SENSOR ERROR REDUCTION SYSTEM AND MODE MANAGEMENT

Abstract

Trailer reversing assistance system (10), comprising the following: a sensor (44) detecting a coupling angle (γ) between a vehicle (14) and a trailer (12); a steering input device (18), providing a reset path (26) of the trailer (12); and a control unit (28) generating a steering instruction for the vehicle (14) based on the clutch angle (γ) and the reset path (26), wherein the control unit (28) generates a countermeasure to operate the vehicle (14) if the sensor (44) cannot detect the clutch angle (γ).

Description

TECHNICAL AREA OF INVENTION

[0001] The disclosure relates generally to trailer motion and parameter estimation, and in particular to coupling angle estimation for a trailer using yaw signals to assist in vehicle steering of the trailer, such as a trailer reversing support system and a sensor error mitigation system. BACKGROUND OF THE INVENTION

[0002] DE 10 2014 201 844 A1 discloses a trailer reversing support system comprising a sensor detecting a coupling angle between a vehicle and a trailer, a steering input device providing a reversing path for the trailer, and a controller generating a steering instruction for the vehicle based on the coupling angle and the reversing path. DE 10 2014 005 681 A1 discloses a sensor error mitigation system for a trailer reversing support system comprising a sensor measuring a coupling angle between a vehicle and a trailer, and a controller detecting sensor errors when measuring the coupling angle and activating a countermeasure if the sensor fails. DE 10 2004 059 596 B4 discloses a method for determining a coupling angle, wherein, in the case of an implausible coupling angle being determined, an old, previous coupling angle is output and the newly determined coupling angle is discarded.Reversing a vehicle while towing a trailer can be challenging for many drivers, especially those who tow trailers infrequently or with different types of trailers. Systems used to assist drivers when reversing a trailer estimate the trailer's position relative to the vehicle using a sensor that determines a coupling angle. The accuracy and reliability of this coupling angle estimate can be critical for the operation of the reversing assistance system. It is understood that reliable coupling angle estimation can also be helpful for additional vehicle characteristics, such as monitoring for trailer sway. BRIEF DESCRIPTION OF THE INVENTION

[0003] The aforementioned problem is solved by a trailer reversing support system with the features of claim 1 and by a sensor error mitigation system with the features of claim 7. Advantageous embodiments are described in the dependent claims. Furthermore, a method for mitigating sensor errors of a trailer reversing support system for detecting a coupling angle between a vehicle and a trailer is described. The method also generates a steering instruction for the vehicle based on the coupling angle. In addition, the method generates a countermeasure instruction for the vehicle if the coupling angle cannot be detected and deactivates the countermeasure instruction upon driver intervention.

[0004] These and other features, advantages and objectives of the present invention will become further understandable and obvious to those skilled in the art by reference to the following description, claims and attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In the drawings: is Fig. 1 a perspective view from above of a vehicle connected to a trailer with an embodiment of a coupling angle sensor for operating a trailer reversing support system; is Fig. 2 a block diagram, representing an embodiment of the trailer reversing support system, comprising a steering input device, a path curvature control and a trailer braking system; is Fig. 3 a schematic representation depicting the geometry of a vehicle and a trailer with a two-dimensional xy-coordinate system superimposed on it, identifying variables used to determine a kinematic relationship of the vehicle and the trailer for the trailer reversing support system according to an embodiment; is Fig. 4 a schematic representation showing a relationship between a coupling angle and a steering angle of the vehicle relative to the track curvature of the trailer and an articulation angle; is Fig. 5 a top view of a steering input device, a rotatable knob for actuating the trailer reversing support system according to an embodiment; is Fig. 6 a top view of a further embodiment of a rotatable knob for selecting a desired track curvature of a trailer and a corresponding schematic representation, showing a vehicle and a trailer with various trailer track curvature paths correlating with possibly selected desired track curvatures; is Fig. 7. A flowchart illustrating a method for operating a trailer reversing support system using an operating routine for steering a trailer reversing vehicle with normalized path curvature according to one embodiment; and is Fig. Figure 8 shows a flowchart illustrating a method according to an embodiment for operating a trailer reversing assistance system after a sensor has failed. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0006] For the purposes of this description, it is understood that the disclosed trailer reversing support system and the associated methods may assume various alternative embodiments and orientations, unless expressly stated otherwise. It is also understood that the specific devices and methods illustrated in the accompanying drawings and described in the following description are merely exemplary embodiments of the concepts according to the invention, which are defined in the accompanying claims.While various aspects of the trailer resetting support system and the 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 can be implemented without departing from the disclosed invention. Therefore, specific dimensions and other physical properties relating to the embodiments disclosed herein are not to be considered limiting unless expressly stated otherwise in the claims.

[0007] Referring to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Reference 8, reference 10, generally designates a trailer reversing support system for controlling a reversing path of a trailer 12 connected to a vehicle 14 by allowing the driver of the vehicle 14 to specify a desired path curvature 26 of the trailer 12's reversing path. In one embodiment, the trailer reversing support system 10 automatically steers the vehicle 14 to guide the trailer 12 along the desired path curvature / reversing path 26 when a driver uses the accelerator and brake pedals to control the reversing speed of the vehicle 14. To monitor the position of the trailer 12 relative to the vehicle 14, the trailer reversing support system 10 may include a sensor system 16 that detects or otherwise determines a coupling angle γ between the trailer 12 and the vehicle 14.In one embodiment, the sensor system 16 can comprise a sensor module 20 attached to the trailer 12, which monitors the dynamics of the trailer 12, such as the yaw rate, and communicates with a controller 28 of the trailer reversing support system 10 to determine the instantaneous coupling angle γ. Accordingly, one embodiment of a sensor module 20 is designed to be attached to the trailer 12 and to generate a trailer yaw rate ω2. The trailer reversing support system 10 according to such an embodiment can also comprise a vehicle sensor system 17, which generates a vehicle yaw rate ω1 and a vehicle speed v1. The controller 28 of the trailer reversing support system 10 can thus estimate a coupling angle γ based on the trailer yaw rate ω2, the vehicle yaw rate ω1, and the vehicle speed v1 with respect to a kinematic relationship between the trailer 12 and the vehicle 14.In another embodiment, the sensor system 16 may additionally or alternatively include a coupling angle sensor 44, such as a vision-based system that uses a camera 46 on the vehicle 14 to monitor a target 52 on the trailer 12 in order to determine the coupling angle γ, and in some embodiments to increase the reliability of the overall estimated coupling angle γ.

