WO2018213980A1 - Robot calibration method, system, and calibration board - Google Patents

Abstract

A robot calibration method, system, and calibration board. The calibration method comprises: controlling, in a predetermined region of a calibration board (12) provided with a flexible film (10), a front robot end (11) to move according to a predetermined rule, the predetermined region containing corner points; measuring, during the moving process, the predetermined region of the calibration board, and calculating edge line deformation caused by the front robot end for each movement; and determining, according to the deformation, positions of calibration points to complete robot calibration. The method is employed to obtain relatively accurate positions of the calibration points, thus improving accuracy of a transform relationship between a robot coordinate system and a vision coordinate system.

Description

Calibration method, system and calibration board for robot

[Technical Field]

The invention relates to the technical field of robot coordinate setting, in particular to a calibration method, a system and a calibration plate of a robot.

 【Background technique】

At present, industrial robots have played an increasingly important role in production in manufacturing industries around the world. In order to make industrial robots more capable of more complex work, robots not only need better control systems, but also need to be more aware of environmental changes. Among them, robot vision has become the most important robot sensing device with its large amount of information and high information integrity. For example, in the welding process, the robot can perform precise welding of the electronic components of the circuit board. During the welding process, the robot can position the workpiece or the working surface by using the camera in the vision system, and calculate the relative position of the working scene relative to the robot to assist the robot to complete the work.

The use of the vision system to calculate the conversion relationship between the visual coordinate system and the robot coordinate system has become an important research topic for the development of robots. Obtaining the conversion relationship between the more accurate coordinate systems is the premise for solving the high-precision operation of the robot. However, existing robots usually manually move the robot directly to the calibration point of the vision system to enable the robot to calculate the conversion relationship between the visual coordinate system and the robot coordinate system using the visual system, but the artificial comparison method cannot guarantee the two. The calibration point of the comparison is the same point. In this way, there is usually a large human error, which leads to a large error in the obtained conversion relationship.

 [Summary of the Invention]

The object of the present invention is to provide a calibration method, a system and a calibration plate for a robot, which can improve the accuracy of the conversion relationship between the robot coordinate system and the visual coordinates.

In order to achieve the above object, the present invention provides a calibration method for a robot, including a calibration plate, the calibration plate includes a checkerboard, and an intersection of a vertical line and a horizontal line on the checkerboard is a corner point on the checkerboard. The vertical line and the horizontal line are boundary lines of the grid, and the calibration method includes:

Controlling the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film, the predetermined area including the corner point;

Detecting the predetermined area of the calibration plate during the movement, and calculating a shape variable of the boundary line caused by the front end of the robot for each movement;

The position of the calibration point is determined according to the shape variable, and the calibration of the robot is completed.

Wherein the predetermined area is determined by at least four reference points, wherein determining the at least four reference points comprises:

Taking an initial position point of the front end of the robot as an origin, at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area.

Wherein, the initial position point of the front end of the robot is taken as an origin, and at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area, including:

Taking the initial position point of the front end of the robot as an origin, controlling the front ends of the robot to move in four directions extending along the boundary line respectively;

Obtaining a reflection image of the calibration plate each time it moves;

Calculating, according to the reflected image, a shape variable of a boundary line caused by the front end of the robot at each movement;

The shape variable with the smallest value is extracted from the shape variable, and the position of the robot front end corresponding to the smallest shape variable is the reference point.

Wherein, the controlling the robot front end moves according to a preset rule in a predetermined area on the calibration plate provided with the flexible film, including:

Within the predetermined area, the front end of the robot is controlled to move at its minimum moving distance until it is spread over the area.

Wherein, determining the location of the calibration point according to the shape variable comprises:

Extracting the shape variable with the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot;

The position of the calibration point is determined based on the shape variable having the smallest value.

Wherein, determining the location of the calibration point according to the shape variable with the smallest value, including:

The position point corresponding to the shape variable having the smallest value is used as the position of the calibration point.

