A local docking method based on QR code navigation

Abstract

The present invention provides a local docking method based on QR code navigation, which controls the logistics robot to enter the scanning area at the starting point of a preset path along the direction from the starting QR code to the end QR code to scan the code and read the QR code information, then establishes a coordinate system with the center point of the QR code as the coordinate origin, judges the deviation between the actual position of the logistics robot and the coordinate of the origin, and then calculates the deviation, the angle corresponding to the corrected deviation, and the distance from the actual deviation position to the preset path, so that the logistics robot returns to the preset path after adjusting the angle, and continues to drive along the preset path to the end point scanning area to scan the code again, and reads the QR code information at the same time, and then stops driving with the information read by the end point scanning as a reference standard, and finally judges whether the logistics robot is within the docking error range and completes the docking.

Description

Technical Field

[0001] The present invention relates to the field of robot navigation technology, and in particular to a local docking method based on QR code navigation. Background Art

[0002] In recent years, with the continuous improvement of production technology, most modern intelligent manufacturing workshops are equipped with AGV carts (Automated Guided Vehicle, referred to as AGV). AGV carts have the advantages of high degree of automation, high level of intelligence, and small footprint. Products are transferred by AGV carts equipped with transmission mechanisms. They can automatically interface with other logistics equipment to realize the automation of the entire process of loading, unloading and handling of goods and materials.

[0003] For example, the patent document with Chinese patent application number 202210109495.6 and publication date 2022.07.26 discloses an AGV high-precision positioning device and a precise docking method, including a positioning plate, an automated production line, a Mecanum wheel AGV and an intelligent tower warehouse. A positioning plate is provided at the bottom of one side of the intelligent tower warehouse and both sides of the automated production line. The positioning plate includes a positioning bushing, a fixing hole, and a navigation QR code. The positioning bushing is conical, with two set diagonally and six fixing holes, four of which are connected to the ground by bolts, and the other two are connected to the automated production line. Transport hoists are equipped at both ends of the inlet and outlet of the automated production line.

[0004] The above-mentioned document achieves high-precision positioning within 0.5mm through conical positioning pins and positioning bushings after the Mecanum wheel AGV scans the QR code for preliminary navigation. It cannot solve the technical problem of accurate docking of the AGV and the machine. In the process of using AGV to transport materials in the workshop, the AGV is often required to determine the starting point of the driving path and then drive to the end point of the machine along the path to dock with the machine to realize functions such as charging or transportation. Especially for long-distance straight paths, there may be deviations in the angle of the AGV during the rotation process of confirming the starting point. For example, a larger angle rotation will cause the center of the AGV to be not at the starting point. In this way, the AGV will subsequently walk according to the non-starting point, which will make it impossible to achieve accurate docking with the machine to complete the material transportation. Summary of the Invention

[0005] The purpose of the present invention is to provide a local docking method based on QR code navigation, which can solve the problem of high-precision docking of logistics robots indoors, so that the logistics robots can accurately reach the destination and realize material handling.

[0006] To achieve the above objectives, the present invention provides a local docking method based on QR code navigation for a logistics robot. The logistics robot is provided with a camera at the bottom, and a QR code is set on the ground of a preset path, comprising the following steps:

[0007] S1. Set a starting QR code in the scanning area at the starting point of the preset path, and set a destination QR code in the scanning area at the end point of the preset path. Set the logistics robot to be able to successfully scan the QR code within the maximum deviation range [-x, x]. Set the logistics robot to adjust the angle a at the maximum deviation, and set the docking error range of the logistics robot at the end point.

[0008] S2. The logistics robot enters the scanning area at the starting point of the preset path along the direction from the starting QR code to the end QR code, scans the starting QR code with the camera, and then recognizes the starting QR code information;

[0009] S3. The logistics robot establishes a coordinate system with the center point of the starting QR code as the coordinate origin, and then calculates the deviation between the actual position coordinates of the logistics robot and the origin coordinates.

[0010] S4, correct the deviation between the actual position coordinates of the logistics robot and the origin coordinates,

[0011] S4.1. Determine the angle a0 at which the logistics robot deviates from the preset path using formula (1).

[0012] (1), is the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate;

[0013] S4.2. Use formula (2) to determine the distance s that the logistics robot travels along the deviation angle a0 to the preset path.

