Steering input system for a trailer reversing assist system, reversing assist system for a vehicle, and method for assisting a vehicle in reversing a trailer

Abstract

Steering input system for a trailer reversing assist system (10), comprising: an input device (18, 218) comprising: a housing (220) and a user-manipulable input element (30, 230) coupled to the housing (220), and a control device (28): which determines a state of a usage condition of the input device (18, 218), and based on the state of the usage condition, implementing or deactivating a trailer backup assist mode, including generating a vehicle steering command based on a current position of the input element (30, 230);characterized in that the first usage condition is a position of the input device (18, 218) relative to a vehicle (14) connected to the trailer backup assist system (10), the state of the usage condition being the presence or absence of the vehicle (14), and the trailer reversing assistance system (10) is deactivated if the condition is absence from the vehicle (14); or wherein the input device (18, 218) has a battery (232) within the housing (220) for supplying power to the device (18, 218), the first usage condition is a state of charge of the battery (232), wherein the state of the usage condition is the state of charge of the battery (232) compared to a predetermined minimum state of charge for reliably executing a trailer backup assist routine, and the trailer reversing assist mode is deactivated if the charge level of the battery (232) is below the predetermined minimum charge level.

Description

FIELD OF THE INVENTIONThe present disclosure relates to a steering input system for a trailer backup assist system according to the preamble of claim 1, a backup assist system for a vehicle according to the preamble of claim 9, and a method for assisting a vehicle in backing a trailer according to the preamble of claim 10.PRIOR ARTIt is well known that reversing a vehicle with a trailer attached is a difficult task for many drivers. This is particularly true for drivers who are not trained in backing with trailers, such as those who do not drive very often with a trailer attached (e.g., who have rented a trailer, do not often use their own trailer, etc.). One reason for such a difficulty is that reversing a vehicle with a trailer attached requires counter-steering that is opposite to normal steering when the vehicle is being reversed without an attached trailer, and / or requires braking to stabilize the vehicle and trailer combination before a breakaway condition occurs. Another reason for such a difficulty is that small errors in steering are amplified during backing of a vehicle with a trailer attached, causing the trailer to deviate from a desired path.To assist the driver in steering a trailer-attached vehicle, a backup assist system must know the driver's intention. A common assumption in known backup assist systems is that a driver of a vehicle with a trailer attached wishes to drive straight backwards and that the system either implicitly or explicitly assumes a zero turn trajectory for the vehicle and trailer combination. Unfortunately, most real applications of backing a trailer involve a curved path, and assuming a zero curvature path would therefore significantly limit the usefulness of the system.US 2013 / 0 268 160 A1 discloses a trailer backup steering input device for providing a steering information signal to a trailer backup assist control module, which comprises a user interface via which commands for changing the trailer track are input and a signal interface, in particular a wireless signal interface, which is connectable to a signal interface of the trailer backup assist control module in order to enable the transmission of the steering information signal from the trailer backup steering input device for reception by the trailer backup assist control module.The generic publication DE 10 2005 043 467 A1 discloses a reversing aid system for regulating the reverse travel of a vehicle combination with a towing vehicle and a trailer, which comprises an input device with an adjusting lever which is held in a zero position by a restoring force and can be deflected by the driver for inputting a longitudinal movement in a longitudinal direction and for inputting a transverse movement in a transverse direction, wherein evaluation means are provided for evaluating the feasibility or dangerousness of the driver specifications, and the input device has adjustment means for influencing the restoring force in order to give the driver haptic feedback about this.Some known systems assume that a path from a map or path planner is known, which may result in such systems having a rather complex human-machine interface (MMS) and vehicle / trailer positioning.Thus, an approach to backing a trailer that provides a simple human-machine interface and overcomes other disadvantages of known trailer backup assist systems would be advantageous, desirable, and useful.SUMMARY OF THE INVENTIONThe object is achieved with a steering input system for a trailer backup assist system having the features of independent claim 1, a backup assist system for a vehicle which drives a trailer backwards having the features of independent claim 9 and a method for assisting a vehicle when driving a trailer backwards having the features of independent claim 10.According to an aspect of the present disclosure, a steering input system for a trailer backup assist system includes an input device having a housing and a user-manipulable input member coupled to the housing. The system further includes a controller that determines a state of a use condition of the input device and, based on the state of the use condition, implements or disables a trailer backup assist mode. The trailer backup assist mode generates a vehicle steering command based on a current position of the input member.According to another aspect of the present disclosure, a backup assist system for a vehicle backing a trailer includes an input device having a housing and a rotating member rotatably coupled to the housing. The system further includes a controller that determines a state of a first use condition of the input device and, based on the state of the use condition, implements or disables a trailer backup assist mode. The trailer backup assist mode generates a vehicle steering command based on a current position of the input member.According to another aspect of the present disclosure, a method of assisting a vehicle in backing a trailer includes determining a presence or absence of a deactivation condition that may be the driver being absent from the vehicle and / or a battery state of charge of an input device being below a threshold. According to the deactivation condition, the method includes respectively implementing or deactivating a trailer backup assist mode. When implemented, the trailer backup assist mode generates a vehicle steering command based on a current position of an input element of the input device.These and other aspects, objects and features of the present invention will become apparent and apparent to those skilled in the art upon reading the following description, claims and accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSIn the drawings:FIG. 1 is a top perspective view of a trailer mounted vehicle with an embodiment of a hitch angle sensor for operating a trailer backup assist system,FIG. 2 is a block diagram illustrating an embodiment of the trailer backup assist system having a steering input device, a turn path controller, and a trailer brake system,FIG. 3 is a top view of a steering input device with a rotatable knob for operating the trailer backup assist