Non-contact calibration method and device of robot workpiece coordinate system

Abstract

The invention discloses a non-contact calibration method and device for a robot workpiece coordinate system, and the method comprises the steps: installing a laser distance measurement sensor on a tail end tool of a robot, setting a virtual tool center point at a position, Lx away from a light source surface, of a laser beam, and carrying out the calibration through a three-point method; afterwards, three special positioning patches are fixed on equipment to be calibrated, the pose of the robot is adjusted, a laser beam is made to sequentially and accurately irradiate center light sensing points of all the positioning patches, the distance measurement reading is always kept to be the set distance Lx, and after the three positions are sequentially recorded, a workpiece coordinate system of the equipment is established through a three-point method; the calibration device comprises a laser distance measuring sensor and a positioning patch, wherein the center of the positioning patch is provided with a white matte photosensitive area, and the periphery of the positioning patch is gray. The method has the advantages of being easy and convenient to operate, low in cost, high in environmental adaptability and the like, and the repeated calibration precision of a workpiece coordinate system can reach + / -0.05 mm.

Description

Technical Field

[0001] This invention belongs to the field of robot workpiece coordinate system calibration technology, and specifically discloses a non-contact calibration method and device for robot workpiece coordinate systems. Background Technology

[0002] Today, industrial robots are increasingly being used in manufacturing across various industrial sectors. Typically, the calibration of the robot's workpiece coordinate system plays a crucial role in its practical application.

[0003] There are various methods for calibrating the workpiece coordinate system of industrial robots. Conventional methods are mostly contact-based, such as the common three-point calibration method (i.e., first calibrating the tool center point (TCP) on the tool, then using the robot's end effector center point to sequentially touch three reference points on the ground or workpiece and record the results). However, in some practical applications, the robot's end effector may not have an actual tool center point (such as grippers, welding clamps, rollers, etc.), or the end effector may interfere with or collide with the equipment when approaching the calibration point. In these cases, traditional contact-based calibration methods cannot be used. Furthermore, conventional contact-based calibration methods are limited by the physical shape of the tool tip and parallax from human operation, resulting in poor calibration accuracy (repeat calibration accuracy is typically around ±2mm), making it difficult to meet the requirements of applications with high positional accuracy.

[0004] To address the interference and accuracy issues associated with contact calibration, some non-contact calibration methods have emerged in the industry. However, existing non-contact calibration solutions still suffer from numerous insurmountable technical shortcomings, specifically: 1. The system has a complex structure, is difficult to adjust, and visual errors are hard to eliminate.

[0005] For example, Chinese authorized invention patent CN112792817B discloses a non-contact calibration device and method for the workpiece coordinate system of a robotic arm. This solution requires installing three laser pointers and a camera on the robotic arm. The laser beams emitted by the three laser pointers are mechanically adjusted to intersect at a point to form a "laser intersection point," and the camera is used to capture the intersection point for coordinate system calibration.

[0006] Its technical shortcomings are as follows: First, it has extremely high requirements for hardware installation and mechanical adjustment. In actual industrial sites, it is very difficult to manually adjust three independent lasers to precisely converge at an absolute point in space, which can easily introduce mechanical adjustment errors. Second, this solution relies too much on video footage captured by a camera for manual judgment or image recognition. It is inevitably affected by the camera's installation angle, lens distortion, and ambient light, making it difficult to effectively guarantee the final calibration accuracy and repeatability.

[0007] 2. It relies heavily on complex and expensive specialized auxiliary tooling and lacks adaptability to the field.

[0008] For example, Chinese authorized invention patent CN113715061B discloses a non-contact industrial robot tool coordinate calibration tool and calibration method. The solution designs a complex calibration stage including a hexagonal smooth mirror base, a prism of a specific height, and multiple photosensitive panels. Teaching is accomplished by emitting a laser from the robot's end effector to the mirror and reflecting it to the center point of the photosensitive panel.

