Measuring device and method for robot end tool

Abstract

The invention discloses a measuring device and method for a robot end tool in the technical field of robot measurement, and the device comprises a lateral measuring block and a normal measuring block which are provided with measuring heads in the horizontal direction and the vertical direction, and one end of each measuring head is connected with a displacement sensor. The other end of the measuring head is in contact with a measuring tool connected with a robot tail end tool, and the displacement sensors located on the lateral measuring block and the normal measuring block can detect displacement data of the measuring tool when the robot tail end tool rotates laterally and normally through the measuring head respectively. The method is simple and convenient to operate, and can effectively improve the measurement precision of the robot end tool and the alignment efficiency of the process robot.

Description

Technical Field

[0001] The present invention relates to a measuring device and method for a robot end tool, belonging to the technical field of robot measurement. Background Art

[0002] The casing of an aeroengine is one of the important parts of an aeroengine. It is the base of the whole engine, and various components of the aeroengine are installed on the casing. The outer shape structure of the casing is complex. For different engines and different parts, the shape of the casing is different. However, its basic structure is a component composed of a cylindrical or conical shell and a support plate. The outer surface of the shell has annular reinforcing ribs, annular bands, and bosses; the inner surface of the shell has annular grooves, cylindrical annular bands, and spiral grooves; the cylindrical annular band is distributed with circumferential inclined holes; the shell wall is provided with radial holes, special-shaped holes, and special-shaped grooves.

[0003] The above-mentioned casing features are mainly completed by a machining center. The edges of bosses, reinforcing ribs, and various shaped holes need to be processed to form fillets with a radius between R0.1 - R0.3 to blunt the edges, reduce stress concentration, and remove burrs. In order to improve the efficiency of casing surface edge treatment, a robot high-efficiency process for treating the casing edge is adopted. The main method of the robot edge treatment process is to install a grinding spindle on the end flange of the robot. The spindle holds a tool and a grinding head through a tool holder to process the casing surface, and the machining accuracy is ±0.2 mm. The grinding tool needs to be programmed according to the curves and surfaces of the edge. Due to the large number and types of edges, the teaching method cannot be used for programming. In order to deal with complex curves and surfaces, this kind of process usually uses the off-line programming method for robot program design.

[0004] Off-line programming requires setting a tool coordinate system. Currently, robot manufacturers provide a measuring method for the tool coordinate system in the system. Taking the KUKA robot as an example, the KUKA robot system KR C4 system provides a four-point method measurement technology. That is, the position to be measured is pointed at a fixed reference point in four different postures, and the system calculates the tool position according to the position of the robot. This method is simple to operate, but the alignment accuracy completely depends on visual inspection and feeling, and there are inevitably large errors in the tool points calibrated each time. Due to the error of the tool point calibrated by the four-point method, when setting the tool coordinate system for programming, there are large deviations in the machining trajectory, resulting in the machining accuracy not being guaranteed. Moreover, the robot end often uses multiple postures. When the tool coordinate system error is large, different postures will amplify the alignment deviation, resulting in the machining accuracy not meeting the machining process requirements. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a measuring device and method for a robot end tool. The solution is simple to operate and can effectively improve the measuring accuracy of the robot end tool and the alignment efficiency of the process robot.

[0006] To achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In a first aspect, the present invention provides a measuring device for a robot end effector, including a lateral measuring block and a normal measuring block with probes installed in both the horizontal and vertical directions. One end of each probe is connected to a displacement sensor, and the other end of the probe is in contact with a measuring tool connected to the robot end effector. The displacement sensors located in the lateral measuring block and the normal measuring block can respectively detect the displacement data of the measuring tool when the robot end effector rotates laterally and normally through the probes.

[0008] Further, a reference hole is machined in the middle of the lateral measuring block. A lateral hole is machined in each of the horizontal and vertical directions of the reference hole, and a probe is installed in each lateral hole. The other end of the probe is threadedly connected to a displacement sensor, and the LVDT displacement sensor is fixed to the lateral measuring block through a sensor mounting seat.

