Method for calibrating coordinate system of robot end tool

Abstract

The invention relates to a method for calibrating a coordinate system of an end tool of a robot, which is characterized by comprising the following steps of: 1, mounting a calibration device: assembling an industrial robot, a calibration plate based on a laser correlation type sensor, a calibration tool and an upper computer control system; the industrial robot is connected with the upper computer control system and the calibration plate based on the laser correlation type sensor. The industrial robot is connected with the calibration plate based on the laser correlation type sensor. The calibration tool is installed at the tail end of an industrial robot flange. The calibration plate composed of the laser correlation type sensors is used as a station transfer reference, the manual participation degree is extremely low, operation of calibration actions and fitting of the key size of a tool coordinate system are automatically completed completely by means of an upper computer, and the whole process is rapid and convenient.

Description

Technical Field

[0001] The invention relates to a method for calibrating a robot end tool coordinate system, and in particular to a robot machining system which uses off-line programming to perform machining trajectory planning. Background Art

[0002] The end tools of cutting robots are mainly cylindrical tools such as milling cutters, drills, and taps. When designing the machining program through offline programming, it is necessary to transform the position matrix of the tool tip relative to the center of the robot flange. The traditional tool coordinate system calibration requires the use of laser trackers, tool setting instruments, specially customized calibration rods, etc. The instruments and equipment are expensive, and require specially trained operators and fully authorized spatial point fitting algorithm software (such as Spatial Analyzer) to achieve calibration, which is time-consuming and labor-intensive; for robot processing systems where actuators and tools need to be disassembled frequently, the cost and time cost of calibration will be further increased. Therefore, a targeted calibration device with faster calibration speed and better fit for robot cutting processing systems is developed to reduce the time required for calibration. An integrated calibration device is designed based on the laser beam sensor, which communicates with the host computer system in conjunction with the calibration point installed on the robot. The calibration action and posture capture are realized through the planned instructions, and the tool coordinate system is quickly fitted and calculated. After integration with the offline programming system, the process files required for machining can be quickly generated. The calibration steps of the tool coordinate system and the offline programming planning steps are integrated into one. Through the intelligent, human-machine interface-friendly process management system, the operating status of the robot machining system that requires frequent replacement of actuators and tools can be controlled in real time. Summary of the invention

[0003] The purpose of the present invention is to provide a robot end tool coordinate system calibration system to solve the problem of tool tip position calibration when a cutting robot is running in an off-line programming mode.

[0004] A method for calibrating a robot end tool coordinate system, characterized in that:

[0005] Step 1: Install the calibration device: The industrial robot, the calibration board based on the laser beam sensor, the calibration tool and the host computer control system are composed; the industrial robot is connected to the host computer control system and the calibration board based on the laser beam sensor, and the calibration board based on the laser beam sensor is connected; the calibration tool is installed at the end of the industrial robot flange;

[0006] Step 2: Complete the calibration process through the host computer program control developed based on the Qt interface;

[0007] Step 3: Manual teaching: Align the tip of the calibration tool installed on the end flange of the industrial robot with the intersection of the two laser beams emitted by the calibration plate based on the laser beam sensor, so that the tip of the calibration tool can block the two laser beams at the same time, and record the position and posture of the robot flange in the base coordinate system;

[0008] Step 4: Calibrate the beam coordinate system: Send motion instructions to the robot through the host computer control software to execute the predetermined calibration action. The calibration tool tip on the flange at the end of the robot is obtained according to the preset motion program of the host computer. When the tip is blocked or connected to the beam during the calibration action, the corresponding flange posture of the robot in the base coordinate system is obtained. The relative posture of the laser beam coordinate system in the robot base coordinate system is obtained through algorithm fitting, so as to transfer the workspace to the laser beam coordinate system.

[0009] Step 5. Calibrate the tool coordinate system: Replace the calibration tool on the robot end flange with the tool actually used, align the tip of the tool with the intersection of its laser beam, execute the preset action of the host computer, and obtain the corresponding posture data of the actual tool when the light is connected and broken in the beam coordinate system. The tool coordinate system of the actual tool can be obtained by fitting; calibration is completed.

