A method and system for calibrating a laser without a calibration object

Abstract

A kind of laser calibration method and system of calibration-free object, including actuator and laser, the laser is rigidly fixed at the end of actuator, and the calibration method includes the following steps: setting mark point A;Move laser, so that the laser point projected by laser falls to mark point A;Translate laser, keep the laser point projected by laser after translation still falls in mark point A;Fitting the direction of laser projection direction in the first coordinate system;Obtain the direction of laser projection direction in the end coordinate system of actuator;The calibration method provided by the application, without special calibration object, quickly and directly calibrates the relationship of laser and flange, easy to operate, and calibration error is small.

Description

Technical Field

[0001] This invention relates to the field of calibration technology, and in particular to a laser calibration method and system that does not require calibration materials. Background Technology

[0002] Industrial robot systems integrate actuators (such as robotic arms), end effectors, and intelligent control systems to perform tasks efficiently and accurately. Lasers are commonly used in cutting, welding, and spraying to pre-measure the working trajectory of the end effector. The laser beam accurately detects the working distance, preventing collisions or failures due to excessive distance during actual operation. For example, in plasma cutting, too close a distance can cause the plasma torch to collide with the object being cut, while too far a distance can cause the plasma arc to break. During use, the relationship between the laser and the end effector needs to be calibrated beforehand to ensure the accuracy and reliability of task execution. The positional deviation between the laser and the end effector is usually calculated theoretically and can be obtained from design parameters. However, errors in manufacturing and assembly processes can cause discrepancies between the design parameters and theoretical values. Furthermore, machine vibration and ambient temperature can also affect the relative spatial position between the sensor and the robotic arm during actual operation.

[0003] The laser's direction also needs to be calibrated. The laser needs to track the distance along the actual path of the end effector. When the direction is inaccurate, the laser will not actually measure the data along the path, resulting in incorrect trajectory compensation values. In some cases, this can lead to collisions, especially when the workpiece surface has unevenness. Due to the randomness of the surface unevenness, this problem is more pronounced.

[0004] Patent document CN115824041A proposes a laser calibration method, which solves the problems caused by assembly errors and environmental factors by calibrating the positional deviation between the laser and the TCP origin of the robotic arm end effector. The drawback of this method is that the calibration process is cumbersome. This technical solution is complex to operate: First, the TCP attitude is adjusted to 0° at all three attitude angles, and the position of the laser point projected by the laser on the calibration board is marked at this time; then, the TCP attitude is adjusted to rotate around a specific axis (such as the Z-axis) of the end-effector coordinate system, and the coordinate values ​​of the TCP origin displayed on the teach pendant are obtained, and the position of the laser point is marked; this rotation is repeated multiple times to obtain multiple sets of corresponding TCP origin coordinate values ​​and laser point positions; next, the TCP attitude is adjusted back to 0°, and the TCP is translated so that it touches the marked laser points in sequence, obtaining the coordinate values ​​of the laser points in the TCP coordinate system; finally, the positional deviation between the TCP origin coordinate values ​​and the corresponding laser point coordinate values ​​in the TCP coordinate system is calculated, thus obtaining the positional deviation between the TCP origin and the laser point; this technical solution is computationally cumbersome: by obtaining the positional deviation between the TCP center point and the laser point, the position of the laser is calculated and maintained using various coordinate values, trigonometric functions, and distance values, making the calculation complex.

