DE102015109537B4 - OBJECT AVOIDANCE FOR A TRAILER REVERSE ASSISTANCE SYSTEM - Google Patents

Abstract

A method for reversing a trailer (12) with a vehicle (14), comprising:generating a plurality of reversing paths of the trailer (12); Displaying the plurality of reversing paths on a display; sensing a hitch angle between a vehicle (14) and the trailer (12); sensing a proximity of an object (19) in a surrounding field; generating an available set of reversing paths for the trailer (12) based on the proximity of the object (19) and the coupling angle; highlighting return paths that have been excluded from the available range; andcontrolling the vehicle (14) using a desired return path (26) from the available set, characterized in that the method further comprises generating a forward maneuver for the vehicle (14) when no paths are present in the available set of return paths, wherein: Forward maneuvers monitor the position of the vehicle (14) and trailer (12) to provide notification when there is at least one reverse path in the available range.

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 designed with object avoidance features to control the guidance of the trailer.

BACKGROUND OF THE INVENTION

Reversing a vehicle while towing a trailer can be challenging for many drivers, especially drivers who drive a trailer or multiple types of trailers at irregular intervals. One reason for such difficulty may be that reversing a vehicle with a trailer attached requires steering inputs that are opposite to the steering inputs when reversing the vehicle without a trailer attached to the vehicle. Another reason may be that there may be objects surrounding the vehicle and 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 difficulty may be that minor errors in steering are magnified while reversing a vehicle with an attached trailer, which may cause the trailer to quickly deviate 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 a runaway condition to occur. A runaway condition can occur when the vehicle's steering cannot control the hitch angle, so the hitch angle would continue to increase and the vehicle must be pulled forward to relieve the hitch angle. However, in addition to creating the adverse situation in which the vehicle must be pulled forward, the breakaway condition may also result in contact between the vehicle and the trailer, thereby causing damage to the trailer and/or the vehicle.

In print DE 10 2004 048 530 A1 a method for operating a collision avoidance system for vehicles and a collision avoidance system for vehicles is described, with means for detecting an existing driving space and with means for determining a required driving space, distance values between the vehicle and obstacles surrounding the vehicle being calculated. Different trajectories are determined depending on different driving strategies. The publications form further prior art in the background of the invention US 2014 / 0 160 276 A1 and DE 10 2012 205 416 A1 .

SUMMARY OF THE INVENTION

A trailer backup assist system includes a steering input device for inputting a desired backup path of a trailer from a plurality of paths. A first sensor senses a coupling angle between a vehicle and the trailer. A second sensor scans the proximity of an object in a surrounding field. A trailer backup assist system control limits the majority of paths to an available range based on the proximity of the object and the hitch angle.

According to one 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 for sensing a proximity of an object in a surrounding field. In addition, the method provides a step for generating an available set of reversing paths for the trailer based on the proximity of the object and the hitch angle. The method further provides a step for entering a desired return path from the available range.

According to another aspect of the present invention, a trailer reversing assistance system includes a steering input device for inputting a desired reversing path of a trailer. The trailer reversing assistance system also includes a first sensor that senses a coupling angle between a vehicle and the trailer. Furthermore, the trailer reversing assistance system includes a second sensor, which detects the proximity of an object in a surrounding field of at least one of the Vehicle and trailer scanned. A trailer backup assist system controller generates an available range of backup paths for the trailer based on the proximity of the object and the hitch angle. The available range of reversing paths does not include reversing paths which cross a space occupied by the object or which 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 description, claims and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1 ist eine perspektivische Draufsicht eines Fahrzeugs, welches an einem Anhänger mit einer Ausführungsform eines Kupplungswinkelsensors zum Betreiben eines Anhänger-Rückfahrassistenzsystems angebracht ist;
• 2 ist ein Blockschaltbild, welches eine Ausführungsform des Anhänger-Rückfahrassistenzsystems mit einer Lenkeingabevorrichtung und einer Krümmungssteuerung veranschaulicht;
• 3 ist eine schematische Darstellung, welche die Geometrie eines Fahrzeugs und eines Anhängers mit einem überlagerten zweidimensionalen x-y-Koordinatensystem veranschaulicht, das Variablen identifiziert, welche verwendet werden, um eine kinematische Beziehung des Fahrzeugs und des Anhängers für das Anhänger-Rückfahrassistenzsystem zu bestimmen, gemäß einer Ausführungsform;
• 4 ist ein schematisches Blockschaltbild, welches Teile einer Krümmungssteuerung gemäß einer weiteren Ausführungsform und andere Komponenten des Anhänger-Rückfahrassistenzsystems gemäß einer derartigen Ausführungsform veranschaulicht;
• 5 ist ein schematisches Blockschaltbild der Krümmungssteuerung aus 4, welches die Rückkopplungsarchitektur und den Signalfluss der Krümmungssteuerung gemäß einer derartigen Ausführungsform zeigt;
• 6 ist eine schematische Darstellung, welche eine Beziehung zwischen einem Kupplungswinkel und einem Lenkwinkel des Fahrzeugs zeigt, wie sie die Krümmung des Anhängers und einen Ausbrechwinkel betrifft;
• 7 ist eine Draufsicht einer Ausführungsform eines drehbaren Knopfs zur Auswahl einer gewünschten Krümmung eines Anhängers und eine entsprechende schematische Darstellung, welche ein Fahrzeug und einen Anhänger mit verschiedenen Anhänger-Krümmungswegen veranschaulicht, die mit gewünschten Krümmungen, die ausgewählt werden können, korrelieren;
• 8 ist eine schematische Darstellung eines Fahrzeugs und eines Anhängers, welche einen Objektnäherungssensor zum Abtasten eines Objekts in einem Umkreisfeld aufweisen, gemäß einem Ausführungsbeispiel;
• 9 ist eine schematische Darstellung eines Fahrzeugs, eines Anhängers und Objekten im Umkreisfeld, welche die verfügbare Reihe von Rückfahrwegen reduzieren, gemäß einer Ausführungsform;
• 9A ist eine schematische Darstellung eines Fahrzeugs, eines Anhängers und eines Objekts im Umkreisfeld, welche die verfügbare Reihe von Rückfahrwegen reduzieren, gemäß einer weiteren Ausführungsform;
• 9B ist eine schematische Darstellung eines Fahrzeugs, eines Anhängers und eines Objekts im Umkreisfeld, welche die verfügbare Reihe von Rückfahrwegen reduzieren, gemäß einer weiteren Ausführungsform; und
• 10 ist ein Flussdiagramm, welches ein Verfahren zum Betreiben eines Anhänger-Rückfahrassistenzsystems mit Objektvermeidung gemäß einer Ausführungsform veranschaulicht.