[0010] The manual teaching of step three is specifically as follows: through the manual quick teaching function of the robot, the adjustment mode is set to "flange surface parallel to the ground", so that the tip is quickly adjusted to a vertical downward state; through the teach pendant, the position of the flange is adjusted in the robot base coordinate system mode so that the tip can simultaneously block the lasers emitted by the two-way sensors; the coordinates of the robot flange center at this time are recorded as [x0 y0 z0] through the upper computer operating software; since the quick adjustment mode is used to set the flange surface parallel to the ground, the posture at this time is [180°0°180°].

[0011] The calibration beam coordinate system in step 4 is specifically constructed based on the high repeatability of the robot to the laser beam of the calibration plate. The operator issues a robot motion command through the host computer software, so that the robot moves with a high-precision point according to the following trajectory:

[0012] (a) The robot is lifted to 50 mm above the beam plane;

[0013] (b) Enable the real-time recording function of the robot's position through the host computer, and at the same time make the cusp translate an appropriate distance R in the plane parallel to the XY plane of the base coordinate system to ensure that the cusp does not cause the sensor to disconnect when it descends. Descend 100 mm along the Z axis of the robot's base coordinate system so that the connection between the cylindrical surface and the conical surface of the cusp is located 50 mm below the plane of the laser beam;

[0014] (c) Start the calibration motion program through the host computer control: the robot flange maintains the posture of [180°0°180°], and the z0-50] is the center of the circle, and the distance R is the radius, and it moves along a full circle trajectory. In the full circle trajectory, the two groups of x and y opposing laser sensors are interrupted and connected four times. Through the interaction between the upper computer software, the robot control system, and the calibration plate sensor, the robot flange positions Dx1, Dy1, Dx2, and Dy2 where the four interruptions occur are recorded, and the robot flange positions where the four connections occur are recorded as Jx1, Jy1, Jx2, and Jy2; the 8 recorded positions are connected to obtain four groups of line segments: Dx1-Dx2, Jx1-Jx2, Dy1-Dy2, and Jy1-Jy2, wherein the intersection of Dx1-Dx2 and Jx1-Jx2 is recorded as X1, and the intersection of Dy1-Dy2 and Jy1-Jy2 is recorded as Y1;

[0015] (d) Take [x0 y0 z0-60], [x0 y0 z0-70], [x0 y0 z0-80], [x0 y0 z0-90] as the center of the circle, and move along the full circle trajectory with distance R as the radius. Repeat the steps of connecting and disconnecting the light and recording the robot posture in step 3 to obtain the following spatial points in the robot base coordinate system: X2, Y2, X3, Y3, X4, Y4, X5, Y5;

[0016] (e) Fitting is performed, and X1, X2, X3, X4, and X5 are fitted to obtain the straight line vector Y1,Y2,Y3,Y4,Y5 are fitted to obtain the straight line vector And do the following processing: vector and Perform a proportional transformation so that its third element becomes 1, that is, the transformation is:

[0017]

[0018] (f) Calculate the following vector:

[0019]

[0020] right Unitize processing:

[0021]

[0022] That is, the vector of the calibration rod axis (flange coordinate system Z axis) in the beam coordinate system;

[0023] (j) Solution The angle α between the two vectors [0 0 1],

[0024]

[0025] The cross product of the two vectors [0 0 1] is:

[0026]

[0027] The attitude transformation matrix between the beam coordinate system and the robot point coordinate system is:

[0028]

[0029] In the robot's flange coordinate system, the tip is located at 150 mm along the Z axis of the flange coordinate system:

[0030] P =

[00150]

[0031] The pose matrix of the flange center point in the beam coordinate system is:

[0032]

[0033] The pose matrix of the flange center point in the robot base coordinate system is:

[0034]

[0035] The transformation relationship between the beam coordinate system and the flange coordinate system is:

[0036]

[0037] At this point, the beam coordinate system calibration is completed.