[0005] The accuracy of this technical solution during calibration depends heavily on the skill of the personnel. The calibration process involves multiple manual operations, including: repeatedly marking the laser point while obtaining the positional deviation between the TCP center point and the laser point; translating the TCP to make it touch the laser point; and moving the TCP along a specific axis (such as the z-axis) of the end-effector coordinate system, causing the laser point on the calibration plate to move from point A to point A. ’ The process includes the operation of marking laser point A, the operation of TCP touching laser point A, and marking laser point A. ’ The operation involves TCP touching laser point A. ’ The above manual operation relies on the quality of the calibration personnel and requires high skill levels. If the operator's skill level is not high or the operation is improper, it is very easy to cause large calibration errors. Moreover, the end effector itself has dimensions, and the problem of obstructed view can cause the operator to be unable to accurately align the points, further causing calibration errors. Summary of the Invention

[0006] The present invention aims to solve the above problems and provides a laser calibration method and system that does not require calibration materials. It can directly calibrate the relationship between the laser and the flange, and is simple to operate with small calibration error.

[0007] The present invention addresses the problem by providing a laser calibration method that eliminates the need for a calibration object. The method comprises an actuator and a laser, wherein the laser is rigidly fixed to the end of the actuator and moves under the influence of the actuator. The laser is used to project a laser beam and to obtain the distance between the laser projection origin and a target point. The method includes the following steps:

[0008] Sa1 sets the marker point A;

[0009] Sa2 controls the actuator to drive the laser to move through the end of the actuator, so that the laser point projected by the laser falls on the marked point A. This position is the initial position P0. Record the coordinates Q0 of the center point of the end of the actuator in the first coordinate system at this time, as well as the transformation matrix H0 between the coordinate system of the end of the actuator and the first coordinate system.

[0010] Sa3 controls the actuator to move the laser to M different positions P via the actuator's end. j (j=1, 2, ..., M), M≥1, at each position P j (j≥1) Keep the laser projected at the marked point A; record the translation to the corresponding position P. j When (j≥1), the coordinates Q of the end effector center in the first coordinate system are... j (j≥1), and the transformation matrix H between the actuator end coordinate system and the first coordinate system. j (j≥1);

[0011] Sa4 is based on the set of center coordinates of the actuator's end effector Q{Q j |j≥0}, the laser projection direction of the laser in the first coordinate system is obtained by fitting the coordinates. norm1 ;

[0012] Sa5 combined with H j The rotation matrix is ​​used to obtain the laser direction of the laser projection direction in the coordinate system of the actuator end effector. norm.

[0013] It also includes calibrating the coordinates of the laser projection origin, which involves the following steps:

[0014] Sb1 sets the marker point B;

[0015] Sb2 controls the actuator to adjust the attitude and position of the end effector so that the laser point projected by the laser falls on the marker point B, and obtains the distance d between the origin of the laser projection and the marker point B when the laser falls on the marker point B, and obtains the coordinates W of the marker point B in the current coordinate system of the end effector.

[0016] Sb3 calculates the coordinates QS of the laser projection origin in the actuator end coordinate system based on the laser direction norm, distance d, and coordinate W.

[0017] The coordinates W are obtained in the following way:

[0018] Record the coordinates of the marked point B in the second coordinate system;

[0019] Record the transformation matrix H between the second coordinate system and the current actuator end-effector coordinate system. T ;

[0020] Combined with the H T The coordinates W of the marker point B in the current actuator end coordinate system are obtained by combining the coordinates of the marker point B in the second coordinate system with the coordinates of the marker point B in the second coordinate system.

[0021] Set N different marker points B i (i=1, 2, ..., N), N≥1; for a single marker point B i The actuator is controlled to adjust the end effector to R. i T at different posture positions ik (k=1, 2, ..., R) i ), R i ≥1, at each attitude position T ik Ensure that all laser points projected by the laser fall on the marked point B. i Above, calculate the coordinates QS of the laser projection origin in the end effector coordinate system. ik The QS ik To control the actuator, adjust the end effector of the actuator to the attitude position T. ik The laser point projected by the laser is projected onto the marked point B. i At that time, the coordinates of the laser projection origin in the actuator end coordinate system are calculated; the calculated QS ik Perform averaging to obtain the coordinates QS.

[0022] The first coordinate system is the base coordinate system or virtual coordinate system of the actuator. The virtual coordinate system is the end coordinate system of the actuator when the actuator moves the laser to the initial position P0.

