereof or can be applied as an offset to the initial endpoint132derived from the initially determined position134of the coupler16when the path20ends with the straight-backing segment136, as illustrated inFIG. 3. As provided herein, once the projected initial endpoint132has been reached, or the vehicle12is proximate to the initial endpoint132, the positioning path142(FIG. 3) may be complete. If the initial endpoint132is offset from the final endpoint140, the alignment path144may begin and move the vehicle12to the final endpoint140.

Referring again toFIGS. 5 and 6, the operating routine130may continue to guide the vehicle12until the hitch ball26is in the desired final endpoint140relative to the coupler16for the coupler16to engage with the hitch ball26when the coupler16is lowered into alignment and/or engagement therewith. In the examples discussed above, the image processing routine58monitors the positioning Dc, αcof the coupler16during execution of the operating routine130, including as the coupler16comes into clearer view of the rear imager40with continued movement of the vehicle12along the path20. As discussed above, the position of the vehicle12can also be monitored by the dead reckoning device68with the position134of the coupler16being updated and fed into the path derivation routine128in case the path20and or the initial endpoint132can be refined or should be updated (due to, for example, improved coupler height Hc, distance Dc, or offset angle αcinformation due to closer resolution or additional image data56), including as the vehicle12moves closer to the trailer18. In some instances, the coupler16can be assumed static such that the position of the vehicle12can be tracked by continuing to track the coupler16to remove the need for use of the dead reckoning device68. In a similar manner, a modified variation of the operating routine130can progress through a predetermined sequence of maneuvers involving steering of the vehicle12at or below a maximum steering angle δmax, while tracking the position Dc, αcof the coupler16to converge the known relative position of the hitch ball26to the desired final endpoint140thereof relative to the tracked position134of the coupler16.

Referring toFIGS. 7-15, as provided herein, the vehicle path20may include a positioning path142and a subsequent alignment path144. The positioning path142may locate the vehicle12proximate the initial endpoint132, which may be a predefined offset vehicle forwardly of the coupler16to mitigate misalignment issues due to potential error from a wide range of variants. For example, various conditions of the brake system, various types of road surfaces, variances in vehicle weight, various tire designs, a level of wear of the tires, a gradient of the terrain, software latency, network interference, etc. may affect the precision of the vehicle12to reach the initial endpoint132. Additionally, because a wide range of variants may lead to the vehicle12backing past the initial endpoint132, the offset may assist in preventing unwanted conditions such as overshooting the coupler16and possibly leading to contact between the trailer18and the vehicle12. To increase the precision of the hitch assembly22in relation to the coupler16, the alignment path144may be performed at a speed that is less than the speed during the positioning path142. The vehicle12may operate at the reduced speed until the final endpoint140is reached. It will be appreciated that in some circumstances the alignment path144may not be needed. For example, when the alignment path144would move the vehicle12to a location further from the final endpoint140than the current position of the vehicle12at the initial endpoint132, the alignment path144may not be performed.

With further reference toFIGS. 7 and 8, once the vehicle path20is determined, the vehicle12may move along the positioning path142. The vehicle12may accelerate during a first portion146of the positioning path142from a standstill, or low speed, to a first speed-setpoint148. A feedback measurement of the actual vehicle speed (i.e., wheel rotations/time) may be used in a control loop to prevent excessive overshoot or undershoot of the first speed-setpoint148. The acceleration during the first portion146of the positioning path142may be designed to match a normal human-operated control of the vehicle's acceleration. Accordingly, the movement of the vehicle12may be comfortable to the user U. Thus, in some instances, the acceleration of the vehicle12may be limited to a maximum acceleration value and may be performed with a smooth (or substantially linear) rate of acceleration, which may assist in preventing vehicle jolt.

Once the vehicle12approaches the first speed-setpoint148, the vehicle12may continue along the positioning path142at a speed proximate the first speed-setpoint148. The vehicle12may maneuver at the first speed-setpoint148to expedite the positioning of the vehicle12proximate the initial endpoint132, and/or the coupler16, but slow enough to allow precise vehicle control, accurate sensor measurements, and tracking, and comfort to the user U. As provided herein, once the vehicle12is approaching the initial endpoint132, the vehicle12decelerates to a speed that is equal to or less than a second speed-setpoint150.