[0038] The specific content of step five is:

[0039] (a) Remove the calibration point fixed to the flange, replace it with the actual actuator and the actual tool, manually align the tool tip and the intersection of the two laser beams, and make the axis direction of the tip roughly perpendicular to the laser beam plane, and record the robot flange center coordinates flangepoint2 = [x2 y2 z2] and Euler angles [A2 B2 C2] at this time;

[0040] (b) The Euler angles [A2 B2 C2] are converted into the corresponding posture matrix R according to the sequence that can be recognized inside the robot control system, and the following posture matrix is ​​formed:

[0041]

[0042] (c) Calculate the following matrix:

[0043]

[0044] The matrix T1 is the posture of the flange coordinate system in the beam coordinate system, and the first three numbers in the fourth column form the point coordinates resultpoint;

[0045] (d) Keeping the robot flange posture unchanged, the robot carrying the actuator and the equivalent point sinks again for 5 steps, and the fitting vector is obtained by using the method similar to the point cloud data and the calibration beam coordinate system.

[0046] (e) In the beam coordinate system, the point coordinate resultpoint is the flange center coordinate, and the origin [0 0 0] is the tool point coordinate. The relative position of the two is the position of the tool coordinate system origin relative to the flange center. The origin information of the tool coordinate system is calibrated;

[0047] (f) Obtain The angle between and [0 0 1] is obtained by using the Rodrigues transformation to obtain the posture transformation matrix T2 between the beam coordinate system and the robot cusp coordinate system (the process is similar to the calculation of T and will not be repeated here), and the posture matrix of the cusp coordinate system in the beam coordinate system is obtained:

[0048]

[0049] The vector composed of the third column of T2 is the direction of the tool axis in the beam coordinate system;

[0050] (j) The posture transformation matrix between the tool coordinate system and the flange coordinate system is:

[0051]

[0052] The pose transformation matrix is:

[0053]

[0054] At this point, the tool coordinate system calibration is completed.

[0055] The calibration tool is composed of a flange adapter and a calibration point, and the material is 45 steel; the size and distribution of the mounting holes of the flange adapter are determined according to the relevant dimensions of the robot flange to be calibrated.

[0056] The step 1 described above can be applied to most industrial robots, collaborative robots and robotic arms that have high-speed IO ports and realize signal transmission and communication functions.

[0057] The laser beam sensor on the calibration board interacts with the high-speed IO port of the robot in real time, thereby realizing communication between the robot and the sensor signal, and realizing the linkage between the robot's posture and the shading point position; the laser beam diameter of the laser beam sensor is 0.5mm, and the installation position accuracy is guaranteed by mechanical processing. The robot IO port response time is 4ms. After experimental verification, when the robot's program control speed does not exceed 20% of the maximum operating speed, it can ensure that the shading and light receiving signals at each point can be accurately and instantly received and analyzed, and ensure the accurate matching of the robot's posture and signal.

[0058] Beneficial effects of the present invention:

[0059] The present invention communicates with the robot through the host computer and sends motion instructions, controls the calibration tip of the end of the robot flange to move according to a predetermined trajectory and block the laser beam sensor signal, automatically records the robot posture when blocking light, and then analyzes the transfer relationship between the calibration plate and the robot base coordinate system; after the robot replaces the actual actuator, the host computer sends a motion instruction again to block the laser signal and record the corresponding posture of the robot. After analysis and calculation, the posture of the actuator tool tip relative to the flange can be determined, thereby calibrating the precise size of the tool coordinate system. By integrating the host computer software into the offline programming software, it can quickly assist in the processing trajectory posture planning, with strong practicality and good popularization.