[0008] With regard to the general operation of the trailer reversing support system 10, a steering input device 18, such as a rotary knob 30, can be provided for a driver to set the desired trajectory curvature 26 of the trailer 12. Therefore, the steering input device 18 can be operated in several modes, such as successive rotation positions of a knob 30, each of which represents an incremental change to the desired trajectory curvature 26 of the trailer 12. Upon input of the desired trajectory curvature 26, the controller 28 can generate a steering instruction for the vehicle 14 to guide the trailer 12 along the desired trajectory curvature 26 based on the estimated coupling angle γ and a kinematic relationship between the trailer 12 and the vehicle 14.Considering that the accuracy of the coupling angle estimation is critical for operating the trailer resetting support system 10, fault transition systems related to the failure of sensors (e.g., the sensor module 20, the coupling angle sensor 44, or the camera 46) used to detect the coupling angle γ are a desirable feature in the trailer resetting support system 10. Accordingly, the controller 28 of the trailer resetting support system 10 can detect the failure of a sensor measuring the coupling angle γ and initiate a countermeasure if the sensor fails, until the driver regains operational control of the vehicle 14. It is understood that such a system for directly estimating the coupling angle and an associated fault transition system for sensor failures can be used in conjunction with additional or alternative vehicle features, such as trailer sway monitoring.

[0009] Referring to the embodiment from Fig. In Figure 1, the vehicle 14 is a pickup truck configuration equipped with an embodiment of the trailer reversing support system 10 for controlling the reversing path of the trailer 12 connected to the vehicle 14. Specifically, the vehicle 14 is rotatably mounted to an embodiment of the trailer 12, which has a box frame 32 with an enclosed loading area 34, a single axle, a right-hand wheel arrangement, a left-hand wheel arrangement, and a drawbar 36 extending longitudinally forward from the enclosed loading area 34. The illustrated trailer 12 also has a trailer coupling connector in the form of a coupling assembly 38, which is connected to a vehicle coupling connector in the form of a coupling ball 40. The coupling assembly 38 locks onto the coupling ball 40 to provide a rotatable ball joint connection 42, which allows for a change in the coupling angle γ.It is understood that additional embodiments of the trailer 12 can alternatively be coupled to the vehicle 14 to provide a rotatable connection, for example via a fifth-wheel coupling. It is also considered that additional embodiments of the trailer may include more than one axle and may have different shapes and sizes, designed for different loads and objects, such as a boat trailer or a flatbed trailer.

[0010] Further referring to Fig. In the illustrated embodiment, the sensor system 16 comprises both a sensor module 20 and a vision-based coupling angle sensor 44 for estimating the coupling angle γ between the vehicle 14 and the trailer 12. The illustrated coupling angle sensor 44 uses a camera 46 (e.g., a video camera) which can be located near the upper area of ​​the vehicle's tailgate 48 at the rear of the vehicle 14, as shown, so that the camera 46 can be elevated relative to the drawbar 36 of the trailer 12. The illustrated camera 46 has a field of view 50, positioned and oriented to capture one or more images of the trailer 12, comprising an area containing one or more target positioning zones for at least one target 52 to be secured.Although it is considered that the camera 46 can capture images of the trailer 12 without a target 52 to determine the coupling angle γ, the trailer reversing support system 10 in the illustrated embodiment includes a target 52 positioned on the trailer 12 to allow the trailer reversing support system 10 to utilize the information obtained from the image capture and processing of the target 52. For example, the illustrated camera 46 can include a video camera that repeatedly captures successive images of the trailer 12, which can be processed to determine the target 52 and its position on the trailer 12 in order to determine the movement of the target 52 and the trailer 12 relative to the vehicle 14 and the associated coupling angle γ.It is also understood that the camera 46 can include one or more video cameras and can be positioned at other locations on the vehicle 14 to capture images of the trailer 12 and the desired target positioning zone, such as on a passenger cabin 54 of the vehicle 14 to capture images of a gooseneck trailer.Furthermore, it is considered that additional embodiments of the clutch angle sensor 44 and the sensor system 16 for providing the clutch angle γ may 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 rotating ball joint 42, energy converters of a reversing support system, a blind spot system and / or a cross-traffic warning system, as well as other suitable sensors or displays of the clutch angle γ for supplementing or using instead of the sight-based clutch angle sensor 44.The sensors or displays of the coupling angle sensor 44 and the sensor system 16 can be used by fault transition systems of the trailer reset support system 10, so that a failure of a sensor (e.g. the coupling angle sensor 44) can be mitigated by using alternative sensors to detect the coupling angle γ, among other countermeasures which are described in more detail below.

[0011] The embodiment of the in Fig. The sensor module 20 shown in Figure 1 comprises an encapsulated sensor group 21 mounted on the drawbar 36 of the trailer 12 near the enclosed loading area 34 and includes left and right wheel speed sensors 23 on laterally opposite wheels of the trailer 12. It is possible that the wheel speed sensors 23 are bidirectional wheel speed sensors for monitoring both forward and reverse speeds. It is also considered that, in additional embodiments, the sensor group 21 can be mounted on alternative parts of the trailer 12.