[0014] (2),

[0015] S4.3. Control the logistics robot to travel a distance s at a preset speed v along a deviation angle a0 and stop. Then control the logistics robot to rotate (90-a0) degrees in the direction of the preset path, correcting the deviation and returning to the preset path.

[0016] S5. Control the logistics robot to continue driving along the preset path to the end point scanning area, then scan the end point QR code again through the camera and read the information to determine whether the logistics robot is within the docking error range.

[0017] The above setting sets a QR code in the code scanning area and makes the logistics robot enter the code scanning area along the direction from the starting QR code to the end QR code, ensuring that the logistics robot can complete the code scanning and obtain the QR code information when it drives into the code scanning area; because after the logistics robot enters the code scanning area along the direction from the starting QR code to the end QR code and completes the code scanning, there may be a deviation between the center of the logistics robot and the center point of the starting QR code, and then by calculating the deviation between the horizontal coordinate of the actual position of the logistics robot and the horizontal coordinate of the origin coordinate, the actual deviation position of the logistics robot and the origin coordinate can be determined; then the angle a0 required to adjust the actual deviation of the logistics robot is calculated, and the distance s from the actual deviation position to the preset path is determined, so that the logistics robot can be controlled to drive to the preset path according to the calculated distance s, and then the logistics robot is rotated counterclockwise (90- a0)°, so that the logistics robot corrects the angle deviation and returns to the preset path; finally, the logistics robot is controlled to continue driving along the preset path to the terminal scanning area, where it can scan the QR code again and read the information. In this way, it can drive to the terminal along the preset path, thereby eliminating the starting point deviation, and can determine whether the logistics robot is within the docking error range and complete the docking, ensuring high-precision docking.

[0018] Furthermore, step S3 includes:

[0019] S3.1. Calculate the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the coordinate of the origin, and then determine the positional relationship between the logistics robot and the coordinate of the origin.

[0020] S3.1.1. If there is a deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate If the value is within the range of [-x, 0], the logistics robot is judged to be on the left side of the starting QR code.

[0021] S3.1.2 If there is a deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate If the value is within the range of [0, x], it is determined that the logistics robot has deviated to the right side of the starting QR code.

[0022] The above settings are based on the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate. Compare with the preset logistics robot within the maximum deviation range to determine whether the deviation is on the left or right side, thereby preliminarily determining the deviation position.

[0023] Furthermore, the preset path is set as the straight-line distance from the starting QR code to the ending QR code.

[0024] The above settings make it easier for logistics robots to arrive along a straight path and achieve precise docking.

[0025] Furthermore, the step S2 further includes the following steps S2.1-S2.2:

[0026] S2.1. If the QR code information at the starting point cannot be read, the logistics robot will exit the scanning area at the starting point of the preset path and then re-enter;

[0027] S2.2. If the starting point QR code information is successfully read, the logistics robot recognizes it as the starting point of the preset path and then proceeds to step S3.

[0028] The above settings make it easy to verify whether the logistics robot can scan the starting point QR code information through the camera and successfully read the starting point QR code information.

[0029] Furthermore, the step S4.2 further includes:

[0030] The distance l0 from the origin to the intersection of the path along the deviation angle a0 and the preset path is determined by formula (3).

[0031] (3),

[0032] Then, the distance L between the logistics robot and the end point of the preset path after the deviation is corrected is determined by formula (4).

[0033] L=l-l0(4)

[0034] Where l is the distance of the preset path.

[0035] The above settings make it easier for the logistics robot to drive in a straight line according to the distance from the terminal scanning area after correcting the deviation, so that it can reach the terminal scanning area to scan the code again and achieve docking.

[0036] Furthermore, step S5 further includes:

[0037] Control the logistics robot to continue driving a distance L along the preset path to the end point scanning area. After the logistics robot successfully scans the end point QR code, the information read in the end point QR code overwrites the information read in the starting point QR code, and then uses the information read in the end point QR code as a reference standard. If the logistics robot is within the preset docking error range of the logistics robot at the end point, the docking is completed; otherwise, enter step S2 to re-dock.