[0060] The present invention uses a calibration plate composed of a laser beam sensor as a transfer station reference, with extremely low human involvement. The execution of the calibration action and the fitting of the key dimensions of the tool coordinate system are completely automatically completed by the host computer. The whole process is fast and convenient, and no high-precision calibration equipment such as a tool setter and a laser tracker is required to complete the identification of the key dimensions from the robot flange end to the tool tip. The tool coordinate system dimension calibration result is output in the form of a process file. By opening a port in the offline programming software of the robot processing system, the process file required for the robot processing operation can be directly generated according to the processing points of the product tooling, which is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a hardware structure diagram corresponding to the robot end tool coordinate system calibration method of the present invention.

[0062] The markings in the figure are as follows: 1-industrial robot, 2-calibration point, 3-calibration board, 4-host computer system. The host computer system and the robot are connected by a network cable, and data and instructions are transmitted through the TCP / IP protocol. The host computer software is developed based on the SDK development kit of the robot itself, and can send motion instructions to the robot. The robot carries the point and moves between the laser beams emitted by the calibration board sensor. The sensor signal line is connected to the robot's IO port. The robot's position and posture are recorded at the moment the sensor is disconnected from the light, and transmitted back to the host computer through the socket for fitting calculation to obtain the tool coordinate system information installed on the flange end.

[0063] Figure 2 Figure 2 is a diagram of the cusp structure used to calibrate the beam coordinate system.

[0064] (a) Calibrated cusp stereogram;

[0065] (b) Front view of the calibration cusp structure;

[0066] (c) is the right side view of (b);

[0067] When calibrating the sharp point, mechanical processing is used to ensure the coaxiality accuracy of the sharp point and the robot flange axis, and the distance accuracy from the flange mounting surface to the sharp point. The hole distribution size of the sharp point mounting surface is designed based on the threaded mounting hole of the robot flange.

[0068] Figure 3 This is a structural diagram of the calibration board based on two sets of laser beam sensors.

[0069] (a) Stereoscopic image of the calibration plate;

[0070] (b) Schematic diagram of the calibration board structure;

[0071] (c) is a top view of the calibration board; this integrated calibration board with two sets of sensors fixed is produced by CAPTRON. The laser transmitter, receiver and signal line are all encapsulated in the groove inside the board, and the structure is simple. The laser beam spot diameter is 0.5mm, and the laser beam is 650nm red. The two laser beams on the calibration board are recorded as x and y.

[0072] The calibration board is not designed to make the two light beams absolutely perpendicular to each other in structure, nor do they intersect at a point in space, because the intersection of the light beams will cause the signals of the two pairs of sensors to interfere with each other (a similar phenomenon will occur when the laser beams of multiple sets of laser ranging sensors intersect). However, the direction of the light beam itself is not used as the coordinate axis during the calibration process. The key point lies in the vector after the cross product of the two laser beam directions. From the following steps, it can be seen that the structure does not affect the calibration results.

[0073] Figure 4, is the operating interface of the host computer software. The host computer software is developed based on the SDK development kit of the robot itself. Its main functions include obtaining robot posture information, identifying and reading the addresses of the host computer and the robot, sending robot motion instructions, recording the robot posture when the tip is connected and disconnected during the fifth-order descent and rotation process, fitting calculation of the end tool axis direction, and calculation of relevant parameters of the tool coordinate system.

[0074] Figure 5 , the present invention calibrates the sharp point to align the intersection of the laser beams;

[0075] Figure 6 , the calibration point of the present invention is raised to 50 mm above the beam plane;

[0076] Figure 7 , the calibration point of the present invention is raised to 50 mm below the beam plane;

[0077] Figure 8 , the present invention calibrates the interaction between the sharp point and the laser beam. DETAILED DESCRIPTION

[0078] The present invention will be further described below in conjunction with the accompanying drawings.

[0079] like Figure 1 As shown, the robot tool coordinate system calibration system of the present invention mainly includes 4 parts: industrial robot, calibration plate, host computer control system, and calibration point. The domestically produced Luoshi XB10 six-axis industrial robot is used as an application during the development of the present invention. Other types of robots can be modified and applied according to their flange assembly dimensions and SDK development kit structures.