[0009] Its technical drawbacks are as follows: this method relies on a large, specially designed mirror calibration base. The manufacturing cost of such high-precision tooling is exorbitant, and its own manufacturing and assembly errors directly contribute to the calibration results. More importantly, in crowded and cluttered actual equipment tooling environments, there is often insufficient space to accommodate such a large calibration platform. This limits the method to laboratories or specific open workstations, preventing direct, in-situ, and rapid calibration of the actual workpiece coordinate system.

[0010] 3. The equipment cost is extremely high, the data processing is extremely complicated, and the calibration efficiency is low.

[0011] For example, Chinese authorized invention patent CN108362240B discloses a method for obtaining a workpiece coordinate system. This method uses a 3D scanner to perform a comprehensive point cloud scan of the robot's end tool and the workpiece. Then, the massive amount of point cloud data is imported into a computer, and reverse engineering software is used for point cloud preprocessing, surface reconstruction, and data alignment. Finally, the deviation is measured to adjust the coordinate system.

[0012] Its technical drawbacks are as follows: First, 3D scanners are expensive precision optical instruments, which greatly increases the cost of use for enterprises; second, the operation process of this method is extremely cumbersome, involving the collection, filtering, modeling and alignment of massive point cloud data, which is not only time-consuming, but also requires operators to have extremely high software skills (proficiency in reverse engineering modeling), which does not meet the requirements of industrial production sites for robot calibration to be "efficient, convenient and low-threshold".

[0013] In summary, current non-contact calibration methods generally suffer from problems such as complex structure, expensive equipment, reliance on large specialized tooling, cumbersome algorithms, or susceptibility to visual errors. Therefore, providing a non-contact calibration device and method for robot workpiece coordinate systems that avoids interference between the end-effector and the equipment, eliminates dependence on complex hardware and software, and offers simple operation, low cost, and extremely high accuracy (meeting the requirement of ±0.05mm repeatability) has become a pressing technical challenge in this field. Summary of the Invention

[0014] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a non-contact calibration device and method for robot workpiece coordinate systems. It solves the problem that existing contact calibration methods are unsuitable because the robot end-effector lacks a physical tool center point (TCP) or is prone to physical interference with the equipment. Simultaneously, it overcomes the technical bottlenecks of existing non-contact calibration methods (such as multi-laser convergence, large-scale dedicated optical fixtures, 3D point cloud scanning, etc.), including complex system structures, high hardware costs, poor adaptability to field environments, extremely cumbersome data processing, and large human visual errors. This allows it to meet the demands of industrial sites for efficient, convenient, and high-precision calibration work.

[0015] To address the aforementioned technical problems, this invention proposes a non-contact calibration method for a robot workpiece coordinate system, comprising the following steps: S1: Install a laser rangefinder that can display the range measurement value on the end effector of the robot, and adjust the direction of the sensor to ensure that the laser beam is not blocked by the tool. S2: Create a virtual tool center point (virtual TCP) at a distance Lx from the laser beam source surface, and then use the three-point method to calibrate the coordinates of the virtual TCP. During calibration, attach a positioning patch at a suitable position within the robot's working range. The robot, in three different directions and postures, allows the laser beam emitted from the laser rangefinder at the end of the robot to illuminate the center photosensitive point of the positioning patch, ensuring that the distance from the source surface of the laser rangefinder to the center photosensitive point of the positioning patch is Lx each time. Record these three positions to complete the calibration of the virtual TCP. S3: Use the known virtual TCP to calibrate the workpiece coordinate system of the device under test, still using the three-point calibration method. Fix three positioning patches on the device, and then adjust the pose of the industrial robot so that the laser beam sequentially illuminates the center photosensitive point of the three positioning patches, while ensuring that the distance from the light source surface of the laser rangefinder to the center photosensitive point of each positioning patch is constant at Lx. Record these three positions sequentially as the zero point, a point on the +X axis, and a point on the +Y axis of the workpiece coordinate system, and the workpiece coordinate system of the device can be calibrated.