The alignment path144may occur at the second speed-setpoint150. The second speed-setpoint150may be a steady, substantially constant, lower speed relative to the first speed-setpoint148. In some circumstances, the second speed-setpoint150may be proximate the slowest continuous speed the vehicle12is capable of robustly achieving. The lower second speed-setpoint150compared to the first speed-setpoint148may assist in a more accurate alignment between the hitch assembly22and the coupler16as the variances/tolerances of the vehicle systems may be further mitigated and the vehicle sensors64,70may be able to provide additional accuracy of the location of the coupler16due to the slower second speed-setpoint150. Further, due to the low vehicle speed, the precision of the positioning of the hitch assembly22relative to the coupler16may be increased. The slower second speed-setpoint150minimizes the possibility of error, or error stack up, during the alignment path144.

As the vehicle12approaches the final endpoint140, the braking system brings the vehicle12to a stop. The stopping, or deceleration portion152, of the alignment path144may be a known average from calibration testing and stored within the memory126of the controller14. It will be appreciated that the deceleration portion152of the alignment path144may be altered over time due to variances in environmental factors and/or changes in vehicle component conditions. This variation may be minimized due to the slower second speed-setpoint150and may also be predicted and adapted to using feedforward data acquired during the positioning path142and alignment path144operations. For example, if the deceleration portion152of the positioning path142takes longer than calculated/predicted by the controller14, the hitch assist system10may deem that the deceleration portion152of the alignment path144will also be longer than originally calculated. Accordingly, the positioning path142and the alignment path144may each include a deceleration period and wherein the alignment path deceleration period is based on a comparison of a detected deceleration period compared to an estimated deceleration period.

In some examples, the hitch assist system10may be initiated when the vehicle starting point is already proximate the vehicle12. In these cases, the hitch assist system10may estimate the distance traveled during the acceleration portion of the positioning path142. The deceleration portion152of the positioning path142may also be known. If the sum of the acceleration portion and the deceleration portion152is greater than or proximate to the measured distance to the coupler16, then the hitch assist system10may skip the positioning path142and operate in the alignment path144.

It will be appreciated that through the positioning path142and the alignment path144, the lateral acceleration/deceleration may be controlled using a feedback controller14that controls vehicle speed and may help with smooth transitions between threshold speed-setpoints. In this way, sharp turns may be executed to align the hitch assembly22and the coupler16in a manner that is both comfortable to the driver and allows the steering system to provided steering wheel motion.

With reference toFIG. 9, a method154of aligning the hitch assembly22with the coupler16is shown. In particular, in step156, the hitch assist system10is initiated. In some examples, the hitch assist system10can be initiated at any point when the coupler16is in the field of view48,50,52a,52bof at least one imager38,40,42,44within imaging system36. Accordingly, once the hitch assist system10is initiated, the controller14can use imaging system36to scan the viewable scene using any or all available imagers38,40,42,44at step158. The scene scan can create the image patch54(FIG. 3) that may be used to then identify the coupler16and, optionally, the associated trailer18. At step160, the hitch assist system10determines an initial endpoint132of the vehicle path20that places the hitch ball26and the coupler16proximate one another.

