Calibration object-free laser calibration method and calibration object-free laser calibration system

Abstract

A calibration object-free laser calibration method and system comprises an execution mechanism and a laser, the laser is rigidly fixed at the tail end of the execution mechanism, and the calibration method comprises the following steps: setting a mark point A; moving the laser to enable a laser point projected by the laser to fall to the mark point A; translating the laser, and keeping a laser point projected by the translated laser to still fall on the mark point A; fitting the direction of the laser projection direction in the first coordinate system; obtaining the direction of the laser projection direction in the end coordinate system of the execution mechanism; the calibration method provided by the invention does not need a special calibration object, can quickly and directly calibrate the relation between the laser and the flange, and is simple and convenient to operate and small in calibration error.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of calibration, in particular to a laser calibration method and system without calibration objects. BACKGROUND

[0002] Industrial robot systems integrate actuators (such as mechanical arms), end tools and intelligent control systems, and can efficiently and accurately perform tasks; lasers are relatively common tools for pre-measuring end tool planning work trajectories in cutting, welding, spraying and other fields, and precise detection of working distance by laser can avoid collision or too far distance of subsequent tools in the actual working process, resulting in not actually performing tasks. For example, in plasma cutting, too close will cause the plasma gun head to collide on the object to be cut, and too far will cause the plasma to break the arc. In the use process, the relationship between the laser and the end execution tool needs to be calibrated in advance to ensure the accuracy and reliability of task execution. The positional deviation of the laser and the end execution tool is usually calculated by theoretical value, which can be obtained depending on the design parameters. However, the error caused by the process accuracy during processing and assembly will cause differences between the design parameters and the theoretical value. In addition, factors such as machine vibration and environmental temperature during actual work will also affect the relative spatial position between the sensor and the mechanical arm.

[0003] The direction of the laser also needs to be calibrated. The laser needs to track the distance on the actual walking trajectory of the end execution tool. When the direction is not accurate, the laser actually measures is not the data on the walking trajectory, which leads to incorrect trajectory compensation value, and in some cases will cause collision consequences, especially when there are concaves and convexes on the workpiece surface, since the randomness of the surface concaves and convexes, this problem is more obvious.

[0004] The patent document CN115824041A proposes a laser calibrating method, which calibrates the position deviation between the laser and the tcp origin of the mechanical arm end to solve the influence caused by assembly error and environmental factors. The disadvantage of this method is that the calibration process is complicated. The technical solution is complex in operation: first, adjust the tcp attitude to three attitude angles of 0°, mark the position of the laser point projected by the laser on the calibration plate at this time; then, adjust the tcp attitude to rotate around a certain specific axis (such as the Z axis) of the end tool coordinate system, obtain the tcp origin coordinate value displayed by the teach pendant and mark the position of the laser point; rotate several times to obtain multiple corresponding tcp origin coordinate values and laser point positions; then adjust the tcp attitude back to 0°, translate the tcp to make it touch the marked laser points in turn to obtain the coordinate values of the laser points in the tcp coordinate system; finally, through the tcp origin coordinate value and the coordinate value of the corresponding laser point in the tcp coordinate system, the position deviation between the two is obtained, and the position deviation between the tcp origin and the laser point is obtained. The technical solution is complicated in calculation: by obtaining the position deviation between the tcp center point and the laser point, various coordinate values, trigonometric functions, and distance values are used to solve and calculate the position of the laser.

[0005] The technical solution depends on the quality of personnel in the calibration process. The calibration process involves multiple human operations, including: in the process of obtaining the position deviation between the tcp center point and the laser point, repeatedly marking the laser point operation, and translating the tcp to touch the laser point operation; in the process of moving the tcp along a certain specific axis (such as the Z axis) of the end tool coordinate system, the laser point on the calibration plate moves from A to A ’ , which includes the operation of marking the laser point A, the operation of the tcp touching the laser point A, the operation of marking the laser point A ’ , and the operation of the tcp touching the laser point A ’ ; the above human operations depend on the quality of the calibration personnel and require high skills of the operators. If the operator is not skilled or operates improperly, it is easy to cause great calibration error; moreover, the end tool itself has a size, and the operator cannot accurately align the point due to the problem of visual angle obstruction, which further causes calibration error. SUMMARY

[0006] The present application aims to solve the above problems and provide a laser calibrating method and system for a calibration-free object, which can directly calibrate the relationship between the laser and the flange, is simple to operate, and has small calibration error.

