Rotary tool, rotary tool position attitude calculation method and rotary tool position attitude calculation system

Abstract

To provide a rotary tool to be used to calculate the position and attitude of the rotary tool having a rotating shaft part with high accuracy, a rotary tool position attitude calculation method capable of calculating the position and attitude of the rotary tool with high accuracy, and a rotary tool position attitude calculation system.SOLUTION: A joining tool (rotary tool) 23 has a shaft part 44 that rotates. The shaft part 44 has a marker 25 for position information detection to detect position information of the joining tool 23 on its surface. The marker 25 for position information detection includes a first marker 47a continuously provided in a circumferential direction of the shaft part 44 with a rotation axis 46 of the shaft part 44 as a center, and a second marker 47b continuously provided in the circumferential direction of the shaft part 44 with the rotation axis of the shaft part 44 as the center at a position separated in an axial direction of the shaft part 44 from the first marker 47a. The first marker and the second marker are used to calculate a tip position and an attitude of the joining tool on the basis of the position information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotary tool, a method for calculating the position and orientation of a rotary tool, and a system for calculating the position and orientation of a rotary tool. [Background technology]

[0002] In recent years, friction stir welding (FSW) has been increasingly adopted as a joining method for structures such as automobile bodies. In FSW, a friction stir welding tool (also called a tool) is pressed against the workpieces to be welded while rotating and advancing linearly. The workpieces are joined together by the friction between the tool and the workpieces, as well as the heat input and agitation caused by the plastic flow of the workpieces. However, during welding, the tool is subjected to material resistance due to rotation and advancement, which can cause the target position to shift in the Y and Z directions, which are perpendicular to the tool's advancement direction (X direction).

[0003] In particular, when friction stir welding is performed using a low-rigidity articulated device, in addition to the Y and Z directions, misalignment is likely to occur in the X direction due to the bending of the device caused by the force applied by the tool. Furthermore, misalignment in the three axes (X, Y, and Z) also causes misalignment in the rotational directions of each axis (Rx, Ry, and Rz). This type of tool misalignment results in a deviation of the tool position from the interface where the workpieces are joined, which can be one of the causes of poor welding. Tool misalignment also changes the depth of the weld, significantly affecting the quality of the welded structure, making friction stir welding using an articulated device difficult to apply to butt welding.

[0004] Patent Document 1 proposes a friction stir welding apparatus and a friction stir welding method that are capable of accurately setting the initial position of the welding tool in the Z-axis direction (vertical direction) in the welding condition setting stage, which is a stage before inserting the welding tool into the workpieces to be welded. The friction stir welding method described in Patent Document 1 is a method that corrects the vertical position of the tool during welding by acquiring an image of the welding tool part before welding.

[0005] Furthermore, Non-Patent Document 1 discloses a method for analyzing the three-dimensional movement of an object using motion capture as a method for measuring the movement of a moving object. In the three-dimensional movement analysis and measurement method disclosed in the above Non-Patent Document, multiple spherical markers are attached to the object to be measured, and the markers are photographed with a camera to measure the movement of the object to be measured. Furthermore, if necessary, by setting a rigid body with multiple markers whose relative positions do not change, it is also possible to measure locations where no markers are attached. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-49533 [Non-patent literature]

[0007] [Non-Patent Document 1] “3D Motion Analysis and Measurement Using Motion Capture, Tutorial, 4. Capture”, [online], [Retrieved November 8, 2023], Acuity Co., Ltd., Internet <URL:https: / / help.acuity-inc.co.jp / hc / ja / articles / 360049530191-4-%E3%82%AD%E3%83%A3%E3%83%97%E3%83%81%E3%83%A3> Summary of the Invention [Problem to be solved by the invention]

[0008] However, the method described in Patent Document 1 is a method for measuring the position of the welding tool part before construction, and therefore is unable to obtain an accurate position during construction.

[0009] Furthermore, when attempting to measure the tool position using the technology of Non-Patent Document 1, the greater the distance from the tool tip (the point to be measured) to the marker, the greater the deflection from the tool tip to the marker position, resulting in a decrease in measurement accuracy. Also, frictional heat is generated when the joining tool rotates, and this heat can change the length of the tool tip, so the greater the distance from the tool tip to the marker, the greater the risk of an error occurring with the actual tool tip position.