In another aspect, the present invention provides a calibration system for a robot, the calibration system comprising: a calibration plate provided with a flexible film, and a visual device, a processor and a memory connected by a bus;

The memory is configured to store a preset movement rule of the robot and an execution instruction of the processor;

The visual device is configured to detect the calibration plate;

The processor is configured to perform the following actions:

Controlling the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film, the predetermined area including the corner point;

Detecting the predetermined area of the calibration plate during the movement, and calculating a shape variable of the boundary line caused by the front end of the robot for each movement;

The position of the calibration point is determined according to the shape variable, and the calibration of the robot is completed.

Wherein the predetermined area is determined by at least four reference points, wherein determining the at least four reference points comprises:

Taking an initial position point of the front end of the robot as an origin, at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area.

Wherein, the initial position point of the front end of the robot is taken as an origin, and at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area, including:

Taking the initial position point of the front end of the robot as an origin, controlling the front ends of the robot to move in four directions extending along the boundary line respectively;

Obtaining a reflection image of the calibration plate each time it moves;

Calculating, according to the reflected image, a shape variable of a boundary line caused by the front end of the robot at each movement;

The shape variable with the smallest value is extracted from the shape variable, and the position of the robot front end corresponding to the smallest shape variable is the reference point.

The controlling the robot front end to move according to a preset rule in a predetermined area on the calibration plate provided with the flexible film, including:

Within the predetermined area, the front end of the robot is controlled to move at its minimum moving distance until it is spread over the area.

The determining, by the processor, the location of the calibration point according to the shape variable, including:

Extracting the shape variable with the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot;

The position of the calibration point is determined based on the shape variable having the smallest value.

The determining, by the processor, the location of the calibration point according to the shape variable with the smallest value, including:

The position point corresponding to the shape variable having the smallest value is used as the position of the calibration point.

In another aspect, the invention provides a calibration plate, the calibration plate comprising:

A calibration plate is provided, and a flexible film is disposed on the calibration plate.

Wherein, the calibration plate block is a checkerboard.

Wherein, a plurality of identification points for positioning the front end contacts of the robot are arranged near the corners of the checkerboard.

Wherein, the flexible film is a flexible film whose surface reflects infrared.

Advantageous Effects: Different from the prior art, the present invention controls the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film, the predetermined area including the corner point; during the moving process The predetermined area of the calibration plate is detected, and a shape variable of a boundary line caused by the front end of the robot is calculated for each movement; the position of the calibration point is determined according to the deformation variable, and the calibration of the robot is completed. Through the above method, the position of the relatively accurate calibration point can be calculated, thereby improving the accuracy of the conversion relationship between the robot coordinate system and the visual coordinate.

 [Description of the Drawings]

1 is a schematic flow chart of a first embodiment of a calibration method of a robot according to the present invention;

2 is a schematic flow chart of an embodiment of a method for determining a predetermined area in the first embodiment of the calibration method shown in FIG. 1;

3a-3b are schematic views showing deformation of a flexible film on a calibration plate in the first embodiment of the calibration method shown in FIG. 1;

4a-4c are schematic structural views of a first embodiment of a calibration method of a robot according to the present invention;

FIG. 5 is a schematic diagram of a trajectory of the movement of the front end of the robot in step S102 in the first embodiment of the calibration method shown in FIG. 1; FIG.

FIG. 6 is a schematic flowchart of step S103 in the first embodiment of the method shown in FIG. 1;

Figure 7 is a functional block diagram of a first embodiment of a calibration system for a robot of the present invention;

Figure 8 is a schematic structural view of an embodiment of a calibration plate of the present invention;

9a-9b are schematic views showing the structure of another embodiment of the calibration plate of the present invention.