The following applies to the drawings:

• 1 is a top perspective view of a vehicle mounted to a trailer with an embodiment of a hitch angle sensor for operating a trailer backup assist system;
• 2 is a block diagram illustrating an embodiment of the trailer backup assist system with a steering input device and a curvature control;
• 3 is a schematic diagram illustrating the geometry of a vehicle and a trailer with an overlaid two-dimensional xy coordinate system identifying variables used to determine a kinematic relationship of the vehicle and the trailer for the trailer backup assist system, according to one embodiment ;
• 4 is a schematic block diagram illustrating portions of a curvature control according to another embodiment and other components of the trailer backup assist system according to such embodiment;
• 5 is a schematic block diagram of the curvature control 4 11 showing the feedback architecture and signal flow of curvature control according to such an embodiment;
• 6 is a schematic diagram showing a relationship between a hitch angle and a steering angle of the vehicle as it relates to the curvature of the trailer and a breakaway angle;
• 7 is a top view of an embodiment of a rotary knob for selecting a desired curvature of a trailer and a corresponding schematic diagram illustrating a vehicle and a trailer with various trailer curvature paths that correlate with desired curvatures that may be selected;
• 8th is a schematic representation of a vehicle and a trailer having an object proximity sensor for scanning an object in a surrounding field, according to an exemplary embodiment;
• 9 is a schematic representation of a vehicle, a trailer, and surrounding objects that reduce the available set of return paths, according to one embodiment;
• 9A is a schematic representation of a vehicle, a trailer, and a surrounding object that reduce the available set of return paths, according to another embodiment;
• 9B is a schematic representation of a vehicle, a trailer, and a surrounding object that reduce the available set of return paths, according to another embodiment; and
• 10 is a flowchart illustrating a method for operating a trailer backup assist system with object avoidance according to an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, it is to be understood that the disclosed trailer backup assist system and associated methods may adopt 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 description are simply exemplary embodiments of the inventive concepts defined in the appended claims. Although various aspects of the trailer backup assist system and associated methods are described with reference to a particular exemplary embodiment, the disclosed invention is not limited to such embodiments, and additional modifications, applications and embodiments may be implemented without departing from the disclosed invention. Accordingly, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be construed as limiting unless expressly stated otherwise in the claims.

With reference to 1-10 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 backup path 26 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 backup path 26 when a driver uses the accelerator and brake pedals to control the reverse travel speed of the vehicle 14. To monitor the position of the trailer 12 relative to the vehicle 14, the trailer backup assistance system 10 may include a sensor system 16 that senses a hitch angle γ between the trailer 12 and the vehicle 14, which may be referred to as a first sensor or a hitch angle sensor 44 . In addition, the trailer reversing assistance system 10 may include an object proximity sensor 17, which may be referred to as a second sensor or a perimeter 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 may also include a steering input device 18 for a driver, such as a mode selector 20 or a rotatable knob 30, to provide the desired backup path 26 of the trailer 12. A curvature control 28 of the trailer reversing assistance system 10 may generate an available series 23 of reversing paths for the trailer 12 based on the proximity of the object 19 and the hitch angle γ, which is reduced from a plurality of possible paths 25 so that the steering input device 18 responds to the input a desired return path 26 from the available row 23 of return paths can be limited. In one embodiment, the available series 23 of return paths does not include the return paths that cross a space occupied by the object 19. After receiving the desired return path 26, a steering command may be generated based on the sampled hitch angle γ and a kinematic relationship between the trailer 12 and the vehicle 14 to guide the trailer 12 on the desired return path 26. It is contemplated that additional embodiments of the trailer backup assist system 10 may also include an additional or alternative steering input device 18 that may be driven when the vehicle 14 and trailer 12 are reversing to adjust the desired backup path of the trailer 12.

With reference to the in 1 In the embodiment shown, 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. In particular, the vehicle 14 is pivotally attached to an embodiment of the trailer 12, which has a box frame 32 with an enclosed loading area 34 and a tongue 36 which extends longitudinally forward from the enclosed loading area 34. The illustrated trailer 12 also includes a trailer hitch connector in the form of a coupler assembly 38 which is connected to a vehicle hitch connector in the form of a hitch ball 40. The coupler assembly 38 engages the coupling ball 40 to provide a pivot ball joint connection 42 that allows articulation of the coupling angle γ. It should be appreciated that other embodiments of trailer 12 may include more than one axle; may have different shapes and sizes designed for different loads and objects, such as boat trailers or flatbed trailers; and alternatively may be coupled to the vehicle 14 to provide a pivotal connection, such as by connecting to a fifth wheel connector.

Further referring to 1 In the illustrated embodiment, the sensor system 16 includes a vision-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 (e.g., video imaging camera) located near an upper portion of the Vehicle tailgate 48 can be arranged at the rear of the vehicle 14 as shown, so that the camera 46 can be increased relative to the tongue 36 of the trailer 12. The illustrated camera 46 includes an image field of view 50 arranged and oriented to capture one or more images of the trailer 12, including a region having one or more desired target placement zones for at least one target 52 to be secured. Although it is contemplated that the camera 46 may capture images of the trailer 12 without a target 52 to determine the hitch angle γ, in the illustrated embodiment, the trailer backup assist system 10 includes a target 52 disposed on the trailer 12 to enable the trailer reversing assistance system 10 to use information captured via image capture and processing of the target 52. For example, the illustrated camera 46 may include a video imaging camera that repeatedly captures sequential images of the trailer 12 that may be processed to identify the target 52 and its location on the trailer 12, the movement of the target 52 and the trailer 12 relative to the vehicle 14 and the corresponding coupling angle γ. It should also be noted that the camera 46 may include one or more video imaging cameras and may be located elsewhere on the vehicle 14 to capture images of the trailer 12 and the desired target placement zone, for example, at a passenger cabin 54 of the vehicle 14 to capture images of a Gooseneck trailer. Furthermore, it is provided that additional embodiments of the coupling angle sensor 44 and the sensor system 16 for providing the coupling angle γ include one 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 mounted on the pivot ball joint 42, a yaw rate sensor on the trailer 12 and vehicle 14, energy converters of a backup assist system, a blind spot system and/or a cross traffic warning system, and others conceivable sensors or indicators of the coupling angle γ, which are used in addition to or instead of the vision-based coupling angle sensor 44.

