Method for acquiring reference point of robot base

Abstract

The invention discloses a reference point obtaining method for a robot base. The method comprises the steps that a first 3D image of the robot base with multiple identifications on the outer wall is collected; obtaining a plurality of first feature points of the plurality of identifiers in the first 3D image in a one-to-one correspondence manner; and positioning a first reference point of the base according to the plurality of first feature points. According to the reference point obtaining method for the robot base, the actual position relation between the robot and the tool after the falling position deviation is effectively measured and calculated; equipment position calibration is carried out by adding calibration round holes in the robot base, manual teaching of the robot is avoided, and the collision risk is reduced; the problem that the robot calibration process is lagged due to factors such as power-on, system configuration and cross construction of the robot in the project site construction process is solved. Compared with a previous calibration mode, the relative position relation between the robot base and the vehicle system is more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a method for acquiring reference points of a robot base. Background Art

[0002] With the increasing application of industrial robots in the field of automobile production, automobile manufacturers have a demand for high-precision factories and "automatic debugging at power-on", and the accuracy and calibration of industrial robot workpiece coordinates have become crucial issues. There is a positioning error between the robot and the tooling, which leads to low utilization of offline programs, increased labor and equipment costs, and increased risk of equipment collision. The calibration methods of robot workpiece coordinates mainly include calibration point method, four-point method, global measurement method, and visual calibration. These operation processes are relatively complicated, requiring the robot to be powered on in advance, and also requiring engineers to manually teach, and the project cost is relatively high. Summary of the invention

[0003] In order to solve the technical problems existing in the background technology, the present invention proposes a method for obtaining reference points of a robot base.

[0004] The present invention provides a method for obtaining a reference point of a robot base, comprising the following steps:

[0005] S1, collecting a first 3D image of a robot base having multiple marks on an outer wall;

[0006] S2, acquiring a plurality of first feature points of a plurality of identifiers in the first 3D image in a one-to-one correspondence;

[0007] S3. Locate a first reference point of the base according to a plurality of first feature points.

[0008] Preferably, step S1 specifically includes:

[0009] S11, obtaining a first 3D simulation image of the base;

[0010] S12, acquiring a second reference point of the base according to the first 3D simulation image, and selecting a plurality of second feature points on the outer wall of the base in the first 3D simulation image that can locate the second reference point;

[0011] S13, processing a plurality of calibration circular holes as a plurality of marks on the base, wherein the center positions of the hole openings corresponding to the plurality of calibration circular holes coincide with the plurality of second characteristic points in a one-to-one correspondence;

[0012] S14, collecting a first 3D image of the robot base having multiple marks on the outer wall.

[0013] Preferably, the mark is specifically a calibration circular hole opened on the base, and the first characteristic point is specifically the center position of the calibration circular hole.

[0014] Preferably, the plurality of first characteristic points are located on the same circumference and are arranged at equal intervals, and the plurality of calibrated circular holes have equal diameters and depths, and the hole openings are all located on the first plane.

[0015] Preferably, the first 3D image also includes a robot component that is assembled with the base, and the acquisition method further includes:

[0016] S4, acquiring a first reference point on the robot component in the first 3D image based on a first preset strategy, and obtaining a first positional relationship between the first benchmark point and the first reference point;

[0017] S5, obtaining a second 3D simulation image including the robot assembly and the base forming an assembly relationship, obtaining a second reference point of the base in the second 3D simulation image through the second 3D simulation image, obtaining a second reference point of the robot assembly based on the first preset strategy, and obtaining a second positional relationship between the second reference point and the second reference point;

[0018] S6. Compare the first position relationship with the second position relationship to verify whether the acquired first reference point is accurate.