【detailed description】

In order to enable a person skilled in the art to better understand the technical solutions of the present invention, a calibration method, a system and a calibration plate of a robot provided by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiment is only a part of the calibration method, system and calibration plate of the robot of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

In the prior art, the unified robot coordinate system and the visual coordinate system are manually moved to move the front end of the robot to the corner point of the calibration plate under the vision system. Since the coordinates of the corner points of the calibration plate under the vision system are known, Assign the coordinates of the corner points of the calibration plate to the front end of the robot to complete the calibration of the robot. However, in practice, the manipulator moves the front end of the robot to the corner of the calibration plate under the vision system. There is often a large error. It is difficult to judge whether the front end of the robot actually falls on the corner of the calibration plate by the naked eye, resulting in the calibration of the front end of the robot. The error is large. In the present invention, the calibration plate is detected to determine the position of the front end of the robot closest to the corner of the calibration plate, thereby improving the accuracy of the calibration robot.

Referring to FIG. 1 , FIG. 1 is a schematic flowchart of a first embodiment of a calibration method for a robot according to the present invention. The method includes the following steps:

S101. Control the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film.

The calibration in this embodiment is a calibration plate provided with a flexible film, and the calibration plate is a checkerboard. The boundary line of the lattice on the checkerboard is divided into a vertical line and a horizontal line, and the corner point of the checkerboard is the intersection of the vertical line and the horizontal line. . Taking the checkerboard of the black and white grids as an example, the corner points on the calibration board are the intersections of the black and white grids on the checkerboard, and the intersection of the black and white grids is the boundary line. Since the flexible film is disposed on the calibration plate, when the front end of the robot contacts the calibration plate, a corresponding pressure is generated on the flexible film on the surface of the calibration plate, resulting in deformation of the flexible film. The deformed flexible film magnifies the reflected image of the calibration plate directly below the front end of the robot. If the position of the front end of the robot in contact with the calibration plate is close to the boundary line, the deformation of the boundary line can be obtained from the reflected image of the acquired calibration plate by the deformation and amplification of the flexible film.

It can be understood that the checkerboard of the black and white grids is only in a specific real-time manner in the checkerboard of the present application. In other embodiments, the calibration board can have a checkerboard of vertical and horizontal lines, and the corner point is The intersection of the vertical line and the horizontal line on the checkerboard, wherein the vertical line and the horizontal line are the boundary lines of each grid on the checkerboard. In other embodiments, the checkerboard may also be a checkerboard of all black squares or both are white. The checkerboard, or any other checkerboard of any color.

In the predetermined area, the front end of the control robot is moved by its minimum moving distance until the predetermined area is traversed to determine the calibration point in the predetermined area.

In this embodiment, the predetermined area is determined by at least four reference points. Therefore, in the embodiment, the at least four reference points need to be determined.

Further, as shown in FIG. 2, determining the predetermined area in step S101 includes the following steps:

S1011: The robot front end is moved in four directions extending along the boundary line with the initial position of the robot front end as the origin.

Move the front end of the robot to a position near the corner of the calibration plate. This position is the initial position of the front end of the robot. The initial position of the front end of the robot on the calibration plate is taken as the origin, and the boundary line on the calibration plate is seen. A ray that extends in four different directions at the origin.

The front end of the robot is sequentially controlled to move in a direction in which one of the boundary lines extends. Since the obtained reference calibration point is used to finalize the calibration point, and the determined calibration point needs to be as close as possible to the corner point on the calibration plate, the front end of the robot is controlled when the front end of the control robot moves in the direction in which the boundary line extends. It is a direction extending along the boundary line and gradually moves on both sides of the boundary line. In order to improve the accuracy of the acquired reference calibration point, the front end of the robot is gradually moved on both sides of the boundary line with its minimum moving step.

S1012: Obtain a reflection image of the calibration plate at each movement.