[0080] Its characteristics are as follows: a calibration plate composed of laser beam sensors is used as the transfer station reference, the degree of manual participation is extremely low, the operation of the calibration action and the fitting of the key dimensions of the tool coordinate system are completely automatically completed by the host computer, the whole process is fast and convenient, and no high-precision calibration equipment such as tool setting instruments and laser trackers is required to complete the identification of the key dimensions from the robot flange end to the tool tip; the tool coordinate system dimension calibration results are output in the form of process files, and by opening a port in the offline programming software of the robot processing system, the process files required for the robot processing operation can be directly generated according to the processing points of the product tooling, which is convenient and fast.

[0081] The calibration plate 2 is fixed within the working space of the industrial robot by means of bolt pressure plates, etc. The power lines of the two sets of laser beam sensors on the calibration plate are connected to the 24V DC power supply, and the signal lines are connected to the high-speed IO port of the robot 1. The robot 1 is connected to the host computer 4 via a network cable. The calibration point with a fixed size is fixed to the flange end of the robot 1 by means of screws. The point is located 150mm from the flange end face on the sixth axis of the robot. There is a pin hole for matching positioning at the connection between the point and the flange to ensure the assembly size accuracy of the point.

[0082] The calibration process is divided into the following three parts:

[0083] (1) Manual quick teaching:

[0084] Fix the calibration point to the end of the robot flange with bolts, and use the manual quick teaching function of the robot to adjust the mode to "flange surface parallel to the ground" to quickly adjust the point to a vertical downward state. Use the teach pendant to adjust the position of the flange in the robot base coordinate system mode so that the point can block the lasers emitted by the two-way sensor at the same time, such as Figure 5 As shown in the figure, the coordinates of the robot flange center are recorded by the host computer operating software as [x0 y0 z0]. Since the flange surface is parallel to the ground in the quick adjustment mode, the posture is [180°0°180°].

[0085] (2) Calibration of beam coordinate system

[0086] The laser beam coordinate system of the calibration plate is constructed based on the robot's high repeatability positioning accuracy. The operator issues robot movement instructions through the host computer software, so that the robot moves with a high-precision point according to the following trajectory:

[0087] 1. Lift the robot to 50mm above the beam plane. Figure 6 ;

[0088] 2. Enable the real-time recording function of the robot's position through the host computer, and at the same time make the cusp translate an appropriate distance R in the plane parallel to the XY plane of the base coordinate system to ensure that the cusp does not cause the sensor to disconnect when it descends. Descend 100mm along the Z axis of the robot's base coordinate system so that the connection between the cusp cylindrical surface and the cone surface is 50mm below the laser beam plane. Figure 7 As shown;

[0089] 3. Start the calibrated motion program through the host computer control: the robot flange maintains the posture of [180°0°180°], and the z0-50] is the center of the circle, and the distance R is the radius, and the robot moves along a full circle trajectory. In the full circle trajectory, the two groups of x and y opposing laser sensors are interrupted and connected four times. Through the interaction between the upper computer software, the robot control system, and the calibration plate sensor, the robot flange positions Dx1, Dy1, Dx2, and Dy2 where the four interruptions occur are recorded, and the robot flange positions where the four connections occur are recorded as Jx1, Jy1, Jx2, and Jy2; the 8 recorded positions are connected to obtain four groups of line segments: Dx1-Dx2, Jx1-Jx2, Dy1-Dy2, and Jy1-Jy2, wherein the intersection of Dx1-Dx2 and Jx1-Jx2 is recorded as X1, and the intersection of Dy1-Dy2 and Jy1-Jy2 is recorded as Y1, as shown in Figure 8 Shown:

[0090] 4. Take [x0 y0 z0-60], [x0 y0 z0-70], [x0 y0 z0-80], and [x0 y0 z0-90] as the center of the circle and the distance R as the radius, and move along the full circle trajectory. Repeat the steps of connecting and disconnecting the light and recording the robot posture in step 3 to obtain the following spatial points in the robot base coordinate system: X2, Y2, X3, Y3, X4, Y4, X5, Y5.