system according to an embodiment,FIG. 4 is a top view of another embodiment of a rotatable knob for selecting a desired curved path of a trailer and a corresponding schematic diagram illustrating a vehicle and a trailer having various trailer curved paths that correlate with desired curved paths that may be selected,FIG. 5 is a schematic view of a long distance steering input device that may be used in conjunction with the system of FIG. 1 ,FIG. 6 is a flow chart illustrating a control system for managing use of the long-distance steering input device of FIG. 5 based on its various conditions,FIG. 7 is a perspective view showing an embodiment of the long-distance steering input device according to the schematic illustration of FIG. 5 ,FIGS. 8A and 8B are sequential side views illustrating implementation of a control mode using the long-distance steering input device of FIG. 7 ,FIGS. 9A and 9B are sequential front views of the long distance steering input device of FIG. 7 during use thereof in controlling a curved path of a vehicle and trailer combination,FIG. 10 is an assembly view of the long distance steering input device of FIG. 7 with a retaining device,FIG. 11 is a perspective view of the long distance steering input apparatus combined with a holder mounted in a vehicle; andFIG. 12 is a rear view of the combination of the long distance steering input device and the holding device of FIG. 10.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSFor purposes of the present specification, the terms "upper / e / es", "lower / e / es", "right / e / es", "left / e / es", "rear / e / es", "front / e / es", "vertical / e / es", "horizontal / e / es", "inner / e / es", "outer / e / es", and derivatives thereof, are intended to refer to the invention as oriented in FIG. 1. It should be understood, however, that the invention may assume various alternative orientations unless expressly stated to the contrary. Further, it is to be understood that the specific devices and processes illustrated in the accompanying drawings and described in the following specification are merely exemplary embodiments of the inventive concepts defined in the appended claims. Therefore, 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. In addition, it should be understood that unless otherwise indicated, the discussion of a particular feature or 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 extends only in such a direction or on such a plane without other directional components or deviations unless otherwise indicated.Referring to FIGS. 1-12, reference numeral 10 generally designates a trailer backup assist system for controlling a backup path of a trailer 12 attached to a vehicle 14 by allowing a driver of the vehicle 14 to specify a desired curvature 26 of the backup path of the trailer 12. In one embodiment, the trailer backup assist system 10 automatically steers the vehicle 14 to guide the trailer 12 on the desired curvature or path of backup 26 while a driver uses the accelerator pedal and brake pedal to control the rearward travel speed of the vehicle 14. To monitor the position of the trailer 12 relative to the vehicle 14, the trailer backup assist system 10 may include a sensor system 16 that detects or otherwise determines a hitch angle γ between the trailer 12 and the vehicle 14. The sensor system 16 may include a hitch angle sensor 44, such as a vision-based system, that uses a camera 46 on the vehicle 14 to monitor a target 52 on the trailer 12 to determine the hitch angle γ while increasing the reliability of the overall estimated hitch angle γ.With reference to the general operation of the trailer backup assist system 10, a steering input device 18 may be provided, such as a rotatable knob 30, such that a driver may provide the desired curvature 26 of the trailer 12. Thus, the steering input device 18 may be operable between a plurality of choices, such as successive rotational positions of a knob 30, each providing a stepwise change in the desired curvature 26 of the trailer 12. Upon entering the desired curvature 26, the controller may generate a steering command for the vehicle 14 to generate the trailer 12 on the desired curvature 26 based on the estimated hitch angle γ and a kinematic relationship between the trailer 12 and the vehicle 14. Thus, the accuracy of the hitch angle estimate is critical to the operation of the trailer backup assist system 10. However, it should be appreciated that such a system for directly estimating hitch angle may be used in conjunction with additional or alternative vehicle features, such as trailer snubbing monitoring.With reference to the embodiment shown in FIG. 1, the vehicle 14 is a pickup truck embodiment equipped with an embodiment of the trailer backup assist system 10 for controlling the backup path of the trailer 12 attached to the vehicle 14. More specifically, the vehicle 14 is pivotally mounted to an embodiment of the trailer 12 that includes a box frame 32 having a closed cargo area 34, a single axle having a right wheel assembly and a left wheel assembly, and a drawbar 36 extending longitudinally forward from the closed cargo area 34. The illustrated trailer 12 also includes a hitch connector in the form of a coupling assembly 38 connected to a vehicle hitch connector in the form of a hitch ball 40. The coupling arrangement 38 latches onto the coupling ball 40 in order to provide a ball joint pivot connection 42 which enables the coupling angle γ to be articulated. It should be appreciated that additional embodiments of the trailer 12 may alternatively be coupled to the vehicle 14 to provide a pivotal connection, such as by connecting to a fifth wheel connection. It is also contemplated that additional embodiments of the trailer may include more than one axle and may have various shapes and sizes designed for different loads and items, such as a boat trailer or a dump trailer.With continued reference to FIG. 1, in the illustrated embodiment, the sensor system 16 includes both a sensor module 20 and a vision-based hitch angle sensor 44 for estimating the hitch angle γ between the vehicle 14 and the trailer 12. the illustrated hitch angle sensor 44 (FIG. 2 ) employs a camera 46 (e.g., a video imaging camera) that, as shown, may be positioned proximate an upper portion of the vehicle rear door 48 at the rear of the vehicle 14 such that the camera 46 may be elevated relative to the drawbar 36 of the trailer 12. The illustrated camera 46 has an imaging field of view 50 positioned and oriented for capturing one or more images of the trailer 12, including an area having one or more desired target placement zones for at least one target 52 to be secured. Although it is contemplated that the hitch angle γ determination camera 46 may capture images of the trailer 12 without a target 52, in the illustrated embodiment, the trailer backup assist system 10 includes a target 52 placed on the trailer 12 to enable the trailer backup assist system 10 to use information captured via image capture and processing of the target 52. It is further contemplated that additional embodiments of the hitch angle sensor 44 and the sensor system 16 for providing the hitch angle γ may include one of or a combination of a potentiometer, a magnetic-based sensor, an optical sensor, a proximity sensor, a rotation sensor, a capacitive sensor, an inductive sensor, or a mechanically-based sensor, such as a mechanical sensor assembly mounted to the ball joint pivot connection 42, energy converters of a backup assist system, a blind spot system, and / or a cross traffic warning system, and other conceivable sensors or display devices of the hitch angle γ in addition to or in place of the vision-based hitch