[0023] The second coordinate system is the actuator base coordinate system or the workpiece coordinate system.

[0024] In step Sa3, the actuator is controlled to move the laser to position P via its end. j At position P j Maintaining the laser projection on the marked point A includes the following steps:

[0025] The end of the actuator drives the laser to translate along the first coordinate direction;

[0026] The position of the laser is fixed in the first coordinate direction;

[0027] The end of the actuator drives the laser to translate along the second coordinate direction and the third coordinate direction respectively, until the laser point projected by the laser falls back onto the marked point A;

[0028] The first coordinate direction, the second coordinate direction, and the third coordinate direction are different axis directions in the first coordinate system.

[0029] It also includes a camera, which is used to acquire the coordinates of the marker point and obtain the coordinates of the marker point B in the second coordinate system through a pre-defined matrix transformation relationship.

[0030] The laser projects a laser beam onto a calibration board, which has a checkerboard pattern, and the corner points of the checkerboard are selected as marker points.

[0031] A laser calibration system that requires no calibration material, using the aforementioned laser calibration method that requires no calibration material, wherein a laser is mounted at the end of an actuator, and the laser is positioned along the y-axis of the coordinate system at the end of the actuator.

[0032] The beneficial effect of this invention is that it provides a convenient method to directly calibrate the relationship between the laser and the flange. Since the end tool and the flange can be calibrated by conventional methods, the transformation relationship between the coordinate systems of the laser and the end tool can be obtained through the relationship between the laser and the flange and the end tool and the flange.

[0033] The method provided by this invention achieves rapid calibration of the laser projection direction without the need for special calibration objects by controlling the actuator to drive the laser to translate to different positions, ensuring that the laser points projected by the laser fall on the same target point at each translation point. Then, by combining the laser direction and laser ranging data, the position of the laser in the end of the actuator is calibrated. The method is simple and easy to operate; it does not require repeated measurement of the marked point position, reducing operation steps and potential human operation errors; it is not affected by factors such as viewing angle, effectively reducing errors.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0036] Figure 1 This is a flowchart of the present invention;

[0037] Figure 2 This is a schematic diagram of the implementation environment of the present invention;

[0038] Figure 3 This is a schematic diagram of the coordinate system of the actuator in this invention;

[0039] Figure 4 This is a schematic diagram illustrating how the laser is shifted in this invention to ensure the laser point falls back on the same marked point.

[0040] Figure 5 This is a schematic diagram of a translation laser in one embodiment of the present invention. Detailed Implementation

[0041] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] An implementation environment calibrated for a laser, such as Figure 2 As shown, it includes an actuator 1 and a laser projection plate 2. A laser 3 is rigidly fixed at the end of the actuator and moves under the drive of the actuator. The laser 3 is used to project laser light, and the laser light projected by the laser 3 falls on the laser projection plate 2 to form a laser point. The laser 3 can also be used to obtain the distance between the origin of the laser projection and the target point.

[0043] The actuator can be a robotic arm, a robotic hand, or other device with similar functions. In one specific embodiment, a robotic arm is used as the actuator, and the laser is rigidly mounted on the end flange of the robotic arm.

[0044] For the robotic arm, establish a base coordinate system and a flange coordinate system.

[0045] The base coordinate system is usually based on the intersection of the J1 rotation axis and the bottom surface of the base as the origin, with the vertical upward direction of the bottom surface of the base as the +z axis, the horizontal leftward direction as the +y axis, and the horizontal forward direction as the +x axis.

[0046] Flange coordinate system as follows Figure 3 As shown, with the flange center as the origin, the direction perpendicular to the flange plane outward is the +z axis. When the six axes are at the origin, the direction horizontally backward is the +y axis, and the direction horizontally to the right is the +x axis.

