DE102015109537A1 - OBJECT PREVENTION FOR A TRAILER REVERSE ASSISTANCE SYSTEM - Google Patents

Abstract

A trailer backup assist system, in one embodiment, includes a steering input device for inputting a desired return travel of a trailer. The trailer backup assist system also includes a first sensor that senses a hitch angle between a vehicle and the trailer. Further, the trailer backup assist system includes a second sensor that senses proximity of an object in a perimeter field of at least one of the vehicle and the trailer. A trailer backup assist system control generates an available set of trail back paths for the trailer based on the proximity of the object and the hitch angle. The available range of return paths does not include return paths that intersect a space occupied by the object or that cause a breakaway condition between the vehicle and the trailer.

Description

FIELD OF THE INVENTION

The present disclosure relates generally to driver assistance and active safety technologies in vehicles, and more particularly to a trailer backup assist system configured with object avoidance features for controlling the guidance of the trailer.

BACKGROUND OF THE INVENTION

Reversing a vehicle while towing a trailer can be a challenge for many drivers, especially for riders who drive at irregular intervals with a trailer or with different types of trailers. One reason for such a difficulty may be that reversing a vehicle with an attached trailer requires steering inputs that are opposite to the steering inputs when the vehicle is reversed without a trailer attached to the vehicle. Another reason may be that there may be objects around the vehicle and the trailer that provide limited space to manipulate the vehicle or otherwise direct the trailer to a desired position or along a desired path. Another reason for such a difficulty may be that slight steering errors are amplified during reversing a vehicle with an attached trailer, which may cause the trailer to deviate rapidly from a desired path. Yet another reason why backing a trailer can prove difficult is the need to control the vehicle in a manner that limits the potential for breakaway to occur. A breakaway condition can occur when the steering of the vehicle can not control the hitch angle, so that the hitch angle would continue to increase and the vehicle must be pulled forward to relieve the hitch angle. However, in addition to the breakaway condition creating the adverse situation in which the vehicle must be pulled forward, it may also result in contact between the vehicle and the trailer, thereby damaging the trailer and / or the vehicle.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a trailer backup assist system includes a steering input device for inputting a desired return travel of a trailer from a plurality of ways. A first sensor senses a hitch angle between a vehicle and the trailer. A second sensor senses proximity of an object in a perimeter field. Control of the trailer backup assist system limits the majority of the routes to an available range based on the proximity of the object and the hitch angle.

In accordance with another aspect of the present invention, a method of reversing a trailer with a vehicle provides a step of sensing a hitch angle between a vehicle and the trailer. The method also provides a step of sensing a proximity of an object in a perimeter field. In addition, the method provides a step of generating an available set of trailer return paths based on the proximity of the object and the hitch angle. Further, the method provides a step of entering a desired return path from the available series.

In accordance with another aspect of the present invention, a trailer backup assist system includes a steering input device for inputting a desired return travel of a trailer. The trailer backup assist system also includes a first sensor that senses a hitch angle between a vehicle and the trailer. Further, the trailer backup assist system includes a second sensor that senses proximity of an object in a perimeter field of at least one of the vehicle and the trailer. A trailer backup assist system control generates an available set of trail back paths for the trailer based on the proximity of the object and the hitch angle. The available range of return paths does not include return paths that intersect a space occupied by the object or that cause a breakaway condition between the vehicle and the trailer.

These and other aspects, objects and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For the drawings:

1 Figure 11 is a top perspective view of a vehicle mounted on a trailer with an embodiment of a hitch angle sensor for operating a trailer backup assist system;

2 Fig. 10 is a block diagram illustrating an embodiment of the trailer backup assist system including a steering input device and a curvature controller;

3 FIG. 12 is a schematic diagram illustrating the geometry of a vehicle and trailer with a superimposed xy coordinate two-dimensional system that identifies variables used to determine a kinematic relationship of the vehicle and the trailer for the trailer backup assist system, according to an embodiment ;

4 FIG. 10 is a schematic block diagram illustrating parts of a turn control according to another embodiment and other components of the trailer backup assist system according to such an embodiment; FIG.

5 is a schematic block diagram of the curvature control 4 showing the feedback architecture and the signal flow of the curvature controller according to such an embodiment;

6 Fig. 12 is a schematic view showing a relationship between a hitch angle and a steering angle of the vehicle, such as the curvature of the trailer and a breakaway angle;

7 Figure 11 is a plan view of one embodiment of a rotatable knob for selecting a desired curvature of a trailer and a corresponding schematic illustrating a vehicle and a trailer having various trailer curvature paths that correlate with desired curvatures that can be selected;

8th FIG. 10 is a schematic illustration of a vehicle and trailer having an object proximity sensor for sensing an object in a perimeter field, according to one embodiment; FIG.

9 FIG. 13 is a schematic illustration of a vehicle, trailer, and objects in the perimeter field that reduce the available number of return routes, according to one embodiment; FIG.

9A FIG. 12 is a schematic illustration of a vehicle, a trailer, and an object in the perimeter field that reduce the available number of return routes, according to another embodiment; FIG.

9B FIG. 12 is a schematic illustration of a vehicle, a trailer, and an object in the perimeter field that reduce the available number of return routes, according to another embodiment; FIG. and

10 FIG. 10 is a flowchart illustrating a method of operating a trailer backup assist system with object avoidance, according to one embodiment. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purpose of describing herein, it is to be understood that the disclosed trailer backup assist system and associated methods may take various alternative embodiments and orientations unless expressly stated to the contrary. It is also to be understood that the specific devices and methods illustrated in the accompanying drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Although various aspects of the trailer backup assistance system and associated method with respect to a particular For example, the disclosed invention is not limited to such embodiments, and additional modifications, applications, and embodiments may be implemented without departing from the disclosed invention. Consequently, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless expressly stated otherwise in the claims.

