A method and system for calibrating the center point of a robot tool

Abstract

The present invention proposes a calibration method and system for the center point of a robot tool, comprising: obtaining two laser beams with fixed and known angles, which are respectively a first laser beam along the X direction and a second laser beam along the Y direction; setting the center point of a sphere of the robot end effector as a TCP point; controlling the robot to move in a small range with different postures, so that the bottom end of the sphere contacts the first laser beam in the X direction for a set number of times, and contacts the second laser beam in the Y direction for a set number of times, and recording the Cartesian coordinate information of the robot end when contacting and separating respectively; establishing a multivariate linear equation group according to the obtained Cartesian coordinate information and the structural parameters of the robot, and solving the equation group to obtain the coordinates of the TCP point, i.e., the sphere in the robot flange coordinate system.

Description

Technical Field

[0001] The invention belongs to the technical field of robot TCP calibration, and in particular relates to a robot tool center point calibration method and system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Robot TCP (Tool Center Point) calibration refers to the process of determining the exact position and posture of the robot's end effector (such as fixtures, tools, etc.) relative to the robot's end flange. Its main purpose is to ensure that the robot can accurately locate the tool and operate the workpiece when performing tasks, thereby improving production efficiency and quality.

[0004] The existing robot TCP calibration methods mainly include the following methods:

[0005] 1. Manual teaching method: This method requires the operator to manually move the robot end effector to a specific position and posture, and then record its coordinate information. This method is simple and easy, but it takes a lot of time and is affected by human factors, so the calibration accuracy is limited.

[0006] 2. Laser measurement-based method: Use a laser tracking system or laser rangefinder to measure the position and posture of the robot's end effector. This method has high accuracy, but the equipment is expensive and requires complex installation and calibration.

[0007] 3. Vision system-based method: Use a camera or other visual sensor to capture the image of the robot's end effector, and determine its position and posture through image processing and computer vision algorithms. This method can achieve automatic calibration, but it is affected by factors such as lighting conditions and background interference, and requires high computing resources and algorithm complexity.

[0008] Although the existing robot TCP calibration methods can meet the actual application needs to a certain extent, there are still some problems: ① Accuracy and stability: Some calibration methods may be affected by factors such as measurement errors and environmental interference, resulting in unstable calibration results or low accuracy. ② High cost: High-precision equipment such as laser measurement systems are expensive, which increases the calibration cost, especially for small enterprises or individual users. ③ Complexity and ease of use: Some calibration methods require complex equipment installation and calibration, or require certain professional knowledge of the operator, which reduces their ease of use and universality.

[0009] In the prior art, the self-calibration of the end tool using a laser sensor is often performed by using a point-to-point method such as the binary approximation method in patent document CN114012784A. This method requires the end tool to be approximated in the laser sensor by moving it multiple times, and requires recording a large amount of teach pendant point information, which greatly increases the storage capacity of the teach pendant's point coordinates. At the same time, it requires a lot of time for point-to-point calibration, resulting in low point-to-point efficiency and reduced calibration efficiency. Other methods that use laser sensors to perform self-calibration on the end tool can avoid multiple movements of the end tool, but require the cross lasers generated by the laser sensor to be in the same plane, and the plane formed by the two laser beams is parallel to the XOY plane of the robot's base coordinate system, which is difficult to achieve in practical applications. Summary of the invention

[0010] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a calibration method for the center point of a robot tool. This calibration method does not require the robot TCP coordinates to coincide with a fixed point multiple times, but rather coincides with points on two laser beams. The coupling effect of the two lasers improves the calibration accuracy, and the accuracy of the TCP calibration can be detected at the same time.

[0011] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0012] In a first aspect, a method for calibrating a center point of a robot tool is disclosed, comprising:

[0013] Obtain two laser beams with a fixed and known angle, the two laser beams may not be on the same plane, and are a first laser beam along the X direction and a second laser beam along the Y direction;

[0014] Set the center point of the ball at the robot's end effector as the TCP point;

[0015] Control the robot to move in a small range with different postures, so that the bottom of the ball contacts the first laser beam in the X direction for a set number of times, and contacts the second laser beam in the Y direction for a set number of times, and record the Cartesian coordinate information of the robot end when contacting and separating respectively;

[0016] According to the obtained Cartesian coordinate information and the structural parameters of the robot, a multivariate linear equation system is established, and the coordinates of the TCP point, i.e. the sphere, in the robot flange coordinate system can be obtained by solving it.