[0007] The application solves the problem, and the technical scheme is as follows: a laser calibration method for a calibration object, comprising an actuator and a laser, the laser is rigidly fixed at the end of the actuator, and the laser moves under the driving of the actuator; the laser is used for projecting laser, and the laser is used for obtaining the distance between the laser projection origin and the target point, comprising the following steps: S a1 sets a mark point A; S a2 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 mark point A, the position is an initial position P0, the center point coordinates Q0 of the end of the actuator in the first coordinate system at this time are recorded, and the conversion matrix H0 between the end of the actuator coordinate system and the first coordinate system is recorded; S a3 controls the actuator to drive the laser to move to M different positions P j (j=1, 2...M), M≥1, at each position P j (j≥1), the laser is kept projecting on the mark point A; the coordinates Q j (j≥1) of the center of the end of the actuator in the first coordinate system at the time of moving to the corresponding position P j (j≥1) are recorded, and the conversion matrix H j (j≥1) between the end of the actuator coordinate system and the first coordinate system is recorded; S a4 obtains the direction of the laser projection direction of the laser in the first coordinate system according to the set of center coordinates Q j |j≥0}; norm1 ; S a5 obtains the laser direction of the laser projection direction in the end of the actuator coordinate system in combination with the rotation matrix in H j ; norm.

[0008] Further comprising calibrating the coordinates of the laser projection origin, the step of calibrating the coordinates of the laser projection origin comprises the following steps: S b1 sets a mark point B; S b2 controls the actuator to adjust the posture position of the end of the actuator mechanism, so that the laser point projected by the laser falls on the mark point B, obtains the distance d between the laser projection origin and the mark point B when falling on the mark point B, and obtains the coordinates W of the mark point B in the current end of the actuator coordinate system; S b3 calculates the coordinates QS of the laser projection origin in the end of the actuator coordinate system according to the laser direction norm, the distance d and the coordinates W.

[0009] The coordinates W are obtained by the following method: record the coordinates of the mark point B in the second coordinate system; record the conversion matrix H of the second coordinate system and the current end-of-executor coordinate system T ; combine the H T and the coordinates of the mark point B in the second coordinate system, obtain the coordinates W of the mark point B in the current end-of-executor coordinate system.

[0010] set N different mark points B i (i=1, 2,..., N), N≥1; for a single mark point B i , control the executor to adjust the end-of-executor mechanism to R i different posture positions T ik (k=1, 2,..., R i ), R i ≥1, keep the laser point projected by the laser at each posture position T ik on the mark point B i , calculate the coordinates QS ik of the laser projection origin in the end-of-executor coordinate system; the QS ik is the calculated coordinates of the laser projection origin in the end-of-executor coordinate system when the laser point projected by the laser is projected to the mark point B ik when the executor is controlled to adjust the end-of-executor mechanism to the posture position T i ; average the calculated QS ik to obtain the coordinates QS.

[0011] The first coordinate system is an executor base coordinate system or a virtual coordinate system, and the virtual coordinate system is the end-of-executor coordinate system corresponding to the executor moving the laser to the initial position P0.

[0012] The second coordinate system is an executor base coordinate system or a workpiece coordinate system.

[0013] The control of the executor in the Sa3 step moves the laser to the position P j through the end-of-executor, and keeps the laser projecting on the mark point A at the position P j , which includes the following steps: The end-of-executor moves the laser along the first coordinate direction; Fix the position of the laser in the first coordinate direction; The end-of-executor moves the laser along the second coordinate direction and the third coordinate direction, respectively, until the laser point projected by the laser falls on the mark point A again. The first coordinate direction, the second coordinate direction and the third coordinate direction are different axis directions in a first coordinate system.