angle sensor 44.The embodiment of the sensor module 20 illustrated in FIG. 1 includes a sensor cluster 21 in a housing mounted on the drawbar 36 of the trailer 12 proximate the closed bed area 34, and left and right wheel speed sensors 23 on laterally opposite wheels of the trailer 12. It is conceivable that the wheel speed sensors 23 may be bidirectional wheel speed sensors for monitoring both the forward travel speed and the rearward travel speed. Further, it is contemplated that sensor cluster 21 may be mounted to alternative portions of trailer 12 in additional embodiments.The sensor module 20 generates a plurality of signals indicative of various dynamic characteristics of the trailer 12. The signals may include a yaw rate signal, a lateral acceleration signal, and wheel speed signals generated by a yaw rate sensor 25, an accelerometer 27, and the wheel speed sensors 23, respectively. Thus, in the illustrated embodiment, the yaw rate sensor 25 and the accelerometer 27 are included in the sensor cluster 21 with housing, although other configurations are conceivable.Referring to the embodiment of the trailer backup assist system 10 shown in FIG. 2, the trailer backup assist system 10 receives information associated with vehicle and trailer condition from additional sensors and devices. This information includes positioning information from a positioning device 56, which may include a global positioning system (GPS) on the vehicle 14 or a handheld device, to determine a coordinate location of the vehicle 14 and the trailer 12 based on the location of the positioning device 56 with respect to the trailer 12 and / or the vehicle 14 and based on the estimated hitch angle γ.As further shown in FIG. 2, an embodiment of the trailer backup assist system 10 is in communication with a power steering system 62 of the vehicle 14 to actuate the steered wheels 64 (FIG. 1 ) of the vehicle 14 to move the vehicle 14 such that the trailer 12 responds in accordance with the desired curvature 26 of the trailer 12.The power steering system 62 provides information to the controller 28 of the trailer backup assist system 10 regarding a rotational position of the steered wheels 64 of the vehicle 14, including a steering angle. The controller 28, in the illustrated embodiment, processes the current steering angle in addition to other conditions regarding the vehicle 14 and the trailer 12 to guide the trailer 12 along the desired curvature 26. It is envisioned that the trailer backup assist system 10 may be an integrated component of the power steering system 62, in additional embodiments.As also shown in FIG. 2, the vehicle brake control system 72 may also communicate with the controller 28 to provide brake information, such as vehicle wheel speeds, to the trailer backup assist system 10 and receive brake commands from the controller 28. The powertrain control system 70 may also interact with the trailer backup assist system 10 to regulate the speed and acceleration of the vehicle 14 during backing of the trailer 12.The trailer backup assist system 10 in the illustrated embodiment may communicate with one or more devices, including a vehicle warning system 76 that may provide visual, audible, and tactile warnings. For example, vehicle brake lights 78 and the vehicle hazard warning system may provide a visual warning, and an / or vehicle horn 79 and / or speaker 81 may provide an audible warning. Additionally, the trailer backup assist system 10 and / or the vehicle warning system 76 may be in communication with a human machine interface (MMS) 80 for the vehicle 14. The MMS 80 may include a vehicle display 82, such as a center console mounted navigation or entertainment display (FIG. 1 ). Further, the trailer backup assist system 10 may communicate via wireless communication with another embodiment of the MMS 80, such as one or more handheld or wearable devices including one or more smart phones. The wearable device may also include the display 82 for displaying one or more images and other information to a user. For example, the wearable device may display one or more images of the trailer 12 and an indication of the estimated hitch angle on the display 82. Additionally, the wearable device may provide feedback information such as visual, audible, and tactile warnings.As further illustrated in FIG. 2, the trailer backup assist system 10 includes a steering input device 18 connected to the controller 28 to allow information transfer therebetween. It is disclosed herein that the steering input device 18 may be coupled to the controller 28 in a wired or wireless manner. The steering input device 18 provides information to the trailer backup assist system 10 that defines the desired backup path of the trailer 12 for the controller 28 to process and generate steering commands. More specifically, the steering input device 18 may provide selection or position information that correlates with a desired curvature 26 of the desired path of return of the trailer 12. The trailer steering commands provided by the steering input device 18 may also include information associated with a commanded change in travel path, such as an incremental change in desired curvature 26, and information associated with an indication that the trailer 12 is to travel along a path defined by a longitudinal centerline axis of the trailer 12, such as a zero desired curvature path value defining a substantially straight travel path for the trailer. As discussed in more detail below, the steering input device 18 according to one embodiment may include a movable control input device to allow a driver of the vehicle 14 to command desired trailer steering actions or otherwise select and modify a desired curvature. For example, the movable control input device may be a rotatable knob 30 that may be rotatable about a rotational axis extending through an upper surface or face of the knob 30. In other embodiments, the rotatable knob 30 may be rotatable about a rotational axis extending substantially parallel to a top surface or face of the rotatable knob 30.With continued reference to the embodiment shown in FIG. 2, the controller 28 is configured with a microprocessor 84 to process logic and routines stored in a memory 86 that receives information from the sensor system 16, including the trailer sensor module 20, the hitch angle sensor 44, the steering input device 18, the power steering system 62, the vehicle brake control system 72, the trailer brake system, the powertrain control system 74, and other vehicle sensors and devices. The controller 28 may generate vehicle steering information and commands as a function of all or a portion of the received information. Thereafter, the vehicle steering information and instructions may be provided to the power steering system 62 to affect steering of the vehicle 14 to achieve a commanded travel path for the trailer 12. The controller 28 may include the microprocessor 84 and / or other analog and / or digital circuitry for processing one or more routines. Further, the controller 28 may include the memory 86 for storing one or more routines including a clutch angle estimation routine 130, an operation routine 132, and a cam path routine 98. It should be appreciated that the controller 28 may be a stand-alone, dedicated controller or may be a common controller integrated with other control functions, such as integrated with the sensor system 16, the power steering system 62, and other conceivable onboard or off-board vehicle control systems.Referring to FIG. 3, an embodiment of the control input device 18 disposed on a center console 108 of the vehicle 14 proximate a shift lever 110 is illustrated. In this embodiment, the steering input