AGV level detection device and method based on reflective plate

Abstract

The present invention discloses an AGV level detection device and method based on a reflector, which is applied to an AGV equipped with a laser radar; comprising: a reflector, wherein a plurality of reflectors are symmetrically arranged on the left and right sides of a designated position on the AGV driving path; the heights of the reflectors on the same side are all different, and the distances from the reflectors on the same side to the designated position are all different; a detection module, connected to the laser radar, for obtaining a first angle between the laser radar plane and the horizontal plane after rotating around the X axis, and obtaining a second angle between the laser radar plane and the horizontal plane after rotating around the Y axis when the AGV drives to the designated position, and judging whether the laser radar is located on the horizontal plane based on the first angle and the second angle. The present invention does not need to set a level sensor on the AGV, and only needs to add a small number of reflectors of different heights to quickly detect whether the laser radar on the AGV is located on the horizontal plane.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic guided vehicles (AGVs), and in particular to a device and method for detecting the level of an AGV based on a reflector. Background Art

[0002] An AGV (automatic guided vehicle) navigated by LiDAR may deviate from the horizontal plane due to road conditions or vibrations during driving, which will cause the AGV's driving path to be inaccurate and deviate from the predetermined driving trajectory.

[0003] Traditional technology uses geometric triangulation positioning, which refers to a mathematical principle. It uses three or more target positions detected by a single-line laser radar at different locations, and then uses triangular geometry principles to determine the position and azimuth of the single-line laser radar. So far, the triangulation positioning method is the most commonly used positioning method because it is simple, fast and widely used. Due to measurement errors, this positioning method is difficult to apply to some high-precision industrial positioning scenarios. There is also a solution for installing a horizontal deflection sensor on the AGV for positioning, but the use of a horizontal deflection sensor will increase costs on the one hand, and installation and positioning are more troublesome on the other hand, requiring certain modifications to the AGV. Summary of the invention

[0004] The main purpose of the present invention is to overcome the above-mentioned defects in the prior art and to propose an AGV level detection device and method based on reflectors. There is no need to set a level sensor on the AGV. Only a small number of reflectors of different heights need to be added to quickly detect whether the laser radar on the AGV is on a horizontal plane.

[0005] The present invention adopts the following technical solution:

[0006] On the one hand, an AGV level detection device based on a reflector is applied to an AGV equipped with a laser radar; comprising:

[0007] Reflectors, wherein a plurality of reflectors are symmetrically arranged on the left and right sides of a designated position on the AGV driving path; the heights of the reflectors on the same side are different, and the distances from the reflectors on the same side to the designated position are different;

[0008] The detection module is connected to the laser radar and is used to obtain a first angle between the plane where the laser radar is located and the horizontal plane after the plane is rotated around the X-axis, and to obtain a second angle between the plane where the laser radar is located and the horizontal plane after the plane is rotated around the Y-axis when the AGV travels to the specified position, and to determine whether the laser radar is on the horizontal plane based on the first angle and the second angle.

[0009] Preferably, the heights of the reflectors on the same side increase or decrease sequentially.

[0010] Preferably, the reflectors on the same side include an odd number, and the midpoint of the vertical height of the middle reflector is equal to the height of the ideal horizontal plane where the laser radar is located.

[0011] Preferably, the multiple reflective plates on the same side are arranged at equal intervals.

[0012] Preferably, the detection module includes an AGV controller.

[0013] On the other hand, a reflector-based AGV level detection method is applied to an AGV equipped with a laser radar; comprising: when a detection module connected to the laser radar detects that the AGV has traveled to a designated position, it is determined whether the laser radar has detected two or more reflectors; if detected, a first angle between the plane where the laser radar is located and the horizontal plane after rotating around the X-axis is obtained, and a second angle between the plane where the laser radar is located and the horizontal plane after rotating around the Y-axis is obtained, and based on the first angle and the second angle, it is determined whether the laser radar is located on the horizontal plane; wherein the reflectors include a plurality of reflectors, and the plurality of reflectors are symmetrically arranged on the left and right sides of a designated position on the AGV travel path; the heights of the reflectors on the same side are different, and the distances from the reflectors on the same side to the designated position are different.

[0014] Preferably, the AGV level detection method based on reflectors further includes: if the laser radar does not detect two reflectors, it is prompted that the laser radar is not located on a horizontal plane and needs to be adjusted.