[0014] Further comprising a camera for collecting coordinates of the mark points, and obtaining coordinates of the mark points B in a second coordinate system through a matrix conversion relationship of prior calibration.

[0015] The laser projects laser light to a calibration board, the calibration board has a chessboard feature, and the corner points of the chessboard are selected as mark points.

[0016] A laser calibration system without a calibration object, applying the laser calibration method without a calibration object, the laser is installed at the end of the actuator, and the laser is arranged along the y-axis direction of the end coordinate system of the actuator.

[0017] The present application has the beneficial effect of providing a convenient method for directly calibrating the relationship between the laser and the flange, since the end tool and the flange can be calibrated by a conventional method, the conversion relationship between the laser and the end tool coordinate system can be obtained through the relationship between the laser and the flange and the relationship between the end tool and the flange.

[0018] The method provided by the present application realizes rapid calibration of the laser projection direction without a special calibration object by controlling the actuator to drive the laser to translate to different position points and ensuring that the laser points projected by the laser on the different position points all fall on the same target point; then the position of the laser in the end of the actuator is calibrated in combination with the laser direction and laser ranging data; the method is simple and easy to operate; repeated measurement of mark point positions is not required, operation procedures and possible human operation errors are reduced; the method is not affected by factors such as viewing angle, and errors are effectively reduced.

[0019] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0021] FIG. 1 is a flowchart of the present application; FIG. 2 is a schematic diagram of the implementation environment of the present application; FIG. 3 is a schematic diagram of the actuator coordinate system in the present application; FIG. 4 is a schematic diagram of the present application in which the laser is translated so that the laser points also fall on the same mark point, FIG. 5 A schematic diagram of a translation laser in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0023] An implementation environment for laser calibration, as shown in FIG. 2 , includes an execution mechanism 1 and a laser projection plate 2, and a laser 3 is rigidly fixed at the end of the execution mechanism, and the laser moves under the driving of the execution mechanism; the laser 3 is used for projecting laser, and the laser 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 laser projection origin and the target point.

[0024] The execution mechanism can adopt a mechanical arm, a mechanical hand or other devices with similar functions. In a specific embodiment, a mechanical arm is adopted as the execution mechanism, and the laser is rigidly installed on the flange at the end of the mechanical arm.

[0025] For the mechanical arm, a base coordinate system and a flange coordinate system are established.

[0026] The base coordinate system usually takes the intersection of the J1 rotating shaft and the bottom surface of the base as the origin, takes the vertical upward direction of the bottom surface of the base as the +z axis direction, takes the horizontal left direction as the +y axis direction, and takes the horizontal forward direction as the +x axis direction. The flange coordinate system, as shown in FIG. 3 , takes the center of the flange as the origin, takes the vertical outward direction of the flange plane as the +z axis direction, takes the horizontal backward direction as the +y axis direction when the six-axis is at the origin, and takes the horizontal right direction as the +x axis direction.

[0027] A method for calibrating the direction of a laser, as shown in FIG. 1 , includes the following steps: Sa1 sets a mark point A on the laser projection plate; the laser projection plate can select a calibration plate with a chessboard feature, and the corner points of the chessboard in the calibration plate are selected as the mark points; Sa2 controls the execution mechanism to move the laser at the end of the execution mechanism so that the laser point projected by the laser falls on the mark point A, and the position is an initial position P0; the center point coordinates Q0 of the end of the execution mechanism in the first coordinate system and the conversion matrix H0 between the end coordinate system of the execution mechanism and the first coordinate system are recorded at this time; Sa3 controls the execution mechanism to move the laser at the end of the execution mechanism to M different positions P j (j=1, 2...M), M≥1, and the laser is kept projecting on the mark point A at each position P j (j≥1); the movement to the corresponding position P jthe coordinates of the center of the actuator end in the first coordinate system Q j (j≥1), and the conversion matrix H j (j≥1) between the actuator end coordinate system and the first coordinate system; FIG. 4 It is shown that the laser projected by the laser falls on the same mark point before and after translation, and the laser is indicated by an arrow; Sa4 obtains the direction of the laser projection in the first coordinate system according to the set of coordinates of the center of the actuator end Q j (j≥0), and fits to obtain the direction of the laser projection of the laser in the first coordinate system norm1 ; Sa5 obtains the direction of the laser projection in the actuator end coordinate system in combination with the rotation matrix in H j norm.