device 18 includes a rotatable knob 30 for providing the desired path of return of the trailer 12 to the controller 28. More specifically, the angular position of the rotatable knob 30 may correlate to a desired curvature such that rotation of the knob to a different angular position provides a different desired curvature with an incremental change based on the amount of rotation, and in some embodiments a normalized rate, as described in more detail herein.The rotatable knob 30 may be biased (e.g., by spring reset) to a mid or rest position P(AR) between opposing ranges of rotational motion R(R), R(L), as illustrated in FIG. 4. In the illustrated embodiment, a first of the opposing ranges of motion R(R) is substantially equal to a second of the opposing ranges of motion R(L), R(R). To provide a tactile indication of an amount of rotation of the rotatable knob 30, a torque biasing the knob 30 to the rest position P(AR) may increase (e.g., non-linearly) depending on the amount of rotation of the rotatable knob 30 with respect to the rest position P(AR). In addition, the rotatable knob 30 with position indicator triggers may be configured such that the driver may sense the rest state position P(AR) positively and sense the approaching of the ends of the opposite moving rotation ranges R(L), R(R) (for example, soft end stops). The rotatable knob 30 may generate a desired turn trajectory value depending on an amount of rotation of the rotatable knob 30 with respect to the rest position P(AR) and a direction of movement of the rotatable knob 30 with respect to the rest position P(AR), which may itself correspond to a zero curvature command. It is also contemplated that the rate of rotation of the rotatable knob 30 may also be used to determine the desired curvature 26 output to the controller 28. The knob rest position P(AR) corresponds to a signal indicating that the vehicle 14 should be controlled such that the trailer 12 is backed along a substantially straight backup path 114 (FIG. 4 ) (zero trailer curvature request from the driver), as defined by the longitudinal direction of the trailer 12 when the knob has been backed up to the rest position P(AR). A maximum clockwise and counterclockwise position of the knob (i.e., boundaries of the opposite ranges of rotation of the motion R(R), R(L)) may each correspond to a respective signal indicative of a closest turning radius (i.e., the top most path or the smallest turning radius) of a travel path of the trailer 12 in the corresponding direction that is possible without the corresponding vehicle steering information causing a break-out state.As shown in FIG. 4, a driver may turn the rotatable knob 30 to provide a desired curvature 26 while the driver of the vehicle 14 is backing the trailer 12. In the illustrated embodiment, the rotatable knob 30 rotates about a central axis between a central or center position 114 corresponding to a substantially straight backup path 26 as defined by the longitudinal direction of the trailer 12 and various rotated positions 116, 118, 120, 122 on opposite sides of the center position 114 that command a desired curvature 26 corresponding to a radius of the desired backup path for the trailer 12 at the commanded rotated position. It is contemplated that rotatable knob 30 may be configured in accordance with embodiments of the disclosed subject matter and a means to be biased to a rest position P(AR) between opposing ranges of rotational motion may be omitted. The lack of such biasing may allow a current rotational position of the rotatable knob 30 to be maintained until the rotational control input device is manually placed in another position.As illustrated in FIG. 5, the vehicle 14 having the system 10 as described above may include a variation of a steering input device 218 that may include a remote control unit (as shown in FIGS. 5, 7, 8A-12 ) coupled to the controller 28 in a wired or wireless manner. Generally, the input device 218 may function similar to the input device 18 described above and may include a rotatable knob 230 (FIG. 7 ) similar to that shown in FIGS. 3 and 4. The steering input device 218 therefore provides information to the controller 28 that provides the commanded travel path 114 of the trailer 12 to the controller 28 (i.e., trailer steering information).As discussed above, there are advantages to a steering input device 218 configured to be self-contained and physically removed or removable from the vehicle 14. Specifically, the steering input device 218 may allow a driver of the vehicle to position or maintain the steering input device 218 at a location and / or orientation that he is preparing. Such a stand-alone and selectively positionable steering input device 218 thus allows a driver to specify their placement to optimize overall effectiveness and preference in operating the vehicle's TBA system. In this way, the steering input device 218 may overcome the aforementioned adverse problems that may result from alternative steering input devices (e.g., the input device 18 of FIG. 3 ) being permanently mounted on the vehicle at a specific fixed location.In an embodiment schematically shown in FIG. 5, the steering input device 218 is a removable driver interface that is connected to the TBA system 10 either wirelessly or via a wired connection. Such a removable steering input device 218 may be independently and selectively positionable at one or more locations of the vehicle 14, for example (e.g., a dedicated device that is a device supplied by the original equipment manufacturer (OEM)). In one implementation, the removable steering input device 218 is configured to fit into a cup holder when in use and to be removed when not in use (e.g., a housing of the removable trailer backup steering input device is complementary to that of the cup holder). In another embodiment, the trailer backup steering input device 218 is a stand-alone device that is connected to the TBA system either wirelessly or via a wired connection.Such a stand-alone device may be, for example, a stand-alone device that does not have physical interconnection with any portion of the vehicle (e.g., a dedicated device that is a device provided by the First Out Of Rest Unit (OEM), a smartphone running a TBA travel path specification application, or the like). Wirelessly, such a connection may be implemented using a WiFi, Bluetooth, or other suitable wireless protocol to provide a signal corresponding to a trailer travel path input by a driver that alters commands to the controller of the TBA system. A wired connection could be connected via a USB, serial, or other suitable connection interface of the controller of the TBA system.Regardless of the specific configuration of such a stand-alone trailer backup steering input device (e.g., knob, slider, knob / knobs, touch screen, etc.), the trailer backup steering input device includes a means by which the driver can provide input to which direction the driver wants to "steer" a trailer attached to his vehicle. In this regard, the trailer backup steering input device is configured to allow the driver of a vehicle to input commands for changing the trailer path (i.e., a command that causes the TBA system to change a travel path of the trailer). As discussed above with reference to FIGS. 3 and 4, such commands affect what direction, extent, and rate a path of travel of the trailer changes.Referring to FIGS. 1-5, the controller 28 and the steering input device 218 may be collectively configured to allow a driver of the vehicle 14 to selectively connect the steering input device 218 to the controller 28 and selectively position the steering input device 218 with respect to an interior of the vehicle 14 (i.e., with