[0047] Methods for calibrating laser orientation, such as Figure 1 As shown, it includes the following steps:

[0048] Sa1 sets a marker point A on the laser projection plate; the laser projection plate can be a calibration plate with checkerboard features, and the corner points of the checkerboard in the calibration plate are selected as marker points;

[0049] Sa2 controls the actuator to move the laser by the end of the actuator, so that the laser point projected by the laser falls on the marked point A. This position is the initial position P0. Record the coordinates Q0 of the center point of the end of the actuator in the first coordinate system, and the transformation matrix H0 between the coordinate system of the end of the actuator and the first coordinate system at this time.

[0050] Sa3 controls the actuator to move the laser to M different positions P via the actuator's end. j (j=1, 2, ..., M), M≥1, at each position P j (j≥1) Keep the laser projection on the marked point A; record the translation to the corresponding position P. j When (j≥1), the coordinates Q of the end effector center in the first coordinate system are... j (j≥1), and the transformation matrix H between the actuator end coordinate system and the first coordinate system. j (j≥1); Figure 4 This illustrates that before and after the translation, the laser beams projected by the laser both fall on the same marked point, indicated by arrows.

[0051] Sa4 is based on the set of center coordinates of the actuator's end effector Q{Q j |j≥0}, the laser projection direction of the laser in the first coordinate system is obtained by fitting the coordinates. norm1 ;

[0052] Sa5 combined with H j The rotation matrix in the equation is used to obtain the direction of the laser projection direction in the coordinate system of the actuator end effector. norm.

[0053] The aforementioned first coordinate system can be selected as the base coordinate system of the actuator.

[0054] For a robotic arm, the actuator base coordinate system is the same as the robotic arm base coordinate system, the actuator end coordinate system refers to the flange coordinate system, and the actuator end center refers to the flange center.

[0055] The robotic arm moves the laser to P0, P1, P2, P3...P M At that time, the corresponding coordinates of the flange center in the base coordinate system are Q0, Q1, Q2, Q3...Q M For points Q0, Q1, Q2, Q3...Q M The fitting process is performed, and the direction of the straight line obtained is the direction of the laser projection direction in the first coordinate system. norm1The direction norm1 can be taken as the unit vector of the fitted straight line direction.

[0056] The robotic arm moves the laser to P0, P1, P2, P3...P M At that time, the transformation matrices between the flange coordinate system and the robot arm base coordinate system are H0, H1, H2, H3...H M For any transformation matrix H j (j≥0), including rotation matrix and translation vector, combined with H j The rotation matrix and the direction of laser projection in the first coordinate system norm1, The direction of the laser projection in the flange coordinate system is calculated. norm .

[0057] In another embodiment, the first coordinate system can be selected as a virtual coordinate system, which refers to the coordinate system of the end of the actuator when the actuator drives the laser to move to the initial position P0.

[0058] For a robotic arm, the virtual coordinate system refers to the flange coordinate system corresponding to when the robotic arm moves the laser to the initial position P0.

[0059] The robotic arm moves the laser to P0, P1, P2, P3...P M At that time, the flange center is located at the corresponding coordinate points Q0, Q1, Q2, Q3...Q in the virtual coordinate system. M , where Q0 is (0,0,0).

[0060] Coordinates Q1, Q2, Q3...Q M Denoted as Q1 (δa1, δb1, δc1), Q2 (δa2, δb2, δc2), Q3 (δa3, δb3, δc3)...Q M (δa) M ,δb M ,δc M Taking point Q1 as an example, δa1, δb1, and δc1 refer to the distances that the flange center corresponding to the laser when it is translated to P1, and the distances that the flange center corresponding to the laser when it is translated to P0, are translated in the x-axis, y-axis, and z-axis directions of the virtual coordinate system.