At step162, the controller14uses the path derivation routine128to determine the path20to align the vehicle12with the initial endpoint132. Once the path20has been derived, the hitch assist system10can ask the user U to relinquish control of at least the steering wheel88of vehicle12(and, optionally, the throttle100and brake control system96, in various implementations of the hitch assist system10wherein the controller14assumes control of the powertrain control system98and the brake control system96during execution of the operating routine130) while the vehicle12is maneuvered along the positioning path142(FIG. 3), which may be performed at a speed equal to the first speed-setpoint148for at least a portion thereof. When it has been confirmed that user U is not attempting to control the steering system80(for example, using the torque sensor94), the controller14moves the vehicle12along the determined path20. Furthermore, the hitch assist system10may determine if the transmission system102is in the correct gear and may shift to the desired gear or prompt the user U to shift to the desired gear. The hitch assist system10may then control the steering system80to maintain the vehicle12along the path20as either the user U or the controller14controls the speed of vehicle12using the powertrain control system98and the braking control system96. As discussed herein, the controller14or the user U can control at least the steering system80, while tracking the position134of the coupler16until the vehicle12reaches the final endpoint140, wherein the vehicle hitch ball26is aligned with the coupler16. It is contemplated that the maneuvering of the vehicle12may occur manually, semi-autonomously, or autonomously. In semi-autonomous or autonomous examples of the hitch assist system10, the controller14generates commands provided to the vehicle brake control system96, the powertrain control system98, and/or the power assist steering system80to maneuver the vehicle12toward the trailer18. In semi-autonomous examples, the driver of the vehicle12may be required to apply gas and/or apply the brakes while the controller14steers the vehicle12. In yet other examples, the user U may move the vehicle12to the desired initial and/or final endpoint132,140.

At step164, the hitch assist system10determines whether the hitch assembly22is offset in a longitudinal direction and/or a latitudinal direction from the coupler16. A longitudinal offset is an offset between the hitch assembly22and the coupler16in a vehicle heading direction, which may be in a vehicle forward and/or a vehicle rearward direction. A latitudinal offset is an offset between the hitch assembly22and the coupler16in which the current steering angle δ of the vehicle12needs to be changed to correct any misalignment issues between the hitch assembly22and the coupler16.

At step166, the offset between the hitch ball26and the coupler16is calculated. At step168, the hitch assist system10moves along the alignment path144to advance the vehicle12towards the final endpoint140, which may be performed at a speed equal to the second speed-setpoint150for at least a portion thereof. During the alignment path144, the hitch assist system10may control the powertrain control system98and/or the brake control system96to move the vehicle12at a speed that is slower than the operational speed of the vehicle12during the positioning path142. In addition, the hitch assist system10may compare the actual movement distance during the positioning path142with a predicted distance. In response to the comparison, the hitch assist system10adapts the brake parameters and prescheduled brake pattern during the alignment path144to achieve the desired movement distances.

Once the system determines that a final endpoint140has been reached, wherein the coupler16may be engaged with the hitch ball26, at step170, the hitch assist system10may maintain the vehicle12in a substantially fixed position since idle torque from the engine or roll from terrain slope would lead to a misalignment with the positioning. The vehicle12may be maintained in a substantially fixed position through the application of continuous service brake torque, an automatic shifting over the gear shifter to park, an automatic engagement of a vehicle parking brake, HMI instructions to the user to perform any of the above steps before the service brakes are automatically released, and/or through any other method at which point the operating routine154may end at step172.

Referring toFIGS. 10-12, as provided herein, the vehicle12may move along the alignment path144at a second speed-setpoint150. For example, as illustrated inFIG. 10, the vehicle12may conclude the positioning path142(FIG. 3) at the initial endpoint132with the hitch ball26longitudinally offset from the coupler16and decelerate prior to initiating the alignment path144. The vehicle12may move along the alignment path144, as illustrated inFIG. 11, at a speed proximate the second speed-setpoint150and may recalculate the offset between the hitch ball26and the coupler16during this time. Based on the updated calculations, the controller14may determine whether to keep moving along the same alignment path144or to define a new alignment path144upon which to move the vehicle12. The vehicle12may then move along the alignment path144until the hitch ball26and the coupler16are positioned in an aligned position, which ends the alignment path144, and the hitch assist process.