As shown in FIGS. 3a and 3b, s1 and s2 are black and white grids on the checkerboard, respectively, and the front end 11 of the robot contacts the calibration plate to generate pressure on the flexible film 10, causing the flexible film 10 to deform. As shown in FIG. 3a, if the position of the robot front end 10 on the calibration plate 12 is close to the boundary line between the black grid s1 and the white grid s2, the boundary image of the obtained calibration plate 12 is deformed, specifically In the reflected image of the calibration plate 12, it can be seen that the boundary line is convex toward the side of the position of the robot front end 11 on the calibration plate 12, and the apex of the protrusion corresponds to the position of the robot front end 11 on the calibration plate 12. . As shown in FIG. 3b, if the contact position of the robot front end 11 and the calibration plate 12 falls exactly above the boundary line, the deformation of the boundary line is not seen from the obtained reflection image of the calibration plate 12; The reflected image can obtain the contact position of the robot front end 11 with the calibration plate 12.

In this embodiment, since in the process of moving the front end of the robot, it is not known which movement causes the front end of the robot to be closest to the boundary line; then, in the direction extending along the boundary line, the front end of the robot is moved once for each time. The reflected image of the calibration plate. Through each acquired image of the calibration plate, the deformation of the boundary line in the reflection image of the calibration plate caused by the front end of the robot is obtained each time the front end of the robot is moved.

S1013. Calculate, according to the acquired reflection image, a shape variable of a boundary line caused by the front end of the robot when moving.

By analyzing the reflection image of each acquired calibration plate, it can be calculated that the deformation of the boundary line in the reflection image of the calibration plate is caused by the front end of the robot pressing the flexible film each time the front end of the robot is moved.

Since the shape of the boundary line becomes a boundary line which is convex toward one side of the position of the robot front end on the index plate, the shape variable of the boundary line is the degree of the protrusion. Further, since the vertex of the protrusion corresponds to the position of the front end of the robot on the calibration plate, the shape variable of the boundary line is the distance from the vertex of the protrusion to the original position of the boundary line. This distance is the distance from the position of the front end of the robot on the calibration plate to the boundary line. Then, after each movement of the front end of the robot, the deformation of the boundary line of the calibration image of the calibration plate is caused by the front end of the robot pressing the flexible film, and the distance between the front end of the robot and the boundary line of the robot on the calibration plate is calculated. the distance.

S1014, extracting the smallest shape variable from the shape variable, and the position of the robot front end corresponding to the smallest value variable is the reference point.

The shape variable with the smallest value is extracted from the shape variable calculated in the reflection image of the calibration plate acquired by each mobile robot front end. The position of the robot front end corresponding to the smallest value is closest to the boundary line on the calibration plate, and the position of the corresponding robot front end on the calibration plate is used as a reference point.

Since the shape variable is the distance from the vertex of the convex to the boundary line in the reflected image of the calibration plate, the smallest variable is the minimum of the distance from the vertex of the convex to the boundary line in the reflected image of the calibration plate. According to the above analysis, the shape variable with the smallest value corresponds to the position of the robot front end closest to the boundary line on the calibration plate, and the position is taken as a reference point determined in the direction.

Steps S1011 to S1014 are repeated in the remaining three directions in which the boundary line extends to complete at least four reference points in the four directions in which the boundary line extends, and at least four reference points can be determined according to the determined at least four reference points. The predetermined area in this embodiment is determined.

Since at least four reference points determined by step S1011 to step S1014 are both near the corner point and close to the boundary line, the range of the calibration point determined by the robot front end can be further narrowed by the four reference points near the corner point.

Specifically, by selecting at least four reference points determined by step S1011 to step S1014, each reference point is connected with the closest reference point on both sides thereof to determine a predetermined area, it can be understood that the corner point of the calibration board is within the area.