[0061] In step Sa3 above, the control actuator drives the laser to translate to position P via the actuator's end. j At position P j To keep the laser projection focused on marker point A, one convenient way to implement this is as follows:

[0062] The actuator end effector drives the laser to translate along the first coordinate direction;

[0063] Fix the position of the laser in the first coordinate direction;

[0064] The actuator drives the laser to translate along the second coordinate direction and the third coordinate direction respectively until the laser point falls back on the marked point A.

[0065] The first coordinate direction, the second coordinate direction, and the third coordinate direction are different axis directions in the first coordinate system.

[0066] The following provides a method that is easy to operate and record.

[0067] Taking the virtual coordinate system as the first coordinate system as an example:

[0068] The robotic arm drives the laser to translate along the first coordinate direction of the virtual flange coordinate system;

[0069] The coordinate position of the fixed laser in the first coordinate direction remains unchanged;

[0070] The robotic arm continues to move the laser along the second and third coordinate directions of the virtual flange coordinate system until the laser point falls back onto the marked point A.

[0071] Record the distances the laser moves in the first, second, and third coordinate directions of the virtual flange coordinate system during the above process, and use the translation amount as coordinates.

[0072] by Figure 2 Taking the robotic arm as an example, the laser is roughly installed along the -y axis direction at the center point of the flange at the end of the robotic arm, and the laser projection point falls on the marked point A, such as... Figure 5 As shown in the left figure, the robotic arm can be controlled to move the laser a certain distance along the y-axis of the virtual flange coordinate system. Due to the installation deviation between the laser and the flange, the laser projection point falls on the marked point A', as shown in the left figure. Figure 5 As shown in the middle figure; the coordinate position of the fixed laser in the y-axis direction remains unchanged, and the robotic arm moves the laser along the x-axis and z-axis directions of the virtual flange coordinate system respectively, until the laser point falls back onto the marked point A, as shown. Figure 5 As shown in the right figure; record the offsets on the x-axis, y-axis, and z-axis as coordinates.

[0073] Since the laser is installed approximately in the -y axis direction, by first controlling the robotic arm to move the laser along the y axis of the virtual flange coordinate system, the offset of the laser point can be intuitively felt. Then, by controlling the laser to move in other axis directions, the laser point can be quickly re-aligned. In contrast, if the laser moves along the x axis first and then along the y axis, the position of the laser in the x axis direction needs to be moved again to align the laser point, which is cumbersome.

[0074] Using the calibrated laser projection direction in the coordinate system of the actuator end effector norm, The coordinates of the laser projection origin can be further determined, and the following implementation method is provided:

[0075] Sb1 sets a marker point B on the laser projection plate; the laser projection plate can be a calibration plate with checkerboard features, and the corner points of the checkerboard in the calibration plate are selected as marker points;

[0076] Sb2 controls the actuator to adjust the attitude and position of the end effector so that the laser point projected by the laser falls on the marker point B. It obtains the distance d between the origin of the laser projection and the marker point B when the laser point falls on the marker point B, and the coordinates W of the marker point B in the current coordinate system of the actuator's end effector.

[0077] Sb3 According to the laser direction norm Given distance d and coordinate W, calculate the coordinates QS of the laser projection origin in the coordinate system of the actuator end effector.

[0078] QS=W- norm *d, the laser direction in this formula norm It is a unit vector.

[0079] One method to obtain the coordinates W of the marker point B in the current actuator end effector coordinate system:

[0080] Record the coordinates of marker B in the second coordinate system;

[0081] Record the transformation matrix H between the second coordinate system and the current actuator end-effector coordinate system. T ;

[0082] Combine H T Given the coordinates of marker B in the second coordinate system, obtain the coordinates W of marker B in the current actuator end coordinate system.

[0083] The second coordinate system is the base coordinate system of the actuator;

[0084] Alternatively, the workpiece coordinate system may be the laser projection plate coordinate system, or the calibration plate coordinate system.