respect to the driver's seat). As shown in FIG. 5, in an embodiment where the steering input device 218 is self-contained and selectively positionable (i.e., located at a user-defined position, at a plurality of vehicle manufacturer-defined positions, and the like), the controller 28 includes a signal interface 210 and the steering input device 218 includes a signal interface 212. Through these signal interfaces 210, 212, a trailer steering information signal can be provided from the steering input device 218 to the controller 28. In this regard, trailer steering information input to the steering input device 218 from the driver of the vehicle 14 is transmitted from the steering input device 218 for receipt by the controller 28.In wired interconnection of the controller 28 and steering input device 218, the signal interfaces 210, 212 are collectively configured to be connected by a cable 214 or similar signal carrier structure. A first end of the cable 214 is electrically connected through the signal interface 212 to signal generation circuits 222 of the steering input device 218. A connector 216 at a second end of the cable 214 is selectively connectable to a mating connector 224 of the controller 28 to allow the steering input device 218 to be selectively plugged into and unplug from the controller 28. The signal generation circuits 222 are configured to generate a signal in response to commands input by the driver to cause a travel path of the trailer 12 to be altered (e.g., as discussed above with reference to FIG. 4 ).In wireless interconnection of the controller 28 and the steering input device 218, the controller 28 has a wireless signal transceiver 226 of the vehicle 14 connected thereto and the steering input device 218 has a wireless transmitter 228 coupled to its signal interface 212. The signal interfaces 210, 212 are collectively configured to allow a signal to be wirelessly transmitted from the steering input device 218 to the controller 28. To enable such wireless communication, the wireless signal transceiver 226 and the wireless transmitter 228 are configured to communicate signals with each other via any suitable wireless protocol (e.g., WiFi, Bluetooth, etc.). In such a wireless implementation, the cable 214 and associated connectors 216, 224 may be omitted, may be retained for use as auxiliary connection means with respect to the wireless connection means, or may be retained in various forms for use in charging an internal battery 232 within the steering input device 218 to provide power thereto, as discussed further below.The housing 220 of the steering input device 218 includes the signal interface 212, the signal generation circuits 222, the wireless transmitter 228, and a user interface 234 mounted thereon (e.g., housed therein). A driver of the vehicle 14 uses the user interface 234 to input trailer path change commands. In the examples of the steering input device 218 illustrated in FIGS. 7-12 and further described below, the user interface 234 includes a rotatable knob 230 that is similar in operation to the knob 30 of the input device 18 discussed above with reference to FIGS. 3 and 4. Other examples of user interfaces 234 include, but are not limited to, a slider, one or more buttons, a touch screen, and / or the like. By thus mounting the signal interface 212, signal generation circuits 222, wireless transmitter 228, and user interface 234 to the housing 220, and by the housing 220 being selectively removable from the vehicle 14 or another otherwise non-integral component of the vehicle 14, for example, from a separate and selectively placeable unit with respect to the vehicle 14), the steering input device 218 is stand-alone and is capable of being selectively placed by a driver of the vehicle 14 with respect to a structure to which the control device 28 is mounted.In conjunction with the above-described variation of the steering input device 218 implementing a wireless connection, the controller 28 may be programmed or otherwise configured to manage use of the steering input device 218 in implementing a curve trajectory routine 98 or otherwise used during control of the vehicle 14 depending on its various sensed conditions. In particular, the controller 28 may be configured to restrict use of the steering input device 218 in controlling the vehicle 14 by preventing the system 10 from activating or otherwise implementing the curve trajectory routine 98 under certain conditions. As illustrated in FIG. 6, the controller 28 may check for certain conditions of the steering input device 218 upon receiving an initiation command (step 260). As shown at step 262, the controller 28 may first determine or infer whether the steering input device 218 is physically present within the vehicle 14, which requires the steering input device 218 and generally a driver of the vehicle 14 to be present within the vehicle 14 before being activated. Such a requirement may be useful when, as described above, the use of the system 10 in assisting the rearward travel of the trailer 12 includes the driver commanding a vehicle-trailer curvature using the steering input device 218 such that the controller 28 actually controls the vehicle steering system 62 while the driver manually controls the speed of the vehicle 14 using the vehicle throttle and brakes. Thus, while disconnecting the steering input device 218 from the vehicle 14 may allow a turn path command to be input from outside the vehicle 14, it is not possible to actually use such implementation of the system 10 from outside the vehicle 14.When a user attempts to activate the system 10 and / or the curve trajectory routine 98, which may be done by using the vehicle MMS 80 or using the input device 218, such as by using the knob 230, the controller 28 may communicate with or attempt to communicate with the steering input device 218 to determine its presence within the vehicle 14. In one example, the wireless transmitter 228, or other circuitry within the vehicle 14, may include one or more proximity-based sensors or transmitters. In one example, such circuits may be similar to those used in fobs of vehicles having keyless push button start mechanisms. In a similar manner, circuits within the wireless transmitter 228 and wireless transceiver 226 may determine whether or not the steering input device 218 is present within the vehicle 14 by determining whether or not the steering input device 218 is within a predetermined range of the controller 28 or another feature of the interior of the vehicle 14. In other variations, the controller 28 may assess signal strength between the wireless transmitter 228 and the wireless transceiver 226 to determine the distance between the steering input device 218 and the wireless transceiver 226 to infer a presence of the steering input device 218 within the vehicle 14. Further, the controller 28 may be configured to deactivate the system 10 and / or the curved path routine 98 when no signal is received from the steering input device 218. Additionally, the controller 28 may be in communication with a weight-based sensor within the driver's seat of the vehicle 14 to determine whether a driver is present within the vehicle 14 to further ensure proper use of the system 10, including disabling the system based on a occupancy state of the driver's seat of the vehicle 14 (i.e., when the driver's seat is unoccupied).As shown in FIG. 6, upon detecting that the steering input device 218 is not in the vehicle 14 (or is, for example, far enough away from the wireless transceiver 226 to infer that the steering input device 218 is not in the vehicle 14), the controller 28 may present an indication of error (step 266). The fault indication