Referring toFIGS. 13 and 14, the controller14may 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 system80for effecting the steering of the vehicle12to achieve a commanded path20of travel for alignment with the coupler16of the trailer18. Based on the commanded path20, the controller14may calculate a vehicle occupation zone180based on a longitudinal axis174of the vehicle12and a wheelbase movement area176may extend a vehicle width outwardly from the axis174to a path178upon which the front and/or rear road wheels82rotate upon the ground surface. In some instances, as the vehicle12moves along the path20, portions of the vehicle12, such as a front portion182of the vehicle12may extend an additional distance dooutwardly of the wheelbase movement area176creating a potential contact event between the vehicle12and an obstacle O proximate the vehicle12. The additional distance dois also disposed within the vehicle occupation zone180. In some instances, the front portion182of the vehicle12may be within a vehicle sensing system blind zone when disposed outwardly of the wheelbase movement area176. The vehicle sensing blind zone may be disposed between a front portion182of the vehicle12and a side mirror184of the vehicle12, which may be created by a lack of sensors64,70and/or imagers38,40,42,44within this area of the vehicle12. By monitoring obstacles in relation to the vehicle occupation zone180, the user U and/or the controller14may be capable of avoiding obstacles O, even when the obstacle is proximate the blind zone of the vehicle12.

To mitigate a potential contact event, the hitch assist system10may calculate the vehicle occupation zone180based on a body trajectory in addition to the path20of the vehicle12. The body trajectory may account for the extension of the body of the vehicle outwardly of the wheelbase when the latitudinal direction of the vehicle12is altered. In some instances, the vehicle occupation zone180may be shown as an occupation zone overlay186on the display118. Accordingly, the user U may view the projected path20of the vehicle12and may verify that the vehicle occupation zone180is free from obstacles. The occupation zone overlay186may also direct the user U to areas of interest around the vehicle12, such as the area between the front portion182of the vehicle12and the side mirror184, where a sensing system blind zone may exist. It will be appreciated that the occupation zone overlay186may be updated at any point during the hitch assist operation as new data is inputted into the hitch assist system10.

Referring toFIGS. 15 and 16, in some examples, more than one potential path20a,20b,20cto move the vehicle12towards the coupler16may be possible. However, some paths20a,20b,20cmay be less desirable due to a final orientation between the vehicle12and the trailer18and/or the vehicle12may be disposed near various obstacles while aligning with the hitch assembly22with the coupler16. Accordingly, in some instances, the hitch assist system10may include a default path (e.g.,20a) and a plurality of secondary paths (e.g.,20b,20c). Various factors may be considered when calculating the default and secondary paths20a,20b,20cincluding, but not limited to, the shortest path, which may be a straight path from the vehicle12to the trailer18, a path where the vehicle12and the trailer18are longitudinally aligned when the hitch assembly22and the coupler16are engaged with one another, and/or a path where the front portion182of the vehicle12is aimed in a similar direction to the direction it was aimed when the hitch assist operation was initiated. In some examples, the various paths20a,20b,20cmay be calculated and a path overlay188of the various paths20a,20b,20cmay be illustrated on the display118. The user U may select any one of the paths20a,20b,20con the display118and the hitch assist system10may direct the vehicle12along the chosen path20a,20b,20c. If the driver continues the hitch assist operation without choosing a path20a,20b,20c, the path20a,20b,20cmay be automatically selected by the vehicle12based on detected obstacles and the desired final orientation between the vehicle12and the trailer18and/or the default path (e.g.,20a) may be selected.

In some examples, the display118may provide the path overlay188of the vehicle12and the trailer18and the driver may have the option to create a path20or dictate a vehicle final heading direction on the display118. For example, the user U may drag their finger along an area between the vehicle12and the trailer18and a path20matching that pattern will be calculated by the hitch assist system10. Likewise, the user U may dictate a final heading direction of the vehicle12by motioning the finger outwardly from the front portion182of the vehicle12.

Referring toFIG. 17, a method190of aligning the hitch assembly22with the coupler16is shown, according to some examples. In particular, in step192, the hitch assist system10is initiated. At step194, the vehicle12scans the scene rearwardly of the vehicle12and may determine whether the hitch ball26and/or the coupler16are within the field of view48,50,52a,52bof the one or more imagers38,40,42,44, and/or other sensors64,70within the vehicle sensing system46. Additionally, once the coupler16has been identified, image processing can designate any other objects as obstacles O and can identify the same obstacle within the image data56from multiple imagers38,40,42,44to determine the positioning and height of the identified obstacles O relative to vehicle12.