[0091] 5. Perform fitting, X1, X2, X3, X4, X5 fitting to obtain the straight line vector Y1,Y2,Y3,Y4,Y5 are fitted to obtain the straight line vector And do the following processing: vector and Perform a proportional transformation so that its third element becomes 1, that is, the transformation is:

[0092]

[0093] 6. Calculate the following vector:

[0094]

[0095] right Unitize processing:

[0096]

[0097] That is, the vector of the calibration rod axis (flange coordinate system Z axis) in the beam coordinate system.

[0098] 7. Solve The angle α between the two vectors [0 0 1],

[0099]

[0100] The cross product of the two vectors [0 0 1] is:

[0101]

[0102] The attitude transformation matrix between the beam coordinate system and the robot point coordinate system is:

[0103]

[0104] In the robot's flange coordinate system, the tip is located at 150 mm along the Z axis of the flange coordinate system:

[0105] P =

[00150]

[0106] The pose matrix of the flange center point in the beam coordinate system is:

[0107]

[0108] The pose matrix of the flange center point in the robot base coordinate system is:

[0109]

[0110] The transformation relationship between the beam coordinate system and the flange coordinate system is:

[0111]

[0112] At this point, the beam coordinate system calibration is completed.

[0113] (2) Calibrate the actual tool coordinate system

[0114] 1. Remove the calibration point fixed to the flange, replace it with the actual actuator and the actual tool, manually align the tool tip and the intersection of the two laser beams, and make the axis direction of the tip roughly perpendicular to the laser beam plane, and record the robot flange center coordinates flangepoint2 = [x2 y2 z2] and Euler angles [A2 B2 C2] at this time;

[0115] 2. Convert the Euler angles [A2 B2 C2] into the corresponding posture matrix R according to the sequence that can be recognized inside the robot control system, and form the following posture matrix:

[0116]

[0117] 3. Calculate the following matrix:

[0118]

[0119] The matrix T1 is the posture of the flange coordinate system in the beam coordinate system, and the first three numbers in the fourth column form the point coordinates resultpoint;

[0120] 4. Keep the robot flange posture unchanged, and make the robot carrying the actuator and the equivalent point sink again for 5 steps. Use the obtained point cloud data and the calibration beam coordinate system to obtain the fitting vector

[0121] 5. In the beam coordinate system, the point coordinate resultpoint is the flange center coordinate, and the origin [0 0 0] is the tool point coordinate. The relative position of the two is the position of the tool coordinate system origin relative to the flange center. The origin information of the tool coordinate system is calibrated;

[0122] 6. Seek The angle between and [0 0 1] is obtained by using the Rodrigues transformation to obtain the posture transformation matrix T2 between the beam coordinate system and the robot cusp coordinate system (the process is similar to the calculation of T and will not be repeated here), and the posture matrix of the cusp coordinate system in the beam coordinate system is obtained:

[0123]

[0124] The vector composed of the third column of T2 is the direction of the tool axis in the beam coordinate system;

[0125] 7. The posture transformation matrix between the tool coordinate system and the flange coordinate system is:

[0126]

[0127] The pose transformation matrix is:

[0128]

[0129] At this point, the tool coordinate system calibration is completed.

[0130] Qt is a cross-platform C++ graphical user interface application framework that provides application developers with all the functions they need to build state-of-the-art graphical interfaces.