may be presented visually, either on the vehicle MMS 80 or on a display 236 (FIG. 7 ) on the user interface 234 of the steering input device 218, or audibly by the vehicle MMS or steering input device 218 (which may include an embedded speaker). Further, such indication of error may be presented by haptic feedback through the steering input device 218, which may include an embedded vibration unit and / or utilize a haptic knob 230, such as that described in detail in co-pending, assigned U.S. Patent Application No. US 2017 / 0 029 024 A1. A visual indication of errors may specifically alert the user of the steering input device 218 to the fact that the driver and steering input device 218 must be within the vehicle 14 to use the system 10. The system 10 and / or the curve trace routine 98 may then be deactivated or disabled (step 268), with the controller 28 waiting for another initiation signal (step 260) before re-determining the location of the steering input device 218 (step 262).If the controller 28 determines that the steering input device 218 is present within the vehicle 14 (and optionally that the driver's seat of the vehicle 14 is occupied), then the controller 28 may communicate with the steering input device 218 to determine a state of charge of the battery 232 used to power the steering input device 218 (step 270). In particular, the controller 28 may be configured to prevent use of the steering input device 218 to control the path of return of the vehicle 14 if the state of charge of the battery 232 is insufficient to reliably complete or otherwise execute a trailer return operation. In other words, the controller 28 may require the state of charge of the battery 232 to be sufficient to power the steering input device 218 during a time period corresponding to at least one average trailer backup operation. Alternatively, the controller 28 may require the state of charge of the battery 232 to be sufficient to power the steering input device 218 for a time period corresponding to an average trailer backup operation plus a safety factor, or corresponding to a statistically long trailer backup operation. In various examples, the controller 28 may require a state of charge of the battery 232 sufficient to operate the steering input device 218 for at least 45 seconds, or, in one embodiment, at least one minute, or at least 3 minutes, or more.In the implementation depicted in FIG. 6, upon determining the state of charge of the battery 232, the controller 28 may first determine whether the charge is above a blocking threshold (step 272) that meets the requirements described above for reliably powering the steering input device 218 during a trailer backup operation. If the state of charge of the battery 232 is below this threshold level, an indication of failure is again presented (step 266). As above, the error input may be presented visually, either on the vehicle MMS 80 or on a display 236 (FIG. 7 ) on the user interface 234 of the steering input device 218, or audibly by the vehicle MMS 80 or steering input device 218 (which may include an embedded speaker). Further, such indication of error may be presented by haptic feedback through the steering input device 218, which may include an embedded vibration unit and / or use a haptic knob 230. A visual indication of failure may specifically indicate to the user of the steering input device 218 that the battery state of charge is too low to reliably use the system 10 and require the user to charge or replace the battery 232 (depending on the type of battery being used and the configuration of the steering input device 218). The system 10 and / or the curve trace routine 98 may then be disabled (step 268), with the controller 28 waiting for another initiation signal (step 260) before re-determining the location of the steering input device 218 (step 262), and then the state of charge of the battery 232 (step 270).If it is determined at step 272 that the state of charge of the battery 232 is above the blocking threshold, the controller 28 may then determine (step 274) whether the state of charge of the battery 232 is still below a predetermined warning threshold. This alert threshold may be, for example, within 10%, 15%, or 20% of the disable threshold such that limited use is available before an disable state is reached. Thus, if the state of charge of the battery 232 is below the warning threshold, the controller 28 may cause a warning to be presented (step 276) indicating that charging of the battery or its replacement is recommended after the current use of the steering input device 218 while the controller 28 allows the system 10 to be activated (step 278). If the state of charge of the battery 232 is above the warning level, the controller 28 continues activation of the system 10 without such warning, and the driver uses the steering input device 218 to command a curvature according to the process described above.Referring now to FIGS. 7-12, a particular embodiment of the steering input device 218 having the joystick 230 is illustrated which can be used to control the vehicle 14 when backing a trailer 12 based on a trailer control command, such as along a curved path 26, by adjusting the desired trailer control command according to a particular selectable control position. In one embodiment, the trailer control command may be a particular curved path 26 of the type discussed above with reference to FIG. 3. Specifically, the knob 230 may be used to adjust the cam path 26 by rotating the knob 230 against a biasing torque from the rest position P(AR) within either the left range of motion R(L) or a right range of motion R(R) (FIGS. 9A and 9B ) extending therefrom. Such a knob 230 may also be used to adjust a controlled hitch angle γ of the trailer 12 with respect to the vehicle 14 using the same type of center-bias motion in conjunction with a backup assist system based on angles instead of based on curvature. As in the above referenced U.S. Patent Application No. US 2017 / 0 029 024 A1 discussed further, the knob 230 may also provide rotation and / or other movement thereof according to additional modes of movement that allow the knob 230 to be used in conjunction with other inputs and systems within the vehicle 14.Referring to FIGS. 8A, 8B, 9A, and 9B, controlling the vehicle 14 when backing the trailer 12 using an embodiment of the knob 230 is described with additional reference to FIG. 4. Specifically, the knob 230 (or a knob included thereon) may be pressed in the direction 248 to activate the cam track routine 98 for reversing the trailer 12 using the vehicle 14. In various embodiments, the user interface 234 may be configured to indicate that the system 10 is ready to start the curve trajectory routine 98, such as by illuminating all or a portion of the knob 230 or a message presented on the display 236. Once the system 10 has been activated, the knob 230 may be turned away from the rest position P(AR), such as within the left range of motion R(L) or the right range of motion R(R), with the controller 28 interpreting the rotated position of the control member 230 as a cam command position. By way of example, the illustrated positions of the control member 230 correspond to the rest position P(AR) in FIG. 9A and, in FIG. 9B, one of the various adjusted cam paths 120 shown in FIG. 4. In this manner, and as discussed further above with reference to FIG. 4, the controller 28 may thus control steering of the vehicle 14 to maintain the trailer 12 along the desired path corresponding to a particular current position of the knob 230. As further shown, an indicator 244, 250 may be provided on the user interface 234, for example, to indicate the direction of