Tractor and trailer included angle measuring system and measuring method

Abstract

The invention relates to a tractor and trailer included angle measuring system and method. A tractor and a trailer are connected through a saddle and a traction pin. The measuring system comprises a pattern structure, a camera and a processor, the pattern structure is arranged in the circumferential direction of the traction pin, and patterns on the pattern structure in the circumferential direction are different. The camera is installed on the saddle, right faces the pattern structure and is used for shooting the part, located right in front of the camera, of the pattern structure. The processor is connected to the camera and used for receiving images shot by the camera and obtaining the included angle between the tractor and the trailer according to the first image when the included angle between the tractor and the trailer is zero and the second image when the included angle is formed. The device is simple in structure, low in cost, small in vehicle body change, easy to implement and capable of being suitable for included angle measurement when the tractor and the trailer rotate at a large angle; and different measurement precisions can be realized by setting the number of the pattern structures in the circumferential direction, for example, high-precision measurement can be realized by setting continuously changing patterns.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a system and method for measuring the angle between a tractor and a trailer. Background Art

[0002] With the development of autonomous driving technology, some of it has been implemented in certain closed scenarios, such as ports, coal transportation, mines, etc.

[0003] As the backbone of medium and heavy commercial vehicles, the tractor is not synchronized with the main vehicle (i.e., tractor, hereinafter referred to as the main vehicle) during driving and reversing, and there is a certain relative angle. In order to ensure the traceability and accuracy of the reversing and driving trajectory during autonomous driving, and to meet the functional requirements of steering and other modules, the relative angle between the trailer and the main vehicle needs to be monitored and fed back in real time.

[0004] At present, the measurement methods for the angle between the main vehicle and the trailer mainly include the following:

[0005] 1. Based on laser radar, reflective plates or the boundaries on both sides of the trailer, the measured point cloud data is analyzed and measured, and then the angle measurement is completed by processing the point cloud data, such as CN108761481A, CN109959352A, and CN113158864A. This measurement method is very costly and difficult to guarantee accuracy, especially for the analysis of the trailer boundary. The measured trailer edge line has a very low accuracy and does not meet current usage requirements.

[0006] 2. Based on the wire displacement sensor, the distance change during the rotation process is measured, and then the angle measurement is completed through geometric calculation, such as CN112389437B. This measurement method requires that the measuring equipment and the measuring point are in the same plane. For the measurement of potholes and large turning angles, the accuracy cannot meet the use requirements. At the same time, this measurement method requires changes to the trailer (drilling or welding), which is difficult to implement. At the same time, for the drop-and-hook transport vehicle, it is also troublesome to disassemble the related equipment.

[0007] 3. Based on inertial sensors, the angular velocity change rate of the main vehicle and the trailer is measured, and then the angle between the main vehicle and the trailer is obtained through integration and accumulation, such as CN113819880A. This measurement method is more reliable for flat roads, but if it is on a slope road, there is no corresponding slope compensation, the vehicle deviation is large and cannot meet the use requirements. In addition, the high-precision inertial sensor is very expensive.

[0008] 4. Based on machine vision, the angle is measured by identifying the mark plate pattern, such as CN216184880U. In this solution, the mark plate is installed on the front side of the trailer. When the angle is greater than a certain angle, the mark plate pattern cannot be photographed. At the same time, the front side of the trailer is currently diverse, and the mark plate cannot be installed on some trailers, such as flatbed trailers. The trailer needs to be modified to complete the installation. The above problems need to be solved urgently. Summary of the invention

[0009] The invention discloses a system and method for measuring the angle between a tractor and a trailer, aiming to solve the technical problems existing in the prior art.