[0016] Furthermore, if the position of the device under test shifts, it is only necessary to repeat the three point teaching steps in step S3 above (i.e., ensure that the laser ranging distance is Lx and align with the center photosensitive point) to restore the workpiece coordinate system of the device.

[0017] Furthermore, the ideal ranging range of the selected laser rangefinder is between 200mm and 1200mm.

[0018] To achieve the above method, the present invention also provides a non-contact calibration device for a robot workpiece coordinate system, comprising: A laser rangefinder sensor is fixedly mounted on the end effector of a robot to emit a laser beam that is not blocked by the tool and display the range value in real time, so as to generate a virtual TCP at a distance Lx from the light source surface. The positioning patch is a specially designed circular patch with a central photosensitive area of ​​approximately 0.5mm to 1mm in diameter. This central photosensitive area has a matte white surface to facilitate signal reflection from laser ranging and manual observation. The rest of the circular patch is gray.

[0019] Furthermore, the positioning patch is made of metal, with an overall diameter of 20mm and a thickness of 1mm.

[0020] Compared with the prior art, the present invention has the following significant advantages: 1. Completely solves the calibration problem of physical interference and lack of actual TCP: cleverly uses a single laser rangefinder to establish a "virtual TCP" at an absolute spatial distance Lx, replacing the real physical point. The robot does not need to directly touch the ground or workpiece, fundamentally avoiding collision interference between end tools (such as grippers, welding clamps) and surrounding equipment.

[0021] 2. Extremely simple structure, low cost and strong environmental adaptability: It abandons the complex three-laser convergence adjustment mechanism, the large and expensive hexagonal mirror calibration stage and the costly 3D scanner of the existing technology. The present invention only requires an ordinary laser rangefinder sensor and a few low-cost metal positioning patches to complete the calibration. It is small in size, does not take up space, and can be implemented in place in any crowded and messy industrial site.

[0022] 3. Extremely high calibration accuracy, eliminating visual parallax and algorithmic errors: Through a special positioning patch design featuring a "white matte photosensitive area + gray contrast background," coupled with an extremely small target center of 0.5mm-1mm, the laser beam alignment is highly unique. Combined with the real-time display of the absolute distance Lx by the laser sensor, parallax caused by relying on camera image judgment is completely eliminated (compared to CN112792817B), and algorithmic errors caused by point cloud data stitching and surface fitting are also avoided (compared to CN108362240B). Actual testing shows that the workpiece coordinate system repeatability calibration accuracy of this method can reach ±0.05mm, significantly improving absolute positioning accuracy.

[0023] 4. Simple operation and fast calibration and recovery: The calibration logic follows the "three-point method," requiring no advanced reverse engineering modeling skills or complex algorithm operation capabilities from the operator. If the equipment experiences a positional shift, the coordinate system can be quickly restored by recalibrating the distance Lx using three fixed positioning patches, greatly improving maintenance efficiency and equipment uptime in industrial production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0025] Figure 1 is a schematic diagram of the structure of the laser ranging sensor installed at the end of the robot in an embodiment of the present invention; Figure 2 is a schematic diagram of the positioning patch in an embodiment of the present invention; Figure 3 is a schematic diagram of the process of calibrating the virtual TCP using a laser ranging sensor in an embodiment of the present invention; Figure 4 is a schematic diagram of the process of calibrating the workpiece coordinate system of the equipment in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached diagram: 1. Robot; 2. End effector; 3. Laser rangefinder; 4. Laser beam; 5. Positioning patch; 6. Central photosensitive area (central photosensitive point); 7. Equipment (equipment to be calibrated); 8. First patch (representing the zero point of the workpiece coordinate system); 9. Second patch (representing a point on the +X axis of the workpiece coordinate system); 10. Third patch (representing a point on the +Y axis of the workpiece coordinate system); Lx, the constant distance from the light source surface of the laser rangefinder to the central photosensitive point of the positioning patch. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a non-contact calibration device and method for a robot workpiece coordinate system. The method mainly consists of two stages: the first stage is the creation and calibration of a virtual TCP (tool center point), and the second stage is the calibration of the workpiece coordinate system using the virtual TCP. The specific implementation steps are as follows: Step S1: As Figure 1 As shown, an end-effector tool 2 is installed at the end of the industrial robot 1. In actual industrial applications, the end-effector tool 2 may be any type such as a gripper, welding clamp, or roller. The end of such tools usually does not have an actual physical tip (i.e., it lacks a physical tool center point TCP), and due to its shape limitations, it is very easy to cause physical interference with surrounding equipment.