[0017] As a further technical solution, when the bottom end of the sphere contacts the X direction of the first laser beam, the laser beam in the X direction is blocked by the bottom end of the sphere, and the first blocking information is issued;

[0018] When the bottom end of the sphere contacts the Y direction of the second laser beam, the laser beam in the Y direction is blocked by the bottom end of the sphere, and the second blocking information is issued.

[0019] As a further technical solution, the robot is controlled to move in a small range with different postures so that the bottom end of the sphere contacts the X direction of the first laser beam, specifically:

[0020] Control the robot to move in a small range with the same posture, first contact the first laser beam in the X direction, and when the end ball blocks the laser, record the position information of the robot end flange in the robot base coordinate system as P1 X1 , angle information is J1 x ;

[0021] Then the robot end effector moves along a straight line so that the end ball no longer blocks the laser, and the position information of the robot end flange in the robot base coordinate system is recorded again as P1 X2 , the angle information is J1 x .

[0022] As a further technical solution, the robot is controlled to move in a small range with different postures so that the bottom end of the sphere contacts the X direction of the first laser beam. The position information obtained twice is averaged as the position information of the robot end flange in the robot base coordinate system when the end ball blocks the laser in the center of the laser.

[0023] As a further technical solution, it also includes: changing the posture of the robot end to overlap with the laser again in the X direction to achieve the set contact times.

[0024] As a further technical solution, the robot is controlled to move in a small range with different postures so that the bottom end of the ball contacts the Y direction of the second laser beam, specifically:

[0025] Control the robot to move in a small range with the same posture, first contact the second laser beam in the Y direction, and when the end ball blocks the laser, record the position information and angle information of the flange at the end of the robot in the robot base coordinate system;

[0026] Then the robot end effector moves along a straight line so that the end ball no longer blocks the laser, and the position information and angle information of the robot end flange in the robot base coordinate system are recorded again.

[0027] As a further technical solution, it also includes: changing the posture of the robot end to overlap with the laser in the Y direction to achieve the set contact times.

[0028] As a further technical solution, it also includes:

[0029] Obtain the relationship expression between the coordinates of the robot TCP point in the robot base coordinate system and the coordinates in the robot flange coordinate system;

[0030] According to the position information of the robot end flange in the robot base coordinate system when the TCP point coincides with the laser in the X direction and the Y direction respectively, the unknown quantities required for TCP calibration are calculated respectively.

[0031] The TCP points in the base coordinate system satisfy the straight line equation in space, and the angle between the two straight lines is known;

[0032] Calculate the coordinates of the TCP point in the robot end flange coordinate system and the expressions of the two laser beams in space.

[0033] In a second aspect, a robot tool center point calibration system is disclosed, comprising:

[0034] A laser beam emitting unit, a probe, a sphere and a controller; the probe is installed on the end effector of the robot, and there is a sphere at the bottom of the cylinder, and the center point of the sphere is the TCP point;

[0035] The laser beam emitting unit is used to emit two laser beams with known angles, namely a first laser beam along the X direction and a second laser beam along the Y direction;

[0036] The robot is configured to move in a small range with different postures, so that the bottom end of the ball contacts the first laser beam in the X direction for a set number of times and the second laser beam in the Y direction for a set number of times, and the laser beam emitting unit records the Cartesian coordinate information of the end of the robot when contacting and separating, and transmits it to the controller;

[0037] The controller establishes a multivariate linear equation system according to the obtained Cartesian coordinate information and the structural parameters of the robot, and the coordinates of the TCP point, i.e., the sphere, in the robot flange coordinate system can be obtained by solving the equations.

[0038] As a further technical solution, the laser beam emitting unit is a laser needle sensor.

[0039] As a further technical solution, the probe is a slender cylinder with a sphere at the bottom of the cylinder.