[0015] Preferably, if detected, obtaining a first angle between the plane where the laser radar is located and the horizontal plane after rotating around the X-axis, and obtaining a second angle between the plane where the laser radar is located and the horizontal plane after rotating around the Y-axis, and judging whether the laser radar is located on the horizontal plane based on the first angle and the second angle specifically includes:

[0016] If two reflectors are detected, calculate the distance R between the laser radar and the two reflectors 1 and R 2 , calculate the angle α between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors 1 and α 2 , and calculate the distance L between the midpoint of the vertical height of the two reflectors and the ideal horizontal plane where the laser radar is located 1 and L 2 ; If more than two reflectors are detected, obtain the two reflectors farthest from the laser radar and calculate the distance R between the laser radar and the two reflectors 1 and R 2 , calculate the angle α between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors 1 and α2 , and calculate the distance L between the midpoint of the vertical height of the two reflectors and the ideal horizontal plane where the laser radar is located 1 and L 2 ;

[0017] Based on the distance R 1 and R 2 , angle α 1 and α 2 and the distance L 1 and L 2 , obtain the first angle θ between the laser radar plane and the horizontal plane after rotating around the X axis x , and obtain the second angle θ between the laser radar plane and the horizontal plane after rotating around the Y axis y ;

[0018] If the first angle θ x is greater than the first preset threshold, or the second angle θ y If it is greater than a second preset threshold, it is determined that the laser radar is not located on a horizontal plane, and an adjustment is required.

[0019] Preferably, based on the distance R 1 and R 2 , angle α 1 and α 2 and the distance L 1 and L 2 , obtain the first angle θ between the laser radar plane and the horizontal plane after rotating around the X axis x , and obtain the second angle θ between the laser radar plane and the horizontal plane after rotating around the Y axis y , as follows:

[0020] From the geometric relationship we can get:

[0021] R 1 cosα 1 sinθ x +R 1 sinα 1 sinθ y =L 1

[0022] R 2 cosα 2 sinθ x +R 2 sinα 2 sinθ y =L 2

[0023] Calculate θ x and θ y They are as follows:

[0024]

[0025]

[0026] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention does not require a level sensor to be installed on the AGV. Instead, only a small number of reflectors at different heights need to be added to quickly detect whether the laser radar on the AGV is on a horizontal plane. The structure is simple, the modification workload is small, and the reliability is high.

[0028] (2) The present invention symmetrically arranges reflectors with height differences on the left and right sides of a designated position on the AGV driving path, and uses the parameters of the two reflectors when performing horizontal angle detection, thereby ensuring the accuracy of the calculation;

[0029] (3) The height, height gradient, spacing and number of the reflectors of the present invention can be flexibly set, so that sensitive detection of horizontal angles can be achieved;

[0030] (4) The detection module of the present invention has a fast detection speed and can complete online detection during the operation of the AGV. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A front view of the reflector arrangement of the present invention;

[0032] Figure 2 A top view of the arrangement of the reflective sheet of the present invention;

[0033] Figure 3 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described below through specific implementation modes.

[0035] See also Figure 1 and Figure 2 As shown, the present invention provides an AGV level detection device based on a reflector, which is applied to an AGV equipped with a laser radar 10; comprising:

[0036] Reflectors 20, wherein a plurality of reflectors 20 are symmetrically arranged on the left and right sides of a designated position on the AGV driving path; the heights of the reflectors 20 on the same side are different, and the distances from the reflectors 20 on the same side to the designated position are different;

[0037] The detection module is connected to the laser radar 10 and is used to obtain a first angle between the plane where the laser radar 10 is located and the horizontal plane after it rotates around the X-axis, and to obtain a second angle between the plane where the laser radar 10 is located and the horizontal plane after it rotates around the Y-axis when the AGV travels to the specified position, and to determine whether the laser radar 10 is on the horizontal plane based on the first angle and the second angle.

[0038] In this embodiment, the heights of the reflectors 20 on the same side are increased or decreased in sequence. The heights of the two reflectors 20 symmetrically arranged on the left and right sides are the same.

[0039] In this embodiment, the reflectors 20 on the same side include an odd number, and the midpoint of the vertical height of the middle reflector 20 is equal to the height of the ideal horizontal plane where the laser radar 10 is located. If five reflectors 20 are set on the left side and five reflectors 20 are set on the right side, the designated position can be set at the middle position of the third reflector 20 on the left and the third reflector 20 on the right, and the midpoint of the vertical height of the third reflector 20 is equal to the height of the ideal horizontal plane where the laser radar 10 is located.

[0040] In this embodiment, the multiple reflectors 20 on the same side are arranged at equal intervals. For example, if five reflectors 20 are arranged on the left side, the distance between the first reflector 20 and the second reflector 20, the distance between the second reflector 20 and the third reflector 20, the distance between the third reflector 20 and the fourth reflector 20, and the distance between the fourth reflector 20 and the fifth reflector 20 can be set to be equal.