With reference to 1 - 10 denotes the reference numeral 10 In general, a trailer backup assist system for controlling a backtrack of a trailer 12 , which is on a vehicle 14 is attached by a driver of the vehicle 14 allows a desired return journey 26 of the trailer 12 specify. In one embodiment, the trailer backup assist system steers 10 the vehicle 14 automatically to the trailer 12 on the desired way back 26 when a driver uses the accelerator and brake pedals to guide the vehicle's reverse vehicle speed 14 to control. To the position of the trailer 12 relative to the vehicle 14 To monitor, the trailer backup assistance system 10 a sensor system 16 comprising a hitch angle γ between the trailer 12 and the vehicle 14 that acts as a first sensor or a hitch angle sensor 44 can be designated. In addition, the trailer backup assistance system 10 an object proximity sensor 17 , which may be referred to as a second sensor or an orbital sensor, for sensing a proximity of an object 19 in a perimeter field 21 of the vehicle and / or the trailer. Further, the trailer backup assist system 10 also a steering input device 18 for a driver, such as a mode selector 20 or a rotatable knob 30 to the desired return journey 26 of the trailer 12 provide. A curvature control 28 of the trailer backup assistance system 10 can be based on the proximity of the object 19 and the hitch angle γ an available row 23 of back roads for the trailer 12 generate which of a number of possible paths 25 is reduced, so the steering input device 18 on the input of a desired return journey 26 from the available series 23 may be limited by return routes. In one embodiment, the available row includes 23 of reversing paths not the return routes crossing a space of the object 19 is taken. After receiving the desired return journey 26 may be a steering command based on the sampled hitch angle γ and a kinematic relationship between the trailer 12 and the vehicle 14 be generated to the trailer 12 on the desired way back 26 respectively. It is contemplated that additional embodiments of the trailer backup assist system 10 also an additional or alternative steering input device 18 may include when reversing vehicle 14 and followers 12 can be driven to the desired return travel of the trailer 12 adapt.

Referring to the in 1 The embodiment shown is the vehicle 14 a pickup truck embodiment, which with an embodiment of the trailer backup assistance system 10 to control the return journey of the trailer 12 equipped on the vehicle 14 is appropriate. In particular, the vehicle 14 pivotable on an embodiment of the trailer 12 attached, which is a box frame 32 with an enclosed loading area 34 and a tongue 36 which extends longitudinally from the enclosed loading area 34 extends to the front. The illustrated trailer 12 also has a trailer hitch connector in the form of a coupler arrangement 38 on, which with a vehicle coupling connector in the form of a coupling ball 40 connected is. The coupler arrangement 38 snaps onto the coupling ball 40 one to a pivot ball joint 42 to provide that allows the articulation of the hitch angle γ. It should be recognized that other embodiments of the trailer 12 may comprise more than one axis; various shapes and sizes, which are designed for different loads and objects, such as boat trailers or flatbed trailers; and alternatively with the vehicle 14 may be coupled to provide a pivotal connection, such as by connecting to a fifth wheel connector.

Further referring to 1 includes the sensor system 16 in the illustrated embodiment, a sight-based hitch angle sensor 44 for sensing the hitch angle γ between the vehicle 14 and the trailer 12 , The illustrated hitch angle sensor 44 uses a camera 46 (eg, video imaging camera), which is near an upper portion of the vehicle tailgate 48 at the rear of the vehicle 14 as shown, so that the camera 46 relative to the tongue 36 of the trailer 12 can be increased. The illustrated camera 46 has an image field of view 50 which is arranged and aligned to one or more images of the trailer 12 including a region having one or more desired destination placement zones for at least one destination 52 to be secured. Although it is considered that the camera 46 Pictures of the trailer 12 without a goal 52 to detect the hitch angle γ includes the trailer backup assistance system 10 In the illustrated embodiment, a destination 52 which is on the pendant 12 is arranged to allow the trailer backup assistance system 10 Uses information through image capture and processing of the target 52 be recorded. For example, the illustrated camera 46 a video imaging camera, which repeatedly successive images of the trailer 12 captured, which can be processed to the destination 52 and his arrangement on the trailer 12 to identify the movement of the target 52 and the trailer 12 relative to the vehicle 14 and to determine the corresponding coupling angle γ. It should also be noted that the camera 46 include one or more video imaging cameras and elsewhere on the vehicle 14 can be arranged to pictures of the trailer 12 and to detect the desired destination placement zone, for example at a passenger cabin 54 of the vehicle 14 to capture images of a gooseneck trailer. It is further provided that additional embodiments of the hitch angle sensor 44 and the sensor system 16 for providing the hitch angle γ, or a combination of a potentiometer, a magnet-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 , which on the pivot ball joint 42 is mounted, a yaw rate sensor on the trailer 12 and vehicle 14 , Energy converter of a rear-assist system, a blind spot system and / or a cross-traffic warning system, and other conceivable sensors or indicators of the hitch angle γ, which complement or replace the vision-based hitch angle sensor 44 be used.

Referring to the in 2 shown embodiment of the trailer backup assistance system 10 represents the hitch angle sensor 44 the sampled hitch angle γ to the trailer backup assist system 10 ready. Similarly, the illustrated embodiment of the trailer backup assistance system receives 10 Information relating to the vehicle condition of other sensors and devices. This information includes positioning information from a positioning device 56 , which is a Global Positioning System (GPS) on the vehicle 14 or a managed device may include a coordinate position of the vehicle 14 and the trailer 12 based on the position of the positioning device 56 in terms of the trailer 12 and / or the vehicle 14 and based on the sampled hitch angle γ. The positioning device 56 Additionally or alternatively, a dead reckoning system for determining the coordinate position of the vehicle 14 and the trailer 12 in a localized coordinate system based at least on the vehicle speed, the steering angle and the hitch angle γ. Other vehicle information coming from the trailer backup assistance system 10 can receive a speed of the vehicle 14 from a speed sensor 58 and a yaw rate of the vehicle 14 from a yaw sensor 60 include. It is considered that the hitch angle sensor 44 and other vehicle sensors and devices in further embodiments may provide sensor signals or other information, such as proximity sensor signals or sequential images of the trailer 12 including a control of the trailer backup assistance system 10 with various routines to determine a value or indicator, such as a hitch angle value or a range of hitch angles γ.

The embodiment of the in 2 Trailer backup assist system shown also includes the object proximity sensor 17 which is the proximity of an object 19 to the curvature control 28 of the trailer backup assistance system 10 provides. More specifically, the object proximity sensor provides 17 the trailer backup assistance system 10 Approximate information of the object 19 ready, which information can include a position of the object 19 or estimate objects relative to the vehicle and / or trailer. The object proximity sensor 17 may include a single sensor, multiple sensors, and various combinations of sensors and sensor systems to capture, generate, and output information relating to the proximity of the object 19 characterize that is adjacent to the vehicle and / or trailer, as described in more detail herein. Accordingly, the object proximity sensor 17 Parts of the hitch angle sensor 44 , the positioning device 56 or other additional sensors and devices, or integrated with it. The trailer backup assistance system 10 can be the approximate information of the object 19 or use objects as input to the curvature control to collide with the object 19 or avoid objects, such as by limiting the available row 23 of reversing paths that are selectable by the steering input device, by correcting a current reversing path or otherwise preventing the trailer and the vehicle from interfering with the object 19 come in contact, as will be disclosed in more detail below.