With reference to the in 2 In the embodiment shown of the trailer reversing assistance system 10, the coupling angle sensor 44 provides the sampled coupling angle γ to the trailer reversing assistance system 10. Similarly, the illustrated embodiment of the trailer backup assist system 10 receives information related to vehicle 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 managed device to determine a coordinate position of the vehicle 14 and the trailer 12 based on the position of the positioning device 56 with respect to the trailer 12 and / or the vehicle 14 and based on the sampled coupling angle γ. The positioning device 56 may additionally or alternatively include 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 received from the trailer backup assist system 10 may include a speed of the vehicle 14 from a speed sensor 58 and a yaw rate of the vehicle 14 from a yaw sensor 60. It is contemplated that, in further embodiments, the hitch angle sensor 44 and other vehicle sensors and devices may provide sensor signals or other information, such as proximity sensor signals or sequential images of the trailer 12, which a controller of the trailer backup assist system 10 may process with various routines to a value or to determine an indicator, such as a coupling angle value or a range of coupling angles γ.

The embodiment of the in 2 Trailer reversing assistance system shown also includes the object proximity sensor 17, which provides the proximity of an object 19 to the curvature control 28 of the trailer reversing assistance system 10. More specifically, the object proximity sensor 17 provides the trailer backup assistance system 10 with proximity information of the object 19, which may include information estimating a position of the object 19 or 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 that characterizes the proximity of the object 19 adjacent to the vehicle and/or trailer, as described in more detail herein is described. Accordingly, the object proximity sensor 17 may include or be integrated with parts of the coupling angle sensor 44, the positioning device 56 or other additional sensors and devices. The trailer backup assist system 10 may use the proximity information of the object 19 or objects as input to the curvature control to avoid a collision with the object 19 or objects, such as by limiting the available range 23 of backup paths determined by the steering input Device can be selected by correcting a current reversing path or otherwise preventing the trailer and vehicle from coming into contact with the object 19, as will be disclosed in more detail below.

As further in 2 shown, an embodiment of the trailer reversing assistance system 10 communicates with a power steering system 62 of the vehicle 14 to steer wheels 64 ( 1 ) of the vehicle 14 to move the vehicle 14 in such a manner that the trailer 12 responds in accordance with the desired curvature of the trailer 12. In the illustrated embodiment, the power steering system 62 is an electric power-assisted steering (EPAS) system that includes an electric steering motor 66 for turning the steered wheels 64 to a steering angle based on a steering command, the steering angle being determined by a steering angle sensor 67 of the power steering system 62 is scanned. The steering command may be provided by the trailer reversing assistance system 10 for autonomous steering during a reversing maneuver and may alternatively be provided manually via a rotational position (e.g. steering wheel angle) of a steering wheel 68 ( 1 ) to be provided. However, in the illustrated embodiment, the steering wheel 68 of the vehicle 14 is mechanically coupled to the steered wheels 64 of the vehicle 14 such that the steering wheel 68 moves in concert with the steered wheels 64, thereby preventing manual engagement with the steering wheel 68 during autonomous steering becomes. More specifically, a torque sensor 70 is provided on the power steering system 62, which senses a torque on the steering wheel 68 that is not expected by the autonomous control of the steering wheel 68 and is therefore indicative of manual intervention, wherein the trailer backup assistance system 10 can warn the driver to end the manual intervention with the steering wheel 68 and/or the autonomous steering.

Referring again to the in 2 In the illustrated embodiment, the power steering system 62 provides the curvature controller 28 of the trailer backup assist system 10 with information regarding a rotational position of the steered wheels 64 of the vehicle 14, including a steering angle. The curvature controller 28 in the illustrated embodiment processes the current steering angle in addition to other conditions of the vehicle 14 and trailer 12 to guide the trailer 12 along the desired return path 26 and/or curvature. It is conceivable that the trailer reversing assistance system 10 can be an integrated component of the power steering system 62 in further embodiments. For example, the power steering system 62 may include a trailer backup assist algorithm for generating vehicle steering information and commands as a function of all or a portion of the information received from 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 are received.

As in 2 As illustrated, the brake control system 72 may also communicate with the camber controller 28 to provide braking information, such as wheel speed, to the trailer backup assist system 10 and to receive braking commands from the camber controller 28. For example, vehicle speed information may be determined from individual wheel speeds as monitored by the brake control system 72. Vehicle speed may also be determined by 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, which may be provided to the trailer backup assist system 10 alternatively or in addition to the yaw sensor 60 for use in determining vehicle steering commands. In certain embodiments, the trailer backup assist system 10 may provide vehicle braking information to the brake control system 72 to enable the trailer backup assist system 10 to control braking of the vehicle 14 while the trailer 12 is reversing. For example, in some embodiments, the trailer backup assist system 10 may control the speed of the vehicle 14 while the trailer 12 is reversing, thereby reducing the potential for unacceptable trailer backup conditions. Examples of unacceptable trailer backup conditions include, but are not limited to, an overspeed condition of the vehicle 14, a high hitch angle rate, dynamic trailer angle instability, a calculated theoretical trailer breakaway condition (defined by a maximum vehicle steering angle, drawbar length, tow vehicle wheelbase, and effective Trailer length) or physical contact breakaway limit (defined by an angular displacement limit relative to the vehicle 14 and trailer 12), and the like. It is disclosed herein that the trailer backup assist system 10 emits a warning signal can output, which corresponds to a notification of an actual, impending and / or expected unacceptable trailer reversing condition.

