CN115178858A - Laser welding robot tool calibration method and system based on focus positioning compensation - Google Patents

Abstract

The invention discloses a method and system for calibrating a laser welding robot tool based on focus positioning compensation, belonging to the technical field of laser welding. Confocal laser pointing light with the welding laser, and adjust the robot so that the focus of the laser pointing light is at point O on the preset sensor plane, and then obtain the coordinate position of tool1 as the initial position; control the robot to revolve around the rotation axis passing through the initial position After rotating a certain angle, control the robot to translate, make the focus return to point O, and obtain the coordinate position of tool1 as the new position; after obtaining N ≥ 3 new positions that are not coplanar, perform spherical fitting together with the initial position, and calculate The initial position points to the vector of the center of the sphere, and the vector is used to compensate P0, and the tool parameters in the robot system are obtained, and the calibration is completed. The invention can improve the calibration accuracy of the robot tool parameters at the focus.

Description

Laser welding robot tool calibration method and system based on focus positioning compensation

technical field

The invention belongs to the technical field of laser welding, and more particularly, relates to a laser welding robot tool calibration method and system based on focus positioning compensation.

Background technique

Laser welding is a process in which the workpiece is irradiated with a high-energy beam of laser light, so that the working temperature is sharply increased, and the workpiece is melted and reconnected to form a permanent connection. Compared with other welding processes, the laser welding process has the advantages of deep penetration, fast speed, small deformation, low requirements for the welding environment, high power density, not affected by magnetic fields, not limited to conductive materials, and does not require vacuum working conditions And the advantages of not producing X-rays during the welding process are widely used in the field of high-end precision manufacturing. Laser welding is generally bound to joint robots. Compared with manual welding, welding robots can greatly reduce the production cost of welding labor and improve the automatic and intelligent operation of welding work. Welding robots can automatically complete a lot of work in a certain workspace. This type of welding action can automatically adjust the posture of each welder at will.

The laser welding process is closely related to the focus position of the laser beam. When setting the tool point of the welding robot, the focus of the laser beam is usually set as the tool point of the robot. However, when calibrating the tool of the robot, since the focus of the laser welding has no entity in space, the four-point method and the six-point method of the traditional robot tool calibration are difficult to use with the tool calibration of the laser welding robot. The tip is installed on the welding head to simulate the focus. The robot tool points measured by traditional calibration methods such as the four-point method and the six-point method are still low in accuracy and cannot be used in high-precision laser welding robot systems, which limits the laser welding robot. application in practice.

SUMMARY OF THE INVENTION

In view of the defects and improvement requirements of the prior art, the present invention provides a laser welding robot tool calibration method and system based on focus positioning compensation, the purpose of which is to ensure that during the welding process, changes in the robot's posture will not affect the position of the laser focus , thereby improving the calibration accuracy of the robot tool parameters at the focus.

In order to achieve the above object, according to an aspect of the present invention, a method for calibrating a laser welding robot tool based on focus positioning compensation is provided, comprising:

Rough calibration steps: set the robot tool in the robot geodetic coordinate system, marked as the setting tool tool1, and calibrate the tool parameter P0 at the setting tool tool1; set the tool coordinate system of the tool tool1 and the coordinates of the robot geodetic coordinate system The axes are in the same or opposite direction;

Initial positioning step: generate laser pointing light that is confocal with the welding laser, and adjust the robot so that the focus of the laser pointing light is on the plane of the preset sensor, and then obtain the coordinate position of the setting tool tool1 in the robot's geodetic coordinate system, record is the initial position; the point of the laser indicating light focus on the sensor plane is marked as point O;

Rotation and translation steps: After controlling the robot to rotate a certain angle around the rotation axis passing through the initial position, control the robot to translate, so that the focus of the laser pointing light returns to the point O in the sensor plane, and obtain the coordinates of the setting tool tool1 in the robot geodetic coordinate system location, recorded as a new location;

Compensation calculation steps: Perform the rotation and translation steps N times to obtain N new positions that are not in the same plane, perform spherical fitting on the initial position and the N new positions, and calculate the vector of the initial position pointing to the center of the sphere obtained by fitting As compensation amount; N≥3;

Compensation step: Use the compensation amount to compensate the tool parameter P0 to obtain the tool parameter in the robot system as the final calibration result.