As further in 2 1, an embodiment of the trailer backup assistance system communicates 10 with a power steering system 62 of the vehicle 14 to steered wheels 64 ( 1 ) of the vehicle 14 to move the vehicle 14 to operate in such a way that the trailer 12 in Match with the desired curvature of the trailer 12 responding. In the illustrated embodiment, the power steering system is 62 an Electric Power-Assisted Steering (EPAS) system that uses an electric steering motor 66 for turning the steered wheels 64 on a steering angle based on a steering command, wherein the steering angle of a steering angle sensor 67 of the power steering system 62 is scanned. The steering command may be from the trailer backup assistance system 10 may be provided for autonomous steering during a reverse maneuver, and may alternatively be manual over a rotational position (eg, steering wheel angle) of a steering wheel 68 ( 1 ) to be provided. In the illustrated embodiment, the steering wheel is 68 of the vehicle 14 but mechanically with the steered wheels 64 of the vehicle 14 coupled so that the steering wheel 68 together with the steered wheels 64 moves, creating a manual intervention with the steering wheel 68 is prevented during autonomous steering. More specifically, a torque sensor 70 on the power steering system 62 provided, which torque on the steering wheel 68 that does not depend on the autonomous control of the steering wheel 68 is expected and thus indicative of a manual intervention, wherein the trailer backup assistance system 10 The driver can warn the manual intervention with the steering wheel 68 and / or to end the autonomous steering.

Referring again to the in 2 illustrated embodiment provides the power steering system 62 the curvature control 28 of the trailer backup assistance system 10 with information relating to a rotational position of the steered wheels 64 of the vehicle 14 , including a steering angle, ready. The curvature control 28 in the illustrated embodiment processes the current steering angle in addition to other states of the vehicle 14 and trailer 12 to the trailer 12 along the desired return route 26 and / or to guide the desired curvature. It is conceivable that the trailer backup assistance system 10 in other embodiments, an integrated component of the power steering system 62 can be. For example, the power steering system 62 include a trailer backup assist algorithm for generating vehicle steering information and commands as a function of all or part of the information provided by the steering input device 18 , the hitch angle sensor 44 , the power steering system 62 a brake control system 72 , a powertrain control system 74 and other vehicle sensors and devices.

As well as in 2 illustrates, the brake control system 72 also with the curvature control 28 communicate to the trailer backup assistance system 10 Provide braking information, such as wheel speed, and braking commands from the curvature control 28 to recieve. For example, vehicle speed information may be determined from individual wheel speeds, such as the brake control system 72 supervised. The vehicle speed may also be from the powertrain control system 74 , the speed sensor 58 and the positioning device 56 , among other conceivable means. In some embodiments, individual wheel speeds may also be used to determine a vehicle yaw rate associated with the trailer backup assist system 10 alternatively or in addition to the yaw sensor 60 can be provided for use in determining vehicle steering commands. In certain embodiments, the trailer backup assist system may 10 Vehicle brake information to the brake control system 72 to enable the trailer backup assist system 10 the braking of the vehicle 14 while reversing the trailer 12 controls. For example, the trailer backup assist system 10 in some embodiments, the speed of the vehicle 14 while reversing the trailer 12 which reduces the potential for unacceptable trailer reversing conditions. Examples of unacceptable trailer backup states include, but are not limited to, an overspeed condition of the vehicle 14 , a high hitch angle rate, trailer angle dynamic instability, a trailer calculated theoretical breakaway condition (defined by a maximum vehicle steering angle, drawbar length, towing vehicle wheelbase and effective trailer length) or physical contact breakout limit (defined by an angular displacement limit relative to the vehicle 14 and followers 12 ) and the same. It is disclosed herein that the trailer backup assist system 10 may issue a warning signal corresponding to notification of an actual, upcoming and / or expected unacceptable trailer backup condition.

With continued reference to 2 Can the trailer backup assistance system 10 communicate with one or more devices, including a vehicle warning system, in the illustrated embodiment 76 which vehicle brake lights 78 and vehicle warning lights for providing a visual warning and a vehicle horn 79 and / or speakers 81 to provide an audible warning. In addition, the trailer backup assistance system 10 with a human-machine interface (HMI) 80 for the vehicle 14 communicate, including a vehicle display 82 such as a navigation stack mounted on the center stack. Entertainment display ( 1 ). Further, the trailer backup assist system 10 via wireless communication with another embodiment of the HMI 80 communicate, such as with one or more handheld or portable devices, including one or more smartphones. The portable device can also display 82 to display one or more images and other information for a user. For example, the portable device may include one or more images of the trailer 12 and indicate the destination location within a desired destination placement zone on the display. In addition, the portable device may provide feedback information about the vehicle target connection, including visual and audible warnings.

As further in 2 includes the trailer backup assist system 10 a steering input device 18 which with the curvature control 28 is connected to allow the communication of information in between. It is disclosed herein that the steering input device 18 in a wired or wireless manner with the curvature control 28 can be coupled. The steering input device 18 provides the trailer backup assistance system 10 Information ready, what the desired return path 26 of the trailer 12 define, thus the curvature control 28 Steering commands processed and generated. The trailer steering commands may include information related to a commanded driveline change, such as a change in the return travel radius 26 (eg curvature), and information that relates to an advertisement that the trailer 12 along a path that passes through a longitudinal centerline axis of the trailer 12 is defined (ie along a substantially straight track). As will be explained in more detail below, the steering input device 18 According to the illustrated embodiment, the mode selector 20 for selecting the longitudinal direction 22 of the trailer 12 , the longitudinal direction 24 of the vehicle 14 or the curvature based on the present hitch angle γ or engagement from another steering input device 18 such as the rotatable knob 30 , include. Accordingly, the steering input device 18 in the illustrated embodiment, also include a rotation control input device to a driver of the vehicle 14 to command desired steering actions of the trailer or otherwise the desired return path 26 select. For example, the rotation control input device may be a rotatable knob 30 which is rotatable about an axis of rotation extending through an upper surface or surface of the knob. In other embodiments, the rotatable knob 30 be rotatable about an axis of rotation which extends to an upper surface or surface of the rotatable knob 30 extends substantially parallel. Furthermore, the steering input device 18 According to further embodiments alternative devices for providing a desired return path 26 include, such as a joystick, printable buttons, slide entry devices, various controls on a portable device, various user interfaces on a touch screen display, vision-based gesture receiving systems, a path planner or other programmable route system, and other conceivable input devices, as commonly understood by one of ordinary skill in the art be understood.