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

As further in 2 As illustrated, the trailer backup assist system 10 includes a steering input device 18 coupled to the curvature controller 28 to enable communication of information therebetween. It is disclosed herein that the steering input device 18 may be coupled to the curvature controller 28 in a wired or wireless manner. The steering input device 18 provides the trailer reversing assistance system 10 with information that defines the desired reversing path 26 of the trailer 12 so that the curvature control 28 processes and generates steering commands. The trailer steering commands may include information related to a commanded change in travel path, such as a change in the radius of the return path 26 (e.g., curvature), and information related to an indication that the trailer 12 is along a path defined by a longitudinal centerline axis of the trailer 12 (ie, along a substantially straight path). As explained in more detail below, the steering input device 18 according to the illustrated embodiment may use the mode selector 20 to select 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 for example the rotatable button 30. Accordingly, in the illustrated embodiment, the steering input device 18 may also include a rotational control input device to enable a driver of the vehicle 14 to command desired steering actions of the trailer or otherwise select the desired return path 26. For example, the rotary control input device may be a rotatable knob 30 rotatable about an axis of rotation extending through an upper surface of the knob. In other embodiments, the rotatable knob 30 may be rotatable about an axis of rotation that extends substantially parallel to an upper surface or surface of the rotatable knob 30. Further, according to further embodiments, the steering input device 18 may include alternative devices for providing a desired return path 26, such as a joystick, pressable buttons, sliding input devices, various controls on a portable device, various user interfaces on a touch screen display, vision-based systems for receiving gestures, a path planner or other programmable routing system and other conceivable input devices generally understood by those of ordinary skill in the art.

Further referring to the in 2 In the embodiment shown, the curvature controller 28 is configured with a microprocessor 84 to process logic and routines stored in memory 86 that receive information from the steering input device 18, the clutch angle sensor 44, the power steering system 62, the brake control system 72, the powertrain control system 74, and other vehicle sensors and devices received. The curvature controller 28 may generate vehicle steering information and commands as a function of all or a portion of the information received from the steering input device 18, the clutch 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 to influence the steering of the vehicle 14 to achieve a commanded path for the trailer 12. The curvature controller 28 may use the microprocessor 84 and/or other analog and/or digital circuitry to process one or more routines include. Also, the curve controller 28 may include the memory 86 for storing one or more routines, including a trailer straight ahead routine, a vehicle straight ahead routine, and a locked curve routine. It should be appreciated that the curvature controller 28 may be a standalone 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 onboard or offboard vehicle control systems.

With reference to 3 Let us now turn to a discussion of vehicle and trailer information and parameters used to calculate a kinematic relationship between a curvature of a path of the trailer 12 and the steering angle of the vehicle towing the trailer 12, a kinematic model Low order may be desirable for a trailer backup assist system 10 designed according to some embodiments. In order to achieve such a low order kinematic model, certain assumptions are made with respect to parameters associated with the vehicle/trailer system. Examples of such assumptions include, but are not limited to, that the trailer 12 is being backed by the vehicle 14 at a relatively low speed, that the wheels of the vehicle 14 and the trailer 12 have negligible (e.g., no) slip, that the tires of the vehicle 14 and the trailer 12 have negligible (e.g. no) deformation, that the actuator dynamics of the vehicle 14 are negligible, that the vehicle 14 and the trailer 12 have negligible (e.g. no) rolling or Pitching movements, among other conceivable factors with the potential to have an influence on the control of the trailer 12 with the vehicle 14.

• 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 system defined by a vehicle 14 and a trailer 12 is based on various parameters associated with the vehicle 14 and the trailer 12. These parameters include:

• δ: steering angle at 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 (axle length may be an equivalent); and
• r ₂ : Radius of curvature for the trailer 12.

One embodiment of a kinematic relationship between the trailer path radius of curvature r ₂ at the center 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 using the equation provided below. As such, if the hitch angle γ is provided, the trailer path curvature κ ₂ can be controlled based on the control of the steering angle δ (where β ^̇ ̇ is the trailer yaw rate and η̇ is the trailer speed). $${\kappa }_2=\frac{1}{r_2}=\frac{\dot{\beta }}{\dot{\eta }}=\frac{\left(W+\frac{K{v}^2}{G}\right)\text{sin}\gamma +L\text{cos}\gamma +\text{tan}\delta }{D\left(\left(W+\frac{K{v}^2}{G}\right)\text{cos}\gamma -L\text{sin}\gamma \text{tan}\delta \right)}$$

This relationship can be expressed to provide the steering angle δ as a function of the trailer path curvature k ₂ and the hitch angle γ. $$\delta ={\text{tan}}^{-1}\left(\frac{\left(W+\frac{K{v}^2}{G}\right)\left[{\kappa }_{2}D\text{cos}\gamma -\text{sin}\gamma \right]}{DL{\kappa }_2\text{sin}\gamma +L\text{cos}\gamma }\right)=F\left(\gamma ,{\kappa }_2,K\right)$$

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

Yet another embodiment of the curvature control 28 of the trailer reversing assistance system 10 is shown in FIG 4 11, which shows the general architectural layout, wherein a measurement module 88, a coupling angle controller 90 and a curvature controller 92 are routines stored in the memory 86 of the curvature controller 28. In the illustrated layout, the steering input device 18 provides the curvature controller 92 of the curvature controller 28 with a desired value for the curvature κ ₂ , which can be determined from the desired return path 26 entered into the steering input device 18. The curvature controller 92 calculates a desired coupling angle γ(d) based on the currently desired curvature κ ₂ together with the steering angle δ, which is provided by a measurement module 88 in this embodiment of the curvature controller 28. The measurement module 88 may be a storage device separate from or integrated with the curvature controller 28 that stores data from sensors of the trailer backup assist system 10, such as the hitch angle sensor 44, the vehicle speed sensor 58, the steering angle sensor, or alternatively, the measurement module 88 may otherwise Transmit data directly from the sensors without acting as a storage device. Once the desired hitch angle γ(d) is calculated by the curvature controller 92, the hitch angle controller 90 generates a steering angle command based on the calculated desired hitch angle γ(d) as well as a measured hitch angle γ(m) and a current speed of the vehicle 14. The steering angle command is given to the Trailer backup assistance system 62 of the vehicle 14 is provided, which is then fed back to the measurement module 88 to reassess 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 92 and the hitch angle controller 90 continuously process information from the measurement module 88 to provide accurate steering angle commands that position the trailer 12 at the desired curvature κ ₂ and the desired return path 26 without significant overshoot or continuous oscillation of the travel path about 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 in 5 shown is the in 4 shown embodiment of the curvature control 28 illustrated in a control system block diagram. Specifically, entering the control system is an input κ ₂ representing the desired curvature of the desired return path 26 of the trailer 12 provided to the curvature controller 92. The curvature controller 92 can be expressed as a static mapping p(κ ₂ ,δ), which in one embodiment is the following equation: $$p\left({\kappa }_2,\delta \right)={\text{tan}}^{-1}\left(\frac{{\kappa }_{2}D+L\text{tan}\left(\delta \right)}{{\kappa }_{2}DL\text{tan}\left(\delta \right)-W}\right)$$

where:

• 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 axis 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 a reference signal γ _ref to the rest of the control system, although the value of the steering angle δ used by the curvature controller 92 is feedback from the non-linear function of the coupling angle controller 90. It is shown that the clutch angle controller 90 uses feedback linearization to define a feedback control law as follows: $$G\left(\text{u},\text{y},\text{v}\right)=\mathrm{\delta }={\text{tan}}^{-1}\left(\frac{W}{\nu \left(1+\frac{L}{D}cOs\left(\gamma \right)\right)}\left(\text{u}-\frac{\nu }{D}\text{sin}\left(\gamma \right)\right)\right)$$

$$\text{tan}\left(\delta \right)=\overline{\delta }=\frac{W}{\nu \left(t\right)\left(1+\frac{L}{D}\text{cos}\left(\gamma \left(t\right)\right)\right)}\left(K_P(p\left({\kappa }_2,\delta \right)-\gamma \left(t\right)\right)-\frac{\nu \left(t\right)}{D}\text{sin}\left(\gamma \left(t\right)\right))$$

As in 5 shown, the feedback control law g(u, γ, v) is implemented with a proportional-integral (PI) control, where the integral component essentially eliminates stationary tracking errors. More precisely, this can be done in 5 The illustrated control system can be expressed as the following differential algebraic equations: $$\dot{\gamma }\left(t\right)=\frac{\nu \left(t\right)}{D}\text{sin}\left(\gamma \left(t\right)\right)+\left(1+\frac{L}{D}cOs\left(\gamma \left(t\right)\right)\right)\frac{\nu \left(t\right)}{W}\overline{\delta }$$

$$\text{tan}\left(\delta \right)=\overline{\delta }=\frac{W}{\nu \left(t\right)\left(1+\frac{L}{D}\text{cos}\left(\gamma \left(t\right)\right)\right)}\left(K_P(p\left({\kappa }_2,\delta \right)-\gamma \left(t\right)\right)-\frac{\nu \left(t\right)}{D}\text{sin}\left(\gamma \left(t\right)\right))$$

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

Now referring to 6 In the illustrated embodiments of the disclosed subject matter, it is desirable to limit the potential for the vehicle 14 and trailer 12 to reach a breakaway angle (ie, the vehicle/trailer system reaches a breakaway condition). A breakaway angle γ(j) refers to a hitch angle γ that cannot be overcome by the maximum steering input for a vehicle during reversing, such as when the steered front wheels of the vehicle 14 are at a maximum steered angle δ with a maximum rate of steering angle change be moved. The breakaway 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 several axles. When the hitch angle γ for the vehicle 14 and trailer 12 reaches or exceeds the breakaway angle γ(j), the vehicle 14 may be pulled forward to reduce the hitch angle γ. Accordingly, in order to limit the potential for a vehicle/trailer system to reach a breakaway angle, it is preferred to control the yaw angle of the trailer 12 while simultaneously keeping the hitch angle γ of the vehicle/trailer system relatively small.

A kinematic model representation of the vehicle 14 and trailer 12 may be used to determine a breakaway angle for the vehicle/trailer combination. Accordingly, a steering angle limitation for the steered front wheels requires reference to 3 and 6 that the coupling angle γ cannot exceed the breakout angle γ(j), which is also referred to as the critical coupling angle γ. Thus, with the restriction that the hitch angle γ cannot exceed the breakout angle γ(j), the breakaway angle γ(j) is the hitch angle γ that maintains circular motion for the vehicle/trailer system when the steered wheels 64 are at one maximum steering angle δ(max). The steering angle for a circular movement with the coupling angle γ is defined using the following equation. $$\text{tan}{\delta }_{\text{Max}}=\frac{\text{w sin}{\gamma }_{\text{Max}}}{\text{D}+\text{L cos}{\mathrm{\gamma }}_{\text{Max}}}$$

wobei: $$\text{a}={\text{L}}^2{\text{tan}}^2\mathrm{\delta }\left(\text{max}\right)+{\text{W}}^2;$$

$$\text{b}=2{\text{ LD tan}}^2\mathrm{\delta }\left(\text{max}\right);\text{ und}$$

$$\text{c}={\text{D}}^2{\text{tan}}^2\mathrm{\delta }\left(\text{max}\right)-{\text{W}}^2.$$

Solving the above equation for the coupling angle γ allows the breakout angle γ(j) to be determined. This solution, shown in the following equation, may be used in implementing the trailer backup assist functionality according to the disclosed subject matter to monitor the hitch angle γ relative to the breakaway angle. $$\text{cos}\overline{\gamma }=\frac{-\text{b}\pm \sqrt{{\text{b}}^2-4\text{ac}}}{2\text{a}}$$

where: $$\text{a}={\text{L}}^2{\text{tan}}^2\mathrm{\delta }\left(\text{Max}\right)+{\text{W}}^2;$$

$$\text{b}=2{\text{LD tan}}^2\mathrm{\delta }\left(\text{Max}\right);\text{and}$$

$$\text{c}={\text{D}}^2{\text{tan}}^2\mathrm{\delta }\left(\text{Max}\right)-{\text{W}}^2.$$

To activate the trailer backup assist system 10, the driver interacts with the trailer backup assist system 10, and the trailer backup assist system 10 automatically steers when the driver reverses the vehicle 14. As explained above, the driver may command the trailer backup path 26 using a steering input device 18, and the curvature controller 28 may determine the vehicle steering angle to achieve the desired backup path 26, with the driver controlling the accelerator and brake while the trailer backup assist system 10 Steering controls.