[0012] The sensor module 20 can generate multiple signals indicating different dynamic behaviors of the trailer 12. These signals can include a yaw rate signal, a lateral acceleration signal, and wheel speed signals, each generated by a yaw rate sensor 25, an accelerometer 27, and the wheel speed sensors 23, respectively. Accordingly, in the illustrated embodiment, the yaw rate sensor 25 and the accelerometer 27 are contained within the housed sensor group 21, although other configurations are possible. It is conceivable that, in some embodiments, the accelerometer 27 could consist of two or more separate sensors and be arranged with an angular offset, such as two sensors positioned at plus and minus forty-five degrees from the longitudinal direction of the trailer, or parallel to the longitudinal and lateral directions of the trailer, to generate a more robust acceleration signal.It is also considered that these sensor signals can be compensated and filtered to remove offset or drift and to smooth noise. Furthermore, the controller 28 can utilize processed signals received from outside the sensor system 16, including standard signals from the brake control system 72 and the power steering system 62, such as vehicle yaw rate ω1, vehicle speed v1, and steering angle δ, to estimate the trailer coupling angle γ, trailer speed, and related trailer parameters. As will be described in detail below, the controller 28 can estimate the coupling angle γ based on the trailer yaw rate ω2, the vehicle yaw rate ω1, and the vehicle speed v1 with respect to a kinematic relationship between the trailer 12 and the vehicle 14.The control unit 28 of the trailer reset support system 10 can also use the estimated trailer variables and trailer parameters to utilize the steering system 62, brake control system 72 and powertrain control system 74, such as to assist in resetting the vehicle and trailer combination or to mitigate the failure of a sensor used by the trailer reset support system 10.

[0013] Referring to the in Fig. In the embodiment of the trailer resetting support system 10 shown in Figure 2, the trailer resetting support system 10 can receive vehicle- and trailer-related information from additional sensors and devices. These additional sensors and devices can be used in place of the coupling angle sensor 44 or the sensor module 20 if one or more of the sensors used to determine the coupling angle γ (e.g., the coupling angle sensor 44) fail. This trailer-related information includes positioning information from a positioning device 56, which may include a global positioning system (GPS) on the vehicle 14 or a handheld device for determining a coordinate position of the vehicle 14 and the trailer 12 based on the location of the positioning device 56 relative to the trailer 12 and / or the vehicle 14 and based on the estimated coupling angle γ.The positioning device 56 may additionally or alternatively include a dead reckoning navigation system for determining the coordinate position of the vehicle 14 and the trailer 12 within a localized coordinate system based at least on vehicle speed, steering angle, and coupling angle γ. Other vehicle information received by the trailer resetting support system 10 may include the vehicle 14's speed from a speed sensor 58 and the vehicle 14's yaw rate from a vehicle yaw rate sensor 60.It is considered that in additional embodiments the coupling angle sensor 44 and other vehicle sensors and devices may provide sensor signals or other information, such as proximity sensor signals or successive images of the trailer 12, which the control of the trailer reversing support system 10 can process with various routines to determine an indicator for the coupling angle γ, such as a range of coupling angles.

[0014] What's next in Fig. Figure 2 shows an embodiment of the trailer reversing support system 10 communicating with a power steering system 62 of the vehicle 14 to control the steered wheels 64 ( Fig. 1) to actuate the vehicle 14 in order to move the vehicle 14 in such a way that the trailer 12 reacts in accordance with the desired path curvature 26 of the trailer 12. In the illustrated embodiment, the power steering system 62 is an electric power steering system (EPAS) comprising an electric steering motor 66 for rotating the steered wheels 64 by a steering angle based on a steering instruction, whereby the steering angle can be detected by a steering angle sensor 67 of the power steering system 62. The steering instruction can be provided by the trailer reversing support system 10 for autonomous steering during a reversing maneuver and can alternatively be given manually via a rotational position (e.g. steering wheel angle) of a steering wheel 68 ( Fig. 1) are 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, so that the steering wheel 68 moves together with the steered wheels 64 via an internal torque, preventing manual intervention with the steering wheel 68 during autonomous steering. In particular, a torque sensor 70 is provided on the power steering system 62, which detects torque (e.g., gripping and / or turning) on ​​the steering wheel 68 that is not expected from autonomous control of the steering wheel 68 and therefore indicates manual intervention by the driver. In some embodiments, external torque acting on the steering wheel 68 can serve as a signal to the control unit 28 that the driver has taken over manual control and that the vehicle 14 aborts steering maneuvers and / or alarms.

[0015] In alternative embodiments, some vehicles have a power steering system 62 that allows a steering wheel 68 to be partially decoupled from the movement of the steered wheels 64 of such a vehicle. Accordingly, the steering wheel 68 can be turned independently of the way in which the vehicle's power steering system 62 controls the steered wheels 64 (e.g., autonomous steering as instructed by the trailer reversing support system 10). Therefore, in these types of vehicles, where the steering wheel 68 can be selectively decoupled from the steered wheels 64 to allow independent operation of the same, the steering wheel 68 can be used as a steering input device 18 for the trailer reversing support system 10, as is disclosed in more detail herein.

[0016] Referring again to the in Fig. In the embodiment shown in Figure 2, the power steering system 62 provides the control unit 28 of the trailer reversing support system 10 with information relating to the rotational position of the steered wheels 64 of the vehicle 14, including a steering angle. In this embodiment, the control unit 28 processes the current steering angle in addition to other conditions of the vehicle 14 and trailer 12 in order to guide the trailer 12 along a desired path curve 26. It is conceivable that in further embodiments, the trailer reversing support system 10 could be an integrated component of the power steering system 62.For example, the power steering system 62 may include a trailer resetting assistance algorithm for generating vehicle steering information and instructions as a function of all or some of the information received from the steering input device 18, the clutch angle sensor 44, the power steering system 62, a vehicle brake control system 72, a powertrain control system 74 and other vehicle sensors and devices.