[0010] Although it is possible to attach markers to the side of the rotating part, the rotating part of the joining tool is a narrow area at the tip of the tool. Attaching a spherical marker that is easily recognized by a camera to the rotating part would likely cause contact with the jig, making position measurement or joining difficult. Furthermore, because the position of the marker on the rotating part cannot be accurately captured by a camera, several markers must be measured within the radius of rotation. As a result, it is difficult to accurately calculate the axis center from the measured positions of several markers. In particular, whether the measurement points move smoothly also affects measurement accuracy. If the rotation of the rotating part is fast relative to the shutter speed, measurement accuracy decreases. Furthermore, even if the rotating part can be recognized as a rotating rigid body, if the rotating part rotates and the marker enters an area that cannot be captured by a camera, the marker may not be recognized continuously. In other words, it is difficult to determine whether a marker that entered an area that cannot be captured by a camera and a marker that reappears in a position where it can be captured are the same marker.

[0011] In this way, even if a marker is attached to the position to be measured, for example, near the tip of the tool, taking into account the effects of tool deflection and size changes due to thermal expansion, it is not possible to measure the position of the tool with high accuracy.

[0012] The present invention has been made in consideration of the above problems, and aims to provide a rotary tool used to calculate with high accuracy the position and attitude of a rotary tool having a rotating shaft, a rotary tool position and attitude calculation method that can calculate with high accuracy the position and attitude of the rotary tool, and a rotary tool position and attitude calculation system. [Means for solving the problem]

[0013] The above object of the present invention is achieved by the following configuration (1) relating to a rotary tool.

[0014] (1) A rotary tool having a rotating shaft, the shaft portion has a position information detection marker on a surface thereof for detecting position information of the rotary tool, the position information detection markers include a first marker provided continuously in a circumferential direction of the shaft portion around the rotation axis of the shaft portion, and a second marker provided continuously in a circumferential direction of the shaft portion around the rotation axis of the shaft portion at a position spaced from the first marker in the axial direction of the shaft portion, The rotary tool, wherein the first marker and the second marker are used to calculate a tip position and an attitude of the rotary tool based on the position information.

[0015] Furthermore, preferred embodiments of the present invention relating to the rotary tool relate to the following (2) and (3).

[0016] (2) The rotary tool described in (1), characterized in that the first marker and the second marker each have a spherical shape that forms part of a sphere centered on a point on the rotation axis of the shaft portion.

[0017] (3) The rotary tool according to (1) or (2), characterized in that the first marker and the second marker are coated with a colored paint or a reflective paint.

[0018] The above object of the present invention is achieved by the following configuration (4) relating to a method for calculating the position and attitude of a rotary tool. (4) A method for calculating a position and orientation of a rotary tool, which calculates a tip position and orientation of the rotary tool according to any one of (1) to (3) by using a marker detection device, a detecting step of detecting positions of the first marker and the second marker by the marker detection device; a position and attitude calculation step of calculating a tip position and attitude of the rotary tool based on the position information of the first marker and the second marker detected in the detection step.

[0019] A preferred embodiment of the present invention relating to a method for calculating the position and attitude of a rotary tool relates to the following (5).

[0020] (5) A corresponding position table is previously obtained, which associates the position information of the first marker and the second marker with the tip position and attitude of the rotary tool; The method for calculating the position and orientation of a rotary tool according to (4), wherein in the position and orientation calculation step, the position and orientation of the rotary tool corresponding to the position information are calculated by referring to the corresponding position table.

[0021] The above object of the present invention is achieved by the following configuration (6) relating to a system for calculating the position and attitude of a rotary tool.

[0022] (6) A position and orientation calculation system for a rotary tool that calculates a position and orientation of the rotary tool according to any one of (1) to (3), a control device for controlling the position and attitude of the rotary tool on which the position information detection marker is formed; a marker detection device having a plurality of detection units that detect the position information detection marker from different directions; the control device has a position and attitude calculation unit that calculates the tip position and attitude of the rotary tool based on the position information of the first marker and the second marker detected by the marker detection device.

[0023] Furthermore, preferred embodiments of the present invention relating to the rotary tool position and attitude calculation system relate to the following (7) to (10).

[0024] (7) The control device includes a storage unit that stores a corresponding position table that associates the position information of the first marker and the second marker with a tip position and an attitude of the rotary tool, The position and orientation calculation system for a rotary tool according to (6), wherein the position and orientation calculation unit calculates the position and orientation of the rotary tool corresponding to the position information by referring to the corresponding position table.

[0025] (8) The position and attitude calculation system for a rotary tool described in (6) or (7), characterized in that the multiple detection units are multiple cameras arranged to capture images of the first marker and the second marker from different directions.