[0009] Further, the normal measuring block has an L-shaped structure and probes are installed on both inner walls perpendicular to each other. The vertical side wall of the normal measuring block is installed with displacement sensors in the vertical and horizontal directions through a sensor mounting seat. The horizontal probe is connected to the horizontal displacement sensor. A cavity is formed in the horizontal side wall of the normal measuring block, and a guide rod is installed in the cavity through a pin. The lower end of the vertical probe contacts one end of the guide rod, and the other end of the guide rod is connected to the vertical displacement sensor. A spring is installed between the guide rod and the inner wall of the cavity.

[0010] Further, the displacement sensor is an LVDT displacement sensor, and the sensor structure includes a magnetic core, an armature, a primary coil, a secondary coil, a return spring, and a sensor housing.

[0011] In a second aspect, the present invention provides a measuring method for a robot end effector, using the above-mentioned measuring device for a robot end effector, including:

[0012] Install a sensor calibration block in the measuring device to obtain the sensor calibration value;

[0013] After the measuring tool connected to the robot is inserted into the lateral measuring block and contacts both the vertical and horizontal probes, collect the displacement data during the rotation of the robot in the Z direction of the tool coordinate system origin;

[0014] After the measuring tool connected to the robot is inserted into the normal measuring block and contacts both the vertical and horizontal probes, collect the displacement data during the rotation of the robot in the X and Y directions of the tool coordinate system origin;

[0015] After obtaining the sensor deviation value based on the displacement data, compare it with the calibration value to calculate the actual deviation value;

[0016] Analyze the measurement error based on multiple groups of actual deviation values. When the measurement error is less than the system error, complete the calibration of the X, Y, and Z directions of the end tool. Otherwise, continue to collect displacement data.

[0017] Further, the formula for the actual deviation value is:

[0018] X = cosα * X1 + sinα * Y1

[0019] Y = cosα * Y1 - sinα * X1

[0020] Where: X and Y are the actual deviation values, X1 and Y1 are the offset displacement values, and α is the rotation angle of the measuring tool.

[0021] Further, the formula for the offset displacement value is:

[0022] X1 = X0 - X′1

[0023] Y1 = Y0 - Y′1

[0024] Where: X0 and Y0 are the calibration values, and X'1 and Y'1 are the displacement values of the measuring tool.

[0025] Further, the formula for the measurement error value is:

[0026]

[0027] Where: δ lim is the measurement error, is the standard error, σ is the population standard deviation, n is the number of measurements, μ is the mean of the data, and xi is multiple groups of actual deviation values.

[0028] Further, the lateral measurement block collects data every 5° during the 360° rotation of the measuring tool, and a total of 72 groups of data are collected.

[0029] Further, the normal measurement block collects data every 5° during the 90° rotation of the measuring tool, and a total of 18 groups of data are collected.

[0030] Compared with the prior art, the beneficial effects achieved by the present invention:

[0031] 1. This solution improves the calibration accuracy of the grinding tool within ±0.05 mm, ensuring the machining accuracy. Secondly, this solution is easy to operate, only requiring the completion of the initial calibration of the grinding tool and the calibration of the LVDT displacement sensor. The robot executes the measurement program and, in cooperation with the measurement system, can quickly achieve high-precision calibration of the grinding tool. In actual applications, the calibration work can be completed during the device's power-on self-check process. Finally, the calibration device has a low cost and has economic benefits.

[0032] 2. This solution forms a complete spatial coordinate system calibration system through phased and multi-axial calibration steps, effectively decomposing complex three-dimensional error problems. At the same time, based on the real-time deviation acquisition during the tool rotation process and combined with the geometric relationship calculation of the rotation center deviation, dynamic correction and compensation of motion errors are achieved.

[0033] 3. This solution uses multi-probe collaborative contact positioning and confidence algorithm to automatically screen valid data and generate optimized calibration values, improving measurement reliability. By repeatedly executing the calibration steps and iteratively calculating the deviation mean, an error convergence control model is established to ensure the stability of the calibration results.