[0010] The present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a system for measuring the angle between a tractor and a trailer, wherein the tractor and the trailer are connected via a saddle and a traction pin; the measurement system comprises: a pattern structure, a camera and a processor; the pattern structure is arranged circumferentially along the traction pin, and the pattern on the pattern structure is different along the circumference; the camera is installed on the saddle and faces the pattern structure, and is used to shoot the portion of the pattern structure located directly in front of the camera; the processor is connected to the camera, and is used to receive an image taken by the camera, and obtain the angle between the tractor and the trailer based on a first image when the angle between the tractor and the trailer is zero and a second image when an angle is formed.

[0012] In the tractor-trailer angle measurement system of the present invention, the pattern structure is a continuous pattern with different characteristics along the circumference of the traction pin.

[0013] In the tractor-trailer angle measurement system of the present invention, the pattern structure is a continuous curve arranged along the circumference of the traction pin.

[0014] In the tractor-trailer angle measurement system of the present invention, the continuous curve has different heights at various points in the axial direction of the traction pin and / or has different tangent slopes at various points in the circumferential direction of the traction pin.

[0015] The tractor-trailer angle measurement system of the present invention further includes a shielding plate;

[0016] The shielding plate is installed on the saddle and is arranged adjacent to the camera to shield the camera from rain and dust.

[0017] In the tractor-trailer angle measurement system of the present invention, the pattern structure is a tubular structure with an opening at the bottom or a top and bottom opening, and is sleeved on the traction pin.

[0018] In a second aspect, the present invention further provides a measurement method of any of the above-mentioned angle measurement systems, comprising the following steps:

[0019] Acquire a first image when the angle between the tractor and the trailer is zero;

[0020] After the tractor rotates relative to the trailer, the camera captures a second image;

[0021] The processor compares the first image and the second image with preset image data to obtain the angle between the tractor and the trailer; the image data includes N images obtained by the camera rotating circumferentially around the pattern structure, and the angle of rotation of the camera around the pattern structure when each image is taken.

[0022] In the method of the present invention, the processor compares the first image and the second image with preset image data to obtain the angle between the tractor and the trailer, comprising:

[0023] Determine the rotation direction of the tractor, determine the angles corresponding to the first image and the second image in the image group corresponding to the rotation direction, and calculate the difference between the corresponding angles of the first image and the second image, where the difference is the angle between the tractor and the trailer.

[0024] In the method of the present invention, the step of obtaining a first image when the angle between the tractor and the trailer is zero comprises:

[0025] Confirm whether the tractor and the trailer are in a disconnected state,

[0026] If yes, after the tractor and the trailer are mounted, when the angle between the tractor and the trailer is zero, an image captured by the camera is used as the first image;

[0027] If not, then the image captured by the camera before parking in which the angle between the tractor and the trailer is zero is used as the first image.

[0028] In the method of the present invention, the step of confirming that the angle between the tractor and the trailer is zero comprises:

[0029] Start the tractor, adjust the steering wheel of the tractor to the zero position, and after driving ≥40m, the angle between the tractor and the trailer is zero.

[0030] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0031] The present invention mainly provides a system for measuring the angle between a tractor and a trailer. The system is based on shooting a circumferential pattern on a pattern structure with a camera, and the patterns on the circumference of the pattern structure are different. The angle between the tractor and the trailer can be obtained by processing the first image and the second image shot by a processor. The system has a simple structure and low cost. The pattern structure is arranged on a traction pin, and the camera is installed on a saddle opposite to the pattern structure. The vehicle body is slightly modified and the implementation is simple. Based on the fixed relative position of the traction pin and the saddle, the system can adapt to measurements under different road conditions. Patterns are arranged circumferentially on the pattern structure, so the system can adapt to angle measurements between the tractor and the trailer when the angle is large. Different measurement accuracies can be achieved by setting the number of pattern structures on the circumference. For example, high-precision measurements can be achieved by setting continuously changing patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0033] Figure 1 It is a three-dimensional structural schematic diagram of a tractor and trailer angle measurement system of the present invention;

[0034] Figure 2 It is a schematic diagram of the main structure of a system for measuring the angle between a tractor and a trailer according to the present invention;

[0035] Figure 3 is a flow chart of the measurement method of the present invention;

[0036] Figure 4 This is a schematic diagram of the angle measured by the measuring system of the present invention.