[0028] The above first coordinate system can be selected as the actuator base coordinate system.

[0029] For a robot arm, the actuator base coordinate system is the robot arm base coordinate system, the actuator end coordinate system refers to the flange coordinate system, and the center of the actuator end refers to the flange center.

[0030] When the robot arm drives the laser to move to P0, P1, P2, P3,..., P M , the corresponding coordinate points of the flange center in the base coordinate system are Q0, Q1, Q2, Q3,..., Q M , and the straight line direction obtained by fitting the points Q0, Q1, Q2, Q3,..., Q M is the direction of the laser projection in the first coordinate system norm1 ; The direction norm1 can be the unit vector of the fitted straight line direction.

[0031] When the robot arm drives the laser to move to P0, P1, P2, P3,..., P M , the corresponding conversion matrices between the flange coordinate system and the robot arm base coordinate system are H0, H1, H2, H3,..., H M , and for any conversion matrix H j (j≥0), which contains a rotation matrix and a translation vector, in combination with the rotation matrix of H j and the direction of the laser projection in the first coordinate system norm1, , the direction of the laser projection in the flange coordinate system norm is calculated.

[0032] In another embodiment, the above first coordinate system can be selected as a virtual coordinate system, which refers to the actuator end coordinate system corresponding to the initial position P0 when the actuator drives the laser to move to the initial position.​

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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: The actuator end effector drives the laser to translate along the first coordinate direction; Fix the position of the laser in the first coordinate direction; 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.

[0037] The first coordinate direction, the second coordinate direction, and the third coordinate direction are different axis directions in the first coordinate system.

[0038] The following provides a method that is easy to operate and record.

[0039] Taking the virtual coordinate system as the first coordinate system as an example: The robotic arm drives the laser to translate along the first coordinate direction of the virtual flange coordinate system; The coordinate position of the fixed laser in the first coordinate direction remains unchanged; 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. Record the distance of the laser in the first coordinate direction, the second coordinate direction and the third coordinate direction of the virtual flange coordinate system in the above process, and take the distance as the coordinate.

[0040] For example, the laser is installed in the approximate -y axis direction of the center point of the flange at the end of the mechanical arm, and the laser projection point falls on the mark point A, as shown in FIG. 2 The left drawing shows that the mechanical arm can first be controlled to drive the laser to translate a 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 mark point A', as shown in FIG. 5 The middle drawing shows that the coordinate position of the laser in the y axis direction is fixed, the mechanical arm drives the laser to translate along the x axis and z axis of the virtual flange coordinate system respectively, until the laser point falls on the mark point A again, as shown in FIG. 5 The right drawing shows that the offset amount in the x axis, y axis and z axis is recorded as the coordinate. FIG. 5

[0041] Since the laser is installed in the approximate -y axis direction, the mechanical arm can be first controlled to drive the laser to translate along the y axis of the virtual flange coordinate system, so that the offset of the laser point can be intuitively felt. Then, the laser is controlled to translate in other axis directions, so that the laser point can be quickly aligned again. In comparison, if the laser is first moved along the x axis, and then moved along the y axis, the laser needs to be moved again in the x axis direction to align the laser point, which is complicated.

[0042] The direction of the laser projection direction in the end coordinate system of the actuator is calibrated norm, The coordinate of the laser projection origin can be further calibrated, and an implementation method is as follows: Sb1 sets a mark point B on the laser projection plate. The laser projection plate can select a calibration plate with a chessboard feature, and the corner points of the chessboard in the calibration plate are selected as the mark points; Sb2 controls the actuator to adjust the posture position of the actuator end mechanism, so that the laser point projected by the laser falls on the mark point B, obtains the distance d between the laser projection origin and the mark point B when the laser falls on the mark point B, and obtains the coordinate W of the mark point B in the current actuator end coordinate system; Sb3 calculates the coordinate QS of the laser projection origin in the actuator end coordinate system according to the laser direction norm , the distance d and the coordinate W.