If the coupler16has not been identified at step196, the scene scan can be continued, including while instructing driver to move the vehicle12to better align with the trailer18, until the coupler16is identified. When the coupler16has been identified, the path derivation routine128can be used to determine one or more possible vehicle paths20a,20b,20c(FIG. 16) to align the hitch assembly22with the coupler16while avoiding any other objects, designated as obstacles O (by default, for example) in step198. Subsequently, the controller14uses the path derivation routine128to determine a default path (e.g.,20a) and secondary paths (e.g.,20b,20c) to align the hitch ball26with the coupler16.

At step200, the various paths20a,20b,20care illustrated as a path overlay188on the display118, as exemplarily shown inFIG. 16. The paths20a,20b,20cmay be of various colors and/or patterns to further separate the paths from one another. With the various paths20a,20b,20cillustrated on the display118, the user U may choose the desired vehicle path20a,20b,20cat step202. The path20a,20b,20cmay be chosen through a user interface within the vehicle12and/or on the portable device122. Alternatively, the user U may touch or otherwise choose the desired path20a,20b,20con the display118. In some instances, at step204, if the user U desires a path that is not illustrated, the user U may dictate the desired path on the display118and the hitch assist system10may calculate a vehicle path20to match the desired path. As provided herein, the user may dictate a backing path20of the vehicle12, a heading direction of the vehicle12, an alignment orientation of the vehicle12relative the trailer18, and/or any other constraint for the hitch assist system10to meet while aligning the hitch assembly22to the coupler16.

At step206, the user U may confirm that the illustrated path20on the display118is the desired path for aligning the hitch assembly22with the coupler16. After the path20has been confirmed by the user U and/or automatically by the hitch assist system10, at step206, the hitch assist system10can ask the user U to relinquish control of at least the steering wheel88of vehicle12(and, optionally, the throttle100and brake, in various implementations of the hitch assist system10wherein the controller14assumes control of the powertrain control system98and the brake control system96during execution of the operating routine130) while the vehicle12performs an auto hitch operation at step208. When it has been confirmed that user U is not attempting to control steering system80(for example, using the torque sensor94), the controller14begins to move vehicle12along the determined path20. Furthermore, the hitch assist system10may determine if the transmission system102is in the correct gear and may shift to the desired gear or prompt the user U to shift to the desired gear. The hitch assist system10may then control the steering system80to maintain the vehicle12along the path20as either the user U or the controller14controls the velocity of vehicle12using the powertrain control system98and the braking control system96. As discussed herein, the controller14or the user U can control at least the steering system80, while tracking the position of the coupler16until the hitch assembly22is aligned with the coupler16, at which point the operating routine130can end at step210.

A variety of advantages may be derived from the use of the present disclosure. For example, use of the disclosed hitch assist system provides a sensing system that may continue to monitor the hitch assembly and/or the coupler through independent imagers and/or sensors to monitor the hitch assembly and/or the coupler when out of the field of view of one or more of the imagers and/or sensors. The hitch assist system further includes a controller configured to generate commands for maneuvering the vehicle along a positioning path and a subsequent alignment path, if desired and/or needed. The vehicle may move at a first speed-setpoint during the positioning path and a second speed-setpoint during the alignment path, which may produce a more accurate alignment between the hitch assembly and the coupler. The controller may further generate a vehicle occupation zone that illustrates an area through which the vehicle may move to align the hitch assembly with the coupler. Additionally, the controller may generate multiple paths that may align the hitch assembly with the coupler. A user may select a desired path from the plurality of generated paths, which may assist in avoiding objects proximate the vehicle and/or the trailer.