[0029] Therefore, a laser rangefinder 3 capable of displaying real-time distance measurement values ​​is installed on the end tool 2 of this invention. During installation, it is necessary to ensure that it is reliably fixed and adjust the direction of the laser rangefinder 3 to ensure that the laser beam 4 emitted by it is not blocked by any part of the end tool 2 throughout the entire working process.

[0030] When selecting the laser rangefinder sensor 3, in order to ensure calibration accuracy, a sensor with higher measurement accuracy and a finer beam is preferred, and its ideal rangefinder detection range is set between 200mm and 1200mm.

[0031] Step S2: As Figure 2 As shown, in order to cooperate with laser for high-precision non-contact alignment, this embodiment designs a special positioning patch 5. During the first stage of calibration, a positioning patch 5 is attached to a suitable position within the robot's working range.

[0032] The positioning patch 5 is preferably made of metal to ensure service life and prevent deformation. Its overall diameter is 20mm and its thickness is 1mm. At the very center of the positioning patch 5, there is a circular central photosensitive area (i.e., central photosensitive point 6) with a diameter of approximately 0.5mm to 1mm. The surface of this central photosensitive point 6 is coated with a matte white finish. This design not only facilitates stable reflection of the laser ranging signal but also greatly facilitates visual observation and alignment by the operator. To create a strong visual contrast, the remaining peripheral areas of the circular positioning patch 5 are all set to gray, thereby completely eliminating visual interference.

[0033] Step S3: As Figure 3 As shown, the operator manipulates the industrial robot 1, adjusting its posture so that the laser beam 4 emitted by the laser rangefinder 3 at the end of the robot precisely illuminates the central photosensitive point 6 (white matte area) of the positioning patch 5. At this time, the current position is recorded in the robot's teach pendant or control system, completing the first point teaching.

[0034] Simultaneously, the absolute distance from the current laser source surface to the center photosensitive point 6 is read from the display screen of the laser rangefinder 3, and this distance is defined as a constant distance Lx. It is necessary to ensure that the set length Lx is within the effective detection range of the laser rangefinder 3.

[0035] Step S4: Change the pose of the industrial robot 1 (i.e., change the approach angle and posture) so that the laser beam 4 accurately illuminates the center photosensitive point 6 of the same positioning patch 5 again. During this process, the operator observes the real-time reading of the laser rangefinder 3 and fine-tunes the distance of the robot's end effector to strictly ensure that the distance from the current light source surface to the center photosensitive point 6 is equal to the previously recorded constant distance Lx. After alignment is completed, the position is recorded, and the second point teaching is completed.

[0036] Step S5: Repeat the operation logic of step S4, and let the laser beam 4 irradiate the central photosensitive point 6 in a third different direction and posture, while strictly ensuring that the distance is Lx, record the position, and complete the third point teaching.

[0037] Through steps S3 to S5, the robot performs three-point teaching at a constant distance of Lx from the target point in three different postures. The robot control system can then calculate and calibrate a "virtual TCP" using the classic "three-point method". This virtual TCP is not a physically existing apex, but rather a spatial coordinate point located at a strictly Lx distance from the surface of the laser rangefinder 3 light source along the direction of the laser beam 4.