[0017] As also in Fig. As shown in Figure 2, the vehicle brake control system 72 can also communicate with the controller 28 to provide braking information, such as vehicle wheel speed, to the trailer resetting support system 10 and to receive braking instructions from the controller 28. For example, vehicle speed information can be determined from the individual wheel speeds monitored by the brake control system 72. Among other possible means, the vehicle speed can also be determined by the powertrain control system 74, the speed sensor 58, and the positioning device 56. In some embodiments, the individual wheel speeds can also be used to determine a vehicle yaw rate, which can be provided to the trailer resetting support system 10 alternatively or additionally to the vehicle yaw rate sensor 60.In certain embodiments, the trailer resetting support system 10 can provide vehicle braking information to the brake control system 72, enabling the trailer resetting support system 10 to control the vehicle's brakes 14 during the resetting of the trailer 12. For example, in some embodiments, the trailer resetting support system 10 can regulate the vehicle's speed 14 during the resetting of the trailer 12, which can reduce the potential for unacceptable trailer resetting conditions.Examples of unacceptable trailer reset conditions include, but are not limited to, an overspeed condition of the vehicle 14, a high coupling angle rate, dynamic instability of the trailer angle, a calculated theoretical trailer buckling condition (defined by a maximum vehicle steering angle, drawbar length, wheelbase of the towing vehicle, and an effective trailer length), or buckling limitation due to physical contact (defined by an angular offset limit relative to the vehicle 14 and the trailer 12), and similar conditions. Unacceptable trailer reset conditions may also occur if one or more sensors (e.g., coupling angle sensor 44) and / or inputs (e.g., steering input device 18) on the vehicle 14 and / or trailer 12 are unable to provide information to the controller 28 of the trailer reset support system 10.In such cases, the driver may not be aware of the sensor fault until the unacceptable trailer reset condition is imminent or has already occurred. Therefore, it is hereby disclosed that the trailer reset support system 10 can generate an alarm signal, corresponding to a notification of an actual, imminent, and / or anticipated unacceptable trailer reset condition, and can generate a countermeasure prior to driver intervention to prevent such an unacceptable trailer reset condition, as described below.

[0018] The powertrain control system 74, as described in Fig. As shown in the embodiment 2, the trailer reversing support system 10 can also interact with the vehicle 14 to regulate its speed and acceleration during trailer reversal. As mentioned above, regulating the vehicle 14's speed may be necessary to limit the potential for unacceptable trailer reversing conditions, such as buckling and dynamic instability of the trailer angle, or when a sensor and / or input device failure is detected. Similar to the considerations regarding high speed, as this is associated with unacceptable trailer reversing conditions, trajectory curvature requirements imposed by the driver with high acceleration and high dynamics can also lead to such unacceptable trailer reversing conditions.

[0019] Further referring to Fig. 2. In the illustrated embodiment, the trailer resetting support system 10 can communicate with one or more devices, comprising a vehicle alarm system 76, which can issue visual, audible, or haptic warnings. For example, the vehicle's brake lights 78 and hazard warning lights can provide a visual alarm, and a vehicle horn 79 and / or a loudspeaker 81 can provide an audible alarm. Furthermore, the trailer resetting support system 10 and / or vehicle alarm system 76 can communicate with a human-machine interface (MMS) 80 for the vehicle 14. The MMS 80 can communicate with a vehicle display 82, such as a center console-mounted navigation and entertainment display ( Fig. 1) include images that can display warnings. Such an embodiment may be desirable to notify the driver of vehicle 14 that a sensor and / or input device used by the trailer reset support system 10 has failed. Furthermore, the trailer reset support system 10 can communicate wirelessly with another embodiment of the MMS 80, such as one or more handheld or portable devices, including one or more smartphones.

[0020] What's next in Fig. As shown in Figure 2, the trailer reversing support system 10 comprises the steering input device 18, which is connected to the controller 28 to allow information exchange between them. It is disclosed here that the steering input device 18 can be coupled to the controller 28 in a wired or wireless manner. The steering input device 18 provides the trailer reversing support system 10 with information that defines the desired reversing path of the trailer 12 for processing by the controller 28 and generation of steering instructions. In particular, the steering input device 18 can provide selection or position information that correlates with a desired path curvature 26 of the desired reversing path of the trailer 12.Furthermore, the trailer steering instructions provided by the steering input device 18 may include information relating to an instructed change of the driving path, such as an incremental change of the desired path curvature 26, as well as information relating to an indication that the trailer 12 is to travel along a path defined by a longitudinal centerline axis of the trailer 12, such as a desired path curvature value of zero, which defines an substantially straight driving path for the trailer.

[0021] As discussed in more detail below, the steering input device 18, according to one embodiment, can comprise a movable control input device to allow a driver of the vehicle 14 to instruct desired trailer steering actions or, alternatively, to select and change a desired path curvature. For example, the movable control input device can be a rotatable knob 30 that can be rotated about an axis of rotation extending through an upper surface or face of the knob 30. In other embodiments, the rotatable knob 30 can be rotatable about an axis of rotation extending substantially parallel to an upper surface or face of the rotatable knob 30.Furthermore, according to additional embodiments, the steering input device 18 may include alternative devices for providing a desired path curvature 26 or other information defining a desired reset path, such as a joystick, a keypad, a series of pushable buttons or switches, a sliding input device, various user interfaces on a touchscreen display, a vision-based gesture detection system, a control interface on a portable device, and other conceivable input devices as generally understood by a person skilled in the art. It is considered that the steering input device 18 may also function as an input device for other features, such as providing inputs for other vehicle features or systems.

[0022] Still referring to the in Fig. In the embodiment shown in Figure 2, the controller 28 is designed with a microprocessor 84 for processing logic and routines stored in memory 86, which receive information from the sensor system 16, including the trailer sensor module 20, the coupling angle sensor 44, the steering input device 18, the power steering system 62, the vehicle brake control system 72, the trailer brake system, the powertrain control system 74, and other vehicle sensors and devices. The controller 28 can generate vehicle steering information and instructions as a function of all or part of the received information. The vehicle steering information and instructions can then be provided to the power steering system 62 to influence the steering of the vehicle 14 in order to achieve a directed path for the trailer 12. The controller 28 can include the microprocessor 84 and / or other analog and / or digital circuits for processing one or more routines.The controller 28 can also include the memory 86 for storing one or more routines, including a clutch angle estimation routine 130, an operating routine 132, and a path curvature routine 98. It is understood that the controller 28 can be a stand-alone, dedicated controller or a shared controller that integrates other control functions, such as the sensor system 16, the power steering system 62, and other relevant onboard and offboard vehicle control systems.