[0040] One or more of the above technical solutions have the following beneficial effects:

[0041] The calibration method in the technical solution of the present invention does not need to coincide the robot TCP coordinates with a fixed point multiple times, but coincides with points on two laser beams. The coupling effect of the two lasers improves the calibration accuracy and can detect the accuracy of TCP calibration at the same time.

[0042] The technical solution of the present invention determines whether the TCP point is in contact with the laser by whether the indicator light of the laser alignment sensor is lit.

[0043] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0045] Figure 1 This is a schematic diagram of the structure of a laser needle sensor according to an embodiment of the present invention;

[0046] Figure 2(a)-Figure 2(b) This is a schematic diagram of a probe touching a laser vertically downward according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the movement of the probe in an embodiment of the present invention;

[0048] Figure 4 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0049] Among them: 1 is the sensor power supply interface, 2 is the Y direction laser transmitter, 3 is the X direction laser, 4 is the X direction laser receiver, 5 is the X direction laser indicator, 6 is the Y direction laser indicator, 7 is the Y direction laser receiver, 8 is the Y direction laser, and 9 is the X direction laser transmitter. DETAILED DESCRIPTION

[0050] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0051] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0052] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0053] Embodiment 1

[0054] This embodiment discloses a method for calibrating a center point of a robot tool, comprising:

[0055] The laser needle sensor generates two laser beams with a known angular relationship in space;

[0056] A probe is installed on the robot end effector. The probe is a slender cylinder with a ball at the bottom of the cylinder. The center point of the small ball is the TCP point. Figure 3 As shown;

[0057] Control the robot to move in a small range with different postures, so that the bottom of the ball contacts the laser emitted by the laser needle sensor three times in the X direction and three times in the Y direction. The Cartesian coordinate information of the robot end needs to be recorded when contacting and separating;

[0058] According to the information obtained and the structural parameters of the robot, a multivariate linear equation group is established. The coordinates of the TCP point, i.e. the small sphere at the bottom of the slender cylinder, in the robot flange coordinate system can be obtained by solving it, and the calibration accuracy can be evaluated.

[0059] The method of the technical solution of this embodiment example is based on manual teaching, but its advantage is that the use of laser sensors and improved algorithms improves the calibration accuracy, is less affected by human factors, and the equipment is easy to install.

[0060] In one implementation example, Figure 1 The laser needle alignment sensor in the embodiment mainly comprises an X-direction laser emitter 9, a Y-direction laser emitter 2, a Y-direction laser receiver 7 and an X-direction laser receiver 4; the X-direction laser emitter 9 emits an X-direction laser 3 to the X-direction laser receiver 4, the Y-direction laser emitter 2 emits a Y-direction laser 8 to the Y-direction laser receiver 7, the X-direction laser emitter 9, the Y-direction laser emitter 2, the Y-direction laser receiver 7 and the X-direction laser receiver 4 are all arranged on the main body structure of the laser needle alignment sensor, and the main body structure is also respectively provided with an X-direction laser indicator light 5, a Y-direction laser indicator light 6 and a sensor power supply interface 1.

[0061] Specifically, after the sensor is powered on, the laser transmitters in the X and Y directions will both emit lasers to the corresponding receivers. If there is an obstruction in the middle that prevents the laser from being received by the receiver, the corresponding indicator light will light up.

[0062] Regarding structural parameters: the robot's posture description method (such as using fixed angles or Euler angles, and which rotation arrangement method to use. There are 24 types of fixed angles and Euler angles). Because there are too many specific details, this belongs to the textbook content. Please refer to the book "Introduction to Robotics 4th Edition, published by China Machine Press, written by John J. Craig, translated by Yun Chao and Wang Wei" Chapter 2, Section 8 - Other Posture Descriptions.

[0063] Regarding the evaluation of calibration accuracy: Because in the solution process, not only can the coordinates of the TCP point in the robot flange coordinate system be solved, but also the spatial equations of the two laser beams can be solved. Therefore, when the TCP point blocks the two laser beams, the coordinates of the robot flange coordinate system in the base coordinate system can be calculated. At this time, the robot can be operated to control it to reach the calculated coordinates. Observe whether the probe can completely block the laser beam to verify the calibration accuracy.