[0085] Taking a robotic arm as an example, the method for obtaining the coordinates of marker point B in the robotic arm's base coordinate system is as follows:

[0086] In one embodiment, such as Figure 2 As shown, a probe 4 is also installed at the center of the robotic arm flange. The probe 4 is rigidly fixed on the z-axis of the coordinate system at the end of the actuator. The probe obtains coordinate information by touching the marked point B.

[0087] In another embodiment, a camera can be set up in the environment to collect the coordinates of the marker points. Through a pre-defined matrix transformation relationship, the coordinates of the marker points in a second coordinate system, such as the base coordinate system of the robotic arm, can be obtained.

[0088] To improve the accuracy of laser projection origin point calibration, different calibration points can be set and calibration can be performed multiple times in different postures.

[0089] Set N different marker points B1, B2...B N N≥1;

[0090] For a single marker point B i The control actuator adjusts the end effector to R. i T at different posture positions ik (k=1, 2, ..., R) i ), R i ≥1;

[0091] For example, for a single marker point B1, the control actuator adjusts the end effector to R1 different orientation positions T. 11 T 12 T 13 ......T 1Ri And so on;

[0092] At each attitude position T ik Ensure that all laser beams projected by the laser fall on the marked point B. i Above, calculate the coordinates QS of the laser projection origin in the end effector coordinate system. ik ;

[0093] QS ik To control the actuator, adjust the end effector of the actuator to the attitude position T. ik The laser point projected by the laser is projected onto the marked point B. i At that time, the coordinates of the laser projection origin in the end-effector coordinate system are calculated;

[0094] For example, for a single marker point B1, at different pose positions T 11 T 12 T 13 ......T 1Ri At all times, the laser beam projected by the laser can be kept falling on the marked point B1.

[0095] Based on the attitude position T of the actuator end effector 11 At that time, the distance d between the laser projection origin and the marked point B1 is... 11 The coordinates W of the marker point B1 in the current actuator end coordinate system 11The laser direction norm is used to calculate the coordinates QS of the laser projection origin in the actuator end effector coordinate system. 11 And so on;

[0096] The QS obtained in the above steps ik Perform averaging to obtain the final coordinates QS.

[0097] Compared with the prior art, the present invention provides a convenient method to directly calibrate the relationship between the laser and the flange. Since the end tool and the flange can be calibrated by conventional methods, the transformation relationship between the coordinate systems of the laser and the end tool can be obtained through the relationship between the laser and the flange and the end tool and the flange.

[0098] The method provided by this invention achieves rapid calibration of the laser projection direction without the need for special calibration objects by controlling the actuator to drive the laser to translate to different positions, ensuring that the laser points projected by the laser fall on the same target point at each translation point. Then, by combining the laser direction and laser ranging data, the position of the laser in the end of the actuator is calibrated. The method is simple and easy to operate; it does not require repeated measurement of the marked point position, reducing operation steps and potential human operation errors; it is not affected by factors such as viewing angle, effectively reducing errors.

[0099] Furthermore, it should be understood that the above embodiments only illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A laser calibration method without a calibration object, comprising an actuator and a laser, wherein the laser is rigidly fixed at the end of the actuator, and the laser moves under the drive of the actuator; the laser is used to project laser light, and the laser is used to obtain the distance between the laser projection origin and the target point, characterized in that, Includes the following steps: Sa1 sets the marker point A; Sa2 controls the actuator to drive the laser to move through the end of the actuator, so that the laser point projected by the laser falls on the marked point A. This position is the initial position P0. Record the coordinates Q0 of the center point of the end of the actuator in the first coordinate system at this time, as well as the transformation matrix H0 between the coordinate system of the end of the actuator and the first coordinate system. Sa3 controls the actuator to move the laser to M different positions P via the actuator's end. j j=1,2......M,M≥1, at each position P j If j≥1, keep the laser projected at the marked point A; record the translation to the corresponding position P. j When j≥1, the coordinates Q of the end effector center in the first coordinate system are... j j≥1, and the transformation matrix H between the actuator end coordinate system and the first coordinate system. j , j≥1; Sa4 is based on the set of center coordinates of the actuator's end effector Q{Q j |j≥0}, the laser projection direction of the laser in the first coordinate system is obtained by fitting the coordinates. norm1 ; Sa5 combined with H j The rotation matrix is ​​used to obtain the laser direction of the laser projection direction in the coordinate system of the actuator end effector. norm.