[0023] Referring to Fig. 3 We now begin with a discussion of vehicle and trailer information and parameters used to calculate a kinematic relationship between the path curvature of the trailer 12 and the steering angle of the vehicle 14 towing the trailer 12. This may be desirable for a trailer reversing support system 10 designed according to some embodiments, including for use by a path curvature routine 98 of the controller 28 in one embodiment. To obtain such a kinematic relationship, certain assumptions can be made regarding parameters related to the vehicle / trailer system. Examples of such assumptions include, but are not limited to, the trailer 12 being reversed by the vehicle 14 at a relatively low speed, the wheels of the vehicle 14 and the trailer 12 exhibiting negligible (e.g., no) slip, and the tires of the vehicle 14 exhibiting negligible (e.g.,exhibiting no lateral elasticity, the tires of the vehicle 14 and the trailer 12 exhibiting negligible (e.g., no) deformation, the actuator dynamics of the vehicle 14 exhibiting negligible, and the vehicle 14 and the trailer 12 exhibiting negligible (e.g., no) roll or pitch movements, among other conceivable factors with the potential to have an effect on the steering of the trailer 12 with the vehicle 14.

[0024] As in Fig. As shown in Figure 3, for a system defined by a vehicle 14 and a trailer 12, the kinematic relationship is based on various parameters related to the vehicle 14 and the trailer 12. These parameters include: δ: Steering angle at the steered front wheels of the vehicle; α: Yaw angle of the vehicle; β: Yaw angle of the trailer; γ: coupling angle (γ=β-α); W: Wheelbase of the vehicle; L: Length of the drawbar between the coupling point and the rear axle of the vehicle; D: Distance (trailer length) between the coupling point and the axle of the trailer, or effective axle for a multi-axle trailer; and r2: Radius of curvature for the trailer.

[0025] One embodiment of a kinematic relationship between the trailer's path radius r2 at the center of an axis of the trailer 12, the steering angle δ of the steered wheels 64 of the vehicle 14, and the coupling angle γ can be expressed in the equation given below. Therefore, if the coupling angle γ is given, the trailer's path radius κ2 can be controlled based on regulating the steering angle δ (where β is the trailer yaw rate and η is the trailer speed). κ2=1r2=β˙η˙=(W+KV2g)sin γ+L cos γ tan δD((W+KV2g)cos γ−L sin γ tan δ

[0026] This relationship can be expressed to provide the steering angle δ as a function of the trailer path curvature κ2 and the coupling angle γ. δ=tan−1((W+KV2g)[κ2Dcosγ−sinγ]DLκ2sinγ+Lcosγ)=F(γ,κ2,K)

[0027] Accordingly, for a specific vehicle-trailer combination, certain parameters (e.g., D, W, and L) of the kinematic relationship are constant and assumed to be known. V is the vehicle's 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 can be predefined in an electronic control system of the vehicle 14, and trailer-specific parameters of the kinematic relationship can be entered by a driver of the vehicle 14, determined from detected trailer behavior in response to vehicle steering commands or otherwise determined from signals provided by the trailer 12. The trailer's path curvature κ2 can be determined from the driver input via the steering input device 18.By using the equation to provide the steering angle, an associated steering instruction can be generated by the path curvature routine 98 to control the power steering system 62 of the vehicle 14.

[0028] In an additional embodiment, the track curvature routine 98 can assume that the longitudinal distance L between the rotating link and the rear axle of the vehicle 14 is zero for the purpose of operating the trailer reversing support system 10 when a gooseneck semi-trailer or other similar trailer is connected via a coupling ball or fifth wheel coupling located above a rear axle of the vehicle 14. This assumption essentially presupposes that the rotating link with the trailer 12 is oriented substantially vertically to the rear axle of the vehicle 14. When such an assumption is made, the controller 28 can generate the steering angle instruction for the vehicle 14 as a function independent of the longitudinal distance L between the rotating link and the rear axle of the vehicle 14.It is understood that the aforementioned gooseneck semi-trailer generally refers to a drawbar design which is raised for connection to the vehicle 14 at an elevated position above the rear axle, such as inside a flatbed of a wagon, whereby embodiments of the gooseneck semi-trailer may include flatbed loading areas, enclosed loading areas, camping trailers, livestock trailers, horse trailers, low loader trailers and other conceivable trailers with such a drawbar design.

[0029] Now referring to Fig. 4. In the illustrated embodiment of the disclosed object, it may be desirable to limit the potential for the vehicle 14 and the trailer 12 to reach an articulation angle (i.e., the vehicle / trailer system to reach an articulation condition). An articulation angle γ(j) refers to a coupling angle γ that cannot be overcome during reversing by the maximum steering input for a vehicle, such as moving the steered front wheels of the vehicle 14 at a maximum steering angle change rate to a maximum steered angle δ. The articulation angle γ(j) is a function of a maximum wheel angle for the steered wheels 64 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 trailer length D between the coupling point and the axle of the trailer 12, or the effective axle if the trailer 12 has multiple axles.If the coupling angle γ for the vehicle 14 and the trailer 12 reaches or exceeds the articulation angle γ(j), the vehicle 14 can be pulled forward to reduce the coupling angle γ. Therefore, to limit the potential for a vehicle / trailer to reach an articulation angle, it is preferable to control the yaw angle of the trailer 12 while keeping the coupling angle γ of the vehicle / trailer system relatively small.

[0030] A kinematic model representation of the vehicle 14 and the trailer 12 can also be used to determine an articulation angle for the vehicle-trailer combination. Accordingly, with reference to Fig. 3 and Fig. 4. A steering angle limitation exists, stipulating that the coupling angle γ must not exceed the articulation angle γ(j), which is also referred to as the critical coupling angle γ. Therefore, subject to the limitation that the coupling angle γ must not exceed the articulation angle γ(j), the articulation angle γ(j) is the coupling angle γ that maintains circular motion for the vehicle / trailer system when the steered wheels 64 are at a maximum steering angle δ(max). The steering angle for circular motion with coupling angle γ is defined by the following equation. tan δmax=w sin γmaxD+L cos γmax

[0031] Solving the above equation for the coupling angle γ allows the articulation angle γ(j) to be determined. This solution, shown in the following equation, can be used when implementing the trailer reversing support function according to the disclosed subject matter to monitor the coupling angle γ in relation to the articulation angle. cos γ¯=−b±b2−4ac2a where a=L 2 tan 2 δ(max) +W 2 ; b=2LDtan 2 δ(max); and c=D 2 tan 2 δ(max) -W 2 .