According to various examples, a hitch assist system is provided herein. The hitch assist system includes a sensing system configured to detect a hitch assembly and a coupler. A controller is configured to generate commands for maneuvering a vehicle along a first path or a second path. A user input device includes a display. The display is configured to illustrate the first and second paths. Examples of the hitch assist system can include any one or a combination of the following features:the user input device is configured to accept instructions for moving the vehicle along the first path or the second path;the display is a touchscreen having circuitry to receive an input corresponding with a location over the display;the touchscreen registers one or more touch events thereon for specifying the first path or the second path;the sensing system includes a rear imager located on a rear portion of the vehicle and is configured to capture one or more images of a rear-vehicle scene;the sensing system further includes a side-view imager configured to capture one or more images along a side portion of the vehicle;the user input device registers one or more touch events thereon for specifying a location of the hitch coupler within a respective field of view from the rear imager or the side-view imager;the display illustrates an overlay of a vehicle occupation zone of the first path or the second path, the vehicle occupation zone extending outwardly of a wheelbase path of the vehicle;the vehicle extends outwardly of the wheelbase path of the vehicle as the vehicle deviates from a longitudinal axis; and/orthe overlay further includes obstacles within a field of view of the sensing system.

Moreover, a hitch assist method is provided herein. The method includes determining an offset of a hitch ball relative to said coupler. The method also includes calculating a first path to align the hitch ball to said coupler, the first path having a positioning path and an alignment path. The method further includes maneuvering a vehicle a predefined distance along the positioning path at a first vehicle speed-setpoint. Lastly, the method includes aligning the hitch ball to said coupler along the alignment path at a second vehicle speed-setpoint, the second speed-setpoint less than the first vehicle speed-setpoint. Examples of the method can include any one or a combination of the following features:calculating a second path to align the hitch ball to said coupler; detecting an obstacle proximate the vehicle; and operating the vehicle along the first path or the second path to avoid the obstacle;displaying the first and second paths on a touchscreen display, the touchscreen display configured to register one or more touch events thereon for specifying a chosen path;displaying a vehicle occupation zone extending outwardly of a wheelbase on a display;detecting obstacles proximate the vehicle or said coupler; and illustrating the obstacles in relation to the vehicle occupation zone on the display; and/orthe positioning path and the alignment path each include a deceleration period and wherein the alignment path deceleration period is based on a comparison of a detected deceleration period compared to an estimated deceleration period.

According to some examples, a hitch assist system is provided herein. The hitch assist system includes an imager for capturing one or more images of a hitch assembly and a coupler. A display generates an image patch based on the one or more images. A controller is configured to identify the hitch assembly, identify a coupler, and display an overlaid vehicle occupation zone on the display that extends through the hitch assembly, the vehicle occupation zone defining an area in which a vehicle travels to align the hitch assembly with the coupler. Examples of the hitch assist system can include any one or a combination of the following features:the imager is further configured to detect one or more obstacles proximate the vehicle and the controller is further configured to display the one or more obstacles in relation to the vehicle occupation zone;the controller generates first and second paths that align the hitch assembly with the coupler; and/orthe display is configured as a touchscreen, the touchscreen configured to accept instructions for moving the vehicle along the first path or the second path.

The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially linear” surface is intended to denote a slope that is constant or approximately constant. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other.

Furthermore, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being “operably couplable” to each other to achieve the desired functionality. Some examples of operably couplable include, but are not limited to, physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components. Furthermore, it will be understood that a component preceding the term “of the” may be disposed at any practicable location (e.g., on, within, and/or externally disposed from the vehicle) such that the component may function in any manner described herein.

It will be noted that the sensor examples discussed above might include computer hardware, software, firmware, or any combination thereof to perform at least a portion of their functions. For example, a sensor may include computer code configured to be executed in one or more processors and may include hardware logic/electrical circuitry controlled by the computer code. These example devices are provided herein for purposes of illustration and are not intended to be limiting. Examples of the present disclosure may be implemented in further types of devices, as would be known to persons skilled in the relevant art(s).

At least some examples of the present disclosure have been directed to computer program products including such logic (e.g., in the form of software) stored on any computer usable medium. Such software, when executed in one or more data processing devices, causes a device to operate as described herein.