Automatic hitching system, automatic hitching method and tractor

Abstract

An automatic hitching system and an automatic hitching method are used for realizing automatic hitching between a traction mechanism of a tractor and a towing member of a trailer, and the automatic hitching system comprises a first detection module and a second detection module which are used for detecting positions and postures of the towing member and a lifting part and a hitching part of the traction mechanism. The lifting part lifts the towing piece, and the hooking part is hooked with the towing piece; a processing module; the control module is used for controlling the tractor to move respectively according to the actual relative positions, so that the lifting part and the hooking part are aligned with the trailer in the vertical direction respectively, when the lifting part and the trailer are aligned in the vertical direction, the control module controls the lifting part to lift the trailer, and when the lifting part and the trailer are aligned in the vertical direction, the control module controls the hooking part to lift the trailer. The control module controls the hitching portion to hitch the towing member when the hitching portion and the towing member are aligned in the vertical direction. The invention further provides a tractor comprising the system.

Description

Technical Field

[0001] The present invention relates to the field of automatic driving, and more specifically to an automatic coupling system, an automatic coupling method and a tractor. Background Art

[0002] In docks and airport warehouses, trailers are usually used to transport goods in batches. One type of trailer includes a tractor (motorcycle) and a trailer, the trailer's load is borne by itself, and is connected to the tractor by a towing member so as to be driven by the tractor to move.

[0003] In actual operation, after the cargo has been loaded onto the trailer or the cargo has been transported to the destination, the tractor and the trailer need to be coupled and detached (also known as "coupling and uncoupling").

[0004] At present, this kind of up and down hooking operation is usually completed manually, but manual up and down hooking has significant disadvantages: First, manual up and down hooking requires the cooperation of the driver and the assistant, and the assistant needs to communicate frequently and cooperate tacitly with the driver to complete this task, which not only affects the success rate of hooking, but also is a great burden on the cost of employment. Secondly, during the alignment process, the mis-docking between the trailer and the tractor may cause equipment damage or personal injury. Therefore, very high safety measures are required during the alignment process. In the event of alignment failure or accident, how to respond quickly and take emergency measures is also an important challenge.

[0005] In order to avoid the above defects, the automatic coupling technology between the tractor and the trailer is currently being studied, that is, the automatic loading and unloading between the tractor and the trailer (including automatic coupling and detaching of the trailer), which is an important research direction for fully automatic driving of tractors.

[0006] It is currently desired to develop an automatic hooking system or device to meet the above requirements as far as possible. Summary of the invention

[0007] In order to solve the problem that manual hooking of a trailer is burdensome and requires very high safety measures, the present invention proposes an automatic hooking system to replace manual hooking, which greatly avoids the burden on the operator and the possibility of injury.

[0008] Specifically, the automatic coupling system is used to realize automatic coupling between a tractor and a trailer, the tractor includes a traction mechanism, the trailer includes a towing part, and the automatic coupling system includes a first detection module, the first detection module is used to detect the position and posture of the towing part and the lifting part of the traction mechanism, the lifting part is configured to lift the towing part; a second detection module, the second detection module is used to detect the position and posture of the hooking part of the towing part and the traction mechanism, the hooking part is configured to be hooked with the towing part; a processing module; and a control module for controlling the movement of the tractor and the traction mechanism, wherein the automatic coupling system operates in a first stage and a second stage, wherein the processing module obtains the position and posture of the towing part and the lifting part of the traction mechanism based on the position and posture of the towing part and the lifting part of the traction mechanism detected by the first detection module. The processing module obtains a second actual relative position between the towing member and the hitching part based on the position and posture of the towing member and the hitching part of the traction mechanism detected by the second detection module, and transmits the second actual relative position to the control module, wherein the control module controls the movement of the tractor based on the first actual relative position and the second actual relative position respectively so that the lifting part and the hitching part are aligned with the towing member in the vertical direction, and wherein, in the first stage, when the lifting part is aligned with the towing member in the vertical direction, the control module controls the lifting part to lift the towing member, and in the second stage, when the hitching part is aligned with the towing member in the vertical direction, the control module controls the hitching part to hitch the towing member.

[0009] In an embodiment of the present invention, the position and posture of the towing part and the lifting part are derived from the first image.

[0010] Preferably, the first image is acquired by a first camera, which is mounted on the top of the tractor so that the viewing angle of the first camera includes the towing part and the lifting part.

[0011] The first detection module converts the first image captured by the first camera into a bird's-eye view based on perspective transformation to obtain the positional relationship between the trailer and the traction mechanism on the horizontal plane, which makes it easier to subsequently calculate the actual physical position between the trailer and the traction mechanism.