[0026] (9) The first marker and the second marker are coated with colored paint, The system for calculating the position and attitude of a rotary tool according to any one of (6) to (8), wherein the detection unit is a camera that captures an image of the colored paint.

[0027] (10) The first marker and the second marker are coated with a reflective paint that reflects infrared rays, the marker detection device includes an infrared irradiator that irradiates the first marker and the second marker with infrared rays; The position and attitude calculation system for a rotary tool described in any one of (6) to (8), characterized in that the detection unit is a camera that captures infrared light reflected by the first marker and the second marker. [Effects of the Invention]

[0028] According to the present invention, a marker is provided in a specific area of ​​the rotary tool, so that it is possible to provide a rotary tool, a rotary tool position and attitude calculation method, and a rotary tool position and attitude calculation system that can calculate the position and attitude of the rotary tool with high accuracy. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic overall view of a friction stir welding system. [Figure 2] FIG. 2 is an enlarged side view showing a welding tool having a marker for detecting position information. [Figure 3] FIG. 3 is an explanatory view showing how the welding tool supported by the tool holding portion is rotated and pressed to friction stir weld the workpieces together. [Figure 4] FIG. 4 is a schematic diagram showing the first and second markers photographed by the detector CAM1. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of a rotary tool, a rotary tool position and orientation calculation method, and a rotary tool position and orientation calculation system according to the present invention will be described in detail with reference to the drawings. First, in order to explain the rotary tool position and orientation calculation system according to the present invention, an example of a friction stir welding system using a welding tool for friction stir welding as the rotary tool will be described.

[0031] 1 is a schematic overall view of a friction stir welding system 100. The friction stir welding system 100 is configured to friction stir weld workpieces (for example, a pair of workpieces 11 and 13) together, and includes a manipulator 15, a control device 17, a position information detection marker 25, and a marker detection device 19. The rotary tool position and attitude calculation system according to this embodiment is included in the friction stir welding system, which will be described in detail below. In the friction stir welding system 100 shown in FIG. 1, the manipulator 15 is connected to a control device 17 installed outside the manipulator 15, but the control device 17 may also be built into the manipulator 15.

[0032] In this embodiment, the manipulator 15 has an articulated robot arm 27, and is exemplified as a six-axis controlled multi-axis robot having mutually orthogonal X, Y, and Z axes and rotation axes Rx, Ry, and Rz about each axis, but may also be configured using a slide table with two orthogonal axes. Here, the Rx axis represents the rotation axis about the X axis, the Ry axis represents the rotation axis about the Y axis, and the Rz axis represents the rotation axis about the Z axis. A welding tool (rotary tool) 23 is supported on a tool holder 21 of the robot arm 27. The position and posture of the welding tool 23 supported on the tool holder 21 can be freely changed by rotating the tool holder 21, each robot arm 27, and the base 29.

[0033] Use of the manipulator 15, which is a multi-axis robot, increases the degree of freedom in controlling the attitude of the joining tool 23. The coordinate system expressed by the X, Y, and Z axes will hereinafter be referred to as the robot coordinate system.

[0034] Here, the rotary tool according to the embodiment of the present invention will be described with reference to FIG. 2, taking the welding tool 23 as an example.

[0035] <Joining tools (rotary tools)> 2 is an enlarged side view showing a welding tool 23 having a position information detection marker. The welding tool 23 is a tool for friction stir welding that has a rotating shaft 44, a probe 23a that protrudes outward from the central axis of the tip of the shaft 44, and a shoulder 23b that connects the shaft 44 and the probe 23a. In addition, a position information detection marker 25 for detecting position information of the welding tool 23 is provided on the surface of the shaft 44.

[0036] The first marker 47a and the second marker 47b constituting the position information detection marker 25 are both provided on the surface of the shank 44 of the welding tool 23 continuously in the circumferential direction of the shank 44, with the rotation axis 46 of the shank 44 as the center. The second marker 47b is provided at a position spaced apart from the first marker 47a in the axial direction of the shank 44. In this embodiment, the first marker 47a has a spherical shape that forms a part of an imaginary sphere 48a whose center is a point on the rotation axis 46 of the shank 44. The second marker 47b similarly has a spherical shape that forms a part of an imaginary sphere 48b whose center is a point on the rotation axis 46 of the shank 44. The surfaces of the first marker 47a and the second marker 47b are coated with, for example, reflective paint.