Further, in the step of calculating the compensation amount, when the acquired N new positions are obtained, the robot rotates around at least two rotation axes.

Further, in the step of calculating the compensation amount, when the acquired N new positions are obtained, the robot rotates around three rotation axes, and the three rotation axes are respectively parallel to the three coordinate axes of the robot's geodetic coordinate system.

Further, N=3.

Further, in the rough calibration step, the four-point method or the six-point method is used to set the robot tool in the robot earth coordinate system, that is, the tool tool1 is set, and the tool parameter P0 at the setting tool tool1 is calibrated.

Further, in the step of calculating the compensation amount, the least square method is used to perform spherical fitting on the initial position and the N newly added positions.

According to another aspect of the present invention, a laser welding robot tool calibration system based on focus positioning compensation is provided, comprising:

The rough calibration module is used to set the robot tool in the robot geodetic coordinate system, which is marked as the setting tool tool1, and calibrate the tool parameter P0 at the setting tool tool1; the tool coordinate system of the setting tool tool1 and the robot geodetic coordinate system are set. The direction of each coordinate axis is the same or opposite;

Laser, used to generate laser pointer light confocal with welding laser;

sensor, set below the welding head;

The initial positioning module is used to adjust the robot to make the focus of the laser pointing light on the plane of the sensor, and then obtain the coordinate position of the setting tool tool1 in the robot's geodetic coordinate system, which is recorded as the initial position; the focus of the laser pointing light is on the sensor plane. Point is marked as point O;

The rotation and translation module is used to control the robot to rotate a certain angle around the rotation axis passing through the initial position, control the robot to translate, make the focus of the laser pointing light return to the point O in the sensor plane, and obtain the setting tool tool1 in the robot geodetic coordinate system The coordinate position of , is recorded as the new position;

The compensation amount calculation module is used to use the rotation and translation module to obtain N new positions that are not in the same plane, perform spherical fitting on the initial position and the N new positions, and calculate the vector of the initial position pointing to the center of the fitted sphere as Compensation amount; N≥3;

and a compensation module for compensating the tool parameter P0 by the compensation amount to obtain the tool parameter in the robot system as the final calibration result.

In general, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

(1) After the present invention uses the existing calibration method to calibrate the tool parameters at the setting tool tool1, based on the characteristic that the spatial relationship between the focus of the laser pointing light and the setting tool tool1 is relatively fixed, the robot is rotated and then translated to make the laser light. By returning the focus of the pointing light to its original position, multiple coordinate positions of the setting tool tool1 are obtained, and then the focus position of the laser pointing light that is confocal with the welding laser is obtained by spherical fitting, and then the setting tool tool1 is obtained. The initial position of , points to the vector of the focus of the laser pointing point, and the vector is used as the compensation amount to compensate the tool parameters at the setting tool tool1 obtained from the calibration of the existing calibration method, and the final calibration result is obtained, that is, the robot default tool tool0 points to The laser indicates the vector of the light focus. Through the compensation, the invention can reduce the calibration error caused by the influence of the focal position by the attitude change of the robot, and effectively improve the calibration accuracy of the robot tool parameters at the focal point.

(2) The present invention obtains multiple coordinate positions of the setting tool tool1 by making the robot perform three single-axis rotations around the coordinate axis, which can ensure that the value of the focus in a certain direction remains unchanged after the rotation, and only two subsequent steps are required. The movement of the direction can bring the focus back to the point O in the sensor plane, which can simplify the implementation of the translation operation.