Further referring to the in 2 The embodiment shown is the curvature control 28 with a microprocessor 84 designed to work in memory 86 stored logic and routines to process which information from the steering input device 18 , the hitch angle sensor 44 , the power steering system 62 , the brake control system 72 , the powertrain control system 74 and other vehicle sensors and devices. The curvature control 28 may generate vehicle steering information and commands as a function of all or part of the information provided by the steering input device 18 , the hitch angle sensor 44 , the power steering system 62 , the brake control system 72 , the powertrain control system 74 and other vehicle sensors and devices. Thereafter, the vehicle steering information and commands may be provided to the power steering system 62 be provided to the steering of the vehicle 14 to influence a commanded driveway for the trailer 12 to reach. The curvature control 28 can the microprocessor 84 and / or other analog and / or digital circuits for processing one or more routines. Also, the curvature control 28 the memory 86 for storing one or more routines, including a straightforward trailer routine, a straightforward vehicle routine, and a locked-curvature routine. It should be recognized that the curvature control 28 may be a stand-alone dedicated controller or a shared controller integrated with other control functions, such as the sensor system 16 , the power steering system 62 and other conceivable on-board or off-board vehicle control systems.

With reference to 3 Turning now to a discussion of vehicle and trailer information and parameters used to establish a kinematic relationship between a curve of a trailer driveway 12 and the steering angle of the vehicle holding the trailer 12 prefers to calculate using a low-order kinematic model for a trailer backup assist system 10 which is designed according to some embodiments may be desired. In order to achieve such a low-order kinematic model, certain assumptions are made with regard to parameters associated with the vehicle / trailer system. Examples of such assumptions include, but are not limited to, the follower 12 through the vehicle 14 is driven backwards at a relatively low speed that the wheels of the vehicle 14 and the trailer 12 have a negligible (eg, no) slip that the tires of the vehicle 14 and the trailer 12 have a negligible (eg no) deformation that the actuator dynamics of the vehicle 14 negligible is that the vehicle 14 and the trailer 12 negligible (eg, no) rolling or pitching, among other conceivable factors with the potential to have an impact on the control of the trailer 12 with the vehicle 14 exhibit.

δ:

Lenkwinkel an den gelenkten Vorderrädern des Fahrzeugs 14;

α:

Gierwinkel des Fahrzeugs 14;

β:

Gierwinkel des Anhängers 12;

γ:

Kupplungswinkel (γ = β – α);

W:

Radstand des Fahrzeugs 14;

L:

Länge zwischen dem Kupplungspunkt und der Hinterachse des Fahrzeugs 14;

D:

Abstand zwischen dem Kupplungspunkt und der Achse des Anhängers 12 oder effektiven Achse für einen mehrachsigen Anhänger 12 (Achsenlänge kann ein Äquivalent sein); und

r₂:

Krümmungsradius für den Anhänger 12.

As in 3 As shown, the kinematic relationship for a vehicle is based 14 and a trailer 12 defined system on different parameters that the vehicle 14 and the trailer 12 assigned. These parameters include:

δ:

Steering angle on the steered front wheels of the vehicle 14 ;

α:

Yaw angle of the vehicle 14 ;

β:

Yaw angle of the trailer 12 ;

γ:

Coupling angle (γ = β - α);

W:

Wheelbase of the vehicle 14 ;

L:

Length between the coupling point and the rear axle of the vehicle 14 ;

D:

Distance between the coupling point and the axle of the trailer 12 or effective axle for a multi-axle trailer 12 (Axis length may be equivalent); and

r ₂ :

Radius of curvature for the trailer 12 ,

An embodiment of a kinematic relationship between the trailer radius of curvature r ₂ at the midpoint of an axle of the trailer 12 , the steering angle δ of the steered wheels 64 of the vehicle 14 and the hitch angle γ can be expressed by the equation provided below. As such, the trailer curvature κ ₂ , if the hitch angle γ is provided, may be controlled based on the control of the steering angle δ (where β is the trailer yaw rate and η is the trailer speed).

This relationship can be expressed to provide the steering angle δ as a function of the trailer path curvature κ ₂ and the hitch angle γ.

Accordingly, certain parameters of the kinematic relationship (eg, D, W, and L) are constant for a particular vehicle and trailer combination and are assumed to be known V is the vehicle longitudinal speed and g is the acceleration due to gravity. K is a speed dependent parameter which, when set to zero, makes the calculation of the steering angle independent of the vehicle speed. For example, vehicle-specific parameters of the kinematic relationship in an electronic control system of the vehicle 14 can be predefined and for the trailer specific parameters of the kinematic relationship by a driver of the vehicle 14 determined by the sensed trailer behavior in response to vehicle steering commands or otherwise determined by signals from the trailer 12 to be provided. The trailer curvature κ ₂ is determined from the driver input via the steering input device. By using the equation for providing the steering angle, a corresponding steering command for controlling the power steering system 62 of the vehicle 14 to be generated.

Yet another embodiment of the curvature control 28 of the trailer backup assistance system 10 is in 4 illustrating the general architectural layout showing a measurement module 88 , a hitch angle regulator 90 and a curvature regulator 92 Routines are in memory 86 the curvature control 28 are stored. In the illustrated layout, the steering input device provides 18 the curvature regulator 92 the curvature control 28 a desired value for the curvature κ ₂ ready, which of the desired return path 26 can be determined in the steering input device 18 is entered. The curvature regulator 92 calculates a desired hitch angle γ (d) based on the currently desired curvature κ ₂ together with the steering angle δ, which of a measuring module 88 in this embodiment, the curvature control 28 provided. The measuring module 88 may be a memory device which is separate from or with the curvature control 28 integrated, the data from sensors of the trailer backup assistance system 10 stores, such as the hitch angle sensor 44 , the vehicle speed sensor 58 , the steering angle sensor, or alternatively, the measuring module 88 otherwise transfer data directly from the sensors without acting as a storage device. Once the desired hitch angle γ (d) from the bend regulator 92 calculated, the hitch angle controller generates 90 a steering angle command based on the calculated desired hitch angle γ (d) and a measured hitch angle γ (m) and a current speed of the vehicle 14 , The steering angle command becomes the trailer backup assist system 62 of the vehicle 14 provided, which then back to the measuring module 88 is used to re-evaluate the effects of other vehicle characteristics that are affected by the implementation of the steering angle command or other changes to the system. Accordingly, the curvature controller process 92 and the hitch angle controller 90 ongoing information from the measuring module 88 to provide accurate steering angle commands to the trailer 12 on the desired curvature κ ₂ and the desired return path 26 position without significant overshoot or continuous oscillation of the driveway around the desired curvature κ ₂ .

wobei:

κ₂

repräsentiert die gewünschte Krümmung des Anhängers 12 oder 1/r₂, wie in 3 gezeigt;

δ

repräsentiert den Lenkwinkel;

L

repräsentiert den Abstand von der Hinterachse des Fahrzeugs 14 zum Kupplungsschwenkpunkt;

D

repräsentiert den Abstand vom Kupplungsschwenkpunkt zur Achse des Anhängers 12; und

W

repräsentiert den Abstand von der Hinterachse zur Vorderachse des Fahrzeugs 14.