[0064] In one or more implementation examples, the specific steps of the robot TCP calibration method include:

[0065] Step (1): First, fix the laser needle sensor on a plane. Do not move the sensor during the subsequent calibration process. The sensor can emit two laser beams with a fixed angle relationship, one in the X direction and the other in the Y direction. There are two indicator lights on the sensor. When the laser in a certain direction is blocked by an object, the corresponding indicator light will light up. When both laser beams are blocked, both indicator lights will light up.

[0066] Step (2): See attached Figure 4 As shown in the figure, the robot is controlled to move in a small range with the same posture, first touching the X direction (or Y direction, for convenience, the following takes the X direction as an example), when the end ball blocks the laser and the display light on the sensor lights up, the position information of the robot end flange in the robot base coordinate system is recorded as P1 X1 , angle information is J1 x , P1 X1 and J1 x The robot end effector then moves along a straight line so that the end ball no longer blocks the laser. When the indicator light on the sensor goes out, the position information of the robot end flange in the robot base coordinate system is recorded again as P1. X2 , P1 X2 It is also a 3×1 matrix. Because the robot’s end posture has not changed, the angle information at this time is still J1 x .

[0067] In one or more implementation examples, for accurate calculation, the position information obtained twice is averaged as the position information of the robot end flange in the robot base coordinate system when the end ball blocks the laser at the center of the laser. The relationship is as follows:

[0068]

[0069] P1 x As the position information of the end flange when the robot first contacts the X-direction laser. x The angle information of the end flange when the robot first contacts the X-direction laser.

[0070] Step (3): Change the robot end position, repeat step (2), overlap the laser in the X direction again, and obtain P2 x 、J2 x 、P3 x and J3 x .

[0071] Step (4): Change the robot end position and repeat steps (2) and (3) on the Y direction laser to obtain P1 Y 、J1 Y 、P2 Y 、J2 Y and P3 Y 、J3 Y .

[0072] Step (5): Now it is known that when the TCP point coincides with the laser in the X direction and the Y direction respectively, the six position information of the robot end flange in the robot base coordinate system.

[0073] The coordinates of the robot TCP point in the robot base coordinate system {B} B P tcp The coordinates in the robot flange coordinate system {E} E P tcp The relationship between them is as follows:

[0074]

[0075] Expanding this formula, it can be written as:

[0076]

[0077] In the above formula, It is a 3×3 rotation matrix from the robot base coordinate system to the robot end flange coordinate system. It can be calculated based on the robot's angle information and structural parameters. Different manufacturers' robots have different posture description methods for the robot's angle information and structural parameters, so the solutions are also different. Taking the comau robot as an example, the Euler angle ZYZ posture description method is adopted.

[0078]

[0079] Among them, γ represents the angle of rotation of the robot base coordinate system around its own Z axis, β represents the angle of rotation of the robot base coordinate system after rotating once around the current Y axis, and α represents the angle of rotation of the robot base coordinate system after rotating twice around the current Z axis. For specific details, please refer to the book "Introduction to Robotics 4th Edition, published by John J. Craig, translated by Yun Chao and Wang Wei" Chapter 2 Section 8 - Other Posture Descriptions.

[0080] According to J1 x ,J2 x ,J3 x ,J1 Y ,J2 Y ,J3 Y Can be found separately

[0081]

[0082] These six different rotation matrices are used to make the robot block the laser in different postures. The data obtained are calculated and known. They can be combined with other equations to calculate the unknown quantities, namely the spatial equations of TCP and the two laser beams. The specific combined equations have been listed, which is (4).

[0083] These six matrices are the three rotation matrices from the robot base coordinate system to the robot end flange coordinate system calculated when the probe touches the three points of the X-direction laser and the three rotation matrices corresponding to the Y-direction laser. Because the robot has different postures when touching these six points with the probe, the rotation matrices are also different.