[0038] The above settings can prevent the distance L calculated by the logistics robot after correcting the deviation from being inconsistent with the information data in the destination QR code, so that the logistics robot continues to travel according to the distance L calculated after correcting the deviation after scanning the destination QR code. This will cause the logistics robot to exceed the docking error range of the preset path end point, and thus make the logistics robot unable to complete the docking. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the working method of the present invention.

[0040] Figure 2 Schematic diagram of the geometry calculated during the deviation correction process of the present invention.

[0041] Figure 3 This is a schematic diagram of entering the starting point scanning area in the present invention.

[0042] Figure 4 This is a schematic diagram of the logistics robot of the present invention after adjusting the body angle.

[0043] Figure 5 This is a schematic diagram of the logistics robot in the present invention rotating to a preset path. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1-5 As shown, a local docking method based on QR code navigation is provided. A camera is provided at the bottom of the logistics robot, which is used to identify QR code information. The QR code is set on the ground of a preset path. In this embodiment, the starting QR code 1 is set in the scanning area of ​​the starting point of the preset path, and the end point QR code 2 is set in the scanning area of ​​the end point of the preset path. The preset path is set as the straight-line distance from the starting QR code to the end point QR code.

[0046] The specific method includes the following steps:

[0047] S1. The logistics robot is preset to be able to successfully scan the QR code within the maximum deviation range [-x, x]. The logistics robot adjusts the angle to a at the maximum deviation, and the docking error range b of the logistics robot at the end point is preset. In this embodiment, x is set to 300 mm, a is set to 30°, and b is 5 mm.

[0048] S2. The logistics robot enters the scanning area at the starting point of the preset path along the direction from the starting QR code to the end QR code, scans the starting QR code with the camera, and then recognizes the starting QR code information;

[0049] S2.1. If the QR code information at the starting point cannot be read, the logistics robot will exit the scanning area at the starting point of the preset path and then re-enter;

[0050] S2.2. If the starting point QR code information is successfully read, the logistics robot recognizes it as the starting point of the preset path and then proceeds to step S3.

[0051] S3. Calculate the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot (i.e. the horizontal coordinate of the center point 3 of the logistics robot) and the origin coordinate, and then determine the positional relationship between the logistics robot and the origin coordinate.

[0052] S3.1.1. If the deviation x0 between the abscissa of the actual position coordinates of the logistics robot (i.e., the abscissa of the center point 3 of the logistics robot) and the origin coordinates is within the range [-x, 0], then the logistics robot is judged to be on the left side of the starting QR code.

[0053] S3.1.2. If the deviation x0 between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate is within the range of [0, x], it is determined that the logistics robot deviates to the right side of the starting point QR code. In this embodiment, x0 is set to 100 mm.

[0054] S4, correct the deviation between the actual position coordinates of the logistics robot and the origin coordinates,

[0055] S4.1. Determine the angle a0 at which the logistics robot deviates from the preset path using the following formula (1):

[0056] (1);

[0057] S4.2. Use formula (2) to determine the distance s that the logistics robot travels along the deviation angle a0 to the preset path.

[0058] (2),

[0059] The distance l0 from the origin of the coordinate to the intersection of the distance s and the preset path is determined by formula (3).

[0060] (3),

[0061] Then formula (4) determines the distance L between the logistics robot and the end point of the preset path after the deviation is corrected.

[0062] L=l-l0(4)

[0063] Where l is the distance of the preset path.

[0064] S4.3. Control the logistics robot to travel a distance s at a speed v along a deviation angle a0 and stop. Then control the logistics robot to rotate (90-a0)° along the preset path. In this embodiment, the rotation is counterclockwise about the plane of the XY axis, so that the logistics robot corrects the deviation and returns to the preset path.

[0065] S5. Control the logistics robot to continue driving a distance L along the preset path to the end point scanning area, and then scan the end point QR code again through the camera. After the logistics robot successfully scans the end point QR code, the information read in the end point QR code overwrites the information read in the starting point QR code, and uses the information read in the end point QR code as the reference standard. If the logistics robot is within the docking error range, the docking is completed; otherwise, enter step S2 to re-dock.