Claims

1. A method for calibrating a robot end tool coordinate system, characterized in that: Step 1: Install the calibration device: The industrial robot, the calibration board based on the laser beam sensor, the calibration tool and the host computer control system are composed; the industrial robot is connected to the host computer control system and the calibration board based on the laser beam sensor, and the calibration board based on the laser beam sensor is connected; the calibration tool is installed at the end of the industrial robot flange; Step 2: Complete the calibration process through the host computer program control developed based on the Qt interface; Step 3: Manual teaching: Align the tip of the calibration tool installed on the end flange of the industrial robot with the intersection of the two laser beams emitted by the calibration plate based on the laser beam sensor, so that the tip of the calibration tool can block the two laser beams at the same time, and record the position and posture of the robot flange in the base coordinate system; Step 4: Calibrate the beam coordinate system: Send motion instructions to the robot through the host computer control software to execute the predetermined calibration action. The calibration tool tip on the flange at the end of the robot is obtained according to the preset motion program of the host computer. When the tip is blocked or connected to the beam during the calibration action, the corresponding flange posture of the robot in the base coordinate system is obtained. The relative posture of the laser beam coordinate system in the robot base coordinate system is obtained through algorithm fitting, so as to transfer the workspace to the laser beam coordinate system. Step 5. Calibrate the tool coordinate system: Replace the calibration tool on the robot end flange with the tool actually used, align the tip of the tool with the intersection of its laser beam, execute the preset action of the host computer, and obtain the corresponding posture data of the actual tool when the light is connected and broken in the beam coordinate system. The tool coordinate system of the actual tool can be obtained by fitting; calibration is completed.

2. A method for calibrating a robot end-tool coordinate system according to claim 1, characterized in that: The manual teaching of step three is specifically as follows: through the manual quick teaching function of the robot, the adjustment mode is "flange surface parallel to the ground", so that the tip is quickly adjusted to a vertical downward state; through the teach pendant, the position of the flange is adjusted in the robot base coordinate system mode so that the tip can simultaneously block the lasers emitted by the two-way sensor; the coordinates of the robot flange center at this time are recorded as [x0 y0 z0] through the upper computer operating software; because the quick adjustment mode is used to make the flange surface parallel to the ground, the posture at this time is [180°0°180°].

3. A method for calibrating a robot end-tool coordinate system according to claim 1, characterized in that: The calibration beam coordinate system in step 4 is specifically constructed based on the high repeatability of the robot to the laser beam of the calibration plate. The operator issues a robot motion command through the host computer software, so that the robot moves with a high-precision point according to the following trajectory: (a) The robot is lifted to 50 mm above the beam plane; (b) Enable the real-time recording function of the robot's position through the host computer, and at the same time make the cusp translate an appropriate distance R in the plane parallel to the XY plane of the base coordinate system to ensure that the cusp does not cause the sensor to disconnect when it descends. Descend 100 mm along the Z axis of the robot's base coordinate system so that the connection between the cylindrical surface and the conical surface of the cusp is located 50 mm below the plane of the laser beam; (c) Start the calibrated motion program through the host computer control: the robot flange maintains the posture of [180°0°180°], and the robot moves in the direction of [x0y0 z0-50] is the center of the circle, and the distance R is the radius, and it moves along a full circle trajectory. In the full circle trajectory, the two groups of x and y opposing laser sensors are interrupted and connected four times. Through the interaction between the upper computer software, the robot control system, and the calibration plate sensor, the robot flange positions Dx1, Dy1, Dx2, and Dy2 where the four interruptions occur are recorded, and the robot flange positions where the four connections occur are recorded as Jx1, Jy1, Jx2, and Jy2; the 8 recorded positions are connected to obtain four groups of line segments: Dx1-Dx2, Jx1-Jx2, Dy1-Dy2, and Jy1-Jy2, wherein the intersection of Dx1-Dx2 and Jx1-Jx2 is recorded as X1, and the intersection of Dy1-Dy2 and Jy1-Jy2 is recorded as Y1; (d) Take [x0 y0 z0-60], [x0 y0 z0-70], [x0 y0 z0-80], [x0 y0 z0-90] as the center of the circle, and move along the full circle trajectory with distance R as the radius. Repeat the steps of connecting and disconnecting the light and recording the robot posture in step 3 to obtain the following spatial points in the robot base coordinate system: X2, Y2, X3, Y3, X4, Y4, X5, Y5; (e) Fitting is performed, and X1, X2, X3, X4, and X5 are fitted to obtain the straight line vector Y1,Y2,Y3,Y4,Y5 are fitted to obtain the straight line vector And do the following processing: vector and Perform a proportional transformation so that its third element becomes 1, that is, the transformation is: (f) Calculate the following vector: right Unitize processing: That is, the vector of the calibration rod axis (flange coordinate system Z axis) in the beam coordinate system; (j) Solution The angle α between the two vectors [0 0 1], The cross product of the two vectors [0 01] is: The attitude transformation matrix between the beam coordinate system and the robot point coordinate system is: In the robot's flange coordinate system, the tip is located at 150 mm along the Z axis of the flange coordinate system: P＝[00150] The pose matrix of the flange center point in the beam coordinate system is: The pose matrix of the flange center point in the robot base coordinate system is: The transformation relationship between the beam coordinate system and the flange coordinate system is: At this point, the beam coordinate system calibration is completed.