Description of drawings

1 is a schematic diagram of a laser welding robot system according to an embodiment of the present invention;

2 is a schematic diagram of a robot setting tool tool1 provided by an embodiment of the present invention;

3 is a flowchart of a method for calibrating a laser welding robot tool based on focus positioning compensation provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of the deviation between the laser pointing light focus and the robot setting tool tool1 according to an embodiment of the present invention;

5 is a schematic diagram of initial parameter setting provided by an embodiment of the present invention;

FIG. 6 is a change diagram of a robot rotating focus around a tool Z-axis according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a focal plane translation of a laser pointing light provided by an embodiment of the present invention;

8 is a schematic diagram of spherical fitting provided by an embodiment of the present invention;

Throughout the drawings, the same reference numbers are used to refer to the same elements or structures, wherein:

1-robot control cabinet; 2-laser; 3-host computer system; 4-industrial six-axis robot; 5-robot flange; 6-optical fiber; 7-qbh connector; 8-laser welding head; 9-laser indicator light focus; 10-sensor; 11-robot earth coordinate system; 12-network cable; 13-robot control line; 14-network cable; 15-default tool; 16-setting tool; 17-adjustment base; 18-sensor photosensitive surface; 19 - Point O in the photosensitive surface of the sensor; 20 - axis of rotation; 21 - direction of translation.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

In the present invention, the terms "first", "second" and the like (if present) in the present invention and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

Before explaining the technical solution of the present invention in detail, the laser welding robot system is briefly introduced as follows:

As shown in Figure 1, the laser welding robot system includes an industrial six-axis robot 4. The industrial six-axis robot 4 is controlled by the robot control cabinet 1 through the robot control line 13, and the host computer system 3 is connected to the robot control cabinet 1 through the network cable 14 to realize Position information reading and translation and rotation control of the industrial six-axis robot 4. The end of the robot flange 5 of the industrial six-axis robot 4 is equipped with a laser welding head 8. During the welding process, the welding laser is incident into the laser welding head 8 from the qbh joint 7, and the laser welding head 8 is collimated and beam-expanded. , and incident on the sample surface after focusing.

In order to calibrate the robot system, in the present invention, a sensor 10 is arranged directly below the laser welding head 8, the sensor 10 can sense the light intensity and has a plane positioning function, which is used to determine the laser indicating light during the calibration process. focus position. The sensor 10 is connected to the host computer system 3 through a network cable 12 . The present invention is also provided as a laser 2, which is used to generate a laser indicating light confocal with the welding laser, the laser indicating light is visible light, and the laser indicating light generated from the laser 2 and confocal with the welding laser is transmitted through the optical fiber 6, and is connected by the qbh connector. 7 is incident on the laser welding head 8, after collimation, beam expansion and focusing in the laser welding head 8, it converges at the laser indicating light focus 9, and can be observed on the photosensitive surface of the sensor 10 by adjusting the position of the sensor 10 To the spot of the laser pointing light, the focus position can be determined by the spot size and intensity; in the whole calibration process, the spatial three-dimensional coordinate information that needs to be substituted into the calculation finally comes from the robot geodetic coordinate system 11 .

As shown in FIG. 2 , a robot default tool 15 is usually set in the center of the robot flange 5 of the industrial six-axis robot 4 , which is denoted as a default tool tool0 . In the present invention, when the industrial six-axis robot 4 uses the robot default tool 15 as a tool, when the robot's attitude parameter is set to (0, 0, 0), the tool coordinate system direction of the default tool 15 is the same as the robot earth coordinate system 11 same direction. The meaning represented by the tool parameters (x, y, z) of the robot setting tool 16 is a vector from the origin of the default tool tool0 coordinate system to the robot setting tool tool1 under the default tool 15 coordinate system.

Through the traditional four-point method, six-point method and other calibration methods, the tool parameters at the setting tool tool1 can be determined, that is, the vector from the default tool tool0 to the setting tool tool1, but the change of the robot posture will affect the laser focus. , therefore, the calibration results obtained by the traditional calibration methods have lower accuracy. In order to solve this problem, the present invention provides a laser welding robot tool calibration method and system based on focus positioning compensation. (fixed and unchanged) characteristics, calculate the compensation amount, that is, set the tool tool1 to point the vector of the laser pointer light focus, and use the compensation amount to compensate the calibration result obtained by the traditional calibration method to obtain the final calibration result, thereby improving the The precision of the calibration result.