As well as in 5 shown is the in 4 shown embodiment of the curvature control 28 in a control system block diagram. In particular, entering the control system is an input κ ₂ which represents the desired curvature of the desired return path 26 of the trailer 12 represents the curvature regulator 92 provided. The curvature regulator 92 can be expressed as a static allocation p (κ ₂ , δ), which in one embodiment is the following equation:

in which:

κ ₂

represents the desired curvature of the trailer 12 or 1 / r ₂ , as in 3 shown;

δ

represents the steering angle;

L

represents the distance from the rear axle of the vehicle 14 to the coupling pivot point;

D

represents the distance from the coupling pivot point to the axle of the trailer 12 ; and

W

represents the distance from the rear axle to the front axle of the vehicle 14 ,

With further reference to 5 the output coupling angle p (κ ₂ , δ) is provided as the reference signal γ _ref for the remainder of the control system, although the value of the steering angle δ, that of the curvature controller 92 is used, feedback from the non-linear function of the hitch angle controller 90 is. It is shown that the hitch angle controller 90 Feedback linearization used for the definition of a feedback control law as follows:

As well as in 5 4, the feedback control law g (u, γ, v) is implemented with proportional-integral (PI) control, where the integral component substantially eliminates steady-state tracking errors. More precisely, that can be done in 5 illustrated control system can be expressed as the following differential-algebraic equations:

It is contemplated that PI control may have gain terms based on trailer length D since shorter trailers typically have faster dynamics. In addition, the hitch angle controller can 90 be designed to prevent the desired hitch angle γ (d) from reaching or exceeding a breaking angle γ (j) as calculated by the controller or otherwise from the trailer backup assist system 10 determined as described in more detail herein.

Referring now to 6 In the illustrated embodiments of the disclosed subject matter, it is desirable to have the potential for the vehicle 14 and the trailer 12 to achieve a breakaway angle (ie the vehicle / trailer system reaches a breakaway state). A breakaway angle γ (j) refers to a hitch angle γ that can not be overcome by the maximum steering input for a vehicle during reverse travel, such as when the steered front wheels of the vehicle 14 be moved to a maximum steered angle δ at a maximum rate of steering angle change. The breaking angle γ (j) is a function of a maximum wheel angle of the steered wheel of the vehicle 14 , the wheelbase W of the vehicle 14 , the distance L between the coupling point and the rear axle of the vehicle 14 and the length D between the coupling point and the axle of the trailer 12 or the effective axle of the trailer 12 if the trailer 12 has multiple axes. When the hitch angle γ for the vehicle 14 and the trailer 12 the breaking angle γ (j) reaches or exceeds the vehicle 14 be pulled forward to reduce the hitch angle γ. Thus, to limit the potential for a vehicle / trailer system to reach a breakaway angle, it is preferred to have the yaw angle of the trailer 12 at the same time as the hitch angle γ of the vehicle / trailer system is kept relatively small.

A kinematic model representation of the vehicle 14 and the trailer 12 can be used to determine a breakaway angle for the vehicle / trailer combination. Accordingly, a steering angle limit for the steered front wheels requires reference to FIG 3 and 6 in that the hitch angle γ can not exceed the breaking angle γ (j), which is also referred to as the critical hitch angle γ. Consequently, the breakaway angle γ (j) is subject to the restriction that the hitch angle γ can not exceed the breakaway angle γ (j), the hitch angle γ which maintains a circular motion for the vehicle / trailer system when the steered wheels 64 at a maximum steering angle δ (max). The steering angle for a circular movement with the hitch angle γ is defined by the following equation.

wobei: a = L²tan²δ(max) + W²; b = 2LDtan²δ(max); und c = D²tan²δ(max) – W². The solution of the above equation for the hitch angle γ enables the determination of the breaking angle γ (j). This solution, shown in the following equation, may be used in implementing the trailer backup assist functionality in accordance with the disclosed subject matter to monitor the hitch angle γ relative to the breakaway angle.

in which: a = L ² tan ² δ (max) + W ² ; b = 2LDtan ² δ (max); and c = D ² tan ² δ (max) - W ² .

To the trailer backup assistance system 10 To activate, the driver interacts with the trailer backup assistance system 10 , and the trailer backup assistance system 10 steers automatically when the driver drives the vehicle 14 moves backwards. As explained above, the driver may change the trailer travel path 26 by means of a steering input device 18 command, and the curvature control 28 can determine the vehicle steering angle to the desired return path 26 with the driver controlling the gas pedal and the brake while the trailer backup assistance system 10 controls the steering.

With reference to 7 when a driver of the vehicle 14 the trailer 12 reversing, the driver can turn the knob 30 turn to the desired return path 26 to provide for the trailer or similar the desired return path 26 to override / change which of the mode selector 20 is ordered. According to the in 7 The embodiment shown is the steering input device 18 as a rotatable button 30 executed to the driver of the vehicle 14 by commanding a desired curvature to command a desired return path, such as one of the desired return routes 26a - 26e , In the illustrated embodiment, the rotatable knob rotates 30 about a central axis between a central position 114 in accordance with a substantially straight return path (eg desired return path 26c ), as by the longitudinal direction 22 of the trailer 12 defined, and different rotated positions 116 . 118 . 120 . 122 on opposite sides of the middle position 114 and commands a desired curvature κ ₂ corresponding to a radius of the corresponding desired return path (eg, desired return paths 26b . 26a . 26d respectively. 26e ) for the trailer 12 at the commanded rotated position.

Referring now to 8th is the trailer backup assistance system 10 with an embodiment of the object proximity sensor 17 for scanning an object 19 in a perimeter field 21 equipped shown. It is well known that there are a variety of sensor technologies and systems used on vehicles to detect the presence of and / or the distance to adjacent objects 19 to recognize the vehicle. For example, in Active Park Assist, ultrasonic sensors and / or cameras are used to detect curbs, walls, and vehicles, and radar is used to keep drivers from objects 19 in blind spots of the vehicle and to warn about blind spots around the vehicle. As such, image cameras, ultrasonic sensors and radar are some examples of an object proximity sensor 17 which is designed to capture information about the proximity of an object 19 characterize. Embodiments of the trailer backup assistance system 10 may use existing onboard sensors on the vehicle, accessory sensors mounted on the vehicle, and sensors permanently or temporarily attached to the trailer, among other conceivable proximity sensor arrangements. It is understood that the object proximity sensor 17 this may include one or more sensors on the vehicle, one or more sensors on the trailer, or a combination of sensors on the vehicle and the trailer.