[0032] In certain cases, when reversing the trailer 12 based on current operating parameters of the vehicle 14 in combination with an associated coupling angle γ, a buckling-enabling condition may arise. This condition may be displayed if one or more specified vehicle operating thresholds are met while a specific coupling angle γ is present. For example, although the specific coupling angle γ is not currently at the buckling angle for the vehicle 14 and the connected trailer 12, certain vehicle operating parameters may cause a rapid (e.g., uncontrolled) transition of the coupling angle γ to the buckling angle for a currently specified trailer track curvature and / or may reduce the ability to steer the trailer 12 away from the buckling angle. One reason for a buckling-enabling condition is that trailer track curvature control mechanisms (e.g.,which, according to the disclosed subject matter, generally calculate steering instructions at an instantaneous point in time during the reversing of a trailer 12. However, these calculations typically do not take into account the delay in the steering control system of the vehicle 14 (e.g., delay in a steering EPAS control). Another reason for the buckling-enabled condition is that trailer curvature control mechanisms generally exhibit reduced steering sensitivity and / or effectiveness when the vehicle 14 is traveling at relatively high speeds and / or when it is subjected to relatively high acceleration.

[0033] According to one embodiment, information for determining buckling can be received by the control unit 28 in order to process and characterize a buckling-enabling condition of the vehicle and trailer combination at a specific time (e.g., at the time when the buckling information was acquired).Examples of information for determining buckling include, but are not limited to, information characterizing an estimated coupling angle γ, information characterizing a vehicle accelerator pedal state, information characterizing a vehicle speed 14, information characterizing a vehicle longitudinal acceleration 14, information characterizing a braking torque applied by a vehicle braking system 14, information characterizing a drivetrain torque applied to the vehicle's driven wheels 14, and information characterizing the magnitude and rate of trailer path curvature requested by the driver. In this context, the information for determining buckling would be continuously monitored, such as by an electronic control unit (ECU) performing the Trailer Backup Assist (TBA) function.After receiving buckling information, a routine can process this information to determine whether the vehicle-trailer combination has reached the buckling-enabling condition at the specified time. The goal of evaluating the buckling information is to determine whether a buckling-enabling condition was reached at the time defined by the buckling information. If it is determined that a buckling-enabling condition exists at the specified time, a routine can also determine an applicable countermeasure or countermeasures to implement. Accordingly, in some embodiments, an applicable countermeasure is selected depending on a parameter identified as a key influencing factor of the buckling-enabling condition.However, in further embodiments, an applicable countermeasure is selected as best suited to reducing the condition enabling buckling. In yet another embodiment, a predefined countermeasure or a predefined set of countermeasures can be the applicable countermeasure(s).

[0034] As already disclosed with reference to the illustrated embodiments, a driver of the vehicle 14 may be restricted during the operation of the trailer reversing support system 10 in such a way that inputs can be made via the steering wheel 68 of the vehicle 14, since the power steering system 62 is directly coupled to the steering wheel 68. Accordingly, the steering input device 18 of the trailer reversing support system 10 can be used to input a desired path curvature 26 of the trailer 12, thus decoupling such instructions from being made via the steering wheel 68 of the vehicle 14.However, additional embodiments of the trailer reversing support system 10 may have the ability to selectively decouple the steering wheel 68 from the movement of the steerable wheels of the vehicle 14, thereby allowing the steering wheel 68 to be used to instruct changes to the desired path curvature 26 of a trailer 12 or otherwise to select a desired reversing path during such trailer reversing support.

[0035] Now referring to Fig. Figure 5 shows an embodiment of the steering input device 18, arranged on a center console 108 of the vehicle 14 near a gearshift lever 110. In this embodiment, the steering input device 18 comprises the rotatable knob 30 for providing the desired reset path of the trailer 12 to the control 28. In particular, the angular position of the rotatable knob 30 can correlate with a desired path curvature, such that rotating the knob to a different angular position provides a different desired path curvature with an incremental change based on the degree of rotation and, in some embodiments, a normalized rate, as will be described in more detail hereafter.

[0036] The rotary knob 30, as in the Fig. 5 and Fig. As shown in Figure 6, a mean or rest position P(AR) 114 can be preset between opposite rotation ranges of the movement R(R), R(L) (e.g., by a spring return). In the illustrated embodiment, a first of the opposite rotation ranges of the movement R(R) is essentially the same as a second of the opposite rotation ranges of the movement R(L), R(R). To provide a haptic indication of the degree of rotation of the rotatable knob 30, a force that presets the knob towards a rest position P(AR) 114 can increase as a function of the degree of rotation of the rotatable knob 30 with respect to the rest position P(AR) 114 (e.g., non-linearly). Furthermore, the rotary knob 30 can be designed with position-indicating indentations so that the driver can clearly feel the rest position P(AR) 114 and feel the approach of the ends of the opposite rotation ranges of the movement R(L), R(R) (e.g. soft end stop).The rotatable knob 30 can generate a desired path curvature value as a function of the degree of rotation of the rotatable knob 30 with respect to the rest position P(AR) 114 and a direction of movement of the rotatable knob 30 with respect to the rest position P(AR) 114. It is also considered that the rotation rate of the rotatable knob 30 can also be used to determine the desired path curvature output for control 28. The rest position P(AR) of the knob corresponds to a signal indicating that the vehicle 14 should be steered so that the trailer 12 is reversed along an substantially straight reset path (trailer path curvature requirement zero from the driver), as defined by the longitudinal direction 22 of the trailer 12 when the knob 30 has been moved back to the rest position P(AR). A maximum position of the knob 30 clockwise and counterclockwise (i.e.,Limits of the opposite rotation ranges of the motion R(R), R(L)) can each correspond to a corresponding signal, indicating a tightest path radius of curvature (i.e. sharpest trajectory or smallest path radius of curvature) of a path of the trailer 12 that is possible without the associated vehicle steering information causing a buckling condition.