[0038] Step S6: As Figure 4 As shown, after the virtual TCP is created, the workpiece coordinate system calibration of the device 7 to be calibrated on site begins. Three positioning patches (patches 8, 9, and 10) are fixed on the reference surface of device 7. The center of patch 8 represents the zero point (origin) of the workpiece coordinate system to be established, the center of patch 9 represents a point on the +X axis, and the center of patch 10 represents a point on the +Y axis.

[0039] Step S7: Adjust the pose of the industrial robot 1 so that the laser beam 4 illuminates the center photosensitive point of the positioning patch 8, and ensure that the measured distance is still strictly equal to Lx by observing the sensor readings. At this point, it means that the robot's "virtual TCP" has accurately landed on the center surface of the patch 8. Record this pose and set this point as the zero point of the workpiece coordinate system.

[0040] Step S8: Continue to adjust the pose of the industrial robot 1 so that the laser beam 4 illuminates the center photosensitive point of the positioning patch 9, while ensuring that the ranging distance remains Lx. Record this pose and set this point as the +X point of the workpiece coordinate system.

[0041] Step S9: Continue to adjust the pose of the industrial robot 1 so that the laser beam 4 illuminates the center photosensitive point of the positioning patch 10, while ensuring that the ranging distance remains Lx. Record this pose and set this point as the +Y point of the workpiece coordinate system.

[0042] Thus, by using virtual TCP combined with the three-point method, the workpiece coordinate system of device 7 is now complete. Throughout the entire process, the robot does not need to contact the device, avoiding all interference issues.

[0043] Step S10: In subsequent industrial production, when the position of equipment 7 shifts due to vibration, maintenance, or other reasons, operators do not need to perform tedious global recalibration. They only need to use the robot with the established virtual TCP to repeat steps S7, S8, and S9 (i.e., aligning the shifted first patch 8, second patch 9, and third patch 10 while ensuring a distance of Lx) to quickly and easily restore the workpiece coordinate system of equipment 7.

[0044] After actual industrial field testing, the workpiece coordinate system obtained by the non-contact calibration method of this invention can achieve a repeatability of ±0.05mm. Compared with traditional contact calibration (±2mm) or ordinary non-contact visual calibration, it significantly improves the calibration accuracy, while greatly reducing the calibration cost and speeding up the calibration process.

[0045] Based on the calibration method described in Embodiment 1, the present invention also provides a non-contact calibration device for a robot workpiece coordinate system specifically designed to implement the above method. For example... Figures 1 to 4 As shown, the non-contact calibration device mainly includes: a laser rangefinder 3 and a series of specially designed positioning patches 5.

[0046] like Figure 1 As shown, the end effector of an industrial robot 1 is usually equipped with an end effector 2 (such as a gripper, welding clamp, roller, etc.) to perform production tasks. These tools often do not have a clear physical tip (i.e., lack a physical tool center point TCP) and are prone to interference and collision when they are close to the equipment to be calibrated.

[0047] In this embodiment, the laser rangefinder 3 is securely mounted on the side of the end effector 2 or on a specific bracket via a mechanical connector. During installation, the direction of the laser rangefinder 3 needs to be adjusted to ensure that the laser beam 4 emitted by it is not blocked by any structure of the end effector 2 itself within the entire motion envelope of the robot.

[0048] Furthermore, the laser rangefinder 3 is equipped with a human-machine interface display screen, which can display the current distance measurement value in real time (in highly automated scenarios, this distance measurement value can also be fed back to the robot control system in real time via a communication bus). To ensure calibration accuracy, the selected laser rangefinder 3 has high measurement accuracy and a narrow beam waist, with its ideal effective distance measurement range set within 200mm to 1200mm. The constant absolute distance Lx measured by this sensor can construct a "virtual TCP" in the void far from the end tool 2, thereby completely replacing the traditional physical contact probe.