[0037] A position and orientation calculation system for calculating the position and orientation of the welding tool 23 using the welding tool 23 configured as above will be described with reference to Figures 1 to 3. Here, the position of the welding tool 23 means the tip position of the probe 23a of the welding tool 23, which is the processing position, and the orientation of the welding tool 23 means the tilt of the central axis of the welding tool 23.

[0038] The surfaces of the first marker 47a and the second marker 47b may be coated with a paint or the like that can be detected by a camera, and colored paint or the like may be used in addition to reflective paint. Methods for applying paint include applying tape and applying paint. Methods for forming the spherical shape that constitutes part of the virtual spheres 48a and 48b include cutting the shaft 44, forming a spherical shape using paint, and applying tape with a spherical shape.

[0039] <Joining tool (rotary tool) position and orientation calculation system> The position and orientation calculation system according to this embodiment includes a control device 17 that controls the position and orientation of the welding tool 23 on which the position information detection marker 25 is formed, and a marker detection device 19 that has a plurality of detection units CAM1 and CAM2 that detect the position information detection marker 25 from different directions. The control device 17 also includes a position and orientation calculation unit (not shown) that calculates the tip position and orientation of the welding tool 23 based on the position information of the first marker 47a and the second marker 47b detected by the marker detection device 19.

[0040] 3 is an explanatory diagram showing how the workpieces 11, 13 are friction stir welded together by rotating and pressing the welding tool 23 supported by the tool holding unit 21. The manipulator 15 rotates the welding tool 23 while supporting it on the tool holding unit 21, and moves it along the weld line L of the workpieces 11, 13 while pressing it axially toward the workpieces 11, 13. As a result, the workpieces 11, 13 undergo plastic flow due to the generated frictional heat, and are joined to each other.

[0041] Specifically, the control device 17 is configured with, for example, a processor (not shown) such as a CPU (Central Processing Unit) or an MPU (Micro Processor Unit), a storage unit (not shown), an input receiving unit (not shown), a communication unit (not shown), a position and orientation calculation unit (not shown), etc. These components are connected to each other via a bus so that they can communicate with each other, and the control device 17 communicates with the manipulator 15 and the marker detection device 19 via the communication unit. The control device 17 outputs a command signal to the manipulator 15 in accordance with drive data based on a predetermined welding plan and a correction amount described below, and drives the manipulator 15 as described above, thereby friction stir welding the workpieces 11 and 13 together.

[0042] The storage unit includes, for example, a hard disk drive (HDD), a solid state drive (SSD), an electrically erasable programmable read-only memory (EEPROM), a read-only memory (ROM), and a random access memory (RAM). The storage unit stores information such as drive data based on the welding plan and a corresponding position table referenced when the position and orientation calculation unit calculates the position and orientation of the welding tool. The information in the corresponding position table is information that associates the position information of the first marker 47a and the second marker 47b with the tip position and orientation of the welding tool 23. Note that the storage unit may be an external storage device connected via a digital input / output port such as a USB instead of being built into the control device 17. The position and orientation calculation unit calculates the position and orientation of the welding tool 23 corresponding to the marker position information detected by the marker detection device 19 by referring to the corresponding position table.

[0043] The processor executes various programs stored in the storage unit, thereby realizing various functions within the control device 17. The input receiving unit is, for example, a keyboard, a mouse, a touchpad, or other input device. The input receiving unit may function as a display unit, and may also be configured as a touch panel. The communication unit is configured to include, for example, a digital input / output port such as a USB, an Ethernet port, etc.

[0044] The marker detection device 19 includes, for example, detectors CAM1 and CAM2 and a position calculation unit (not shown). The detectors CAM1 and CAM2 are cameras that detect the positions of the position information detection markers 25. The detectors CAM1 and CAM2 are arranged with their detection directions offset from each other so as to capture images of the position information detection markers 25 (first marker 47a and second marker 47b) provided on the welding tool 23 from different directions. While the number of detectors is two is illustrated here as an example, the number of detectors may be two or more, more preferably three or more, and the more the number is, the more preferable it is, as long as it does not interfere with the calculation process. When using two detectors CAM1 and CAM2, the two detectors CAM1 and CAM2 are preferably arranged so that a line connecting one detector CAM1 and the welding tool 23 and a line connecting the other detector CAM2 and the welding tool 23 form a nearly right angle. Furthermore, the xy plane on which one detector CAM1 is arranged and the xy plane on which the other detector CAM2 is arranged are preferably offset from each other in the height direction.