As in the 8th In the illustrated embodiment, the obstacle proximity sensor includes a sensor system having a plurality of sensors mounted on the vehicle and the trailer. The illustrated embodiment provides sensors on side mirrors, a rear of the vehicle, and a rear of the trailer to provide a perimeter field 21 define. Accordingly, the perimeter field includes 21 in the illustrated embodiment, a majority of the area surrounding the vehicle and the trailer, thereby increasing the proximity of the objects 19 can be determined if they are near a rear part of the vehicle, lateral sides of the vehicle, a front part of the trailer, lateral sides of the trailer and a rear part of the trailer. Examples of sensors mounted on the vehicle or trailer include, but are not limited to, one or more ultrasonic sensors, one or more cameras, and one or more radar transceivers. As already mentioned, the object proximity sensor 17 additionally or alternatively parts of the hitch angle sensor 44 , the positioning device 56 or other additional sensors and devices on or in the vehicle, or to be integrated therewith to capture, generate, and output information regarding the proximity of the object 19 characterize that is adjacent to the vehicle and / or trailer.

Further referring to the in 8th illustrated embodiment, the proximity of an object 19 in the vicinity field 21 based on the type of sensor near the object 19 be determined in different ways. For example, if a camera is one of the devices used by the object proximity sensor 17 used, which is the position of the object 19 relative to the vehicle and / or Can scan trailer, the controller can 28 be adapted to process images from the camera to the distance from the vehicle and / or trailer for the purpose of processing an object recognition routine 130 and an available path routine 132 as more fully disclosed herein. In addition, if an ultrasonic sensor is one of the devices used by the object proximity sensor 17 is used, which is the position of the object 19 relative to the vehicle and / or trailer can scan, the controller 28 be adapted to process the feedback signals from the ultrasonic sensor to the distance from the vehicle and / or trailer for the purpose of processing the object recognition routine 130 and the available path routine 132 to determine. It is contemplated that more than one sensor of the object proximity sensor 17 can be used to close the proximity of an object 19 to scan simultaneously.

Referring to the in 9 embodiment shown become three objects 19 in the vicinity field 21 the vehicle and the trailer scanned. The objects 19 may include a danger area, a structure, another vehicle, a natural object or other obstacles that the curvature control based on proximity to it will avoid. The objects 19 can also through the positioning device 56 predefined, such as water hazards identified by a GPS device. Of the majority of possible ways 25 which the trailer can cross becomes an available range 23 shown that the trailer can cross without the vehicle or trailer being one of the objects 19 contacted. In other words, the available row becomes 23 of the plurality of paths generated by removing return paths with each part of the vehicle or trailer crossing a space different from the objects 19 is taken. The return routes, which of the majority of possible paths 25 are highlighted to illustrate the limited availability of reversing paths that can be selected or entered by the steering input device. Accordingly, it is considered that the illustration 9 As an image on the display can be generated to the position of the vehicle and the trailer relative to the object 19 to show along with the available series 23 the plurality of return paths that can be selected by the steering input device to the object 19 to avoid.

Other embodiments are in 9A - 9B shown which objects 19 illustrate, alternatively with the corresponding available rows 23 of reversing paths are arranged behind the trailer in the in 9 shown in the general format shown. As in 9A shown is a single object 19 disposed adjacent to the vehicle near a left driver side of the vehicle. Accordingly, the object proximity sensor 17 such as an onboard vehicle proximity sensor, the curvature control 28 the proximity of the object 19 provide. It is considered that the object proximity sensor 17 a camera coupled to a side mirror as in 8th illustrated embodiment is shown. Considering the proximity of the in 9A shown object 19 Can the trailer backup assistance system 10 Restrict the steered wheels of the vehicle from adjusting beyond a threshold angle to the right when reversing to contact the object 19 to avoid making the available row 23 of return paths of the trailer is similarly restricted.

As in 9B illustrates is the proximity of the object 19 arranged, so no return paths in the available range 23 available. In particular, the object 19 behind the trailer at close distance to the rear of the trailer, allowing a forward maneuver 134 may be necessary to reposition the trailer for the vehicle to guide the trailer on a return path, which is the area that the object 19 takes, does not cross. If such a determination is made, the trailer backup assist system may provide a notification to the driver, such as via the display. The forward maneuver 134 can be generated by the curvature control according to an embodiment, wherein the hitch angle and the object 19 can be monitored to determine if at least one return path for the trailer in the available range 23 provided by reversing paths. As shown in dashed lines, a forward maneuver will occur 134 in accordance with one embodiment, to propel the vehicle and trailer to a position that includes at least one return path in the available row 23 of return routes. It is considered that the forward maneuver 134 can be generated to command the powertrain control system to automatically drive the automatic transmission of the vehicle in the drive mode and to generate steering commands to the power steering system to position the vehicle and the trailer at a location having at least one return path in the available row 23 of return routes. Furthermore, it is conceivable that the object proximity sensor 17 continue the perimeter field 21 monitor, including the area in front of the vehicle and on the forward travel path, in a similar manner to a collision with an object 19 to avoid.

Referring now to 10 A method of providing trailer backup assist functionality with object avoidance is shown. In the illustrated embodiment, the object recognition routine may 130 comprise a first part of the method, and the available route routine 132 may provide a subsequent second part of the process. The method in the illustrated embodiment is determined at step 136 initiated by sensing the hitch angle between the vehicle and the trailer, during operation of the trailer backup assist system 10 can be done continuously. In addition, at step 138 the perimeter field 21 as by the object proximity sensor 17 defined on an object 19 monitors that in the perimeter field 21 entry. While the perimeter field is being monitored, at step 140 a determination is made as to whether an object is 19 in the vicinity field 21 located. In one embodiment, the object becomes 19 as in the perimeter field 21 when the proximity is greater than a threshold proximity for the particular vehicle and attached trailer. As such, the threshold proximity may be a fixed distance between the object 19 and the closest of the vehicle and the trailer may be a different distance for different areas of the vehicle and the trailer, or may be further dependent on the speed of the vehicle and other operating parameters that may affect the likelihood that the object 19 is relevant for the reversing maneuver. Once the object 19 in the vicinity field 21 is detected, the proximity sensor determines at step 142 the proximity of the object 19 relative to the vehicle and to the trailer. For example, the one or more sensors of the proximity sensor may determine the position of the object 19 that from the object 19 assumed mass and area and the speed of the object 19 , among other conceivable approximate information, determine. It is considered that the proximity of the object 19 simultaneously with the determination of whether an object 19 in the vicinity field 21 is present, can be determined. If no object 19 in the vicinity field 21 is present, the trailer backup assist system allows the driver to enter a desired back-up path for the trailer at step 144 as disclosed above for autonomous or semi-autonomous reversing of the trailer.