[0012] Specifically, obtaining the first actual relative position of the trailer and the lifting part also includes cutting and converting the bird's-eye view into a sub-view; detecting the images of the trailer and the lifting part in the sub-view; calculating the pixel distance from the image of the trailer to the image of the lifting part in the sub-view; calculating the central axis of the image of the trailer in the sub-view; and obtaining the first actual relative position based on the pixel distance and the central axis.

[0013] In an embodiment of the present invention, the position and posture of the towing member and the hitch portion are derived from the second image.

[0014] Preferably, the second image is acquired by a second camera, and the second camera is installed at the side of the tractor, so that the viewing angle of the second camera includes the towing component and the hitch portion.

[0015] In a specific embodiment, the towing member has a towing head at its front end, the towing head has a towing hole, and the hooking part of the towing mechanism includes a towing bolt, wherein the control module is capable of controlling the towing bolt to rise or fall, and wherein the control module controls the hooking part to hook the towing member, including controlling the towing bolt to descend through the towing hole through the control module.

[0016] In another specific embodiment, the lifting portion of the traction mechanism includes a traction saddle, wherein the control module is capable of controlling the traction saddle to rise or fall, and wherein the control module controls the lifting portion to lift the towing component including the control module controlling the traction saddle to rise to contact and lift the towing component.

[0017] In a further embodiment, after the second stage, the automatic hitch system operates in a third stage, wherein in the third stage, the second detection module detects the positions of the towing hitch and the towing saddle.

[0018] Advantageously, the traction bolt may have a traction bolt positioning nut, wherein the second detection module detects the position of the traction bolt by detecting the position of the traction bolt positioning nut. The traction saddle may also have a traction saddle positioning nut, wherein the second detection module detects the position of the traction saddle by detecting the position of the traction saddle positioning nut.

[0019] The present invention also provides an automatic coupling method for coupling a traction mechanism of a tractor to a towing member, the method comprising the following steps: detecting the position and posture of the towing member and the lifting part of the traction mechanism; obtaining a first actual relative position of the towing member and the lifting part based on the position and posture of the towing member and the lifting part; controlling the movement of the tractor based on the first actual relative position so that the lifting part and the towing member are aligned in the vertical direction; controlling the lifting part to lift the towing member; detecting the position and posture of the towing member and the coupling part of the traction mechanism; obtaining a second actual relative position of the towing member and the coupling part based on the position and posture of the towing member and the coupling part; controlling the movement of the tractor based on the second actual relative position so that the coupling part and the towing member are aligned in the vertical direction; and controlling the coupling part to couple the towing member.

[0020] In another aspect, the present invention further provides a vehicle-mounted unit, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the automatic coupling method as described above.

[0021] In another aspect, the present invention also provides a computer program product storing a program, which, when executed by a computer, enables the computer to execute the steps of the automatic mounting method as described above.

[0022] In another aspect, the present invention further provides a non-transitory computer-readable storage medium storing a program executed by a computer, wherein the program causes the computer to execute the steps of the automatic mounting method as described above.

[0023] The present invention also provides a tractor for coupling with a trailer, the tractor comprising a traction mechanism and the automatic coupling system as described above.

[0024] Additional features and advantages of the described automatic hitch system will be set forth in the detailed description that follows, and will be apparent to those skilled in the art from the following or will be recognized by those skilled in the art from practicing the embodiments described herein, including the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] With reference to the above objects, the technical features of the present invention are clearly described in the following claims, and its advantages are apparent from the following detailed description with reference to the accompanying drawings, which show preferred embodiments of the present invention by way of example without limiting the scope of the inventive concept.

[0026] Figure 1 The overall flow chart of the method for automatic attachment using the automatic attachment system according to the present invention is shown;

[0027] Figure 2 A schematic diagram of a tractor using an automatic hitch system according to an embodiment of the present invention is shown;

[0028] Figure 3 Shows Figure 2 A schematic diagram of the coupling relationship between the traction mechanism of the tractor and an exemplary trailer;

[0029] Figure 4 shows a schematic wireframe diagram of a first image according to an embodiment of the present invention;

[0030] Figure 5 showing a sub-view of the bird's-eye view converted from the first image;

[0031] Figure 6 Shown based on Figure 5 A schematic diagram of a pixel subview obtained from an image;

[0032] Figure 7 A flow chart showing an exemplary method of obtaining a first actual relative position of a towing member and a traction mechanism by using a processing module;

[0033] Figure 8 a schematic wireframe diagram showing a second image according to an embodiment of the present invention; and

[0034] Fig. 9 A hooking flow chart using an automatic hooking system according to an embodiment of the present invention is shown.