[0034] 4. This solution integrates CAD data pre-calibration and robot four-point method measurement to form a hierarchical operation logic of initial calibration - fine calibration, taking into account both efficiency and accuracy requirements. Through the combined use of lateral and normal measurement devices, precise contact measurement of the tool coordinate system in different spatial dimensions is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention. In the drawings:

[0036] Figure 1 is a working schematic diagram of a measuring device for a robot end tool provided by an embodiment of the invention;

[0037] Figure 2 is a schematic diagram of a lateral calibration block of a measuring device for a robot end tool provided by an embodiment of the invention;

[0038] Figure 3 is a schematic diagram of a normal calibration block of a measuring device for a robot end tool provided by an embodiment of the invention.

[0039] In the figure: 1, lateral calibration block; 2, normal calibration block; 3, probe; 4, sensor calibration block; 5, sensor mounting base; 6, LVDT displacement sensor; 7, measuring tool 1; 8, measuring tool 2; 9, spring; 10, guide rod. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0041] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed explanations of the present invention. Unless otherwise specified, all technical terms adopted by the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0042] Embodiment:

[0043] This solution provides a measuring device and method for the end machining tool of a robot. The tip of the grinding tool is the origin of the tool coordinate system for machining, which is the tool coordinate system to be measured in this method. This method obtains the origin reference value of the tool coordinate system through the CAD data of the end machining device; the 4-point method provided by the robot system can be used, that is, the origin of the tool coordinate system to be measured is pointed to a fixed reference point in four different postures, and the system calculates the tool position according to the position of the robot. The above two steps can both obtain the tool coordinate system values, but the accuracy cannot meet the processing technology requirements, and subsequent methods are needed to calibrate the robot accuracy. Generally speaking, the calibration method in this solution includes the following steps:

[0044] Step 1: Connect one end of the measuring tool to the spindle tool holder and connect it to the spindle; the other end of the measuring tool is the machining tool coordinate system (the calibration value has been obtained through the above method).

[0045] Step 2: Install the sensor calibration block on the measuring device to obtain the sensor calibration value.

[0046] Step 3: Move the robot to insert the measuring tool into the lateral measuring device, ensuring that the measuring tool contacts the vertical and horizontal probes.

[0047] Step 4: The robot rotates in the Z direction of the tool coordinate system origin, and collects the sensor readings at specific angles during the rotation. Due to calibration errors, there is a deviation between the actual rotation center point and the tool coordinate system origin. The deviation value of the sensor is obtained according to the rotation angle.

[0048] Step 5: Compare the deviation value with the calibration value to obtain the actual deviation value. By calculating the confidence level of the deviation value, calculate the average value of the deviation value and write it into the robot system. Repeat Step 4 until the average value of the deviation value is within the control range to complete the calibration of the X and Y directions of the end tool.

[0049] Step 6: Move the robot to place the measuring tool on the normal measuring device, ensuring that the measuring tool contacts the vertical and horizontal probes.

[0050] Step 7: The robot rotates in the X and Y directions with the origin of the tool coordinate system. During the rotation, sensor readings are collected at specific angles. Due to calibration errors, there is a deviation between the actual rotation center point and the origin of the tool coordinate system. The deviation value of the sensor is obtained according to the rotation angle.

[0051] Step 8: Compare the deviation value with the calibration value to obtain the actual deviation value. By calculating the confidence level of the deviation value, the average value of the deviation value is calculated and written into the robot system. Repeat Step 7 until the average value of the deviation value is within the control range, and the calibration of the Z direction of the end tool is completed.

[0052] The present invention has the following technical effects: First, the calibration accuracy of the grinding tool is improved within ±0.05 mm, ensuring the machining accuracy. Second, the operation of this solution is simple. Only the initial calibration of the grinding tool and the calibration of the LVDT displacement sensor need to be completed. The robot executes the measurement program and cooperates with the measurement system to quickly achieve the high-precision calibration of the grinding tool. The calibration work can be completed during the self-check process when the equipment is powered on in actual applications. Finally, the calibration device has a low cost and has economic benefits.