rotation of the control element 230 (e.g., within the right range of motion R(R) and that the corresponding direction within which the cam path is included is implemented (i.e., corresponding to the current position of the control element 230).Additionally, the knob 230 may be configured to notify that the curvature corresponding to the rotated position of the control member 230 may be implemented by the system 10, such as according to the parameters discussed above, including based on a determination whether the commanded turning path would guide the trailer 12 to a hitch angle γ that is, for example, beyond the maximum steerable angle. For example, a warning may be presented on the display 236 to notify the user that the curved path routine 98 has determined that a commanded curvature could not be implemented and that the current curved path for the trailer 12 thus deviates from the selected curved path command 26. Additional haptic warnings or limits of rotation of the knob 230 may be implemented according to such a determination, as also further described in above referenced U.S. Patent Application No. US 2017 / 0 029 024 A1.As further illustrated in FIGS. 7 through 12, the steering input device 218 may be configured as a stand-alone wireless unit, as discussed above, that may be hand held by the user in controlling the path of return of the vehicle 14 as the trailer 12 is being backed up. The steering input device 218 may include an outer housing 220 that conceals and houses the battery 232, signal interface 212, signal generation circuitry 222, and the wireless transmitter 228. The user interface 234 includes a display 236 (which may be a video display such as a liquid crystal display (LCD), a light emitting diode (LED), an organic light emitting diode (OLED), a thin film transistor (TFT), or the like), and a knob 230 may be mounted on the housing 220 to be externally visible and accessible for use and interaction by a user. Further, the knob 230 and display 236 may be in communication with the signal generation interface 222 and the wireless transmitter 228 either directly or through additional circuitry, including a microprocessor, an application specific integrated circuit (ASIC) chip, or the like). In one embodiment, the steering input device 218 may be configured to act as a key fob for the vehicle 14, for example by having a loop 240 for attaching the steering input device 218 to a key ring or the like, and by incorporating additional functionality for locking / unlocking the vehicle 14, which may be implemented using the knob 230 or by additional knobs (not shown) on the exterior of the housing 220.As shown in FIG. 10, the steering input device 218 may be paired with a holding and / or charging housing shown in the form of a holding device 242 or the like that may be installed within the vehicle 14 to hold the steering input device 218 when not in use. In one embodiment, the fixture 242 may include a mating connector, such as the plug 224 schematically depicted in FIG. 5. A portion of the cable 214 connected to the vehicle 14 is connected to the steering input device 218 to provide power for charging a rechargeable variation of the battery 232. In one embodiment, the steering input device 218 may include a connector 216 that couples thereto to couple the steering input device 218 to the cable 214 (FIG. 12 ). In one variation, the connector 216 and mating connector 224 may be inductive charging devices such that the coupling established between them is purely electrical without requiring physical coupling or other connection to charge the battery 232 using the fixture 242 (or a charging mat 14 that may replace the fixture 242). In other variations, physical connections or couplings may be incorporated on the housing 220 and within the fixture 242 to achieve physical and electrical coupling of the battery 232 (and, as the case may be, other internal components) when the steering input device 218 is received within the fixture 242.As shown in FIG. 11, the restraint 242 may be mounted on a portion of the interior of the vehicle 14, which may be, for example, a portion of the console 246 (which may be similar to, for example, portions of the console 108 depicted in FIG. 3 ). In particular, the fixture 242 may be installed within a chamber of the console 246 (or within a glove box or the like) such that the steering input device 218 is not visible and / or out of range when not in use and / or loads. Alternatively, the restraint 242 may be positioned along (or integrated with) a portion of the console 246 that is generally accessible by a driver of the vehicle 14 such that the steering input device 218 may be used when located in the restraint 242 if convenient or desirable for the driver, or may be removed from the restraint 242 as desired (as long as the state of charge of the battery 232 is acceptable and the steering input device 218 is located in the vehicle 14, according to the control system depicted in FIG. 6 and discussed above). In such a variation, the control system of FIG. 6 would be bypassed if the controller 28 were aware that the steering input device 218 is within the fixture 242. As shown in FIG. 12, the cable 214 may extend through a mounting portion 254 of the bracket 242 to extend through the console 246 (or other vehicle structure) to couple to the vehicle 14, such as by the controller 28 or other system thereof, as needed, to provide power from a power source of the vehicle 14 therethrough and / or through an optional wired interface to the steering input device 218.It is to be understood that changes and modifications may be made to the above 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 expressly state otherwise.For purposes of this disclosure, the term "coupled" (in all its forms, couple, coupling, coupled, etc.) generally means the direct or indirect interconnecting of two components (electrical or mechanical). Such a connection may be of a stationary type or of a movable type. Such connection may be achieved with the two components (electrical or mechanical) and any additional intermediate members integrally formed as a single unitary body with each other or with the two components. Such a connection may be of a permanent type or of a releasable or releasable type, unless otherwise stated.It is also important to note that the construction and arrangement of the elements of the invention as illustrated in the embodiments are illustrative only. While only a few embodiments of the present innovations have been described in detail in this disclosure, one skilled in the art who reads this disclosure will readily appreciate that many modifications are possible (for example, variations in sizes, dimensions, structures, shapes and proportions of the various elements, parameter values, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter set forth. For example, elements shown as integrally formed may be made from multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and / or the links or connectors or other elements of the system may be varied, the type or number of adjustment positions provided between the elements may be varied. It should be appreciated that the elements and / or arrangements of the system may be made of any of a wide variety of materials that provide sufficient strength or durability, and in any of a wide variety of colors, structures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other embodiments without departing from the spirit of the present innovations.It should be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present invention. The example structures and processes disclosed herein are illustrative and are not to be interpreted as limiting.