[0035] Reference numerals

[0036] 1 Tractor

[0037] 2 trailer

[0038] 11First Camera

[0039] 12 Second Camera

[0040] 20 trailer parts

[0041] 20' trailer pixel image

[0042] 21 trailer head

[0043] 22 trailer holes

[0044] 100 Traction mechanism

[0045] 110 Traction upper base

[0046] 120 Traction lower base

[0047] 130 Traction Saddle

[0048] 130' Hauling Saddle Pixel Image

[0049] 131 Traction saddle positioning nut

[0050] 140 Traction Hitch

[0051] 141 Drawbar retaining nut. DETAILED DESCRIPTION

[0052] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention in any way.

[0053] The terms "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal" and their derivatives used herein refer to the orientation of components in actual use, such as the "rear" or "rear end" of a vehicle refers to the rear of the vehicle in actual normal driving, "horizontal plane" refers to a plane parallel to the ground (assuming the ground is flat), and so on. However, it should be understood that unless explicitly specified to the contrary, the components may adopt various alternative orientations.

[0054] The term "pose" as used herein refers to the appearance of an object as detected by a detector. The poses detected by different detectors may be different. For example, a cylinder viewed from above may appear circular, while the same cylinder viewed from the side may appear rectangular.

[0055] The term “center” used in this document, unless otherwise specified, generally refers to the center of gravity of the object in the image.

[0056] The term "distance" as used herein refers to the distance between the centers of two objects.

[0057] As used herein, the term "aligned" means that the centers of two objects are approximately in a straight line in a certain direction, but not necessarily aligned at every point.

[0058] The term "actual relative position" used in this article refers to the distance, heading angle, etc. of an object in reality.

[0059] The term "central axis" as used herein refers to a straight line passing through a vertex of a figure and dividing the area of ​​the figure into equal parts.

[0060] Figure 1-9An automatic coupling system is generally shown, which is used to realize automatic coupling between a tractor and a trailer, wherein the tractor includes a traction mechanism, and the trailer includes a towing part. The automatic coupling system includes a first detection module, which is used to detect the position and posture of the towing part and the lifting part of the traction mechanism, and the lifting part is configured to lift the towing part; a second detection module, which is used to detect the position and posture of the towing part and the hooking part of the traction mechanism, and the hooking part is configured to be hooked with the towing part; a processing module, which obtains the actual relative position between the objects based on the position and posture of the objects detected by the first detection module or the second detection module; and a control module, which is used to control the movement of the traction mechanism of the tractor, wherein the automatic coupling system operates in a first stage and a second stage, wherein the processing module obtains the actual relative position between the objects based on the position and posture of the objects detected by the first detection module or the second detection module; The processing module obtains a first actual relative position of the towing member and the lifting part based on the position and posture of the lifting part of the towing mechanism, and transmits the first actual relative position to the control module, wherein the processing module obtains a second actual relative position of the towing member and the hitching part based on the position and posture of the towing member and the hitching part of the towing mechanism detected by the second detection module, and transmits the second actual relative position to the control module, wherein the control module controls the movement of the tractor based on the first actual relative position and the second actual relative position respectively so that the lifting part and the hitching part are aligned with the towing member in the vertical direction, wherein in the first stage, when the lifting part is aligned with the towing member in the vertical direction, the control module controls the lifting part to lift the towing member, and in the second stage, when the hitching part is aligned with the towing member in the vertical direction, the control module controls the hitching part to hitch the towing member.

[0061] Reference Figure 1 , shows an overall flow chart of a method for automatic hooking using an automatic hooking system according to the present invention. Specifically, the method includes detecting the position and posture of the towing member and the lifting part of the traction mechanism; obtaining a first actual relative position of the towing member and the lifting part based on the position and posture of the towing member and the lifting part; controlling the tractor to move based on the first actual relative position so that the lifting part and the hooking part are aligned with the towing member in the vertical direction respectively; controlling the lifting part to lift the towing member; detecting the position and posture of the towing member and the hooking part of the traction mechanism; obtaining a second actual relative position of the towing member and the hooking part based on the position and posture of the towing member and the hooking part; controlling the tractor to move based on the second actual relative position so that the lifting part and the hooking part are aligned with the towing member in the vertical direction respectively; and controlling the hooking part to hook the towing member.

[0062] Reference Figure 2-3 , which schematically show the specific structures of a tractor 1 and a part of an exemplary trailer 2 using an automatic coupling system according to an embodiment of the present invention. Figure 2As shown, the tractor 1 includes a first camera 11, a second camera 12 and a traction mechanism 100. The first camera 11 is also called a roof camera, which takes a picture of the towing part 20 of the trailer 2 at a roughly downward angle (see FIG. Figure 4 ) at a distance. The second camera 12 is also called a side camera, which captures the towing part 20 of the trailer 2 at a roughly side-shooting angle (see Figure 4 )'s position and posture when approaching the traction mechanism 100.