[0053] Please refer to Figures 1-3 , this device includes a lateral measurement block 1 and a normal measurement block 2. The lateral measurement block 1 is used to calibrate the X and Y values. The lateral measurement block 1 serves as a measurement base, with a reference hole machined in the middle. Two lateral holes are machined in the horizontal and vertical directions of the reference hole for installing two probe heads 3. The other end of the probe head 3 is threadedly connected to the LVDT displacement sensor 6. The structure of the LVDT displacement sensor 6 consists of a magnetic core, an armature, a primary coil, a secondary coil, a return spring, and a sensor housing. When the primary coil is connected to an excited AC signal source, if the magnetic core moves, it will cause the secondary coil to generate current due to mutual inductance, making the sensor output signal change linearly with the displacement. The two secondary coils are connected in series. The voltages VA and VB of the two secondary coils change in opposite directions. Therefore, the sensor voltage is VA - VB. When the iron core moves in one direction, the voltage of the secondary coil in that direction will increase, and the voltage of the secondary coil on the other side will decrease. Therefore, the signal output of the sensor corresponds one-to-one with the magnitude of the movement. When the voltage and frequency of the excitation signal are known, the position and movement direction of the iron core can be obtained according to the change in the output signal of the secondary coil. The return spring controls the position of the magnetic core when it moves inside the coil.

[0054] The LVDT displacement sensor 6 is inserted into the mounting hole of the sensor mounting seat 5 and pre-fixed by clamping through the threaded hole; the sensor calibration block 4 is inserted into the reference hole, ensuring the concentricity between the sensor calibration block 4 and the reference hole. The probe 3 contacts the sensor calibration block 4, the sensor magnetic core moves, and the spring fixes the magnetic core; the position of the sensor is adjusted so that the LVDT displacement sensor 6 is at the midpoint of the measuring range to prevent the sensor measurement from being in the non-linear region; the sensor is fixedly clamped in the mounting hole of the sensor mounting seat 5 by screws; the measuring system records the voltage value of the sensor at this time as the calibrated displacement data, denoted as X0 and Y0 respectively.

[0055] The robot end grinding spindle clamps the tool shank of the measuring tool 1-7, and moves the measuring tool 1-7 to insert it into the side measuring block 1 as a reference, ensuring that the probe 3 contacts the measuring tool 1-7. The position of the robot is finely adjusted to ensure that the LVDT displacement sensor 6 is at the midpoint of the measuring range; the robot starts to rotate by an angle around the origin of the initial coordinate system. Due to the error in coordinate calibration, the actual rotation point and the theoretical rotation point are eccentric. The LVDT displacement sensor 6 reads the measured value and compares it with the calibrated data to obtain the sensor displacement data.

[0056] Through the coordinate rotation formula, the robot tool coordinate system is denoted as the origin of the rotation center, and the calibrated error value is the coordinate value of the initial coordinate system in the tool coordinate system, denoted as X and Y;

[0057] When the measuring tool rotates by α°, the displacement of the measuring tool is denoted as X'1 and Y'1; the displacement sensor reads the measured value and compares it with the calibrated data to obtain:

[0058] X1 = X0 - X′1

[0059] Y1 = Y0 - Y′1

[0060] X0 and Y0 are the calibrated values, and X1 and Y1 are the offset displacement values.

[0061] A system of binary linear equations is established:

[0062] X1 = cosα * X - sinα * Y

[0063] Y1 = cosα * Y - sinα * X

[0064] X and Y are the required errors, and the solutions are:

[0065] X = cosα * X1 + sinα * Y1

[0066] Y = cosα * Y1 - sinα * X1

[0067] When the robot rotates the measuring tool 1-7 to a specific angle, the sensor data is collected and substituted into the formula for solution. When the measuring tool rotates 360°, data is collected every 5°, and a total of 72 groups of data are collected.

[0068] Analyze the measurement data. First, calculate the mean value of the data Population standard deviation Then, use the 3σ method to remove gross errors and take values within the interval [μ - 3σ, μ + 3σ]. Next, calculate the standard error n represents the number of measurements, and σ represents the population standard deviation. The measurement error value can be calculated The confidence level is 99.7%. When the calculated measurement error (system error), and the system error is the precision requirement of the grinding system (±0.2 mm), it can be considered that the measurement result meets the requirements of the grinding system. When the error does not meet the precision requirements of the grinding system, write the new measurement result into the tool coordinate system and continue iterative measurement until (system error). After the measurement is completed, write the correct measurement values in the X and Y directions into the tool coordinate system