[0084] E P tcp That is, the unknown quantity required by TCP calibration. B P E This is the obtained P1 x 、P2 x 、P3 x and P1 Y 、P2 Y 、P3 Y The coordinates of . B P tcp It is the coordinate of the robot's TCP point in the base coordinate system. The coordinate is unknown, but can be expressed by an equation. Its physical meaning is the coordinate of the robot's TCP point in the base coordinate system.

[0085] Step (6): TCP point in base coordinate system B P1 x , B P2 x , B P3 x Right now B P tcp The equation of a straight line in space should be satisfied.

[0086]

[0087] B P1 y , B P2 y , B P3 y It should also satisfy the equation of a straight line in space.

[0088]

[0089] And there is a known angle relationship between the two straight lines, let the angle be θ:

[0090] 1+k1n1+k2n2=cosθ(3)

[0091] Step (7): Substitute the coordinates of the TCP point obtained by the above measurement into equations (1) and (2) to obtain

[0092]

[0093] Substitute the coordinates of the TCP points obtained from the above measurements into equations (1) and (2), specifically P1x, P2x, P3x, P1y, P2y, P3y; and All of the above are known or have been calculated.

[0094] Combining (4) with (3), we can solve E P tcp and x1,x2,x3,y1,y2,y3,k1,k2,b1,b2,n1,n2,a1,a2. The coordinates of the TCP point in the robot end flange coordinate system and the expressions of the two laser beams in space can be calculated.

[0095] The TCP above should be solved to be a vector (x, y, z), and the two laser beams should be the unknowns in equations (1) and (2), namely k1, b1, k2, b2, n1, a1, n2, a2.

[0096] The laser needle sensor only needs to be fixed, and there are no special requirements for its position and rotation angle in space.

[0097] Whether the TCP point is in contact with the laser can be determined by whether the indicator light of the laser alignment sensor is on.

[0098] Embodiment 2

[0099] See attached Figure 4 As shown, the purpose of this embodiment is to provide a robot TCP calibration system, including:

[0100] A laser beam emitting unit, a probe, a sphere and a controller; the probe is installed on the end effector of the robot, and there is a sphere at the bottom of the cylinder, and the center point of the sphere is the TCP point;

[0101] The laser beam emitting unit is used to emit two laser beams with fixed angles, namely a first laser beam along the X direction and a second laser beam along the Y direction;

[0102] The robot is configured to move in a small range with different postures, so that the bottom end of the ball contacts the first laser beam in the X direction for a set number of times and the second laser beam in the Y direction for a set number of times, and the laser beam emitting unit records the Cartesian coordinate information of the end of the robot when contacting and separating, and transmits it to the controller;

[0103] The controller establishes a multivariate linear equation system according to the obtained Cartesian coordinate information and the structural parameters of the robot, and the coordinates of the TCP point, i.e., the sphere, in the robot flange coordinate system can be obtained by solving the equations.

[0104] The structure of the laser needle sensor is shown in the attached Figure 1 shown.

[0105] Embodiment 3

[0106] When the laser beam emitting unit emits two mutually perpendicular laser beams, it is only necessary to modify formula (3) to

[0107] 1+k1n1+k2n2=0

[0108] The other processes do not need to be changed.

[0109] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A method for calibrating the center point of a robot tool, characterized in that: include: Obtain two laser beams with a fixed angle, the two laser beams are not on the same plane, and are a first laser beam along the X direction and a second laser beam along the Y direction; Set the center point of the ball at the robot's end effector as the TCP point; Control the robot to move in a small range with different postures, so that the bottom of the ball contacts the first laser beam in the X direction for a set number of times, and contacts the second laser beam in the Y direction for a set number of times, and record the Cartesian coordinate information of the robot end when contacting and separating respectively; Obtain the relationship expression between the coordinates of the robot TCP point in the robot base coordinate system and the coordinates in the robot flange coordinate system; According to the position information of the robot end flange in the robot base coordinate system when the TCP point coincides with the laser in the X direction and the Y direction respectively, the unknown quantities required for TCP calibration are calculated respectively; The TCP points in the base coordinate system satisfy the straight line equation in space, and the angle between the two straight lines is fixed; Calculate the coordinates of the TCP point in the robot end flange coordinate system and the expressions of the two laser beams in space; According to the obtained Cartesian coordinate information and the structural parameters of the robot, a multivariate linear equation system is established, and the coordinates of the TCP point, i.e. the sphere, in the robot flange coordinate system can be obtained by solving it.