[0037] Description of reference numerals:

[0038] 1. Pattern structure; 2. Camera; 3. Shield; A. Saddle; B. Tow pin. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically limited.

[0041] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In order to solve the problems existing in the prior art, the embodiments of the present application provide a system and method for measuring the angle between a tractor and a trailer.

[0043] Example 1

[0044] This embodiment provides a system for measuring the angle between a tractor and a trailer. Figure 1-2 As shown, the tractor and the trailer are connected by a saddle A and a traction pin B; the measurement system includes: a pattern structure 1, a camera 2 and a processor (not shown); the pattern structure 1 is arranged along the circumference of the traction pin B; the patterns at different positions on the circumference of the pattern structure 1 are different, that is, different positions have different patterns; the camera 2 is installed on the saddle A and faces the pattern structure 1, and is used to shoot the part of the pattern structure 1 located directly in front of the camera 2; the processor is connected to the camera 2, and is used to receive the image shot by the camera 2, and based on the first image when the angle between the tractor and the trailer is zero and the second image when the angle is The angle between the tractor and the trailer is obtained; that is, the processor obtains N different images obtained by rotating around the pattern structure 1 through the camera 2, and records the angle of rotation of the camera 2 around the pattern structure 1 when shooting the image; when the tractor rotates, the first image and the second image before and after the rotation, as well as the angles corresponding to the images, are obtained, and the difference between the corresponding angles of the first image and the second image is calculated, which is the relative rotation angle of the tractor and the trailer; when the angle between the tractor A and the trailer B corresponding to the first image is 0, the rotation angle calculated at this time is the angle between the tractor A and the trailer B (such as Figure 4 The measurement accuracy can be controlled by controlling the number of different patterns of the pattern structure 1 in the circumferential direction and the number n of images in the image group.

[0045] The present invention discloses a system for measuring the angle between a tractor and a trailer. The system uses a camera 2 to shoot a circumferential pattern on a pattern structure 1. The patterns on the circumference of the pattern structure 1 are different. The angle between the tractor and the trailer can be obtained by processing the first image and the second image shot by a processor. The system has a simple structure and low cost. The pattern structure 1 is arranged on a traction pin B. The camera 2 is installed on a saddle A opposite to the pattern structure 1. The vehicle body is slightly modified and the implementation is simple. The relative positions of the traction pin A and the saddle B are fixed (rigidly connected). The angle measurement is more direct (equal to the relative rotation angle of the traction pin B and the saddle A), and the system can adapt to measurements under different road conditions. Patterns are arranged circumferentially on the pattern structure 1. This can adapt to angle measurement when the tractor and the trailer turn at a large angle. Different measurement accuracies can be achieved by setting the number of different patterns on the circumference of the pattern structure. For example, high-precision measurement can be achieved by setting a continuously changing pattern.

[0046] In some preferred embodiments, the pattern structure 1 has a continuous pattern with different characteristics along the circumference of the traction pin B, that is, at this time, the number of different patterns of the pattern structure 1 in the circumferential direction is the largest, that is, the camera 2 can take any number of images to achieve adjustable accuracy.

[0047] In some preferred embodiments, the pattern structure 1 is a continuous curve arranged along the circumference of the traction pin B; based on the continuous curve as the pattern structure 1, the structure is simple and easy to process.

[0048] Preferably, the continuous curve has different heights at each point in the axial direction of the traction pin B and / or has different tangent slopes at each point in the circumferential direction of the traction pin B; that is, specifically, the continuous curve may be fixed in position on the pattern structure 1, such as along the axial direction of the traction pin B. At this time, images may be distinguished based on different heights in the axial direction of the traction pin B, or different shapes in the circumferential direction of the traction pin B, such as different slopes, to distinguish the images.