[0063] like Figure 3 As shown, the traction mechanism 100 includes an upper traction base 110, a lower traction base 120, a traction saddle 130 and a traction bolt 140. The upper traction base 110 and the lower traction base 120 are fixedly installed at the rear of the tractor, and the two bases are arranged substantially in parallel and spaced apart in the vertical direction to define a towing member 20 for receiving a trailer (see also Figure 4 ) is a receiving space for a part of the towing member 20, in which the towing upper base 110 and the towing lower base 120 restrict the vertical movement of the towing member 20. The towing saddle 130 can be threadedly connected to the towing upper base 110 and the towing lower base 120 by, for example, a lead screw, and can be driven to rise or fall by, for example, a stepping motor. The towing saddle 130 is used to lift the towing member 20 to a height between the towing upper base 110 and the towing lower base 120 to receive a part of the towing member 20 between the towing upper base 110 and the towing lower base 120. The towing bolt 140 is installed at the rear of the towing vehicle, above the towing upper base 110 and passing through the towing upper base 110. The towing bolt 140 can be driven by, for example, a hydraulic mechanism to perform the action of rising or falling. For this purpose, both the towing upper base 110 and the towing lower base 120 can have through holes aligned in the vertical direction for the towing bolt 140 to descend through the towing upper base 110 and the towing lower base 120. Preferably, the traction saddle 130 has an opening aligned with the through hole of the traction lower base 120 in the vertical direction, so that the traction pin 140 can be lowered through the opening of the traction saddle 130 without hindering the movement of the traction pin 140 .

[0064] Reference Figure 3 and additionally refer to Figure 4An exemplary trailer 2 may include a towing member 20, and a towing head 21 may be provided at the front end of the towing member 20, and the towing head 21 has a towing hole 22. When the towing head 21 of the towing member 20 is received between the towing upper base 110 and the towing lower base 120, the towing hole 22 may be aligned with the towing bolt so that the towing bolt sequentially passes through the through hole of the towing upper base, the towing hole 22, and the through hole of the towing lower base 120, thereby achieving the towing vehicle to the trailer 2. The towing member 20 is substantially triangular in shape and is pivotally connected to the trailer 2 so that the towing member 20 can be pivoted upward or downward. It should be understood that the towing member 20 shown in the figure is only an example and is not intended to be limiting.

[0065] The following describes in detail the stages experienced by the automatic coupling system and the specific operation modes in these stages. The automatic coupling system operates in the first stage, the second stage and the optional third stage, and completes the automatic coupling between the tractor and the trailer after experiencing these stages.

[0066] Phase 1

[0067] In the first stage, the automatic hooking system first uses the first detection module to detect the position and posture of the lifting part of the towing member 20 and the traction mechanism 100. The position and posture of the lifting part of the towing member 20 and the traction mechanism 100 are derived from the following: Figure 4 In this context, the lifting portion of the traction mechanism 100 is a traction saddle 130 (see Figure 3 ).

[0068] Preferably, as described above, the first image is acquired by a first camera, which is mounted on the top of the tractor, so that the viewing angle of the first camera includes the towing member 20 and the lifting part of the traction mechanism 100. Figure 2 and 4 As shown, the first camera 11 is positioned at the middle of the rear edge of the roof of the tractor 1, but it may also be offset from the middle of the rear edge. In other embodiments, the first camera 11 may not be installed at the rear edge of the roof of the tractor 1, as long as the shooting angle of the first camera 11 can satisfy the requirement of including the traction mechanism 100 and the trailer in the captured image. It should be understood that although the first camera is used to obtain the image in the embodiment of the present invention, other methods may also be used to obtain the specific position and posture of the trailer and the lifting part, such as scanning with a laser radar.

[0069] In practice, due to the position and viewing angle, it is difficult for the first camera to shoot from the top (i.e., the shooting direction is perpendicular to the ground). Therefore, in a preferred embodiment, the first detection module first converts the image shot by the first camera into a bird's-eye view (BEV view) based on perspective transformation to obtain the positional relationship between the trailer 20 and the traction saddle 130 on the horizontal plane, which is more convenient for subsequent calculation of the actual physical position between the trailer 20 and the traction saddle 130. The image can be converted into a bird's-eye view by a machine learning software library such as OpenCV.