2. The laser calibration method without calibration material as described in claim 1, characterized in that, It also includes calibrating the coordinates of the laser projection origin, which involves the following steps: Sb1 sets the marker point B; Sb2 controls the actuator to adjust the attitude and position of the end effector so that the laser point projected by the laser falls on the marker point B, and obtains the distance d between the origin of the laser projection and the marker point B when the laser falls on the marker point B, and obtains the coordinates W of the marker point B in the current coordinate system of the end effector. Sb3 calculates the coordinates QS of the laser projection origin in the actuator end coordinate system based on the laser direction norm, distance d, and coordinate W.

3. The laser calibration method without calibration material as described in claim 2, characterized in that, The coordinates W are obtained in the following way: Record the coordinates of the marked point B in the second coordinate system; Record the transformation matrix H between the second coordinate system and the current actuator end-effector coordinate system. T ; Combined with the H T The coordinates W of the marker point B in the current actuator end coordinate system are obtained by combining the coordinates of the marker point B in the second coordinate system with the coordinates of the marker point B in the second coordinate system.

4. The laser calibration method without calibration material as described in claim 2, characterized in that, Set N different marker points B i , i=1,2......N,N≥1; for a single marker point B i The actuator is controlled to adjust the end effector to R. i T at different posture positions ik k=1,2......R i R i ≥1, at each attitude position T ik Ensure that all laser points projected by the laser fall on the marked point B. i Above, calculate the coordinates QS of the laser projection origin in the end effector coordinate system. ik The QS ik To control the actuator, adjust the end effector of the actuator to the attitude position T. ik The laser point projected by the laser is projected onto the marked point B. i At that time, the coordinates of the laser projection origin in the actuator end coordinate system are calculated; the calculated QS ik Perform averaging to obtain the coordinates QS.

5. The laser calibration method without calibration material as described in claim 1, characterized in that, The first coordinate system is the base coordinate system or virtual coordinate system of the actuator. The virtual coordinate system is the end coordinate system of the actuator when the actuator moves the laser to the initial position P0.

6. The laser calibration method without calibration material as described in claim 3, characterized in that, The second coordinate system is the actuator base coordinate system or the workpiece coordinate system.

7. The laser calibration method without calibration material as described in claim 1, characterized in that, In step Sa3, the actuator is controlled to move the laser to position P via its end. j At position P j Maintaining the laser projection on the marked point A includes the following steps: The end of the actuator drives the laser to translate along the first coordinate direction; The position of the laser is fixed in the first coordinate direction; The end of the actuator drives the laser to translate along the second coordinate direction and the third coordinate direction respectively, until the laser point projected by the laser falls back onto the marked point A; The first coordinate direction, the second coordinate direction, and the third coordinate direction are different axis directions in the first coordinate system.

8. The laser calibration method without calibration material as described in claim 3, characterized in that, It also includes a camera, which is used to acquire the coordinates of the marker point and obtain the coordinates of the marker point B in the second coordinate system through a pre-defined matrix transformation relationship.

9. The laser calibration method without calibration material as described in claim 1, characterized in that, The laser projects a laser beam onto a calibration board, which has a checkerboard pattern, and the corner points of the checkerboard are selected as marker points.

10. A laser calibration system that requires no calibration material, characterized in that, The laser calibration method for a calibration-free object as described in any one of claims 1 to 9 is provided, wherein a laser is installed at the end of the actuator, and the laser is positioned along the y-axis of the coordinate system at the end of the actuator.

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