The following are examples.

Example 1:

A laser welding robot tool calibration method based on focus positioning compensation, as shown in Figure 3, includes: a rough calibration step, an initial positioning step, a rotation and translation step, a compensation amount calculation step and a compensation step.

In this embodiment, the rough calibration step specifically includes: setting the robot tool in the robot geodetic coordinate system, which is marked as the setting tool tool1, and calibrating the tool parameter P0 at the setting tool tool1;

In order to facilitate the calculation, in this embodiment, the tool coordinate system of the tool tool1 is set in the same or opposite directions as the coordinate axes of the robot geodetic coordinate system;

As an optional implementation manner, in this embodiment, the commonly used four-point method is used to set the robot tool in the robot earth coordinate system, that is, the tool tool1 is set, and the tool parameter P0 at the setting tool tool1 is calibrated. In some other embodiments of the present invention, other calibration methods such as the six-point method can also be used to obtain the setting tool tool1.

As shown in FIG. 4 , the robot setting tool tool1 is roughly set by the four-point method and the laser pointing light focus 9 formed by the qbh joint 7 output after collimation and focusing by the laser welding head 8 does not coincide; in the three-dimensional space , when the direction of the x, y, z single axis of the tool coordinate system of the robot setting tool tool1 is the same or opposite to the direction of the x, y, z single axis of the robot geodetic coordinate system 11, the laser pointing light focus 9 is obtained and the robot setting The relative positional relationship of the fixed tool tool1 in the robot earth coordinate system 11 is (det_x, det_y, det_z), that is, the setting tool tool1 points to the vector of the laser pointer light focus. In this embodiment, by solving the relative positional relationship between the laser pointing light focal point 9 and the robot setting tool tool1 in the robot geodetic coordinate system 11 of the industrial six-axis robot 4, the tool setting of the industrial six-axis robot 4 can be solved as follows: Tool parameters in the robotic system when the laser points to the optical focus 9.

In this embodiment, the initial positioning step specifically includes: generating laser pointing light that is confocal with the welding laser, adjusting the robot so that the focus of the laser pointing light is on the plane of the preset sensor, and then acquiring the geodetic coordinates of the setting tool tool1 on the robot The coordinate position under the system is denoted as the initial position; the point of the laser pointing light focus on the sensor plane is denoted as point O.

As shown in FIG. 5 , in order to make the laser pointing light focus 9 easy to be observed, first adjust the adjustment base 17 of the sensor 10 so that the sensor photosensitive surface 18 of the sensor 10 is parallel to the xy plane of the robot geodetic coordinate system 11, and then adjust the industrial six-axis The robot 4 makes the laser pointing light perpendicular to the photosensitive surface 18 of the sensor, and adjusts the height of the laser welding head 8 through the spot size read by the sensor 10 so that the focus 9 of the laser pointing light just falls on the photosensitive surface 18 of the sensor, and is read by the host computer system 3 Take the two-dimensional coordinates of the sensor plane photosensitive point O19 in the plane coordinate system of the sensor 10, and simultaneously read the coordinates of the robot setting tool 16 in the robot geodetic coordinate system 11, and set the tool point A1 for the robot, which is recorded as the initial position. It is also ensured that at the robot setting tool point A1, the xyz axis of the robot setting tool 16 is in the same or opposite direction as the xyz axis of the robot geodetic coordinate system 11 .

In this embodiment, the step of rotating and translating specifically includes: after controlling the robot to rotate around the rotation axis passing through the initial position by a certain angle, controlling the robot to translate so that the focus of the laser pointing light returns to the point O in the sensor plane, and obtaining the setting tool tool1 at The coordinate position in the robot's geodetic coordinate system is recorded as a new position; it is easy to understand that in the rotation and translation step, the angle at which the robot is controlled to rotate around the rotation axis should be within a safe angle range.