[0069] Use the normal measurement block 2 to calibrate the Z value of the tool coordinate system. The normal measurement block 2 is used to calibrate the Z value; the normal measurement block 2 serves as the measurement base. The measurement block is designed in an L shape. The probe 3 is installed on two mutually perpendicular side walls of the L shape and is guided through a guide groove installed in the measurement block. The probe 3 in the horizontal direction is directly connected to the horizontally installed LVDT displacement sensor 6; the probe 3 in the vertical direction is guided through a guide groove installed in the measurement block; the lower end of the probe 3 contacts one end of the guide rod 10. A spring 9 is installed between the guide rod 10 and the inner wall of the measurement block cavity to ensure that the probe 3 can contact the measuring tool; the other end of the guide rod 10 is connected to the LVDT displacement sensor 6 for measurement. By changing the installation position of the sensor through the guide rod 10, the volume of the measuring device is ensured to be compact; the guide rod 10 is installed inside the measurement block using a pin in the middle to ensure that the distance from the pin to the probe 3 is the same as the distance from the pin to the sensor, aiming to ensure that the measurement distance of the probe 3 is accurately transmitted to the sensing distance of the sensor; install the calibration block on the normal measurement block 2 to ensure the parallelism and perpendicularity requirements between the calibration block and the reference; the probe 3 contacts the calibration block, the sensor core moves, and the spring fixes the core; adjust the position of the sensor so that the LVDT displacement sensor 6 is at the midpoint of the range to prevent the sensor measurement from being in the non-linear region; clamp and fix the sensor by connecting a screw through the threaded hole on the measurement block; the measurement system records the voltage value of the sensor at this time as the calibration displacement data, denoted as X0 and Y0 respectively

[0070] The tool shank of the clamping and measuring tool II 8 of the robot end grinding spindle, and a spherical probe is installed at the other end of the measuring tool II 8; move the spherical probe to contact the probe 3 in the vertical direction, adjust the position to make the LVDT displacement sensor 6 at the midpoint of the range, move the spherical probe downward to contact the probe 3 in the horizontal direction, and adjust the position to make the LVDT displacement sensor 6 at the midpoint of the range; move the robot to start rotating around the center of the spherical probe. Due to the error in coordinate calibration, the actual rotation point and the theoretical rotation point are eccentric. The LVDT displacement sensor 6 reads the measured value and compares it with the calibration data to obtain the sensor displacement data.

[0071] Through the coordinate rotation formula, record the robot tool coordinate system as the origin of the rotation center, and record the coordinate values of the calibration error value in the initial coordinate system under the tool coordinate system as X and Y;

[0072] When the measuring tool rotates by α°, the displacements of the measuring tool are recorded as X'1 and Y'1; the displacement sensor reads the measured value and compares it with the calibration data to obtain:

[0073] X1 = X0 - X′1

[0074] Y1 = Y0 - Y′1

[0075] X0 and Y0 are calibration values, and X1 and Y1 are offset displacement values.

[0076] Establish a system of binary linear equations:

[0077] X1 = cosα * X - sinα * Y

[0078] Y1 = cosα * Y - sinα * X

[0079] X and Y are the required errors, and the solutions are:

[0080] X = cosα * X1 + sinα * Y1

[0081] Y = cosα * Y1 - sinα * X1

[0082] When the robot rotates the measuring tool II 8 to a specific angle, collect the sensor data and substitute it into the formula for solution. When the measuring tool rotates 90°, data is collected every 5°, and a total of 18 groups of data are collected.

[0083] Analyze the measurement data. First, calculate the mean value of the data Population standard deviation Adopt the 3σ method to remove gross errors and take values within the interval [μ - 3σ, μ + 3σ]. Then calculate the standard error n represents the number of measurements, and σ represents the population standard deviation. The measurement error value can be calculated The confidence level is 99.7%. When the calculated measurement error (system error), and the system error is within the precision requirement of the grinding system (±0.2 mm), it can be considered that the measurement result meets the requirements of the grinding system. When the error does not meet the precision requirement of the grinding system, the new measurement result is written into the tool coordinate system, and iterative measurement continues until (system error). After the measurement is completed, the measured value in the Y direction is written into the tool coordinate system as the error value in the Z direction.