With further reference to the embodiment of the in 10 method illustrated in step 146 the proximity of the object 19 and the sampled hitch angle used to the available row 23 generate return paths for the trailer. For this, the kinematic relationship between the vehicle 14 and the trailer 12 which is based on various vehicle and trailer parameters that may be sampled, entered by the driver or otherwise determined. As with reference to 3 - 6 disclosed, the kinematic parameters for defining the kinematic relationship include a length of the trailer 12 , a wheelbase of the vehicle 14 , a distance from a coupling connection to a rear axle of the vehicle 14 and a hitch angle γ between the vehicle 14 and the trailer 12 , among other variables and parameters, as previously described. It is contemplated that the steps of determining the kinematic relationship and sensing the hitch angle γ in other embodiments of the trailer backup assist system 10 at other times before steering commands are generated. It is considered that the available range 23 can also be generated with a railway planner or other conceivable management system. An example of a web designer is further described in U.S. Patent Application No. 14 / 257,384, which is incorporated herein by reference in its entirety.

Accordingly, after the available series 23 of return routes through the available path routine 132 of the trailer backup assistance system 10 was generated, the procedure at step 148 continue to monitor and determine if an override command is activated to enable a desired return path outside the generated available range 23 is selected. In one embodiment, it is conceivable that the driver can activate the override command when the driver determines that the object to be avoided 19 from the vehicle and / or trailer is passable. In this embodiment, a notification may be provided when an input is attempted with the steering input device and the associated return path is not in the available row 23 of reversing paths, so that the notification may prompt the driver if an override command should be activated. It is contemplated that the override may be activated in various ways, such as by overriding the command by turning the rotatable knob over the available row 23 from reverse paths, pressing the rotatable knob to operate an integrated button, raising the rotatable knob simultaneously with turning to the desired return path, selecting an override option from a menu, pressing a dedicated button, and other conceivable options. If the system recognizes that the override is activated, the desired return path can be selected accordingly at step 144 be entered to handle steering commands without considering the proximity of the object 19 to generate.

Further referring to 10 After determining that the override is not activated, proceed to step 150 another determination of whether the generated available series 23 could at least generate a potential return path. If it is determined that no return routes are available to the object 19 To avoid, can step to the driver 152 such an alert notification will be provided, and a forward maneuver 134 can be generated. Warning communications include, but are not limited to, a visual alert, an audible alert, and a tactile alert. A visual alert may include a display strategy that includes an intelligent device of the driver of the vehicle (eg, a mobile phone or tablet) and / or one or more subsystems in the vehicle (eg, steering wheel / steering wheel illumination, camera display lighting, heads-up Display, mirrored text or schematic screen). These visual warnings may include color, intensity, and blinking frequencies to provide feedback to the driver that a collision mitigation function is active and / or to help direct the driver to avoid the collision. An audible alert may include audible tones or voice commands to instruct the driver to avoid the collision or to inform the driver that an automated collision mitigation function is active. A tactile warning may include steering wheel torque and / or vibration (ie, haptic feedback) to help the driver avoid the collision or inform the driver that an automated collision mitigation function is active. Other subsystems or devices, such as phones, tablets, vibrating seats, may also be used. The changing of frequencies of the vibration can be used to give the driver additional information about the likelihood of the collision.

As in 9B shown can be generating the forward maneuver 134 reposition the trailer for the vehicle at a location where there is a return path in the available row 23 is generated, which is the area of an object 19 is taken, does not cross. The forward maneuver 134 According to one embodiment, the trailer backup assist system may be generated to command the powertrain control system to automatically drive the vehicle's automatic transmission in the drive mode, then to actuate the vehicle acceleration to propel the vehicle and trailer forward, and then to provide steering commands to the power steering system generate to position the vehicle and the trailer at a location which at least one return path in the available range 23 of return routes. After achieving such a position, an embodiment of the forward maneuver 134 also the brake control system 72 drive to stop the vehicle and the trailer, then automatically drive the vehicle's automatic transmission in reverse mode and then resume the reversing maneuver. It is contemplated that the system can continually try the available range 23 of return routes during the forward maneuver 134 to generate. Furthermore, it is conceivable that the object proximity sensor 17 continue the perimeter field 21 including the area in front of the vehicle during the forward maneuver 134 to similarly collide with an object 19 to avoid.

Referring again to 10 after it is determined that at least one return path is in the available row 23 is present, the steering input device at step 154 the desired return journey 26 from the available series 23 enter. Using the entered desired return route 26 and the sampled hitch angle can be determined at step 156 Steering commands are generated for the vehicle to the trailer on the desired return path 26 respectively. In some embodiments, the kinematic relationship is reused to allow the trailer backup assist system 10 Steering commands for the power steering system 62 according to the desired return journey of the trailer 12 generated. As previously described, the desired return path 26 be equated to a desired curvature input, so that the curvature control 28 Steering commands generated based on the sampled hitch angle and other kinematic parameters. Therefore, the desired return path 26 within the available range 23 and is essentially followed by the curvature control, which generates corresponding adjustments to the steering angle of the vehicle.

In another embodiment, the trailer backup assist system 10 First, the proximity of an object 19 within the perimeter field 21 determine to determine if the trailer's current return travel needs to be changed to limit a potential that the vehicle and / or trailer will have with the object 19 collide. Changing or otherwise correcting the way back to the object 19 To avoid this, can be done autonomously by slowing or stopping the vehicle to avoid the collision, or otherwise steering the vehicle around the trailer on a return path in the available range 23 of return paths. As such, an operation for determining an appropriate and appropriate action to correct the trailer / vehicle combination path (ie, path correction action) may be performed to reduce the potential for collision with the object 19 and then an operation may be performed to apply the path correction action to implement. The path correction action may be implemented by completely guiding the driver through a human-machine interface (HMI) and / or automatically controlling the vehicle using a variety of the vehicle's electromechanical systems. Determining the path correction action can be done on any number of bases. For example, the object avoidance mode having the highest likelihood of collision mitigation and / or the lowest influence on the operation of the vehicle may be given priority. Examples of object avoidance strategies for implementing the path correction action include, but are not limited to, speed control strategy, steering control strategy and trailer curvature control strategy. A speed control strategy may include a combination of accelerator deactivation or restriction, and automatic friction or transmission braking may be used to reduce the speed of the vehicle to reduce the collision probability, when prescribed collision avoidance criteria (eg, a corresponding collision avoidance threshold) Avoid collision with the object 19 have been fulfilled. A steering control strategy may include steering rates, steering angle limits, relative road wheel angles and speeds, and transient control inputs that are reduced or limited to prescribed collision avoidance criteria that prevent the collision with the object 19 comply with. A trailer curvature control strategy may include reducing a trailer curvature control target (ie, a commanded value) in the trailer backup assist system using, for example, automated steering or HMI guidance based on mappings that use vehicle speed, acceleration, steering rate, and / or transient steering angle behavior the potential for a collision with the object 19 to reduce. Accordingly, implementing the path correction action may include issuing a path correction action command to effect the initiation of one or more object avoidance strategies.