In this embodiment, the step of calculating the compensation amount specifically includes: performing the step of rotation and translation 3 times, after obtaining 3 new positions that are not on the same plane, performing spherical fitting on the initial position and the 3 new positions, and calculating the initial position pointing The vector of the resulting sphere center is fitted as the compensation amount.

Since the spatial position of the setting tool tool1 and the laser pointing light focus is relatively fixed, and the distance between the two remains unchanged, therefore, each time the rotation and translation steps are performed to bring the focus back to point O, the newly added position of the setting tool tool1 is obtained. It should be located on the spherical surface with the point O as the center of the sphere and the distance between the tool1 and the focus of the laser pointer as the radius. Therefore, in this embodiment, after acquiring multiple new positions of the setting tool tool1, the spherical fitting is performed together with the initial position of the setting tool tool1, and the obtained spherical center position is the point O in the sensor plane, which is also The laser indicates the focal point of the light.

It should be noted that in order to perform spherical fitting, at least four positions of the tool tool1 need to be set, that is to say, together with the initial position, at least three new positions need to be acquired. In this embodiment, only the acquisition 3 new locations have been added.

In order to ensure the accuracy of the focal position obtained by fitting and facilitate the control and calculation of the robot, as a preferred implementation manner, in this embodiment, the acquired three new positions are rotated by the robot around three different rotations. The three axes of rotation are obtained after the axes are rotated and translated, and the three axes of rotation are respectively parallel to the three axes of the robot's geodetic coordinate system. The acquisition process of the three new locations is as follows:

As shown in FIG. 6 , the industrial six-axis robot 4 is controlled by the host computer system 3 to rotate around the initial position, that is, the rotation axis 20 extended by the Z axis of the robot setting tool tool1 at the robot setting tool point A1. At this time, The spatial position of the laser pointing light focus 9 changes, but since the rotation axis 20 is parallel to the Z axis of the robot geodetic coordinate system 11, and the sensor photosensitive surface 18 is parallel to the xy plane of the robot geodetic coordinate system 11, the laser pointing light focus 9 is still in the position. on the photosensitive surface 18 of the sensor.

As shown in FIG. 7 , the industrial six-axis robot 4 is controlled by the host computer system 3 to move in the xy plane on the robot geodetic coordinate system 11 along the translation direction 21, and the laser pointing light focus 9 is moved back to the point in the photosensitive surface of the sensor again. O19. During the moving process, the robot setting tool tool1 will also move along the translation direction 21 in the xy plane of the robot geodetic coordinate system, and the robot setting tool point A1 will move to the robot setting tool point A2. Since the spatial relationship between the laser pointing light focus 9 and the robot setting tool tool1 is relatively fixed, the distance between the two is a fixed value. When the upper computer system 3 reads the size of the spot in the plane coordinate system of the sensor 10 and the two Dimensional coordinate value, so that when the laser pointing light focus 9 coincides with the point O19 in the photosensitive surface of the sensor again, the sensor plane photosensitive point O19 and the robot set tool point A2 are equal to the distance between the sensor plane photosensitive point O19 and the robot set tool point A1 .

It can be seen from FIG. 7 that after the robot setting tool tool1 of the industrial six-axis robot 4 is rotated uniaxially, the laser pointer focal point 9 is again overlapped with the photosensitive point O19 of the sensor plane through the translation of the corresponding plane, and the upper computer system 3 reads it. In the obtained robot geodetic coordinate system 11, the coordinate value of the robot setting tool tool1 and the sensor plane photosensitive point O19 are equal to the distance between the robot setting tool point A1 and the sensor plane photosensitive point O19. Rotate the industrial welding robot 4 by a certain angle around the X-axis and Y-axis of the robot setting tool tool1 at the robot setting tool point A1 in turn, in the yz plane of the tool1 tool coordinate system at A1 and the xz plane of the tool1 tool coordinate system at A1 After successive translations, the robot setting tool point A3 and the robot setting tool point A4 are obtained.