[0084] As is known to those skilled in the art, the present invention can be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the above-disclosed embodiments are illustrative in all respects and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific embodiments of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A measuring device for a robot end effector, characterized in that, It includes a lateral measurement block (1) and a normal measurement block (2) with probes (3) installed in both the horizontal and vertical directions. One end of each probe (3) is connected to a displacement sensor, and the other end of the probe (3) is in contact with a measurement tool connected to the end effector of the robot. The displacement sensors located in the lateral measurement block (1) and the normal measurement block (2) can respectively detect the displacement data of the measurement tool when the end effector of the robot rotates laterally and normally through the probes (3).

2. The measuring device for the end effector of the robot according to claim 1, characterized in that, A reference hole is machined in the middle of the lateral measurement block (1). One lateral hole is machined in each of the horizontal and vertical directions of the reference hole, and a probe (3) is installed in each lateral hole. The other end of the probe (3) is threadedly connected to a displacement sensor, and the LVDT displacement sensor (6) is fixed to the lateral measurement block (1) through a sensor mounting base (5).

3. The measuring device for the robot end effector according to claim 1, characterized in that, The normal measurement block (2) has an L-shaped structure, and probes (3) are installed on both mutually perpendicular inner walls. The vertical side wall of the normal measurement block (2) is installed with displacement sensors in the vertical and horizontal directions through a sensor mounting base (5). The probe (3) in the horizontal direction is connected to the displacement sensor in the horizontal direction. A cavity is formed in the horizontal side wall of the normal measurement block (2), and a guide rod (10) is installed in the cavity through a pin. The lower end of the probe (3) in the vertical direction contacts one end of the guide rod (10), and the other end of the guide rod (10) is connected to the displacement sensor in the vertical direction. A spring (9) is installed between the guide rod (10) and the inner wall of the cavity.

4. The measuring device for the end tool of the robot according to claim 1, characterized in that, The displacement sensor is an LVDT displacement sensor (6), and the sensor structure includes a magnetic core, an armature, a primary coil, a secondary coil, a return spring, and a sensor housing.

5. A measurement method for a robot end effector, characterized in that, Adopt a measuring device for the end effector of a robot as described in claim 1, including:[[]] Install a sensor calibration block in the measuring device to obtain the sensor calibration value; After the measuring tool connected to the robot is inserted into the lateral measurement block and contacts both the vertical and horizontal probes, collect the displacement data during the rotation of the robot in the Z direction with the origin of the tool coordinate system as the axis; After the measuring tool connected to the robot is inserted into the normal measurement block and contacts both the vertical and horizontal probes, collect the displacement data during the rotation of the robot in the X and Y directions with the origin of the tool coordinate system as the axis; After obtaining the sensor deviation value based on the displacement data, compare it with the calibration value to calculate the actual deviation value; Analyze the measurement error based on multiple groups of actual deviation values. When the measurement error is less than the system error, complete the calibration of the end effector in the X, Y, and Z directions, otherwise continue to collect the displacement data.

6. The measurement method of the robot end effector according to claim 5, characterized in that The formula for the actual deviation value is: X = cosα * X1 + sinα * Y1 Y = cosα * Y1 - sinα * X1 In the formula: X and Y are the actual deviation values, X1 and Y1 are the offset displacement values, and α is the rotation angle of the measuring tool.

7. The measurement method of the robot end tool according to claim 6, characterized in that, The formula for the offset displacement value is: X1 = X0 - X′1 Y1 = Y0 - Y′1 In the formula: X0 and Y0 are the calibration values, and X'1 and Y'1 are the displacement values of the measuring tool.

8. The measurement method of the robot end tool according to claim 5, characterized in that, The formula for the measurement error value is: Where: δ lim is the measurement error, is the standard error, σ is the population standard deviation, n is the number of measurements, μ is the mean of the data, and xi is the actual deviation values of multiple groups.

9. The measuring method of the robot end effector according to claim 5, characterized in that, The lateral measurement block collects data every 5° during the 360° rotation of the measuring tool, and a total of 72 groups of data are collected.

10. The measurement method of the robot end effector according to claim 5, characterized in that, The normal measurement block collects data every 5° during the 90° rotation of the measuring tool, and a total of 18 groups of data are collected.

Images