[0041] In this embodiment, the detection module includes an AGV controller. Of course, it can also be other controllers, as long as it can obtain the parameters between the laser radar 10 and the reflector 20 and perform online calculations.

[0042] See also Figure 3 As shown, a reflector-based AGV level detection method is applied to an AGV equipped with a laser radar 10; comprising: when a detection module connected to the laser radar 10 detects that the AGV has traveled to a specified position, it is determined whether the laser radar 10 has detected two or more reflectors 20, and if detected, a first angle between the plane where the laser radar 10 is located and the horizontal plane after rotating around the X-axis is obtained, and a second angle between the plane where the laser radar 10 is located and the horizontal plane after rotating around the Y-axis is obtained, and based on the first angle and the second angle, it is determined whether the laser radar 10 is located on the horizontal plane; wherein the reflector 20 includes a plurality of reflectors 20, and the plurality of reflectors 20 are symmetrically arranged on the left and right sides of a specified position on the AGV travel path; the heights of the reflectors 20 on the same side are all different, and the distances from the reflectors 20 on the same side to the specified position are all different.

[0043] In this embodiment, the AGV level detection method based on reflectors further includes: if the laser radar 10 does not detect the two reflectors 20, it is prompted that the laser radar 10 is not located on a horizontal plane and needs to be adjusted.

[0044] Further, if it is detected, obtaining a first angle between the plane where the laser radar 10 is located and the horizontal plane after rotating around the X-axis, and obtaining a second angle between the plane where the laser radar 10 is located and the horizontal plane after rotating around the Y-axis, and judging whether the laser radar 10 is located on the horizontal plane based on the first angle and the second angle specifically includes:

[0045] If two reflectors 20 are detected, the distance R between the laser radar 10 and the two reflectors 20 is calculated. 1 and R 2 , calculate the angle α between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors 20 1 and α 2 , and calculate the distance L between the midpoint of the vertical height of the two reflectors 20 and the ideal horizontal plane where the laser radar 10 is located 1 and L 2 If more than two reflectors 20 are detected, the two reflectors 20 detected farthest from the laser radar are obtained, and the distance R between the laser radar 10 and the two reflectors 20 is calculated. 1 and R 2 , calculate the angle α between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors 20 1 and α 2 , and calculate the distance L between the midpoint of the vertical height of the two reflectors 20 and the ideal horizontal plane where the laser radar 10 is located 1 and L 2 ;

[0046] Based on the distance R 1 and R 2 , angle α 1 and α 2 and the distance L 1 and L 2 , obtain the first angle θ between the plane where the laser radar 10 is located and the horizontal plane after rotating around the X axis x , and obtain the second angle θ between the plane where the laser radar 10 is located and the horizontal plane after rotating around the Y axis y ;

[0047] If the first angle θ x is greater than the first preset threshold offset1, or the second angle θ y If it is greater than the second preset threshold offset2, it is determined that the laser radar 10 is not located on a horizontal plane, and an adjustment is required.

[0048] Furthermore, based on the distance R 1 and R 2 , angle α 1 and α 2 and the distance L 1 and L 2 , obtain the first angle θ between the plane where the laser radar 10 is located and the horizontal plane after rotating around the X axis x , and obtain the second angle θ between the plane where the laser radar 10 is located and the horizontal plane after rotating around the Y axis y , as follows:

[0049] From the geometric relationship we can get:

[0050] R 1 cosα 1 sinθ x +R 1 sinα 1 sinθ y =L 1

[0051] R 2 cosα 2 sinθ x +R 2 sinα 2 sinθ y =L 2

[0052] Calculate θ x and θ y They are as follows:

[0053]

[0054]

[0055] It should be noted that a method for detecting the level of an AGV based on a reflector may further include: when the laser radar 10 detects two or more reflectors 20 with a height difference of zero, it means that the laser radar 10 is parallel to the horizontal plane at this time, and the above calculation formula may not be used for calculation (of course, in this scenario, the θ calculated using the above calculation formula is x and θ y are all 0, it can also be judged that the laser radar 10 is parallel to the horizontal plane at this time); when the laser radar 10 detects two or more reflectors 20 with a non-zero height difference, the rotation angle θ of the laser radar 10 about the x-axis and the y-axis can be calculated according to the geometric relationship (the above calculation formula) x and θ y , and according to θ x and θ yThe size of can be used to determine whether the laser radar 10 is parallel to the horizontal plane at this time.