[0049] To achieve high-precision spatial point alignment in conjunction with the laser rangefinder 3, a positioning patch 5 was specifically designed in this embodiment. For example... Figure 2As shown, during the calibration process, at least three such positioning patches 5 (as shown in the attached diagram) need to be placed. Figure 4 Patches 8, 9, and 10 are fixed on the reference surface of the device 7 to be calibrated, representing the origin, X-axis reference point, and Y-axis reference point of the workpiece coordinate system, respectively. Additionally, at least one positioning patch 5 is required for initial spatial calibration of the virtual TCP.

[0050] The positioning patch 5 has the following key structural and optical features: (1) Material and size: The positioning patch 5 is made of metal to ensure that it will not warp or deform in various complex industrial environments, thereby ensuring the flatness of the calibration reference surface. Its overall shape is circular with a diameter of 20mm and a thickness of 1mm, which is both compact and easy to stick and fix in the narrow space of the equipment. (2) Design of the central photosensitive point: At the absolute center of the circular positioning patch 5, there is a circular photosensitive area with a very small diameter, namely the central photosensitive point 6. The diameter of the central photosensitive point 6 is precisely controlled between 0.5mm and 1mm. By reducing the target center to the sub-millimeter level, the alignment tolerance of the operator when aligning the laser beam 4 can be greatly reduced, thereby ensuring high-precision repeatability from the hardware design. (3) Optical Coating Anti-interference Design: In order to ensure that the laser beam 4 can stably reflect the ranging signal when it hits the positioning patch 5, and to facilitate visual observation in strong industrial lighting environments, the surface of the central photosensitive point 6 is coated with a white matte surface (diffuse reflection surface). In stark contrast, the surrounding areas of the positioning patch 5, except for the central photosensitive point 6, are all set to gray. This high-contrast design of "white point + gray background" makes the visual contrast obvious when the red laser beam 4 deviates from the center and hits the gray area, and the reflectivity of the ranging signal will change, thereby effectively reminding the operator to make fine adjustments and completely avoiding misreading and visual parallax.

[0051] When using the calibration device of this embodiment, the industrial robot 1, carrying the laser rangefinder 3, moves to the vicinity of the device 7 to be calibrated. Through manual teaching or fine-tuning of the program, the laser beam 4 is precisely irradiated onto the center white photosensitive point 6 of the positioning patch 5. When the operator or the system reads that the distance displayed by the laser rangefinder 3 is exactly equal to the set Lx, it means that the robot's "virtual TCP" has accurately and non-contactly "touched" the calibration reference point on the surface of the device 7. Through this ingenious hardware cooperation, this calibration device successfully transforms contact calibration into high-precision non-contact optical calibration, and the actual measured repeatability of the workpiece coordinate system can reach ±0.05mm.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention, as long as the same technical effects are achieved by the same means, should be included within the scope of protection of the present invention.

Claims

1. A non-contact calibration method for a robot workpiece coordinate system, characterized in that, The process includes the following steps: Installing a laser rangefinder sensor on the robot's end effector and adjusting the direction of the laser rangefinder sensor so that the emitted laser beam is not blocked by the end effector; virtually generating a tool center point TCP at a spatial position Lx from the light source surface of the laser rangefinder sensor, and calibrating the coordinates of the virtual TCP using the triangular method; fixing a predetermined number of positioning patches on the device to be calibrated, adjusting the industrial robot's pose so that the laser beam sequentially illuminates the center photosensitive point of each positioning patch, and ensuring that the distance from the light source surface to the center photosensitive point is Lx each time the laser beam is illuminated by reading the real-time values ​​of the laser rangefinder sensor; sequentially recording the robot's pose information when the distance Lx is reached, and creating the workpiece coordinate system of the device using the triangular method based on the recorded pose information.