[0043] QS = W- norm *d, wherein the laser direction norm in the formula is a unit vector.

[0044] An implementation method for obtaining the coordinate W of the mark point B in the current actuator end coordinate system is as follows:​ record the coordinates of the mark point B in the second coordinate system; record the conversion matrix H of the second coordinate system and the current end coordinate system of the actuator T ; combine H T and the coordinates of the mark point B in the second coordinate system, obtain the coordinates W of the mark point B in the current end coordinate system of the actuator.

[0045] The second coordinate system is an actuator base coordinate system; or a workpiece coordinate system, in the present application, the work coordinate system can be a laser projection plate, or a calibration plate coordinate system.

[0046] Taking a mechanical arm as an example, the method for obtaining the coordinates of the mark point B in the mechanical arm base coordinate system is as follows: In one embodiment, as shown in FIG. 2 , the mechanical arm flange center is also provided with a probe 4, which is rigidly fixed on the z-axis of the end coordinate system of the actuator, and the coordinates are obtained by touching the mark point B with the probe.

[0047] In another embodiment, a camera can be set up in the environment, which is used to collect the coordinates of the mark point, and through the matrix conversion relationship obtained by prior calibration, the coordinates of the mark point in the second coordinate system, such as the mechanical arm base coordinate system, are obtained.

[0048] In order to improve the accuracy of the laser projection origin position calibration, different calibration points can be set to perform multiple calibrations in different postures.

[0049] N different mark points B1, B2,..., BN N , N≥1; For a single mark point B i , control the actuator to adjust the end mechanism of the actuator to R i different posture positions T ik (k=1, 2,..., R i ), R i ≥1; For example, for a single mark point B1, control the actuator to adjust the end mechanism of the actuator to R1 different posture positions T 11 , T 12 , T 13 ,..., T 1Ri ; and so on. Keep the laser point projected by the laser falling on the mark point B i at each posture position T ik , calculate the coordinates QS ik of the laser projection origin in the end coordinate system of the actuator. QS ikTo control the actuator to adjust the end of the actuator mechanism to the posture position T ik When the laser point projected by the laser is projected to the mark point B i , the calculated coordinates of the laser projection origin in the end of the actuator coordinate system are calculated. For example, for a single mark point B1, at different posture positions T 11 , T 12 , T 13 ... T 1Ri , the laser point projected by the laser can always fall on the mark point B1, According to the distance d 11 between the laser projection origin and the mark point B1 when the end of the actuator mechanism is at the posture position T 11 , the coordinates W 11 of the mark point B1 in the current end of the actuator coordinate system, and the laser direction norm, the coordinates QS 11 of the laser projection origin in the end of the actuator coordinate system are calculated; and the like. The QS ik obtained in the above steps is averaged to obtain the final coordinates QS.

[0050] Compared with the prior art, the present application provides a convenient method for directly calibrating the relationship between the laser and the flange. Since the end tool and the flange can be calibrated by a conventional method, the conversion relationship between the laser and the end tool coordinate system can be obtained through the relationship between the laser and the flange and the relationship between the end tool and the flange.

[0051] The method provided by the present application controls the actuator to drive the laser to translate different position points, and ensures that the laser points projected by the laser fall on the same target point at the translated different position points, so as to realize the rapid calibration of the laser projection direction without the need for special calibration objects. Then, the position of the laser in the end of the actuator is calibrated in combination with the laser direction and the laser ranging data. The method is simple and easy to operate, does not need to repeatedly measure the position of the mark point, reduces the operation procedures and possible human operation errors, is not affected by factors such as viewing angle, and effectively reduces errors.

[0052] In addition, it should be understood that the above embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application.

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 (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 drives the laser to move 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 arranged along the y-axis direction of the coordinate system at the end of the actuator.

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