[0037] As in Fig. As shown in Figure 6, a driver can turn the rotatable knob 30 to provide a desired path curvature 26 while the driver of the vehicle 14 reverses the trailer 12. In the illustrated embodiment, the rotatable knob 30 rotates about a central or middle position 114, corresponding to a substantially straight reversing path 26 as defined by the longitudinal direction 22 of the trailer 12, and various rotation positions 116, 118, 120, 122 on opposite sides of the central position 114, instructing a desired path curvature 26 corresponding to a radius of the desired reversing path for the trailer 12 at the instructed rotation position. It is considered that, according to embodiments of the disclosed object, the rotatable knob 30 can be designed to omit a means for presetting to a rest position P(AR) between opposite rotation ranges of the movement.The absence of such a preset may allow the current rotational position of the rotary knob 30 to be maintained until the rotary control input device is manually moved to a different position. It is also conceivable that the steering input device 18 may include a non-rotating control device designed to selectively provide a desired path curvature 26 and to override or supplement an existing path curvature value. Examples of such a non-rotating control input device include, but are not limited to, multiple pressable buttons (e.g., turn left, turn right, go straight), a touchscreen on which a driver draws or otherwise inputs a path curvature for route instructions, a button that is movable along an axis to allow a driver to input reset path instructions, or a cross-beam type input, and the like.

[0038] Referring to Fig. Figure 7 presents a method for operating an embodiment of the trailer resetting support system 10, shown as an embodiment of the operating routine 132 ( Fig. 2) In step 134, the procedure is initiated by activating the trailer reset support system 10. It is considered that this can be done in various ways, such as by making a selection on the display 82 of the vehicle MMS 80. The next step 136 then determines the kinematic relationship between the connected trailer 12 and the vehicle 14. To determine the kinematic relationship, various parameters of the vehicle 14 and the trailer 12 must be acquired, entered by the driver, or otherwise determined for the trailer reset support system 10 in order to generate steering instructions for the power steering system 62 in accordance with the desired path curvature or reset path 26 of the trailer 12. As referred to in Fig. 3 and Fig. As disclosed in Figure 4, the kinematic parameters for defining the kinematic relationship include the length of the trailer 12, the wheelbase of the vehicle 14, the distance from a coupling connection to a rear axle of the vehicle 14, and a coupling angle γ between the vehicle 14 and the trailer 12, among other variables and parameters as previously described. Accordingly, after determining the kinematic relationship at step 160, the trailer reversing support system 10 can proceed to determine the current coupling angle by processing the coupling angle estimation routine 130.

[0039] Referring to Fig. 8. Due to the automated nature of the trailer resetting support system 10, it is desirable to provide fault transition systems designed for this purpose, which are implemented if a sensor used in the operation of the trailer resetting support system 10 fails during use. In such a circumstance, it would be desirable for the system to warn the driver of the sensor failure, implement at least one countermeasure to prevent an unacceptable trailer resetting condition (e.g., a jackknife condition or an overspeed condition) from occurring before the driver is able to react to the sensor failure, and terminate the alarm and countermeasure after the driver has regained manual control of the vehicle 14.

[0040] Accordingly, a method for operating a sensor error reduction routine 180 is presented. Similar to other trailer reset support routines, the sensor error reduction routine 180 can also be stored in memory 86 of the controller 28 ( Fig. 2) The sensor fault mitigation routine 180 takes place during the operating routine 132 and is activated by step 182 of detecting a sensor fault. Sensors that can fail and activate the sensor fault mitigation routine 180 are those used by the trailer resetting support system 10 in the operating routine 132 during the reversing of the vehicle 14 and trailer 12. After the failure of the sensor (e.g., the coupling angle sensor 44) is detected, step 184 is performed to generate an alarm. The alarm can be audible, visual, and / or haptic and can include any of the alarms mentioned above. The alarm is designed to notify the driver that a sensor has failed and that manual control of the vehicle 14 is required. After step 184 is performed to generate an alarm, step 186 is performed to generate a countermeasure.It is also considered that, in an additional embodiment, step 184 for generating the alarm and step 186 for generating the countermeasure could also be performed simultaneously or in a manner different from the representation in . Fig. 8 can be performed in reverse order without deviating from the disclosure. Step 188 for detecting driver intervention (e.g., an external torque acting on the steering wheel 68) is then determined. If the controller 28 does not detect driver intervention, the fault mitigation routine 180 will retrigger or continue step 184 for generating the alarm and / or step 186 for generating the countermeasure. If driver intervention is detected in step 188, step 190 for deactivating the countermeasure and the alarm is performed.

[0041] Referring again to Fig. 8. Step 182 of detecting a sensor fault can include more than just mechanical or electrical faults of the sensor. For example, the sensor fault can include: failure of controller 28 to receive a signal from the sensor after a threshold time period, a power failure at the sensor and / or controller 28, a mechanical and / or electrical failure within the controller 28, an inability of the controller 28 to detect and / or process signals sent by the sensor, wiring or transmission problems between the sensor and the controller 28, and any malfunction or fault that can prevent the controller 28 from generating a steering instruction based on signals from the sensor.

[0042] Further referring to Fig. Step 186 may involve generating a countermeasure, such as a braking instruction, a powertrain instruction, and / or a steering instruction from the controller 28. In some embodiments, a combination of instructions may be generated or activated during step 186, depending on the nature of the sensor fault and the vehicle-trailer dynamics. In other embodiments, the intensity, or extent, of the generated countermeasure may vary depending on the nature of the sensor fault and the vehicle-trailer dynamics. The countermeasures are designed to prevent the vehicle 14 and trailer 12 from entering an unacceptable trailer reset condition (e.g., a jackknife condition or an overspeed condition) before the driver has time to respond to the sensor fault by resuming manual control.The brake instruction countermeasure instructs the brake control system 72 to increase the brake pressure on the vehicle 14 and / or trailer 12, thereby reducing the speed regardless of the brake pedal position. The powertrain instruction countermeasures instruct the powertrain control system 74 to reduce the power of the vehicle 14's powertrain, thereby decelerating the vehicle 14 regardless of the accelerator pedal position. A steering instruction countermeasure can be generated that instructs the steering control system to steer the vehicle 14 and the trailer 12 toward a coupling angle γ of zero degrees, thereby reducing the possibility of an unacceptable trailer reversal condition before the driver resumes manual control.