[0056] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. An AGV level detection device based on a reflector, applied to an AGV equipped with a laser radar; characterized in that: include: Reflectors, wherein a plurality of reflectors are symmetrically arranged on the left and right sides of a designated position on the AGV driving path; the heights of the reflectors on the same side are different, and the distances from the reflectors on the same side to the designated position are different; a detection module connected to the laser radar, and configured to obtain, when the AGV travels to the designated position, a first angle between the plane where the laser radar is located and the horizontal plane after rotating around the X-axis, and a second angle between the plane where the laser radar is located and the horizontal plane after rotating around the Y-axis, based on the number of reflectors and the positions of the reflectors detected by the laser radar, and to determine whether the laser radar is located on the horizontal plane based on the first angle and the second angle; The first angle and the second angle are respectively as follows: Among them, θ x represents the first angle; θ y represents the second angle; if the number of reflectors detected is two, R1 and R2 represent the distance between the laser radar and the two reflectors, α1 and α2 represent the angle between the Y axis of the AGV and the line connecting the two reflectors on the horizontal plane, and L1 and L2 represent the distance between the midpoint of the vertical height of the two reflectors and the ideal horizontal plane where the laser radar is located; if the number of reflectors detected is more than two, R1 and R2 represent the distance between the laser radar and the two reflectors farthest from the laser radar, α1 and α2 represent the angle between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors farthest from the laser radar, and L1 and L2 represent the distance between the midpoint of the vertical height of the two reflectors farthest from the laser radar and the ideal horizontal plane where the laser radar is located.

2. The AGV level detection device based on a reflective plate according to claim 1 is characterized in that: The heights of the reflectors on the same side increase or decrease in sequence.

3. The AGV level detection device based on a reflective plate according to claim 1 is characterized in that: The reflectors on the same side include an odd number, and the midpoint of the vertical height of the middle reflector is equal to the height of the ideal horizontal plane where the laser radar is located.

4. The AGV level detection device based on a reflective plate according to claim 1 is characterized in that: Multiple reflectors on the same side are arranged at equal intervals.

5. The AGV level detection device based on a reflective plate according to claim 1 is characterized in that: The detection module includes an AGV controller.

6. A method for detecting the level of an AGV based on a reflector, applied to an AGV equipped with a laser radar; characterized in that: include: When the detection module connected to the laser radar detects that the AGV has traveled to the designated position, it is determined whether the laser radar has detected two or more reflectors. If detected, based on the positions of the reflectors detected by the laser radar, a first angle between the plane where the laser radar is located and the horizontal plane after rotating around the X-axis is obtained, and a second angle between the plane where the laser radar is located and the horizontal plane after rotating around the Y-axis is obtained, and based on the first angle and the second angle, it is determined whether the laser radar is located on the horizontal plane; wherein the reflectors include a plurality of reflectors, and the plurality of reflectors are symmetrically arranged on the left and right sides of the designated position on the AGV travel path; the heights of the reflectors on the same side are all different, and the distances from the reflectors on the same side to the designated position are all different; The first angle and the second angle are respectively as follows: Among them, θ x Represents the first angle; θ y represents the second angle; if the number of reflectors detected is two, R1 and R2 represent the distance between the laser radar and the two reflectors, α1 and α2 represent the angle between the Y axis of the AGV and the line connecting the two reflectors on the horizontal plane, and L1 and L2 represent the distance between the midpoint of the vertical height of the two reflectors and the ideal horizontal plane where the laser radar is located; if the number of reflectors detected is more than two, R1 and R2 represent the distance between the laser radar and the two reflectors farthest from the laser radar, α1 and α2 represent the angle between the Y axis of the AGV on the horizontal plane and the line connecting the two reflectors farthest from the laser radar, and L1 and L2 represent the distance between the midpoint of the vertical height of the two reflectors farthest from the laser radar and the ideal horizontal plane where the laser radar is located.

7. The AGV level detection method based on a reflector according to claim 6 is characterized in that: Also includes: If the laser radar does not detect two reflectors, it indicates that the laser radar is not located on a horizontal plane and needs to be adjusted.

8. The AGV level detection method based on a reflector according to claim 6, characterized in that: Determining whether the laser radar is located on a horizontal plane based on the first angle and the second angle specifically includes: If the first angle θ x is greater than the first preset threshold, or the second angle θ y If it is greater than a second preset threshold, it is determined that the laser radar is not located on a horizontal plane, and an adjustment is required.

9. The AGV level detection method based on a reflector according to claim 6, characterized in that: The first angle θ x and the second angle θ y From the geometric relationship we can get:

Images