[0049] In some preferred embodiments, the tractor and trailer angle measurement system also includes a shielding plate 3; the shielding plate 3 is installed on the saddle A and is arranged adjacent to the camera 2 to shield the camera 2 from rain and dust; to reduce the accumulation of oil or dust on the camera 2, resulting in unclear shooting problems; specifically, the shielding plate 3 is welded, bonded or screwed to the saddle A.

[0050] In some preferred embodiments, the pattern structure 1 is a cylindrical structure with an opening at the bottom or at the top and bottom, and different patterns are arranged on the cylindrical structure along the circumference; the pattern structure 1 is fitted on the traction pin B, such as being connected to the traction pin B by elastic interference fit or magnetic connection; based on the fitting connection method, the vehicle body structure is slightly modified, and the fitting method is combined with the different circumferential patterns of the pattern structure 1, and there is no need to have special requirements for the installation angle of the pattern structure 1, and the installation is easier. When it is a cylindrical structure with an opening at the top and bottom, it can be a cylindrical structure surrounded by plates or an integrally formed cylindrical structure.

[0051] In some preferred embodiments, the camera 2 is screwed, bonded or welded to the saddle A; preferably, the connection is screwed.

[0052] In some preferred embodiments, the processor can be set up separately or use a vehicle FCWS\LDWS (forward collision warning and lane departure warning system) controller.

[0053] In some preferred embodiments, the pattern structure 1 is directly set on the traction pin B or another structure connected to the traction pin B. Preferably, the pattern structure 1 is directly set on the traction pin B so that it can be processed and completed when leaving the factory, and the patterns of the pattern structure 1 at different circumferential positions can be pre-stored in the controller of the traction vehicle.

[0054] Example 2

[0055] This embodiment provides a method for measuring the angle between a tractor and a trailer. Figure 3 As shown, it includes the following steps:

[0056] Acquire a first image when the angle between the tractor and the trailer is zero;

[0057] After the tractor rotates relative to the trailer, the camera 2 captures a second image;

[0058] The processor compares the first image and the second image with the preset image data to obtain the angle between the tractor and the trailer; the image data includes N different images obtained by the camera 2 rotating around the pattern structure 1, N is a positive integer, and the angle at which the camera rotates around the pattern structure when each image is taken. The camera 2 continuously shoots when rotating around the pattern structure 1, that is, a photo is taken every time it rotates by an angle, and the rotation angle value is matched one-to-one with the image. This process can be completed in the factory, such as recording the rotation angle of the camera 2 through an angle measuring element.

[0059] The measuring method of the present invention is based on obtaining the first image and the second image at different positions along the circumference of the pattern structure 1 by a processor, and the patterns of the first image and the second image are not the same. Therefore, the first image and the second image can be compared with the preset image data to determine the angles of the images corresponding to the first image and the second image in the image group of the image data. By calculating the difference between the corresponding angles of the first image and the second image, the angle between the tractor and the trailer can be obtained. The measuring method of the present invention is simpler, and the measurement accuracy can be controlled by controlling the number of images in the image group. The pattern structure 1 is provided with patterns all around, so the full-angle measurement of the angle between the tractor and the trailer can be achieved, and it has a higher scope of application.

[0060] In some preferred embodiments, the processor compares the first image and the second image with the preset image data to obtain the angle between the tractor and the trailer, comprising:

[0061] In some preferred embodiments, the turning direction of the tractor is determined, the angles corresponding to the first image and the second image in the image group corresponding to the turning direction are determined, and the difference between the corresponding angles of the first image and the second image is calculated, and the difference is the angle between the tractor and the trailer; that is, the image group can be divided into a left-turn image group and a right-turn image group according to the turning direction, and when turning left or right, the angle is measured by the angles corresponding to the first image and the second image.

[0062] In some preferred embodiments, the step of acquiring the first image when the angle between the tractor and the trailer is zero includes:

[0063] Confirm whether the tractor and trailer are in the unhook and unhook state.