4. A method for calibrating a robot end-tool coordinate system according to claim 1, characterized in that: The specific contents of step five are as follows: (a) Remove the calibration point fixed to the flange, replace it with the actual actuator and the actual tool, manually align the tool tip and the intersection of the two laser beams, and make the axis direction of the tip roughly perpendicular to the laser beam plane, and record the robot flange center coordinates flangepoint2 = [x2 y2 z2] and Euler angles [A2 B2 C2] at this time; (b) The Euler angles [A2 B2 C2] are converted into the corresponding posture matrix R according to the sequence that can be recognized inside the robot control system, and the following posture matrix is ​​formed: (c) Calculate the following matrix: The matrix T1 is the posture of the flange coordinate system in the beam coordinate system, and the first three numbers in the fourth column form the point coordinates resultpoint; (d) Keeping the robot flange posture unchanged, the robot carrying the actuator and the equivalent point sinks again for 5 steps, and the fitting vector is obtained by using the method similar to the point cloud data and the calibration beam coordinate system. (e) In the beam coordinate system, the point coordinate resultpoint is the flange center coordinate, and the origin [0 0 0] is the tool point coordinate. The relative position of the two is the position of the tool coordinate system origin relative to the flange center. The origin information of the tool coordinate system is calibrated; (f) Obtain The angle between and [0 01] is obtained by using the Rodrigues transformation to obtain the posture transformation matrix T2 between the beam coordinate system and the robot cusp coordinate system (the process is similar to the calculation of T and will not be repeated here), and the posture matrix of the cusp coordinate system in the beam coordinate system is obtained: The vector composed of the third column of T2 is the direction of the tool axis in the beam coordinate system; (j) The posture transformation matrix between the tool coordinate system and the flange coordinate system is: The pose transformation matrix is: At this point, the tool coordinate system calibration is completed.

5. The method for calibrating the robot end tool coordinate system according to claim 1, characterized in that: The calibration tool is composed of a flange adapter and a calibration point, and the material is 45 steel; the size and distribution of the mounting holes of the flange adapter are determined according to the relevant dimensions of the robot flange to be calibrated.

6. A method for calibrating a robot end-tool coordinate system according to claim 1, characterized in that: The step 1 described above can be applied to most industrial robots, collaborative robots and robotic arms that have high-speed IO ports and realize signal transmission and communication functions.

7. A method for calibrating a robot end-tool coordinate system according to claim 1, characterized in that: The laser beam sensor on the calibration board interacts with the high-speed IO port of the robot in real time, thereby realizing communication between the robot and the sensor signal, and realizing the linkage between the robot's posture and the shading point position; the laser beam diameter of the laser beam sensor is 0.5mm, and the installation position accuracy is guaranteed by mechanical processing. The robot IO port response time is 4ms. After experimental verification, when the robot's program control speed does not exceed 20% of the maximum operating speed, it can ensure that the shading and light receiving signals at each point can be accurately and instantly received and analyzed, and ensure the accurate matching of the robot's posture and signal.

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