In parallel with performing the operations to receive the trailer backup assist requests, determining the desired return path 26 and the curvature of the trailer 12 and generating vehicle steering commands may be the trailer backup assist system 10 perform an operation to monitor if an unacceptable trailer backup condition exists. Examples of such monitoring include, but are not limited to, evaluating a hitch angle γ to determine whether a threshold of hitch angle γ is exceeded, evaluating a reverse speed to determine whether a reverse speed threshold is exceeded, rating a vehicle steering angle to determine whether a vehicle steering angle threshold is exceeded, evaluating other operating parameters (eg, vehicle longitudinal acceleration, accelerator pedal request rate, and hitch angle rate) to determine whether a corresponding threshold is exceeded, and the like. The return speed may be determined by the wheel speed information provided by one or more wheel speed sensors 58 of the vehicle 14 to be obtained. If it is determined that an unacceptable trailer backup condition exists, an operation may be performed to cause the trailer's current travel path to be effected 12 is prevented (eg stopping the movement of the vehicle 14 ) followed by the operation performed to terminate the current trailer backup assist case. Herein, it is disclosed that prior to and / or in conjunction with causing the current trailer path to be prevented, one or more actions (eg, operations) for providing feedback to the driver (eg, a warning) such an unacceptable hitch angle condition is imminent or approaching, can be implemented. In one example, if such feedback causes the unacceptable hitch angle condition to be resolved before a critical condition is reached, the method may proceed to provide trailer backup assist functionality in accordance with the operations. Otherwise, the method may continue with the operation to terminate the current trailer backup assist case. In conjunction with performing the operation to terminate the current trailer backup assist case, an operation for controlling the movement of the vehicle 14 to correct or limit a breakaway condition (eg, steering the vehicle 14 , Slowing down the vehicle 14 Limiting the magnitude and / or rate of driver requested trailer curvature input and / or rate of steering command and / or the like to preclude exceeding the hitch angle).

It is to be understood that variations and modifications may be made to the structures and methods mentioned above 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 Their language does not expressly state otherwise.

Claims (20)

Trailer backup assist system, comprising: a steering input device for inputting a desired return travel of a trailer from a plurality of ways; a first sensor which senses a hitch angle between a vehicle and the trailer; a second sensor which senses proximity of an object in a perimeter field; and a controller that limits the plurality of paths to an available row based on the proximity of the object and the hitch angle. The trailer backup assist system according to claim 1, wherein the available row of the plurality of paths is generated by removing return paths crossing a space occupied by the object. The trailer backup assist system according to any one of claims 1 and 2, wherein the plurality of ways are generated by removing return paths causing a breakaway condition between the vehicle and the trailer. The trailer backup assist system of any one of claims 1-3, wherein the controller generates a forward maneuver for the vehicle when there are no return lanes in the available queue. The trailer backup assist system of claim 4, wherein the forward maneuver drives an automatic transmission of the vehicle to a drive mode and generates steering commands for the vehicle to position the vehicle and the trailer at a location that provides at least one return path in the available range. The trailer backup assist system of any one of claims 1-5, wherein the object comprises at least one of a hazard area, a structure, another vehicle, and a natural object. The trailer backup assist system of any one of claims 1-6, wherein the steering input device includes an override command for inputting a desired return travel that is not present in the available train. The trailer backup assist system of any one of claims 1-7, wherein the controller provides a notification to a driver of the vehicle when an attempted input with the steering input device is not present in the available row. The trailer backup assist system of any of claims 1-8, further comprising: a display for viewing by a driver of the vehicle, the controller configured to generate images on the display that depict the vehicle, the trailer, and the object. A method of reversing a trailer with a vehicle, comprising: Sensing a hitch angle between a vehicle and the trailer; Sensing a proximity of an object in a perimeter field; Generating an available set of trail back paths for the trailer based on the proximity of the object and the hitch angle; and Enter a desired return path from the available row. The method of claim 10, further comprising: Generate a warning when the proximity of the object reduces the available range of trail back paths. A method according to any one of claims 10 and 11, wherein the available series of return paths are generated by removing paths crossing a space occupied by the object and paths causing a breakaway condition between the vehicle and the trailer. The method of any of claims 10-12, further comprising: Generating a forward maneuver for the vehicle when there are no lanes in the available series of return lanes, the forward maneuver monitoring the position of the vehicle and the trailer to provide notification when there is at least one return path in the available lane. The method of any of claims 10-13, further comprising: Generate images on a display showing the vehicle, trailer, and object. The method of claim 14, wherein the display comprises images representing the available series of return paths and the desired return path. Trailer backup assist system, comprising: a steering input device for inputting a desired return travel of a trailer; a first sensor which senses a hitch angle between a vehicle and the trailer; a second sensor which senses proximity of an object in a perimeter field of at least one of the vehicle and the trailer; and a controller that generates an available series of trailer return paths based on the proximity of the object and the hitch angle, the available row not including return routes that intersect a space occupied by the object or a breakaway state between the vehicle and vehicle cause the trailer. The trailer backup assist system of claim 16, wherein the controller generates a forward maneuver for the vehicle when there are no return lanes in the available line, the forward maneuver monitoring the hitch angle and the object to provide a notification if at least one return path in the available line is available. The trailer backup assist system of any one of claims 16 and 17, wherein the steering input device comprises a knob which is rotatable to define the desired return path such that a first position of the button has a different curvature than a rotated second position, and wherein second sensor comprises an ultrasonic sensor. The trailer backup assist system of any of claims 16-18, further comprising: a display for viewing by a driver of the vehicle, wherein the controller generates images on the display that show a position of the vehicle and the trailer relative to the object. The trailer backup assist system of claim 19, wherein the controller generates an image on the display indicative of the available range of trailer return paths.

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