[0070] After taking a top view image of the towing part and the lifting part of the traction mechanism through a first camera and converting the top view image taken by the first camera into a bird's-eye view based on perspective transformation, the present invention provides a specific method for obtaining the actual physical position between the towing part and the traction mechanism. First, the bird's-eye view is cut and converted into Figure 5 The subview shown, and then the first detection module detects the image of the trailer and the image of the lifting part in the subview using the algorithm model of target detection. In the above steps, cutting and converting into a subview includes cutting out a square subview with the center of the bird's-eye view as the reference point, which helps the image segmentation and target detection of the subsequent algorithm model. The subview can be, for example, a subview of 640*640 pixels or other sizes, depending on the algorithm model used. Regarding the detection step, the Yolo series algorithm model (for example, Yolo v5) can be used to train and detect the characteristic parts of the trailer and the lifting part, such as the triangular frame of the trailer and the trailer head (the trailer head has a circular ring part sprayed with red paint) and the traction saddle (black), thereby outputting the horizontal cross-sectional pixel images of the two. Figure 6 The horizontal cross-sectional pixel images of the trailer and traction saddle detected using the Yolo v5 algorithm model are shown, the roughly triangular shape above is the trailer pixel image 20', and the black rectangle below can be regarded as the traction saddle pixel image 130' (due to the bird's-eye view, the horizontal cross-section of the traction saddle covers other components).

[0071] It should be understood that the first detection module may not be limited to detecting the characteristic parts of the towing part and the lifting part. For example, when the towing mechanism is the same, the position of the towing saddle is fixed, so only the characteristic parts of the towing part can be detected to determine the pixel image of the towing part. In addition, since the position of the first camera and the size of the subview are fixed, the algorithm model can omit the scaling step to further optimize the code. In addition, the color of the characteristic parts of the towing part and the lifting part, such as the towing head and the towing saddle, is not limited to the described colors.

[0072] Continue to refer to Figure 6Next, the processing module will obtain the first actual relative position of the trailer and the traction saddle based on the position and posture between the trailer and the traction saddle detected by the first detection module. The processing module can use the algorithm model such as Yolo v5 as described above, or can also use a computer program programmed in other languages ​​to calculate the distance between the trailer head image 20' and the traction saddle image 130'. Specifically, after the first detection module transmits the data of the trailer pixel image 20' and the traction saddle pixel image 130' to the processing module, the processing module will calculate the pixel distance from the trailer to the lifting part, such as the pixel distance from the center of the trailer hole to the center of the traction saddle. Further, the processing module calculates the central axis of the characteristic part of the trailer. Specifically, in the case where the trailer is roughly triangular, the bottom ( Figure 6 The lower vertex of the roughly triangular trailer pixel image 20' is used as the vertex of the central axis, and then an initial central axis is drawn, the areas of the triangles on both sides of the central axis are calculated and the central axis is adjusted until the areas of the triangles on both sides of the central axis are the same. The obtained central axis vector represents the heading angle of the trailer, and the heading angle can indicate the deflection angle between the tractor and the trailer.

[0073] Then, the processing module obtains the first actual relative position based on the pixel distance and the central axis, where the first actual relative position mainly includes two data: the actual physical distance from the center of the towing hole to the center of the towing saddle on the horizontal plane and the heading angle of the towing component on the horizontal plane. In actual operation, since the position of the first camera is fixed and the towing component and the towing saddle do not move when the first detection module performs detection, the pixel distance can be directly converted into the actual distance through the calibration coefficient; and since the processing module performs processing based on the bird's-eye view, the heading angle can be directly used to indicate the deflection angle between the tractor and the trailer.

[0074] Afterwards, the processing module transmits the first actual relative position (actual distance and deflection angle) to the control module. The control module uses the first actual relative position to control the tractor to perform movements such as steering and reversing, so that the towing part is aligned with the lifting part (for example, the center of the towing eye and the center of the towing saddle) in the vertical direction, completing the first stage.

[0075] In actual operation, the alignment of the center of the towing eye and the center of the towing saddle can be determined in the following way: Since the position of the first camera and the size of the subview are fixed, it can be directly Figure 6 The target coordinates are set in the pixel image as the coordinates of the center of the towing saddle. When the coordinates of the center of the towing hole are equal to the target coordinates, it can be considered that the center of the towing hole coincides with the center of the towing saddle, and the alignment is considered to be completed.

[0076] Figure 7The above steps of obtaining the first actual relative position using the automatic hooking system of the present invention are summarized.

[0077] Phase II

[0078] After the first stage is completed, the towing part is aligned with the lifting part (such as the center of the towing hole and the center of the towing saddle) in the vertical direction, and then the control module can control the towing saddle to rise to contact and lift the towing part, entering Figure 8 Status shown.