As shown in Figure 8, finally the distances from the sensor plane photosensitive point O19 to the robot setting tool point A1, the robot setting tool point A2, the robot setting tool point A3 and the robot setting tool point A4 are equal, and the robot setting tool The coordinates of point A1, the robot setting tool point A2, the robot setting tool point A3 and the robot setting tool point A4 are fitted as spherical surfaces, and the coordinate value of the sensor plane photosensitive point O19 in the robot geodetic coordinate system 11 can be obtained, Compare with the position coordinates of the robot setting tool point A1, and solve the relative position (det_x, det_y, det_z). .

Optionally, in this embodiment, the least squares method is specifically used to perform spherical fitting.

In this embodiment, the compensation step specifically includes: using the compensation amount to compensate the tool parameter P0 to obtain the tool parameter in the robot system as the final calibration result;

The tool parameter P0 at the setting tool tool1 is the vector of the default tool tool0 pointing to the setting tool tool1. In this embodiment, on the basis of the tool parameter P0, the compensation amount can be added to reduce the influence of the focus position on the robot posture change. The resulting calibration error finally obtains the vector pointing to the laser pointing light focus by the default tool tool0, which is the tool parameter at the laser pointing light focus. Compared with the tool parameters obtained by using the traditional calibration method, this embodiment finally obtains The tool parameter accuracy has been effectively improved.

In general, this embodiment collects the laser pointing light beam with the same focus as the laser beam and irradiates the same position on the plane coordinate system of the sensor plane through the host computer system that communicates with the robot. When the roughly calibrated welding tool tool1 sets the tool for the robot, the tool point position information displayed by the laser welding robot can be obtained by three rotations to obtain four points, which are obtained by least squares fitting when the laser pointer light focus is located at one point on the sensor plane , the positional relationship between this point and the robot's setting tool, that is, the relative positional relationship between the laser pointing light focus and the roughly calibrated setting tool tool1, and then obtain the vector pointing to the laser pointing light focus by the robot's default tool tool0, and inversely obtain The machine laser indicates the tool parameters at the focal point of the light. In this embodiment, the tool parameters roughly calibrated by the four-point method are compensated through focus positioning, and the tool information at the focus of the robot tool and the laser pointing light is obtained, so as to ensure that during the welding process, the change of the robot's posture will not affect the position of the laser focus. Solve the problem of high-precision tool calibration required in the actual generation process of welding robots.

Example 2:

A laser welding robot tool calibration system based on focus positioning compensation, as shown in Figure 1, includes:

The rough calibration module is used to set the robot tool in the robot geodetic coordinate system, which is marked as the setting tool tool1, and calibrate the tool parameter P0 at the setting tool tool1; the tool coordinate system of the setting tool tool1 and the robot geodetic coordinate system are set. The direction of each coordinate axis is the same or opposite;

Laser, used to generate laser pointer light confocal with welding laser;

sensor, set below the welding head;

The initial positioning module is used to adjust the robot to make the focus of the laser pointing light on the plane of the sensor, and then obtain the coordinate position of the setting tool tool1 in the robot's geodetic coordinate system, which is recorded as the initial position; the focus of the laser pointing light is on the sensor plane. Point is marked as point O;

The rotation and translation module is used to control the robot to rotate a certain angle around the rotation axis passing through the initial position, control the robot to translate, make the focus of the laser pointing light return to the point O in the sensor plane, and obtain the setting tool tool1 in the robot geodetic coordinate system The coordinate position of , is recorded as the new position;

The compensation amount calculation module is used to use the rotation and translation module to obtain N new positions that are not in the same plane, perform spherical fitting on the initial position and the N new positions, and calculate the vector of the initial position pointing to the center of the fitted sphere as Compensation amount; N≥3;

and a compensation module, which is used to compensate the compensation amount to the tool parameter P0, and obtain the tool parameter in the robot system as the final calibration result;

In this embodiment, for the specific implementation of each module, reference may be made to the descriptions in the foregoing method embodiments, which will not be repeated here.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (7)