With reference to 7 When a driver of the vehicle 14 is reversing the trailer 12, the driver may rotate the rotary knob 30 to provide the desired backup path 26 for the trailer or similarly override/change the desired backup path 26 commanded by the mode selector 20. According to the in 7 In the embodiment shown, the steering input device 18 is configured as a rotatable knob 30 to enable the driver of the vehicle 14 to command a desired return path, such as one of the desired return paths 26a-26e, by displaying a desired curvature. In the illustrated embodiment, the rotatable knob 30 rotates about a central axis between a center position 114 corresponding to a substantially straight return path (e.g., desired return path 26c) as defined by the longitudinal direction 22 of the trailer 12 and various rotated positions 116, 118, 120, 122 on opposite sides of the center position 114 and commands a desired curvature κ ₂ corresponding to a radius of the corresponding desired return path (e.g., desired return paths 26b, 26a, 26d, and 26e, respectively) for the trailer 12 at the commanded rotated position .

Now referring to 8th the trailer reversing assistance system 10 is shown equipped with an embodiment of the object proximity sensor 17 for scanning an object 19 in a surrounding field 21. 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 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 warn drivers of objects 19 in and around vehicle blind spots. As such, image cameras, ultrasonic sensors and radar are some examples of an object proximity sensor 17 designed to capture information that characterizes the proximity of an object 19. Embodiments of the trailer backup assist system 10 may utilize 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 can include one or more sensors on the vehicle, one or more sensors on the trailer or a combination of sensors on the vehicle and on the trailer.

As in the in 8th As shown in the illustrated embodiment, the obstacle proximity sensor comprises a sensor system which has a plurality of sensors located on the vehicle and on the trailer are mounted. The illustrated embodiment provides sensors on side mirrors, a rear portion of the vehicle, and a rear portion of the trailer to define a perimeter field 21. Accordingly, in the illustrated embodiment, the perimeter field 21 includes a majority of the area surrounding the vehicle and the trailer, whereby the proximity of the objects 19 can be determined when 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 the vehicle or trailer mounted sensors 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 may additionally or alternatively comprise or be integrated with parts of the coupling angle sensor 44, the positioning device 56 or other additional sensors and devices on or in the vehicle in order to detect, 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 In the illustrated embodiment, the proximity of an object 19 in the surrounding field 21 may be determined in various ways based on the type of sensor near the object 19. For example, if a camera is one of the devices used by the object proximity sensor 17 that can sense the position of the object 19 relative to the vehicle and/or trailer, the controller 28 may be configured to process images from the camera to determine the distance of the vehicle and/or trailer for purposes of processing an object detection routine 130 and an available path routine 132, as disclosed in more detail herein. Furthermore, if an ultrasonic sensor is one of the devices used by the object proximity sensor 17 that can sense the position of the object 19 relative to the vehicle and/or trailer, the controller 28 may be configured to process the feedback signals from the ultrasonic sensor to determine the distance from the vehicle and/or trailer for the purpose of processing the object detection routine 130 and the available path routine 132. It is contemplated that more than one sensor of the object proximity sensor 17 may be used to sense the proximity of an object 19 simultaneously.

With reference to the in 9 In the embodiment shown, three objects 19 are scanned in the surrounding field 21 of the vehicle and the trailer. The objects 19 may include a hazard area, a structure, another vehicle, a natural object, or other obstacles that the curvature control will avoid based on proximity thereto. The objects 19 may also be predefined by the positioning device 56, such as water hazards identified by a GPS device. Of the plurality of possible paths 25 that the trailer can cross, one available row 23 is shown that the trailer can cross without the vehicle or trailer contacting any of the objects 19. In other words, the available series 23 of the plurality of paths is generated by removing return paths with each part of the vehicle or trailer that crosses a space occupied by the objects 19. The return paths that are removed from the plurality of possible paths 25 are highlighted to illustrate the limited availability of return paths that can be selected or entered by the steering input device. Accordingly, it is considered that the illustration 9 can be generated as an image on the display to show the position of the vehicle and trailer relative to the object 19, along with the available series 23 of the plurality of return paths that can be selected by the steering input device to avoid the object 19.

Further embodiments are in 9A-9B shown illustrating objects 19 alternatively arranged with the corresponding available rows 23 of return paths located behind the trailer in the in 9 shown in the general format shown. As in 9A shown, a single object 19 is located adjacent to the vehicle near a left driver's side of the vehicle. Accordingly, the object proximity sensor 17, such as an onboard vehicle proximity sensor, may provide the proximity of the object 19 to the curvature controller 28. It is contemplated that the object proximity sensor 17 may include a camera coupled to a side mirror, as shown in FIG 8th illustrated embodiment is shown. Given the proximity of the in 9A 19 shown, the trailer reversing assistance system 10 can restrict the steered wheels of the vehicle from adjusting beyond a threshold angle to the right when reversing to avoid contacting the object 19, so that the available range 23 of trailer reversing paths is similarly restricted.

As in 9B illustrated, the proximity of the object 19 is arranged so that there are no return paths in the available row 23. In particular, the object 19 is located behind the trailer at a close distance from the rear of the trailer, so that a forward maneuver 134 may be required to reposition the trailer for the vehicle to guide the trailer on a reverse path that covers the area which the object 19 occupies 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 may be generated by the curvature control according to one embodiment, wherein the hitch angle and the object 19 may be monitored to determine when at least one reverse path is provided for the trailer in the available range 23 of reverse paths. As shown in dashed lines, according to one embodiment, a forward maneuver 134 is performed to drive the vehicle and trailer forward to a position that provides at least one return path in the available range 23 of return paths. It is contemplated that the forward maneuver 134 may be generated to command the powertrain control system to automatically drive the vehicle's automatic transmission in drive mode and generate steering commands to the power steering system to position the vehicle and trailer at a location that is at least one Return path provides 23 return paths in the available row. Furthermore, it is conceivable that the object proximity sensor 17 can continue to monitor the surrounding field 21, including the area in front of the vehicle and in the forward path, in order to similarly avoid a collision with an object 19.