[0079] like Figure 8 As shown, since the towing saddle 130 moves in the vertical direction and the trailer 20 makes a rotational motion, after the trailer 20 is lifted, the distance between the towing head 21 of the trailer 20 and the towing bolt 140 in the horizontal plane changes compared with before the trailer 20 is lifted, so it is necessary to re-detect the positions and postures of the two to determine the actual distance.

[0080] In the second stage, the automatic coupling system first uses the second detection module to detect the position and posture of the coupling part between the towing part 20 and the traction mechanism. The position and posture of the coupling part between the towing part 20 and the traction mechanism 100 are derived from the following: Figure 8 In this context, the hooking portion of the traction mechanism 100 is a traction bolt 140 (see Figure 3 ).

[0081] Similar to the first detection module, the second detection module detects the position and posture of the towing component 20 and the traction bolt 140 of the traction mechanism 100 based on the image captured by the second camera. Figure 2 and 8 As shown, the second camera 12 is positioned on the side of the rear of the tractor 1, and its shooting angle can satisfy the requirement of including the traction bolt 140 of the traction mechanism 100 and the towing part 20 in the captured image. The reason why two cameras with different shooting angles are used is that the first camera 11 at the rear edge of the roof can better capture the outline of the towing part 20, so as to facilitate the subsequent relative position calculation. However, the installation position of the first camera 11 makes it difficult to clearly capture the traction bolt of the traction mechanism 100, so that it is difficult to know the positional relationship between the towing part and the traction bolt and the timing of the traction bolt falling. Therefore, the second camera 12 is added to help obtain the positional relationship between the towing part and the traction bolt, so as to facilitate automatic hooking. It should also be understood that although in the embodiment of the present invention, the second camera is used to obtain the second image, other methods can also be used to obtain the specific position and posture of the towing part and the hooking part, such as scanning with a laser radar.

[0082] Unlike the first detection module, since the second camera is quite close to the trailer 20 (specifically the trailer head 21) and the traction mechanism 100, it is not necessary to adjust the viewing angle, but directly cut and identify the position and posture of the trailer head 21 and the traction bolt 140 in the image, which results in very small errors. Similarly, although the second camera is used to obtain images in the embodiment of the present invention, it should be understood that other methods can be used to obtain the specific postures of the traction mechanism and the trailer, such as using a laser radar for scanning.

[0083] Similarly, after detecting the images of the towing head 21 and the towing bolt 140, the processing module will calculate the pixel distance from the towing part to the lifting part, for example, the horizontal pixel distance from the center of the towing hole 22 to the center of the towing bolt 140. Since the position of the second camera is fixed and the towing part 20 and the towing bolt 140 do not move when the second detection module performs detection, the horizontal pixel distance can be directly converted by the calibration coefficient to obtain the second actual relative position of the towing head 21 to the towing bolt 140. Here, the second actual relative position mainly includes the actual horizontal distance.

[0084] Afterwards, the processing module transmits the second actual relative position to the control module. The control module controls the tractor to further reverse based on the second actual relative position so that the towing hole 22 and the towing bolt 140 are aligned in the vertical direction, and then controls the towing bolt 140 to drop through the towing hole 22 to complete the second stage, that is, complete the automatic coupling.

[0085] Phase 3

[0086] Continue to refer to Figure 8 In order to ensure the completion of the automatic coupling, there is a subsequent safety inspection stage, i.e., the third stage. In a preferred embodiment, the traction bolt 140 may have a traction bolt positioning nut 141, wherein the second detection module detects the position of the traction bolt 140 by detecting the position of the center of the traction bolt positioning nut 141, i.e., whether it is in the rising position or the falling position. For example, a picture height threshold in the image may be defined, and the processing module may determine whether the traction bolt 140 is in the rising position or the falling position by determining whether the height of the center of the traction bolt positioning nut 141 in the vertical direction is higher or lower than the picture height threshold. After the second stage is completed, i.e., after the traction bolt 140 is lowered through the towing hole 22, if it is detected that the traction bolt 140 is in the rising position, the processing module may provide the information to the control module to inform that an error has occurred in the coupling between the tractor and the trailer (e.g., the traction bolt 140 has not passed through the towing hole 22 but is stuck by the towing head 21), so as to improve the safety of the automatic coupling system.