2. A method for calibrating the center point of a robot tool as claimed in claim 1, characterized in that: When the bottom end of the sphere contacts the X direction of the first laser beam, the laser beam in the X direction is blocked by the bottom end of the sphere, and the first blocking information is issued; When the bottom end of the sphere contacts the Y direction of the second laser beam, the laser beam in the Y direction is blocked by the bottom end of the sphere, and the second blocking information is issued.

3. A method for calibrating the center point of a robot tool as claimed in claim 1, characterized in that: Control the robot to move in a small range with different postures so that the bottom of the ball contacts the X direction of the first laser beam. Specifically: Control the robot to move in a small range with the same posture, first contact the first laser beam in the X direction, and when the end ball blocks the laser, record the position information of the robot end flange in the robot base coordinate system as follows: P1X1, angle information is J1x; Then the robot end effector moves along a straight line so that the end ball no longer blocks the laser, and the position information of the robot end flange in the robot base coordinate system is recorded again as P1X2, and the angle information is J1x.

4. A method for calibrating the center point of a robot tool as claimed in claim 1, characterized in that: The robot is controlled to move in a small range with different postures so that the bottom of the ball contacts the X direction of the first laser beam. The position information obtained twice is averaged as the position information of the flange at the end of the robot in the robot base coordinate system when the end ball blocks the laser at the center of the laser.

5. A method for calibrating the center point of a robot tool as claimed in claim 1, characterized in that: Also includes: Change the robot end posture to overlap with the laser again in the X direction to achieve the set contact times.

6. A robot tool center point calibration method as claimed in claim 1, characterized in that: Control the robot to move in a small range with different postures so that the bottom of the ball contacts the Y direction of the second laser beam. Specifically: Control the robot to move in a small range with the same posture, first contact the second laser beam in the Y direction, and when the end ball blocks the laser, record the position information and angle information of the flange at the end of the robot in the robot base coordinate system; Then the robot end effector moves along a straight line so that the end ball no longer blocks the laser, and the position information and angle information of the robot end flange in the robot base coordinate system are recorded again.

7. A method for calibrating the center point of a robot tool as claimed in claim 1, characterized in that: Also includes: Change the robot end position to overlap with the laser in the Y direction to achieve the set contact times.

8. A robot tool center point calibration system, comprising: A laser beam emitting unit, a probe, a sphere and a controller; the probe is installed on the end effector of the robot, and there is a sphere at the bottom of the cylinder, and the center point of the sphere is the TCP point; The laser beam emitting unit is used to emit two laser beams with a fixed angle, the two laser beams are not on the same plane, and are respectively a first laser beam along the X direction and a second laser beam along the Y direction; The robot is configured to move in a small range with different postures, so that the bottom end of the ball contacts the first laser beam in the X direction for a set number of times and the second laser beam in the Y direction for a set number of times, and the laser beam emitting unit records the Cartesian coordinate information of the end of the robot when contacting and separating, and transmits it to the controller; Obtain the relationship expression between the coordinates of the robot TCP point in the robot base coordinate system and the coordinates in the robot flange coordinate system; According to the position information of the robot end flange in the robot base coordinate system when the TCP point coincides with the laser in the X direction and the Y direction respectively, the unknown quantities required for TCP calibration are calculated respectively; The TCP points in the base coordinate system satisfy the straight line equation in space, and the angle between the two straight lines is fixed; Calculate the coordinates of the TCP point in the robot end flange coordinate system and the expressions of the two laser beams in space; The controller establishes a multivariate linear equation system according to the obtained Cartesian coordinate information and the structural parameters of the robot, and the coordinates of the TCP point, i.e., the sphere, in the robot flange coordinate system can be obtained by solving the equations.

9. A robot tool center point calibration system as claimed in claim 8, characterized in that: The laser beam emitting unit is a laser needle sensor; The probe is a slender cylinder with a sphere at the bottom of the cylinder.

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