[0064] If yes, after the tractor and the trailer are mounted, when the angle between the tractor and the trailer is zero, the image captured by the camera 2 is used as the first image, that is, the first image recaptured is used as the image when the angle between the tractor and the trailer is zero;

[0065] If not, the image captured by the camera 2 before parking with the angle between the tractor and the trailer being zero is used as the first image, that is, the last first image is used as the first image this time.

[0066] In some preferred embodiments, the step of confirming that the angle between the tractor and the trailer is zero includes:

[0067] Start the tractor, adjust the steering wheel of the tractor to the zero position, and after driving ≥40m, the angle between the tractor and the trailer is zero. Specifically, the steering wheel is judged whether it is in the zero position by the steering angle sensor on the tractor, that is, when the steering angle sensor measures 0°±0.5°, it is considered that the steering wheel is in the zero position.

[0068] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A system for measuring the angle between a tractor and a trailer, wherein the tractor and the trailer are connected via a saddle and a traction pin; characterized in that: The measurement system comprises: a pattern structure, a camera and a processor; The pattern structure is arranged along the circumference of the traction pin, and the patterns on the pattern structure are different along the circumference; The camera is mounted on the saddle and faces the pattern structure, and is used to shoot the portion of the pattern structure that is located directly in front of the camera; The processor is connected to the camera, and is used to receive images taken by the camera, and obtain the angle between the tractor and the trailer based on a first image when the angle between the tractor and the trailer is zero and a second image when there is an angle between the tractor and the trailer.

2. The tractor-trailer angle measurement system according to claim 1, characterized in that: The pattern structure is a continuous pattern with different characteristics along the circumference of the traction pin.

3. The tractor-trailer angle measurement system according to claim 2, characterized in that: The pattern structure is a continuous curve arranged along the circumference of the traction pin.

4. The tractor-trailer angle measurement system according to claim 3, characterized in that: The continuous curve has different heights at various points in the axial direction of the traction pin and / or has different tangent slopes at various points in the circumferential direction of the traction pin.

5. The tractor-trailer angle measurement system according to claim 1, characterized in that: Also includes a shielding panel; The shielding plate is installed on the saddle and is arranged adjacent to the camera to shield the camera from rain and dust.

6. The tractor-trailer angle measurement system according to claim 1, characterized in that: The pattern structure is a tubular structure with an opening at the bottom or a top and bottom opening, and is sleeved on the traction pin.

7. A measurement method using the angle measurement system according to any one of claims 1 to 6, characterized in that: The steps include: Acquire a first image when the angle between the tractor and the trailer is zero; After the tractor rotates relative to the trailer, the camera captures a second image; The processor compares the first image and the second image with preset image data to obtain the angle between the tractor and the trailer; the image data includes N images obtained by the camera rotating circumferentially around the pattern structure, and the angle of rotation of the camera around the pattern structure when each image is taken.

8. The method according to claim 7, characterized in that The processor compares the first image and the second image with preset image data to obtain the angle between the tractor and the trailer, comprising: Determine the rotation direction of the tractor, determine the angles corresponding to the first image and the second image in the image group corresponding to the rotation direction, and calculate the difference between the corresponding angles of the first image and the second image, where the difference is the angle between the tractor and the trailer.

9. The method according to claim 7, characterized in that: The step of obtaining a first image when the angle between the tractor and the trailer is zero comprises: Confirm whether the tractor and the trailer are in a disconnected state, If yes, after the tractor and the trailer are mounted, when the angle between the tractor and the trailer is zero, an image captured by the camera is used as the first image; If not, then the image captured by the camera before parking in which the angle between the tractor and the trailer is zero is used as the first image.

10. The method according to claim 9, characterized in that The step of confirming that the angle between the tractor and the trailer is zero comprises: Start the tractor, adjust the steering wheel of the tractor to the zero position, and after driving ≥40m, the angle between the tractor and the trailer is zero.

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