The determination of the reference point is exemplified: as shown in FIG. 4a, the calibration plate is a checkerboard set between the black and white grids, and the corner point A is the intersection of the black grid and the white grid, and the four boundary lines a, b, c and d extends in four directions of the corner A direction, respectively. First, in step S1011, the front end of the robot is moved to a position near the corner point A, and the position is used as an initial position point of the robot front end, and the initial position point is used as an origin, and the front end of the control robot is started from the origin, along the boundary line a. The direction of the extension moves in the vicinity of the boundary line a, and the reference point B is determined through steps S1012 to S1014; and the steps S1011 to S1014 are repeated in the direction in which the boundary lines b, c, and d extend, respectively, to determine the reference points C, D, respectively. And E, and then reference points B, C, D, E are sequentially connected to determine a predetermined area enclosed by the broken line in Fig. 4b, and the corner point A of the calibration plate is in the area. In order to facilitate the marking of the reference calibration point and the area determined by the reference calibration point, the black grid portion is not filled in Fig. 4b, it being understood that the distribution of the black and white grids of Fig. 4b is the same as that of Fig. 4a.

S102: Detecting a predetermined area of the calibration plate during the movement, and calculating a shape variable of the boundary line caused by the front end of the robot for each movement.

In the predetermined area, the front end of the control robot is gradually moved. In order to make the finally obtained corrected calibration point as close as possible to the corner point of the calibration plate, the front end of the robot gradually moves with its minimum moving step, and gradually moves from one reference calibration point to another reference calibration point until the predetermined area is traversed. Full range. It can be understood that since the moving distance of the robot front end is its minimum moving step, the robot front end moves in a matrix from one reference calibration point to another reference calibration point in a predetermined area.

In this embodiment, the front end of the robot moves from one reference calibration point to another reference point in a matrix in a predetermined area, specifically, at least four reference points determined in steps S1011 to S1014, with the robot front end The minimum moving step setting matrix controls the front end of the robot to move from one point to another in the matrix. As shown in Figure 5, the four reference points determined on the checkerboard are A, B, C, and D, respectively. In a predetermined area composed of A, B, C, and D, a 3×3 matrix (123, 456, 789) can be set according to the minimum moving step of the front end of the robot, and the front end of the control robot is gradually moved in numerical order in the matrix until all the steps are traversed. Step position.

Further, each time the robot front end moves once in the predetermined area, the reflected image of the calibration plate is acquired once. Since the front end of the robot moves in the predetermined area, it is not known which movement causes the front end of the robot to be positioned closest to the corner of the calibration plate on the calibration plate. Then, each time the front end of the robot moves, the reflected image of the calibration plate is acquired once. Through each acquired image of the calibration plate, the deformation of the boundary line in the reflection image of the calibration plate caused by the front end of the robot is obtained each time the front end of the robot is moved.

Further, according to the acquired reflected image, the reflected image of the calibration plate obtained each time is analyzed, and the boundary line in the reflection image of the calibration plate caused by the flexible front film being pressed by the front end of the robot after each movement of the front end of the robot can be calculated. Shape variable.

It is worth noting that the position of the corrected calibration point is finally determined by the calculated shape of the boundary line, and the corrected calibration point needs to be as close as possible to the corner of the calibration plate; When the corner points of the plate are calibrated, in the reflection image of the calibration plate, the deformation of the adjacent two boundary lines may occur at the same time. Therefore, the shape variable of the boundary line calculated in this step may be more than a boundary line shape. A variable, but a shape variable of two adjacent boundary lines.

Here, the shape variable of the boundary line is the same as the shape variable of the boundary line in steps S1011 to S1014, and both refer to the distance from the vertex of the protrusion in the reflected image to the original position of the boundary line. Correspondingly, each time the movement is calculated in this step, the shape variable of the boundary line caused by the front end of the robot is the distance from the boundary line of the front end of the robot on the calibration plate after each movement of the robot.

S103. Determine a position of the calibration point according to the shape variable, and complete calibration of the robot.

In the process of moving the front end of the robot in step S102, the reflection image of the calibration plate is continuously acquired.

Further, as shown in FIG. 6, step S103 includes the following steps:

S1031: Extract a shape variable having the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot.

The detection result in this step is the shape variable of the boundary line in the reflection image of the calibration plate caused by the extrusion of the flexible film by the front end of the robot calculated in step S102, that is, the distance of the front end of the robot on the calibration plate after each movement of the robot The distance of the line.