[0019] Preferably, the robot assembly specifically comprises: a robot body that can be assembled on the base and an execution tool that can be assembled on the robot body;

[0020] The obtaining of the first reference point on the robot component in the first 3D image based on the first preset strategy is specifically obtaining a third reference point of the execution tooling from the first 3D image as the first reference point;

[0021] The obtaining of the second reference point of the robot assembly based on the first preset strategy specifically involves obtaining the fourth reference point of the execution tooling from the second 3D simulation image as the second reference point.

[0022] Preferably, step S6 specifically includes:

[0023] Calculating an average calibration point error value based on the first position relationship and the second position relationship;

[0024] Calculate the coordinate item difference between the first position relationship and the second position relationship coordinate item by coordinate item;

[0025] When the difference values ​​of each coordinate item meet the preset difference value and the average calibration point error value meets the preset threshold value, the first reference point obtained is accurate.

[0026] A storage medium stores a computer-readable program, which can execute the steps of any of the above-mentioned methods for obtaining reference points of a robot base when called by a controller.

[0027] In the present invention, a method for acquiring a reference point of a robot base is proposed, which collects a first 3D image of a robot base having multiple markings on an outer wall; acquires multiple first feature points of multiple markings in the first 3D image in a one-to-one correspondence; locates a first reference point of the base according to the multiple first feature points; acquires a first reference point from a robot component in the first 3D image based on a first preset strategy, and acquires a first positional relationship between the first reference point and the first reference point; acquires a second 3D simulated image including a robot component and a base forming an assembly relationship, acquires a second reference point of the base in the second 3D simulated image through the second 3D simulated image, acquires a second reference point of the robot component based on the first preset strategy, and acquires a second positional relationship between the second reference point and the second reference point; compares the first positional relationship with the second positional relationship to verify whether the acquired first reference point is accurate. The actual positional relationship between the robot and the tooling after the positioning deviation is effectively calculated; the equipment position is calibrated by adding calibration holes on the robot base, which avoids manual teaching of the robot and reduces the risk of collision; the problem of robot calibration process delay caused by factors such as robot power-on, system configuration, and cross-construction during the project site construction process is solved; compared with previous calibration methods, the relative position relationship between the robot base and the vehicle system is more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the workflow structure of a method for obtaining reference points of a robot base proposed by the present invention Figure 1 ;

[0029] Figure 2 A schematic diagram of the workflow structure of a method for obtaining reference points of a robot base proposed by the present invention Figure 2 . DETAILED DESCRIPTION

[0030] Reference Figure 1 and Figure 2 The present invention proposes a method for obtaining a reference point of a robot base, comprising the following steps:

[0031] Step S1, collecting a first 3D image of a robot base having multiple marks on an outer wall.

[0032] In this embodiment, step S1 specifically includes:

[0033] Step S11, obtaining a first 3D simulation image of the base;

[0034] Step S12, acquiring a second reference point of the base according to the first 3D simulation image, and selecting a plurality of second feature points on the outer wall of the base in the first 3D simulation image that can locate the second reference point;

[0035] Step S13, processing a plurality of calibration circular holes as a plurality of marks on the base, wherein the center positions of the hole openings corresponding to the plurality of calibration circular holes coincide with the plurality of second characteristic points in a one-to-one correspondence;

[0036] Step S14: Acquire a first 3D image of the robot base having multiple marks on the outer wall.

[0037] Specifically, the first 3D simulation image is obtained by simulating the robot base 3D data and planning layout. During the simulation process, the robot base is selected according to the robot brand model to ensure that the robot body and the base hole positions match each other. The first 3D image is a 3D image of the actual scene of the robot base containing multiple calibrated circular holes collected by a three-coordinate measuring device.

[0038] In this embodiment, the mark is specifically a calibration circular hole opened on the base, and the first characteristic point is specifically the center position of the calibration circular hole.

[0039] In this embodiment, the plurality of first characteristic points are located on the same circumference and are arranged at equal intervals, and the plurality of calibrated circular holes have equal diameters and depths and the hole openings are all located on the first plane.