Now referring to 10 A method for providing trailer reversing assistance functionality with object avoidance is shown. In the illustrated embodiment, the object detection routine 130 may comprise a first part of the method, and the available path routine 132 may provide a subsequent second part of the method. The method in the illustrated embodiment is initiated at step 136 by sensing the hitch angle between the vehicle and the trailer, which may occur continuously during operation of the trailer backup assist system 10. Furthermore, at step 138, the perimeter field 21, as defined by the object proximity sensor 17, is monitored for an object 19 entering the perimeter field 21. While the surrounding field is being monitored, a determination is made at step 140 as to whether an object 19 is located in the surrounding field 21. In one embodiment, the object 19 is considered to have entered the perimeter field 21 if the proximity is greater than a threshold proximity for the particular vehicle and attached trailer. As such, the threshold proximity may be a set distance between the object 19 and the closest one of the vehicle and trailer, a different distance for different areas of the vehicle and trailer, or may further be dependent on the speed of the vehicle and other operating parameters. which can influence the probability that the object 19 is relevant for the reversing maneuver. As soon as the object 19 is detected in the surrounding field 21, the proximity sensor determines the proximity of the object 19 relative to the vehicle and the trailer in step 142. For example, the one or more sensors of the proximity sensor can determine the position of the object 19, the mass and area occupied by the object 19 and the speed of the object 19, among other conceivable proximity information. It is contemplated that the proximity of the object 19 may be determined simultaneously with determining whether an object 19 is present in the surrounding field 21. If no object 19 is present in the perimeter field 21, the trailer reversing assistance system allows the driver to enter a desired reversing 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 in 10 In the method illustrated, at step 146 the proximity of the object 19 and the sampled hitch angle are used to generate the available range 23 of return paths for the trailer. For this purpose, the kinematic relationship between the vehicle 14 and the trailer 12 can be used, which is based on various vehicle and trailer parameters that can be sensed, entered by the driver or otherwise determined. Like referring 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 hitch 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 described previously. It is contemplated that the steps of determining the kinematic relationship and sensing the hitch angle γ in further embodiments of the trailer backup assist system 10 may occur at other times before steering commands are generated. It is considered that the available row 23 can also be generated with a path planner or other conceivable guidance system. An example of a railway planner is further in the US Patent Application No. 14/257,384 , which is incorporated herein by reference in its entirety.

Accordingly, after the available set 23 of back-up paths is generated by the available path routine 132 of the trailer back-up assist system 10, the method may proceed to step 148 to monitor and determine whether an override command is activated to enable that a desired return path outside the generated available row 23 is selected. In one embodiment, it is conceivable that the driver can activate the override command if the driver determines that the object 19 to be avoided is passable by the vehicle and/or trailer. 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 included in the available set 23 of return paths, so that the notification may prompt the driver as to whether an override command should be activated. It is contemplated that the override may be activated in various ways, such as giving the override command by rotating the rotary knob beyond the available range 23 of reverse travels, pressing the rotary knob to actuate an integrated button, lifting of the rotating knob simultaneously with rotating to the desired return path, selecting an override option from a menu, pressing a dedicated button, and other conceivable possibilities. Accordingly, if the system detects that the override is activated, the desired return path may be entered at step 144 to generate steering commands without regard to the proximity of the object 19.

Further referring to 10 After determining that the override is not activated, a further determination is made at step 150 as to whether the generated available row 23 was able to generate at least one potential return path. If it is determined that no reversing paths are available to avoid the object 19, such a warning notification may be provided to the driver at step 152 and a forward maneuver 134 may be generated. Warning communications include, but are not limited to, a visual warning, an audible warning and a tactile warning. A visual warning may include a display strategy that includes an intelligent device of the driver of the vehicle (e.g., a cell phone or tablet) and/or one or more subsystems in the vehicle (e.g., steering wheel/steering button lighting, camera display lighting, heads-up display, mirror text lighting or schematic screen). These visual alerts may include color, intensity, and flashing frequencies to provide feedback to the driver that a collision mitigation feature is active and/or to help instruct the driver to avoid the collision. An audible warning may include audible sounds or voice commands to instruct the driver to avoid the collision or to inform the driver that an automated collision mitigation feature is active. A tactile warning may include steering wheel torque and/or vibration (ie, haptic feedback) to help the driver avoid the collision or to inform the driver that an automated collision mitigation feature is active. Other subsystems or devices such as phones, tablets, vibrating seats may also be used. Changing frequencies of the vibration can be used to provide the driver with additional information about the likelihood of the collision.

As in 9B As shown, generating the forward maneuver 134 may reposition the trailer for the vehicle to a location that generates a return path in the available row 23 that does not cross the area occupied by an object 19. The forward maneuver 134 according to one embodiment may be generated by the trailer backup assist system to command the powertrain control system to automatically drive the vehicle's automatic transmission in drive mode, then apply vehicle acceleration to move the vehicle and trailer forward, and then provide steering commands for generate the power steering system to position the vehicle and trailer at a location that provides at least one return path in the available series 23 of return paths. After reaching such a position, an embodiment of the forward maneuver 134 may also drive the brake control system 72 to stop the vehicle and trailer, then automatically drive the vehicle's automatic transmission in reverse mode, and then resume the reversing maneuver. It is contemplated that the system may continuously attempt to generate the available series 23 of return paths during the forward maneuver 134. Furthermore, it is conceivable that the object proximity sensor 17 can continue to monitor the surrounding field 21, including the area in front of the vehicle during the forward maneuver 134, in order to similarly avoid a collision with an object 19.