[0043] The use of the clutch angle estimation routine 130 can advantageously be employed in conjunction with the sensor error mitigation routine 180 to provide the driver with a smoother response to the sensor failure than could otherwise be provided. For example, if the clutch angle sensor 44 fails, the clutch angle estimation routine 130 can be used to estimate the clutch angle γ based on the still functioning sensors (e.g., sensor module 20 and / or wheel speed sensors 23). The estimated clutch angle γ can then be used by the controller 28 when generating a countermeasure. By utilizing existing sensors and the clutch angle estimation routine 130, the sensor error mitigation routine 180 can provide a countermeasure tailored to the specific dynamics of the vehicle 14 and trailer 12 at the time of the sensor failure.Furthermore, the sensor error mitigation routine 180 can provide the driver with a longer period of time to react to the sensor error. For example, when estimating the dynamics between vehicle 14 and trailer 12, the sensor error mitigation routine 180 does not require immediate driver intervention or stopping of vehicle 14 to prevent an unacceptable trailer reversing condition.

[0044] Further referring to Fig.8. The driver intervention from step 188 can include various actions signaling to the controller 28 that the driver has resumed manual control of the vehicle 14. For example, in one embodiment, the controller 28 can be configured to detect an external torque applied to the torque sensor 70 of the steering wheel 68. An external torque at the steering wheel 68 can indicate that the driver is gripping or turning the wheel 68 to resume manual control. In another embodiment, the controller 28 can be configured to respond to the depressing of the vehicle 14's brake pedal. Activation of the brake pedal indicates that the driver is aware of the alarm and is intervening to resume manual control of the vehicle 14.In further embodiments, step 188 for detecting a driver intervention can be fulfilled by the driver acknowledging the alarm by means of a voice confirmation, an interactive button on the human-machine interface 80 or by other conceivable methods for communicating the driver's perception of the alarm to the controller 28.

[0045] It is understood that variations and modifications to the above-mentioned structures and methods may be made without deviating from the concepts of the present invention, and it is further understood that such concepts are to be understood as being covered by the following claims, unless these claims expressly state otherwise by their language.

Claims

[1] Trailer resetting support system (10), comprising the following: a sensor (44) detecting a coupling angle (γ) between a vehicle (14) and a trailer (12); a steering input device (18), providing a reset path (26) of the trailer (12); and a control unit (28) generating a steering instruction for the vehicle (14) based on the clutch angle (γ) and the reset path (26), wherein the control unit (28) generates a countermeasure to operate the vehicle (14) if the sensor (44) cannot detect the clutch angle (γ). [2] Trailer reversing support system (10) according to claim 1, wherein the countermeasure comprises a braking instruction, a powertrain instruction and / or a steering instruction. [3] Trailer reversing support system (10) according to one of claims 1 and 2, further comprising: a steering wheel (68) of the vehicle (14) for instructing a steering angle (δ) of the vehicle (14), wherein the control (28) deactivates the countermeasure when an external torque is applied to the steering wheel (68). [4] Trailer reversing support system (10) according to claim 3, wherein the steering wheel (68) comprises a torque sensor (70) for detecting an internal torque applied by a power steering system (62) and the external torque applied by a driver of the vehicle (14). [5] Trailer reversing support system (10) according to any one of claims 1 to 4, wherein the countermeasure is generated after the coupling angle (γ) is not detected for a threshold time interval, and wherein the countermeasure is designed to prevent a buckling condition. [6] Trailer reversing support system (10) according to any one of claims 1 to 5, wherein the steering input device (18) comprises a rotatable knob (30) designed to provide a path curvature of the trailer (12) defining the reversing path (26). [7] Sensor error reduction system for a trailer reset support system (10) comprising: a sensor (44) measuring a coupling angle (γ) between a vehicle (14) and a trailer (12); and a control (28) detecting faults of the sensor (44) when measuring the clutch angle (γ), activating a countermeasure when the sensor (44) fails, and deactivating the countermeasure when the driver intervenes to operate the vehicle (14). [8] Sensor error reduction system according to claim 7, further comprising: a steering input device (18) providing a reset path (26) of the trailer (12), wherein the controller (28) generates a steering instruction for the vehicle (14) to guide the trailer (12) along the reset path (26) based on the coupling angle (γ) and a kinematic relationship. [9] Sensor error reduction system according to claim 8, further comprising: a steering wheel (68) of the vehicle (14) for instructing a steering angle (δ) of the vehicle (14), wherein the control (28) deactivates the countermeasure when an external torque is applied to the steering wheel (68). [10] Sensor error reduction system according to one of claims 7 to 9, wherein the countermeasure comprises a braking instruction, a powertrain instruction and / or a steering instruction. [11] Sensor error reduction system according to any one of claims 7 to 10, further comprising: comprising a steering wheel (68) of the vehicle (14), a torque sensor (70) for detecting an internal torque applied by a steering system (62) of the vehicle (14), and an external torque applied by a driver of the vehicle (14) for manually controlling the vehicle (14), wherein the control (28) deactivates the countermeasure when the external torque is detected. [12] Sensor error reduction system according to any one of claims 7 to 11, further comprising: a vehicle brake control system (14) detecting when a brake pedal is depressed, wherein the countermeasure is deactivated when the brake pedal is depressed. [13] Sensor error reduction system according to any one of claims 7 to 12, wherein the countermeasure is designed to prevent a buckling condition and / or an overspeed condition. [14] Sensor error reduction system according to one of claims 7 to 13, wherein the steering input device (18) comprises a rotatable knob (30) designed to provide a path curvature of the trailer (12) defining a reset path (26).

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