[0040] Specifically, the plurality of calibration circular holes have equal diameters and depths and the openings are all located in the first plane in order to facilitate the collection of the calibration circular holes.

[0041] Step S2: Acquire multiple first feature points of multiple markers in the first 3D image in a one-to-one correspondence.

[0042] Step S3: locate the first reference point of the base according to the multiple first feature points.

[0043] In this embodiment, the first reference point is a reference point for defining the position and posture of the robot in space in the first 3D image, which is a standard rectangular coordinate system, that is, the origin of the robot's world coordinate system.

[0044] In this embodiment, the first 3D image also includes a robot component that is assembled with the base, and the acquisition method further includes:

[0045] Step S4: acquiring a first reference point on the robot component in the first 3D image based on a first preset strategy, and obtaining a first positional relationship between the first benchmark point and the first reference point.

[0046] Step S5, obtaining a second 3D simulation image including the robot component and the base forming an assembly relationship, obtaining a second reference point of the base in the second 3D simulation image through the second 3D simulation image, obtaining the second reference point of the robot component based on the first preset strategy, and obtaining a second positional relationship between the second reference point and the second reference point.

[0047] Specifically, the second 3D simulation image is a 3D simulation image obtained by simulating 3D data of the robot components and the base that form an assembly relationship.

[0048] In this embodiment, the second reference point is a reference point for defining the position and posture of the robot in space in the second 3D simulation image, and is a standard rectangular coordinate system, that is, the origin of the robot's world coordinate system.

[0049] In this embodiment, the robot assembly specifically includes: a robot body that can be assembled to the base and an execution tool that can be assembled to the robot body;

[0050] Acquire a first reference point on the robot component in the first 3D image based on a first preset strategy, specifically, acquire a third reference point of the execution tooling from the first 3D image as the first reference point;

[0051] The second reference point of the robot component is obtained based on the first preset strategy, specifically, the fourth reference point of the execution tool is obtained from the second 3D simulation image as the second reference point.

[0052] In this embodiment, the first reference point is the origin of the coordinate system used in the design of the automobile body in the first 3D image, which is a virtual origin and is used to determine and maintain the reference point of the relative spatial position of the panel and the fixture. The fixture origin and the body origin should be consistent in the definition, that is, the origin of the vehicle coordinate system. The first reference point is the origin of the coordinate system used in the design of the automobile body in the second 3D simulation image, which is a virtual origin and is used to determine and maintain the reference point of the relative spatial position of the panel and the fixture. The fixture origin and the body origin should be consistent in the definition, that is, the origin of the vehicle coordinate system.

[0053] Step S6: Compare the first positional relationship with the second positional relationship to verify whether the acquired first reference point is accurate.

[0054] In this embodiment, step S6 specifically includes:

[0055] Calculating an average calibration point error value based on the first position relationship and the second position relationship;

[0056] Calculate the coordinate item difference between the first position relationship and the second position relationship coordinate item by coordinate item;

[0057] When the difference values ​​of each coordinate item meet the preset difference value and the average calibration point error value meets the preset threshold value, the acquired first reference point is accurate.

[0058] Specifically, assuming that the first position relationship is (X1, Y1, Z1, A1, B1, C1), and the second position relationship is (X2, Y2, Z2, A2, B2, C2); the coordinate item difference of each coordinate item specifically includes:

[0059] x = |X1-X2|;

[0060] y = |Y1-Y2|;

[0061] z = |Z1-Z2|;

[0062] a=|A1-A2|;

[0063] b = |B1-B2|;

[0064] c = |C1-C2|;

[0065] Among them, when x, y, and z are all smaller than the preset difference, a, b, and c are all smaller than the preset angle value, and the average calibration point error is smaller than the preset threshold, the first reference point obtained is accurate.

[0066] Specifically, the preset difference between x, y, and z is 50 mm; the preset angle value corresponding to a, b, and c is 1°, and the preset threshold corresponding to the average calibration point error is 0.3 mm.