Referring again to 10 After determining that there is at least one return path in the available row 23, the steering input device may enter the desired return path 26 from the available row 23 at step 154. Using the entered desired return path 26 and the sampled coupling angle, steering commands for the Vehicle can be generated in order to guide the trailer on the desired return path 26. In some embodiments, the kinematic relationship is reused to have the trailer backup assist system 10 generate steering commands to the power steering system 62 according to the desired backup path of the trailer 12. As previously described, the desired return path 26 may be equivalent to a desired curvature input for the curvature controller 28 to generate steering commands based on the sensed hitch angle and other kinematic parameters. Therefore, the desired return path 26 can be adjusted 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 reversing assistance system 10 may first determine the proximity of an object 19 within the perimeter field 21 to determine whether the current reversing path of the trailer needs to be changed to limit a potential that the vehicle and/or the trailer collide with object 19. Changing or otherwise correcting the backing path to avoid the object 19 can be done autonomously by slowing or stopping the vehicle to avoid the collision or otherwise steering the vehicle to set the trailer on a backing path in the available range 23 of return routes to be positioned. As such, an operation to determine an appropriate and appropriate action to correct the path of the trailer/vehicle combination (ie, path correction action) may be performed to mitigate the potential of a collision with the object 19, and thereafter an operation may be performed to correct the path of the trailer/vehicle combination Implement path correction action. The path correction action may be implemented by fully 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 based on any number of bases. For example, priority may be given to the object avoidance mode that has the highest probability of mitigating a collision and/or the lowest impact on the operation of the vehicle. 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 pedal deactivation or restriction, and automatic friction or transmission braking may be used to reduce the speed of the vehicle to reduce the likelihood of a collision when prescribed collision avoidance criteria (e.g., a corresponding collision avoidance threshold) which a Avoiding collision with the object 19 corresponds to have been met. 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 meet prescribed collision avoidance criteria corresponding to avoiding collision with the object 19. A trailer curvature control strategy may include reducing a trailer curvature control target (ie, a commanded value) in the trailer backup assist system, for example, using automated steering or HMI guidance based on mappings that use vehicle speed, acceleration, steering rate, and/or transitional steering wheel angle behavior to reduce the potential for a collision with the object 19. Accordingly, implementing the path correction action may include issuing a path correction action command to cause one or more object avoidance strategies to be initiated. In parallel with performing the operations of receiving the trailer backup assist requests, determining the desired backup path 26 and the curvature of the trailer 12, and generating the vehicle steering commands, the trailer backup assist system 10 may 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 hitch angle γ is exceeded, assessing a reverse speed to determine whether a reverse speed threshold is exceeded, assessing a vehicle steering angle to determine whether a vehicle steering angle threshold is exceeded, evaluating other operating parameters (e.g., vehicle longitudinal acceleration, accelerator pedal request rate, and clutch angle rate) to determine whether a corresponding threshold is exceeded, and the like. The return speed may be determined from the wheel speed information obtained from one or more wheel speed sensors 58 of the vehicle 14. If it is determined that an unacceptable trailer backup condition exists, an operation may be performed to cause the current travel path of the trailer 12 to be prevented (e.g., stopping movement of the vehicle 14), followed by the operation resulting in Ending the current trailer reversing assistance case is carried out. It is disclosed herein that before and/or in connection with causing the current trailer path to be prevented, one or more actions (e.g., operations) are required to be ready providing feedback (e.g. a warning) to the driver that such an unacceptable clutch angle condition is impending or approaching can be implemented. In one example, if such feedback results in the unacceptable hitch angle condition being corrected before a critical condition is reached, the method may continue to provide the trailer backup assistance functionality in accordance with the operations. Otherwise, the method may continue with the operation to end the current trailer backup assist case. In conjunction with performing the operation to terminate the current trailer backup assist event, an operation to control movement of the vehicle 14 may be performed to correct or limit a runaway condition (e.g., steering the vehicle 14, slowing 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 prevent the hitch angle from being exceeded).

It is to be understood that variations and modifications may be made to the aforementioned structures and methods 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 insofar as these claims are characterized their language does not explicitly say otherwise.

Claims (9)

Method for reversing a trailer (12) with a vehicle (14), comprising: generating a plurality of reversing paths of the trailer (12); displaying the plurality of return routes on a display; scanning a coupling angle between a vehicle (14) and the trailer (12); scanning a proximity of an object (19) in a surrounding field; generating an available set of back-up paths for the trailer (12) based on the proximity of the object (19) and the hitch angle; highlighting return paths that have been excluded from the available range; and controlling the vehicle (14) using a desired return path (26) from the available series, characterized in that the method further comprises generating a forward maneuver for the vehicle (14) if there are no paths in the available series of return paths, wherein the forward maneuver monitors the position of the vehicle (14) and the trailer (12) to provide notification when there is at least one reverse path in the available range. Procedure according to Claim 1 , further comprising: generating a warning when the proximity of the object (19) reduces the available range of return paths for the trailer (12). Method according to any of the Claims 1 or 2 , wherein the available set of return paths is generated by removing paths that cross a space occupied by the object (19) and paths that cause a breakaway condition between the vehicle (14) and the trailer (12). Method according to any of the Claims 1 - 3 , further comprising: generating images on a display (82) showing the vehicle (14), the trailer (12) and the object (19). Procedure according to Claim 4 , wherein the display (82) includes images representing the available range of return paths and the desired return path (26). Trailer reversing assistance system (10), comprising: a controller that generates an available series of reversing paths for the trailer (12) based on the proximity of the object (19) and the hitch angle, wherein the available series does not include reversing paths that cross a space which is occupied by the object (19), or which cause a breakaway condition between the vehicle (14) and the trailer (12); a steering input device (18) for entering a desired reversing path of a trailer (12), the steering input device (18) being able to activate an override command to enable a desired reversing path (26) to be selected outside of the generated available range, characterized , that the controller generates a forward maneuver for the vehicle (14) if there are no reversing paths in the available row, the forward maneuver monitoring the hitch angle and the object (19) to provide notification when there is at least one reversing path in the available row . Trailer reversing assistance system (10). Claim 6 , wherein the steering input device (18) includes a knob (30) rotatable to define the desired return path (26) such that a first position of the knob (30) has a different curvature than a rotated second position, and wherein a second sensor comprises an ultrasonic sensor. Trailer reversing assistance system (10) according to any one of the claims 6 or 7, further comprising: a display (82) for viewing by a driver of the vehicle (14), the controller generating images on the display (82) showing a position of the vehicle (14) and the trailer (12) relative to the object (19). Trailer reversing assistance system (10). Claim 8 , wherein the control generates an image on the display (82) which is indicative of the available range of return paths for the trailer (12).

Images