Claims

A steering input system for a trailer backup assist system (10), comprising: an input device (18, 218) comprising: a housing (220); and a user manipulatable input member (30, 230) coupled to the housing (220); and a controller (28): determining a condition of use of the input device (18, 218), and based on the condition of use, implementing or disabling a trailer backup assist mode including generating a vehicle steering command based on a current position of the input member (30, 230); characterized in that the first use condition is a location of the input device (18, 218) relative to a vehicle (14) connected to the trailer backup assist system (10), wherein the condition of the use condition is the presence or absence of the vehicle (14), and the trailer backup assist system (10) is deactivated if the condition is the absence of the vehicle (14); or wherein the input device (18, 218) includes a battery (232) within the housing (220) for supplying power to the device (18, 218), the first use condition is a state of charge of the battery (232), wherein the condition of the use condition is the state of charge of the battery (232) compared to a predetermined minimum state of charge for reliably executing a trailer backup assist routine, and the trailer backup assist mode is deactivated if the state of charge of the battery (232) is below the predetermined minimum state of charge.The steering input system of claim 1, wherein if the first usage condition is the state of charge of the battery (232), the controller (28) or the input device (18, 218) includes a battery state of charge warning if the state of charge of the battery (232) is below a warning threshold that is above the predetermined minimum state of charge.The steering input system of claim 2, wherein the battery state of charge warning is an audible signal and / or a visual indication and / or a haptic indicator.The steering input system of claim 1, wherein the input device (18, 218) is a separate unit in electrical communication with the controller (28) for transmitting the first instantaneous position of the input member (30, 230) to the controller (28).The steering input system of claim 1, wherein the input device (18, 218) further comprises a display (82, 236) connected to the controller (28) for presenting information to a user associated with at least one function of the trailer backup assist mode.The steering input system of claim 1, wherein the input device (18, 218) is further included in a key fob associated with a vehicle (14) having the steering input system.The steering input system of claim 1, further comprising a charging receptacle selectively receiving the input device (18, 218) and in communication with a power source of a vehicle (14) comprising the steering input system, wherein: the input device (18, 218) further comprises a rechargeable battery (232) electrically couplable to a portion of the charging receptacle to charge the battery (232).The steering input system of claim 1, wherein the user manipulatable input member (30, 230) is a rotary member biased to a rest position (P(AR)) and rotatably coupled to the housing (220), and when implementing the trailer backup assist mode, the controller (28) generates the vehicle steering command based on a desired turn trajectory position corresponding to the first current position of the rotary member.A backup assist system for a vehicle (14) backing a trailer (12), comprising: an input device (18, 218) having a housing (220) and a rotating member (30, 230) rotatably coupled to the housing (220); and a controller (28): determining a state of a first use condition of the input device (18, 218), and based on the state of the use condition, implementing or disabling a trailer backup assist mode including generating a vehicle steering command based on a current position of the input member (30, 230); characterized in that the first use condition is a location of the input device with respect to the vehicle (14) associated with the trailer backup assist system (10), wherein the state of the use condition is the presence or absence of the vehicle (14), and the trailer backup assist system (10) is deactivated if the state is the absence of the vehicle (14); or wherein: the input device (18, 218) includes a battery (232) within the housing (220) for supplying power to the device (18, 218); the first use condition is a state of charge of the battery (232); wherein the state of the use condition is the state of charge of the battery (232) compared to a predetermined minimum state of charge for reliably executing a trailer backup assist routine; and the trailer backup assist mode is disabled if the state of charge of the battery (232) is below the predetermined minimum state of charge.A method for assisting a vehicle (14) in backing a trailer (12), comprising: determining a presence or absence of a deactivation condition, and according to the deactivation condition, respectively implementing or deactivating a trailer backup assist mode, including generating a vehicle steering command based on a current position of an input element (30, 230) of the input device (18, 218), characterized in that the deactivation condition comprises: a driver absent from the vehicle (14) or a battery state of charge of an input device (18, 218) below a threshold.The method of claim 10, wherein: the input member (30, 230) is a rotary member biased to a rest position (P(AR)), and the cam trace command corresponds to a rotational position of the rotation of the rotary member (30, 230) away from the rest position (P(AR)).The method of claim 10, wherein the presence or absence of the deactivation condition that includes the driver being absent from the vehicle (14) is inferred based on a sensed location of the input member (30, 230) within the vehicle (14).

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