[0087] In addition, preferably, in the third stage, the traction saddle 130 needs to be lowered to the original position for the next hooking. For this purpose, the traction saddle 130 may have a traction saddle positioning nut 131, wherein the second detection module detects the position of the traction saddle 130 by detecting the position of the center of the traction saddle positioning nut 131. The position of the center of the traction saddle positioning nut 131 can also be determined by defining a screen height threshold. After the second stage is completed, that is, after the traction bolt 140 is lowered through the towing hole 22, if it is detected that the traction bolt 140 is in the ascending position, the processing module can provide the information to the control module to prevent the situation where the traction saddle control signal is issued but not executed successfully, thereby improving the safety of the system.

[0088] Fig. 9 A hooking flow chart utilizing an automatic hooking system according to an embodiment of the present invention is summarized.

[0089] Specifically, in the first stage, the first detection module uses the first camera, that is, the top camera, to capture the overall posture of the trailer and the traction saddle from a bird's-eye view, corrects the image based on the internal and external parameters of the camera, and converts the camera image into a bird's-eye view based on perspective transformation, and then uses the Yolo series algorithm model to segment the adjusted image to detect the features of the trailer and the traction saddle. After calibration (pixel distance corresponds to actual physical distance), the relative physical position information of the trailer image in the picture to the target point of the lifting part at the bottom of the picture can be obtained, and the position of the trailer hole relative to the traction saddle is known. Subsequently, the processing module is used to calculate the pixel distance from the trailer hole to the traction saddle, and the actual physical distance can be converted by the calibration coefficient. Then, the central axis of the trailer (triangle-like) is calculated based on the geometric method to obtain the heading angle representing the trailer. Next, the processing module transmits the physical distance and heading angle data to the control module. Finally, the control module controls the movement of the tractor to align the traction saddle and the trailer hole in the vertical direction and lift the trailer.

[0090] In the second stage, the image of the second camera, i.e., the side camera, is segmented and detected to detect the position of the towing eye and calculate the pixel distance between the center of the towing eye and the center of the towing bolt in the image. Then, based on the calibration coefficient, the actual physical distance from the center of the towing eye to the center of the towing bolt can also be obtained. Finally, the control module controls the movement of the tractor to align the towing bolt and the towing eye in the vertical direction, and controls the towing bolt to drop.

[0091] In addition, there is a third stage to detect the position of the center of the traction bolt positioning nut. If the height of the center of the traction bolt positioning nut is lower than the screen height threshold, it means that the traction bolt is down, otherwise it is not. The traction saddle positioning nut can also be used to detect whether the position of the traction saddle has risen or fallen. This information is provided to the vehicle control system to prevent the control command from being executed successfully and improve the safety of the system.

[0092] The automatic hooking system of the present invention has the following technical advantages:

[0093] 1. No human intervention at all: It does not rely on the operator’s experience and skills, and is completely implemented through software.

[0094] 2. High positioning accuracy: The identification position error of the trailer is kept within plus or minus 2 cm, and the heading angle error is kept within plus or minus 2 degrees, which can achieve precise positioning.

[0095] 3. Low hardware cost: Only two cameras are needed, and no further modification of the tractor, trailer or other site facilities is required.

[0096] 4. High adaptability to trailers. Regardless of the type of trailer, the position and posture of the trailer can be accurately detected after model training.

[0097] Although the structure and operation method of the present invention are described above in conjunction with the preferred embodiments, it should be recognized by those skilled in the art that the above examples are only for illustration and cannot be used as limitations of the present invention. Therefore, the present invention may be modified and varied, and these modifications and variations will fall within the scope defined by the appended claims of the present application.

Claims

1. An automatic coupling system for realizing automatic coupling between a tractor and a trailer, wherein the tractor comprises a traction mechanism, the trailer comprises a towing member, and the automatic coupling system comprises: A first detection module, the first detection module is used to detect the position and posture of the trailer and the lifting part of the traction mechanism, the lifting part is configured to lift the trailer; A second detection module, the second detection module is used to detect the position and posture of the hooking part of the towing member and the traction mechanism, the hooking part is configured to be hooked with the towing member; Processing module; as well as a control module, for controlling the movement of the tractor and the traction mechanism, The automatic hooking system operates in the first and second stages. wherein the processing module acquires a first actual relative position of the towing member and the lifting part based on the position and posture of the towing member and the lifting part of the traction mechanism detected by the first detection module, and transmits the first actual relative position to the control module, The processing module acquires a second actual relative position of the towing member and the hooking part based on the position and posture of the towing member and the hooking part of the traction mechanism detected by the second detection module, and transmits the second actual relative position to the control module. The control module controls the movement of the tractor based on the first actual relative position and the second actual relative position so that the lifting part and the hooking part are aligned with the towing part in the vertical direction, respectively. wherein, in the first stage, when the lifting portion is aligned with the towing member in the vertical direction, the control module controls the lifting portion to lift the towing member, and Wherein, in the second stage, when the hooking portion is aligned with the towing component in the vertical direction, the control module controls the hooking portion to hook the towing component.