From each of the plurality of shape variables calculated by the front end of the mobile robot, the shape variable with the smallest value is extracted, that is, the distance from the vertex of the convex to the boundary line in the reflection image of the calibration plate is extracted from the calculated plurality of distances. The minimum value in . Further, from the calculated plurality of distances, the minimum values of the distances from the vertices of the protrusions in the reflection image of the calibration plate to the adjacent two boundary lines are respectively extracted.

S1032: Determine the position of the calibration point according to the smallest shape variable.

According to the minimum value of the distance between the raised vertex and the adjacent two boundary lines in the reflected image of the calibration plate extracted in step S1031, it can be determined that in the process of moving the front end of the robot in the area determined by the reference calibration point, The position of the front end of the robot on the calibration plate closest to the corner of the calibration plate, which is the corrected punctuation point.

As shown in FIG. 4c, according to step S1031 and step S1032, the position of the corrected calibration point H is finally calculated near the corner point of the calibration plate. The black grid portion is not filled in Fig. 4c, it being understood that the distribution of the black and white grids of Fig. 4c is the same as Fig. 4a.

According to the embodiment, the distance between the front end of the robot and the adjacent two boundary lines when the corner of the front end of the robot is closest to the calibration plate can be obtained. Since the coordinates of the corner point of the calibration plate in the visual coordinate system are known, the front end of the robot can be directly passed. The distance between the adjacent two boundary lines is used to obtain a conversion relationship between the robot coordinate system and the visual coordinate system.

Referring to Figure 7, Figure 7 is a functional block diagram of an embodiment of a calibration system for a robot of the present invention. The calibration system 200 of the robot includes a calibration plate 201 provided with a flexible film, and a visual device 202, a processor 203 and a memory 204 connected by a bus;

The memory 204 is used to store a preset movement rule of the robot and an execution instruction of the processor 203. The calibration plate 201 is disposed within the line of sight of the vision device 202, and the vision device 204 is used to detect the calibration 201. The processor 203 is configured to perform the following actions:

Controlling the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate 201 provided with the flexible film, the predetermined area including a corner point; detecting a predetermined area of the calibration plate during the movement, and calculating each movement, The shape variable of the boundary line caused by the front end of the robot; the position of the calibration point is determined according to the calculated shape variable, and the calibration of the robot is completed.

In this embodiment, the calibration plate 201 is a checkerboard; the corner point is the intersection of the vertical line and the horizontal line on the checkerboard, wherein the vertical line and the horizontal line are the boundary lines of the grid on the checkerboard. In a specific embodiment, a checkerboard in which the black and white grids intersect can be selected as the calibration plate 201.

In this embodiment, the predetermined area is determined by at least four reference points, wherein determining the at least four reference points comprises: determining, by using the initial position of the robot as an origin, determining at least one reference point in each of four directions of the boundary line to determine At least four reference points constituting a predetermined area.

Further, determining at least four reference points is specifically: taking the initial position of the front end of the robot as an origin, controlling the front end of the robot to move in four directions extending along the boundary line respectively; acquiring a reflection image of the calibration plate for each movement; calculating according to the reflected image The shape variable of the boundary line caused by the front end of the robot is obtained for each movement; the shape variable with the smallest value is extracted from the shape variable, and the position of the robot front end corresponding to the smallest value variable is the reference point.

Further, the processor 203 performs control on the calibration plate provided with the flexible film to move the front end of the robot according to a preset rule in a predetermined area, so that the robot front end gradually moves from the minimum moving distance by the controller 205 in the predetermined area. One reference point is moved to another reference point until the predetermined area is traversed.

Further, the processor 203 performs a detection on a predetermined area of the calibration plate during the movement, and calculates a shape variable of the boundary line caused by the front end of the robot for each movement, which specifically includes the following contents:

Each time the robot front end is moved by the controller 205 in the predetermined area, the reflected image of the calibration plate 201 is acquired by the visual device 202; the reflected image is analyzed, and the shape of the boundary line caused by the front end of the robot is calculated for each movement. variable.