2. The non-contact calibration method for the robot workpiece coordinate system according to claim 1, characterized in that, The specific steps for calibrating the virtual TCP include: attaching a positioning patch at a suitable position within the robot's working range; adjusting the robot's pose in three different directions and orientations so that the laser beam emitted by the laser range sensor at the end of the robot illuminates the central photosensitive point of the positioning patch; reading the ranging value each time the laser beam is illuminated to ensure that the distance from the light source surface to the central photosensitive point remains constant at Lx; and recording the pose information at these three positions to complete the calibration of the virtual TCP.

3. The non-contact calibration method for the robot workpiece coordinate system according to claim 1, characterized in that, A first positioning patch, a second positioning patch, and a third positioning patch are fixed on the device to be calibrated. The virtual TCP is used to align the first positioning patch: the industrial robot's pose is adjusted so that the laser beam emitted by the laser rangefinder illuminates the center photosensitive point of the first positioning patch, and the distance from the light source surface to this center photosensitive point is Lx, so that the virtual TCP is exactly located on this center photosensitive point. This position is recorded as the zero point of the workpiece coordinate system. The virtual TCP is then used to align the second positioning patch: the industrial robot's pose is further adjusted so that the laser beam illuminates the center photosensitive point of the second positioning patch, and the distance from the light source surface to this center photosensitive point is Lx. The distance to the central photosensitive point is Lx, so that the virtual TCP is exactly located on the central photosensitive point. This position is recorded as a point on the +X axis of the workpiece coordinate system. The virtual TCP is used to align with the third positioning patch: the industrial robot pose is adjusted so that the laser beam illuminates the central photosensitive point of the third positioning patch, and the distance from the light source surface to the central photosensitive point is Lx, so that the virtual TCP is exactly located on the central photosensitive point. This position is recorded as the third point in the XY plane. Using the three-point method of the workpiece coordinate system, the workpiece coordinate system of the equipment is calibrated based on the recorded zero point, the point on the +X axis, and the third point in the XY plane.

4. The non-contact calibration method for the robot workpiece coordinate system according to claim 3, characterized in that, It also includes a coordinate system restoration step: when the position of the device to be calibrated is offset, the first positioning patch, the second positioning patch and the third positioning patch after the offset are irradiated at a distance of Lx and the position is recorded in sequence, so that the workpiece coordinate system of the device can be restored.

5. The non-contact calibration method for the robot workpiece coordinate system according to any one of claims 1 to 4, characterized in that, The value of the distance Lx is set between 200mm and 1200mm.

6. A non-contact calibration device for implementing the method according to any one of claims 1-5, characterized in that, include: A laser rangefinder (3) is fixedly mounted on the end tool (2) of the robot to emit a laser beam (4) and display the distance measurement value in real time. The installation direction of the laser rangefinder (3) ensures that the laser beam (4) avoids interference with the end tool (2). At least three positioning patches (5) are used to fix the laser beam (4) on the working environment or the device to be calibrated (7). The center of the positioning patch (5) is provided with a central photosensitive point (6) for the laser beam (4) to be aligned and irradiated. A virtual TCP is defined on the laser beam (4) based on the constant distance Lx measured by the laser rangefinder (3), and the non-contact calibration of the workpiece coordinate system is achieved by aligning the central photosensitive point (6) of the positioning patch (5).

7. The non-contact calibration device according to claim 6, characterized in that, The positioning patch (5) is a circular patch with a circular photosensitive area at its center as the central photosensitive point (6). The circular photosensitive area is a white matte surface to facilitate signal reflection from laser ranging and manual observation.

8. The non-contact calibration device according to claim 7, characterized in that, The outermost area of ​​the positioning patch (5) except for the central circular photosensitive area is gray, and the central circular photosensitive area of ​​the positioning patch (5) is a white matte surface.

9. The non-contact calibration device according to claim 7 or 8, characterized in that, The diameter of the circular photosensitive area ranges from 0.5 mm to 1 mm.

10. The non-contact calibration device according to claim 9, characterized in that, The overall diameter of the positioning patch (5) is 20mm and the thickness is 1mm, and the overall material of the positioning patch (5) is metal.

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