[0067] In this embodiment, the calculation process of the average calibration point error value is as follows:

[0068]

[0069] Among them, P Baseframe is the coordinate of the first reference point; P Carframe is the coordinate of the first reference point; P Carframe-Baseframe is the coordinate corresponding to the first position relationship; n is the number of identifications; RMSE is the average calibration point error value.

[0070] In this embodiment, the method further includes: when the first reference point is verified to be accurate, replacing the data corresponding to the second reference point with the collected data corresponding to the first reference point.

[0071] A storage medium stores a computer-readable program, which can execute the steps of any of the above-mentioned methods for obtaining reference points of a robot base when called by a controller.

[0072] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for obtaining reference points of a robot base, characterized in that: The following steps are involved: S1, collecting a first 3D image of a robot base having multiple marks on an outer wall; S2, acquiring a plurality of first feature points of a plurality of identifiers in the first 3D image in a one-to-one correspondence; S3. Locate a first reference point of the base according to a plurality of first feature points.

2. The method for obtaining reference points of a robot base according to claim 1, characterized in that: Step S1 specifically includes: S11, obtaining a first 3D simulation image of the base; S12, acquiring a second reference point of the base according to the first 3D simulation image, and selecting a plurality of second feature points on the outer wall of the base in the first 3D simulation image that can locate the second reference point; S13, processing a plurality of calibration circular holes as a plurality of marks on the base, wherein the center positions of the hole openings corresponding to the plurality of calibration circular holes coincide with the plurality of second characteristic points in a one-to-one correspondence; S14, collecting a first 3D image of the robot base having multiple marks on the outer wall.

3. The method for obtaining reference points of a robot base according to claim 2, characterized in that: The mark is specifically a calibration circular hole opened on the base, and the first characteristic point is specifically the center position of the calibration circular hole.

4. The method for obtaining reference points of a robot base according to claim 3, characterized in that: The plurality of first characteristic points are located on the same circumference and are arranged at equal intervals, and the plurality of calibrated circular holes have equal diameters and depths, and the hole openings are all located on the first plane.

5. The method for obtaining reference points of a robot base according to claim 2, characterized in that: The first 3D image also includes a robot component that is assembled with the base, and the acquisition method further includes: S4, acquiring a first reference point on the robot component in the first 3D image based on a first preset strategy, and obtaining a first positional relationship between the first benchmark point and the first reference point; S5, obtaining a second 3D simulation image including the robot assembly and the base forming an assembly relationship, obtaining a second reference point of the base in the second 3D simulation image through the second 3D simulation image, obtaining a second reference point of the robot assembly based on the first preset strategy, and obtaining a second positional relationship between the second reference point and the second reference point; S6. Compare the first position relationship with the second position relationship to verify whether the acquired first reference point is accurate.

6. The method for obtaining reference points of a robot base according to claim 5, characterized in that: The robot assembly specifically includes: a robot body that can be assembled on the base and an execution tool that can be assembled on the robot body; The obtaining of the first reference point on the robot component in the first 3D image based on the first preset strategy is specifically obtaining a third reference point of the execution tooling from the first 3D image as the first reference point; The obtaining of the second reference point of the robot assembly based on the first preset strategy specifically involves obtaining the fourth reference point of the execution tooling from the second 3D simulation image as the second reference point.

7. The method for obtaining reference points of a robot base according to claim 5, characterized in that: Step S6 specifically includes: Calculating an average calibration point error value based on the first position relationship and the second position relationship; Calculate the coordinate item difference between the first position relationship and the second position relationship coordinate item by coordinate item; When the difference values ​​of each coordinate item meet the preset difference value and the average calibration point error value meets the preset threshold value, the first reference point obtained is accurate.

8. A storage medium, characterized in that: A computer-readable program is stored therein, and when the computer-readable program is called by a controller, the steps of the method for obtaining the reference point of the robot base as described in any one of claims 1 to 7 can be executed.

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