Further, the determining, by the processor 203, the location of the calibration point according to the shape variable, specifically including the following content:

Extracting the shape variable with the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot; determining the position of the calibration point according to the shape variable with the smallest value

It can be understood that, in this embodiment, the content of the action performed by the processor 203 corresponds to the calibration method of the robot shown in FIG. 1 to FIG. 7 . For details, refer to the detailed description of the method for calibrating the robot, and details are not described herein again.

On the other hand, the present invention also proposes a calibration plate embodiment, as shown in FIG. 8, which is a schematic structural view of an embodiment of the calibration plate of the present invention.

As shown in FIG. 8, the calibration plate 800 of the present embodiment includes a calibration plate block 81 on which a flexible film 82 is disposed. The flexible film 82 deforms when it is squeezed.

Further, the calibration plate block 81 is provided with a calibration object for calibration, such as a colored calibration ring, a calibration point, and the like.

Further, as shown in FIG. 9a, the calibration plate 81 is a checkerboard, FIG. 9a is a top view of the calibration plate 800 in the present embodiment, and FIG. 9b is a cross-sectional view along LL in FIG. 9a. This embodiment uses a black and white grid. For example, in the case of a checkerboard, the shaded portion in Figure 9a is a black grid, and the left side of the black grid represents a white grid. It can be understood that there are several numbers of black and white grids on the checkerboard. Only a part of the black and white grids are shown in Fig. 9a, and the entire calibration board is not represented.

It can be understood that the checkerboard of the black and white grids is only in a specific real-time manner in the checkerboard of the present application. In other embodiments, the calibration board can have a checkerboard of vertical and horizontal lines, and the corner point is The intersection of the vertical line and the horizontal line on the checkerboard, wherein the vertical line and the horizontal line are the boundary lines of each grid on the checkerboard. In other embodiments, the checkerboard may also be a checkerboard of all black squares or both are white. The checkerboard, or any other checkerboard of any color.

Further, a plurality of marker points 83 for positioning the front end contacts of the robot are disposed near the corners of the checkerboard. The corner point of the checkerboard is the intersection of the black grid and the white grid. A marker point 83 is provided near the intersection point, and the corner point can be easily found by the reflection image of the calibration plate 800 when the object is calibrated by the calibration plate 800.

Further, the flexible film 82 disposed on the calibration plate 81 is a flexible film whose surface reflects infrared. When the reflected image of the calibration plate 800 is obtained by visible light irradiation, the calibration point 83 disposed on the calibration plate 81 may not be visible in the reflected image, and the infrared plate is used to illuminate the calibration plate by infrared light. Further, the calibration point 83 provided on the calibration plate 81 is observed in the reflected image of the calibration plate.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformation made by the specification and the drawings of the present invention may be directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims (16)

1. A calibration method for a robot includes a calibration plate, the calibration plate includes a checkerboard, and an intersection of a vertical line and a horizontal line on the checkerboard is a corner point on the checkerboard, and the vertical line and the horizontal line are The boundary line of the grid is characterized by comprising:

   Controlling the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film, the predetermined area including the corner point;

   Detecting the predetermined area of the calibration plate during the movement, and calculating a shape variable of the boundary line caused by the front end of the robot for each movement;

   The position of the calibration point is determined according to the shape variable, and the calibration of the robot is completed.
2. The calibration method according to claim 1, wherein the predetermined area is determined by at least four reference points, wherein determining the at least four reference points comprises:

   Taking an initial position point of the front end of the robot as an origin, at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area.
3. The calibration method according to claim 2, wherein the initial position point of the front end of the robot is taken as an origin, and at least one reference point is respectively determined in four directions of the boundary line to determine that the At least four reference points for the predetermined area, including:

   Taking the initial position point of the front end of the robot as an origin, controlling the front ends of the robot to move in four directions extending along the boundary line respectively;

   Obtaining a reflection image of the calibration plate each time it moves;

   Calculating, according to the reflected image, a shape variable of a boundary line caused by the front end of the robot at each movement;

   The shape variable with the smallest value is extracted from the shape variable, and the position of the robot front end corresponding to the smallest shape variable is the reference point.
4. The calibration method according to claim 1, wherein the controlling the robot front end to move according to a preset rule in a predetermined area on the calibration plate provided with the flexible film comprises:

   Within the predetermined area, the front end of the robot is controlled to move at its minimum moving distance until it is spread over the area.
5. The calibration method according to claim 1, wherein the determining the position of the calibration point according to the shape variable comprises:

   Extracting the shape variable with the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot;

   The position of the calibration point is determined based on the shape variable having the smallest value.
6. The calibration method according to claim 5, wherein the determining the position of the calibration point according to the shape variable having the smallest value comprises:

   The position point corresponding to the shape variable having the smallest value is used as the position of the calibration point.
7. A calibration system for a robot, comprising: a calibration plate provided with a flexible film, and a visual device, a processor and a memory connected by a bus;

   The memory is configured to store a preset movement rule of the robot and an execution instruction of the processor;

   The visual device is configured to detect the calibration plate;

   The processor is configured to perform the following actions:

   Controlling the front end of the robot to move according to a preset rule in a predetermined area of the calibration plate provided with the flexible film, the predetermined area including the corner point;

   Detecting the predetermined area of the calibration plate during the movement, and calculating a shape variable of the boundary line caused by the front end of the robot for each movement;

   The position of the calibration point is determined according to the shape variable, and the calibration of the robot is completed.
8. The calibration system according to claim 7, wherein said predetermined area is determined by at least four reference points, wherein determining at least four reference points comprises:

   Taking an initial position point of the front end of the robot as an origin, at least one reference point is respectively determined in four directions of the boundary line to determine at least four reference points constituting the predetermined area.
9. The calibration system according to claim 8, wherein said initial position point of said robot front end is taken as an origin, and at least one reference point is respectively determined in four directions of said boundary line to determine said composition At least four reference points for the predetermined area, including:

   Taking the initial position point of the front end of the robot as an origin, controlling the front ends of the robot to move in four directions extending along the boundary line respectively;

   Obtaining a reflection image of the calibration plate each time it moves;

   Calculating, according to the reflected image, a shape variable of a boundary line caused by the front end of the robot at each movement;

   The shape variable with the smallest value is extracted from the shape variable, and the position of the robot front end corresponding to the smallest shape variable is the reference point.
10. The calibration system according to claim 7, wherein the controlling the movement of the robot front end by a predetermined rule in a predetermined area on the calibration plate provided with the flexible film, comprising:

    Within the predetermined area, the front end of the robot is controlled to move at its minimum moving distance until it is spread over the area.
11. The calibration system according to claim 7, wherein the determining, by the processor, the position of the calibration point according to the deformation variable comprises:

    Extracting the shape variable with the smallest value from the calculated shape variable of the boundary line corresponding to the front end of each mobile robot;

    The position of the calibration point is determined based on the shape variable having the smallest value.
12. The calibration method according to claim 11, wherein the determining, by the processor, the location of the calibration point according to the shape variable having the smallest value comprises:

    The position point corresponding to the shape variable having the smallest value is used as the position of the calibration point.
13. A calibration plate, comprising: a calibration plate block, wherein the calibration plate plate is provided with a flexible film.
14. The calibration plate of claim 13 wherein said calibration plate block is a checkerboard.
15. The calibration plate according to claim 14, wherein a plurality of marking points for positioning the front end contact of the robot are disposed near a corner of the checkerboard.
16. The calibration plate of claim 15 wherein said flexible membrane is a flexible membrane having a surface that reflects infrared.