[0066] like Figure 3-5 As shown, the distance between the midpoint 3 of the logistics robot and the starting point QR code 1 at the beginning , control the logistics robot body to travel a distance s along the deviation angle a0, so that the midpoint of the logistics robot body moves to the preset path, and then continues to travel a distance L along the preset path, and confirms whether it returns to the key QR code, thereby ensuring the reliability of docking.

[0067] The working principle of the present invention is as follows: the logistics robot is controlled to enter the scanning area at the starting point of the preset path along the direction from the starting point QR code to the end point QR code to scan the code and read the QR code information, and then a coordinate system is established with the center point of the QR code as the coordinate origin, and the deviation between the actual position of the logistics robot and the origin coordinate is judged, and then the deviation, the angle corresponding to the corrected deviation and the distance from the actual deviation position to the preset path are calculated, so that the logistics robot returns to the preset path after adjusting the angle, and continues to drive along the preset path to the end point scanning area to scan the code again, and read the QR code information at the same time, and then stops driving with the information read by the end point scanning as the reference standard, and finally judges whether the logistics robot is within the docking error range and completes the docking.

Claims

1. A local docking method based on QR code navigation for a logistics robot, wherein a camera is provided at the bottom of the logistics robot and a QR code is provided on the ground of a preset path, characterized in that: The following steps are involved: S1. Set a starting QR code in the scanning area at the starting point of the preset path, and set a destination QR code in the scanning area at the end point of the preset path. Set the logistics robot to be able to successfully scan the QR code within the maximum deviation range [-x, x]. Set the logistics robot to adjust the angle a at the maximum deviation, and set the docking error range of the logistics robot at the end point. S2. The logistics robot enters the scanning area at the starting point of the preset path along the direction from the starting QR code to the end QR code, scans the starting QR code with the camera, and then recognizes the starting QR code information; S3. The logistics robot establishes a coordinate system with the center point of the starting QR code as the coordinate origin, and then calculates the deviation between the actual position coordinates of the logistics robot and the origin coordinates. S4. Correct the deviation between the actual position coordinates of the logistics robot and the origin coordinates. S4.

1. Determine the angle a0 of the logistics robot deviating from the preset path using formula (1). (1), is the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate; S4.

2. Use formula (2) to determine the distance s that the logistics robot travels along the deviation angle a0 to the preset path. （2）， The distance l0 from the origin to the intersection of the path along the deviation angle a0 and the preset path is determined by formula (3). （3）， Then, the distance L between the logistics robot and the end point of the preset path after the deviation is corrected is determined by formula (4). L=l-l0（4）， Where l is the distance of the preset path; S4.

3. Control the logistics robot to travel a distance s at a preset speed v along a deviation angle a0 and stop. Then control the logistics robot to rotate (90-a0) degrees in the direction of the preset path, correcting the deviation and returning to the preset path. S5. Control the logistics robot to continue driving along the preset path to the destination scanning area, then use the camera to scan the destination QR code again and read the information to determine whether the logistics robot is within the docking error range; after the logistics robot successfully scans the destination QR code, the information read from the destination QR code overwrites the information read from the starting QR code, and then uses the information read from the destination QR code as a reference standard. If the logistics robot is within the docking error range, the docking is completed; Otherwise, proceed to step S2 to re-docking.

2. The local docking method based on QR code navigation according to claim 1, characterized in that: Step S3 includes: S3.1, calculating the deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate, and then determining the positional relationship between the logistics robot and the origin coordinate, S3.1.

1. If there is a deviation between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate If the value is within the range of [-x, 0], the logistics robot is judged to be on the left side of the starting QR code. S3.1.

2. If the deviation x0 between the horizontal coordinate of the actual position coordinate of the logistics robot and the origin coordinate is within the range of [0, x], it is determined that the logistics robot deviates to the right of the starting point QR code.

3. The local docking method based on QR code navigation according to claim 1, characterized in that: The preset path is set as the straight-line distance from the starting QR code to the ending QR code.

4. The local docking method based on QR code navigation according to claim 1, characterized in that: The step S2 further includes the following steps S2.1-S2.2: S2.

1. If the QR code information at the starting point cannot be read, the logistics robot will exit the scanning area at the starting point of the preset path and then re-enter; S2.

2. If the starting point QR code information is successfully read, the logistics robot recognizes it as the starting point of the preset path and then proceeds to step S3.

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