1. a laser welding robot tool calibration method based on focus positioning compensation, is characterized in that, comprises: Rough calibration step: set the robot tool under the robot geodetic coordinate system, denoted as the setting tool tool1, and calibrate the tool parameter P0 at the setting tool tool1; the tool coordinate system of the setting tool tool1 and the robot geodetic coordinate system are the same. The direction of each coordinate axis is the same or opposite; Initial positioning step: generate laser pointing light that is confocal with the welding laser, and adjust the robot so that the focus of the laser pointing light is on the plane of the preset sensor, and then obtain the setting tool tool1 in the robot's geodetic coordinate system. The coordinate position is recorded as the initial position; the point of the laser pointing light focus on the sensor plane is recorded as point O; Steps of rotation and translation: After controlling the robot to rotate around the rotation axis passing through the initial position by a certain angle, control the robot to translate, so that the focus of the laser pointing light returns to the point O in the sensor plane, and obtain the setting tool tool1 in the robot geodetic coordinate system The coordinate position of , is recorded as the new position; Compensation amount calculation step: perform the rotation and translation steps N times to obtain N new positions that are not in the same plane, perform spherical fitting on the initial position and the N new positions, and calculate the initial position to point to the desired position. The vector of the resultant sphere center is used as the compensation amount; N≥3; Compensation step: using the compensation amount to compensate the tool parameter P0 to obtain the tool parameter in the robot system as the final calibration result. 2. The laser welding robot tool calibration method based on focus positioning compensation as claimed in claim 1, wherein in the compensation amount calculation step, when the acquired N new positions are obtained, the robot revolves around at least two rotation axes rotate. 3. The laser welding robot tool calibration method based on focus positioning compensation as claimed in claim 2, wherein in the compensation amount calculation step, when the acquired N new positions are obtained, the robot rotates around three rotation axes , and the three rotation axes are respectively parallel to the three coordinate axes of the robot's geodetic coordinate system. 4 . The laser welding robot tool calibration method based on focus positioning compensation according to claim 3 , wherein N=3. 5 . 5. The laser welding robot tool calibration method based on focus positioning compensation according to any one of claims 1 to 4, wherein in the rough calibration step, a four-point method or a six-point method is used in the robot geodetic coordinate system Next, set the robot tool, that is, set the tool tool1, and calibrate the tool parameter P0 at the setting tool tool1. 6. The laser welding robot tool calibration method based on focus positioning compensation according to any one of claims 1 to 4, wherein in the compensation amount calculation step, the initial position and the N Add a new location for spherical fitting. 7. A laser welding robot tool calibration system based on focus positioning compensation is characterized in that, comprising: The rough calibration module is used to set the robot tool in the robot geodetic coordinate system, denoted as the setting tool tool1, and calibrate the tool parameter P0 at the setting tool tool1; the tool coordinate system of the setting tool tool1 and the robot geodetic coordinate The direction of each coordinate axis of the system is the same or opposite; Laser, used to generate laser pointer light confocal with welding laser; sensor, set below the welding head; The initial positioning module is used to adjust the robot so that the focus of the laser pointing light is on the plane of the sensor, and then obtain the coordinate position of the setting tool tool1 in the robot's geodetic coordinate system, which is recorded as the initial position; the focus of the laser pointing light is at The point on the sensor plane is marked as point O; The rotation and translation module is used to control the robot to rotate by a certain angle around the rotation axis passing through the initial position, control the robot to translate, make the focus of the laser pointing light return to the point O in the sensor plane, and obtain the geodetic coordinates of the setting tool tool1 in the robot The coordinate position under the system is recorded as the new position; The compensation amount calculation module is used to perform spherical fitting on the initial position and the N newly added positions after obtaining N new positions that are not in the same plane by using the rotation and translation module, and calculate that the initial position points to the sphere obtained by fitting The vector of the heart is used as the compensation amount; N≥3; and a compensation module for compensating the tool parameter P0 by the compensation amount to obtain the tool parameter in the robot system as the final calibration result.

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