2. The automatic hooking system according to claim 1, characterized in that: The position and posture of the towing part and the lifting part are derived from a first image, wherein the first image is acquired by a first camera, and the first camera is mounted on the top of the tractor so that the viewing angle of the first camera includes the towing part and the lifting part.

3. The automatic hooking system according to claim 2, characterized in that: The first detection module converts the first image captured by the first camera into a bird's-eye view based on perspective transformation.

4. The automatic hooking system according to claim 3, characterized in that: The first detection module is also configured as follows: Cutting and converting the bird's-eye view into sub-views; and detecting the images of the towing part and the lifting part in the subview, and Wherein, the processing module is further configured as follows: Calculating the pixel distance between the image of the trailer and the image of the lifting part in the subview; Calculating and obtaining the central axis of the image of the trailer in the subview; and The first actual relative position is obtained based on the pixel distance and the central axis.

5. The automatic hooking system according to claim 1, characterized in that: The position and posture of the towing component and the hitch portion are derived from a second image, wherein the second image is acquired by a second camera, and the second camera is mounted on the side of the tractor so that the viewing angle of the second camera includes the towing component and the hitch portion.

6. The automatic hooking system according to claim 1, characterized in that: The towing member has a towing head at its front end, the towing head has a towing hole, and the hooking part of the towing mechanism includes a towing bolt. The control module can control the traction bolt to rise or fall, and The control module controlling the hooking part to hook the towing component includes controlling the towing bolt to descend through the towing hole through the control module.

7. The automatic hooking system according to claim 6, characterized in that: The lifting part of the traction mechanism includes a traction saddle, The control module can control the traction saddle to rise or fall, and The control module controlling the lifting part to lift the towing component includes the control module controlling the towing saddle to rise so as to contact and lift the towing component.

8. The automatic hooking system according to claim 7, characterized in that: The second detection module is further configured to detect positions of the towing hitch and the towing saddle after the towing hitch is lowered through the towing hole.

9. The automatic hooking system according to claim 8, characterized in that: The traction bolt has a traction bolt positioning nut, wherein the second detection module detects the position of the traction bolt by detecting the position of the traction bolt positioning nut, and / or The traction saddle has a traction saddle positioning nut, and the second detection module detects the position of the traction saddle by detecting the position of the traction saddle positioning nut.

10. An automatic coupling method for coupling a traction mechanism of a tractor to a towing member, the method comprising the following steps: Detecting the position and posture of the towing member and the lifting part of the traction mechanism; Acquire a first actual relative position of the towing member and the lifting part based on the position and posture of the towing member and the lifting part; controlling the movement of the tractor based on the first actual relative position to align the lifting portion with the hitch in a vertical direction; controlling the lifting portion to lift the towing member; Detecting the position and posture of the hooking portion between the towing member and the traction mechanism; Acquire a second actual relative position of the towing component and the hooking portion based on the position and posture of the towing component and the hooking portion; controlling the tractor to move based on the second actual relative position so that the hitch portion is aligned with the towing member in a vertical direction; as well as The hooking portion is controlled to hook the towing member.

11. The automatic attachment method according to claim 10, characterized in that: The step of detecting the position and posture of the towing member and the lifting part of the traction mechanism comprises: Acquire a first image including the towing member and the lifting part; converting the first image into a bird's-eye view based on a perspective transformation; Cutting and converting the bird's-eye view into sub-views; and The images of the towing part and the lifting part are detected in the sub-view.

12. The automatic attachment method according to claim 11, characterized in that: The step of obtaining a first actual relative position between the towing member and the lifting portion comprises: Calculating the pixel distance between the image of the trailer and the image of the lifting part in the subview; Calculating and obtaining the central axis of the image of the trailer in the subview; and The first actual relative position is obtained based on the pixel distance and the central axis.

13. The automatic attachment method according to claim 10, characterized in that: After the step of controlling the hitch portion to hitch the towing component, the automatic hitch method further comprises detecting positions of the lifting portion and the hitch portion.

14. A vehicle-mounted unit, comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the automatic mounting method according to claim 10.

15. A computer program product storing a program, when the program is executed by a computer, the program causes the computer to execute the steps of the automatic mounting method according to claim 10.

16. A non-transitory computer-readable storage medium storing a program executed by a computer, the program causing the computer to execute the steps of the automatic mounting method according to claim 10.

17. A tractor for coupling with a trailer, the tractor comprising a traction mechanism and an automatic coupling system according to claims 1 to 9.

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