[0045] In this embodiment, the first marker 47a and the second marker 47b are coated with a reflective paint that reflects infrared rays. Therefore, the marker detection device 19 has an infrared irradiating unit (not shown) that irradiates the first marker 47a and the second marker 47b with infrared rays, and the detection units CAM1 and CAM2 can be cameras that capture images of the infrared rays reflected by the first marker 47a and the second marker 47b.

[0046] The first marker 47a and the second marker 47b may be coated with colored paint, in which case cameras for capturing images of the colored paint can be used as the detectors CAM1 and CAM2.

[0047] <Method for calculating the position and orientation of the joining tool (rotating tool)> The method for calculating the position and attitude of a rotary tool according to this embodiment can be explained by taking as an example the method for calculating the position and attitude of a welding tool using the above-described welding tool and friction stir welding system.

[0048] (Detection process) Regardless of whether the shaft 44 of the welding tool 23 is rotating or stationary, the positions of the first marker 47a and the second marker 47b are detected by the marker detection device 19. As described above, the positions of the first marker 47a and the second marker 47b are detected by photographing the first marker 47a and the second marker 47b from different directions using the detection units CAM1 and CAM2.

[0049] 4 is a schematic diagram showing the first marker 47a and the second marker 47b photographed by the detection unit CAM1. The first marker 47a and the second marker 47b are spaced apart from each other in the axial direction of the shaft portion 44, and therefore, as shown in FIG. 4, the detection unit CAM1 can detect the first marker 47a and the second marker 47b individually. The image of the first marker 47a (first marker image 57a) and the image of the second marker 47b (second marker image 57b) are recognized as spheres with portions missing.

[0050] (Position / orientation calculation process) The position and orientation calculation unit calculates the tip position and orientation of the welding tool 23 based on the position information of the first marker 47a and the second marker 47b detected in the detection process. Specifically, a line 56 connecting the center of the first marker image 57a and the center of the second marker image 57b coincides with the rotation axis 46 of the welding tool 23 shown in FIG. 2. Therefore, by capturing images of the first marker 47a and the second marker 47b using the detection units CAM1 and CAM2, the tilt (orientation) of the welding tool 23 can be detected. Furthermore, the tip position of the welding tool 23, which is the processing position, is on the axis of the welding tool 23 and is located a known distance away from the first marker 47a and the second marker 47b. Therefore, once the position and orientation of the tool holder 21 can be identified, the tip position of the welding tool 23 and the direction (orientation) of the axis of the welding tool 23 can also be uniquely identified. Specifically, by measuring in advance the relationship between the positions of the first marker 47a and the second marker 47b and the tip position of the welding tool 23, the actual tip position of the welding tool 23 can be calculated from the first marker image 57a and the second marker image 57b.

[0051] In addition, if a corresponding position table correlating the position information of the first marker 47a and the second marker 47b with the position and posture of the tip of the welding tool 23 is stored in advance in the memory unit, the position and posture calculation unit can easily calculate the tip position and posture of the welding tool 23 based on the position information detected in the detection process and the corresponding position table.

[0052] In the present embodiment configured as described above, the first marker 47a and the second marker 47b provided as the position information detection marker 25 are provided continuously in the circumferential direction of the shaft portion 44, with the rotation axis of the shaft portion 44 as the center.

[0053] Furthermore, in this embodiment, the position information detection marker 25 is provided on the rotating shaft portion 44, so the position of the position information detection marker 25 can be brought closer to the position of the tip of the welding tool 23. Therefore, even if the shaft portion 44 is deflected during welding or the length of the shaft portion 44 changes due to the influence of heat generated during friction stir welding, errors in calculating the tip position of the welding tool 23 can be minimized. Furthermore, the first marker 47a and the second marker 47b are provided continuously in the circumferential direction around the rotation axis of the shaft portion 44. Therefore, when the first marker 47a and the second marker 47b are photographed by the detectors CAM1 and CAM2, the first marker 47a and the second marker 47b can be detected without interruption even while the shaft portion 44 is rotating (during welding), and the accurate position and attitude of the welding tool 23 can be easily calculated.

[0054] When reflective paint is applied to the surfaces of the first marker 47a and the second marker 47b, infrared cameras that also have infrared light emitting functions for optical motion capture can be suitably used as the detection units CAM1 and CAM2. When using infrared cameras, it is preferable to use multiple cameras equipped with infrared irradiation units and capture the light reflected by the position information detection marker 25 from the infrared irradiation units. This enables highly accurate detection of the position information detection marker 25. When colored paint is applied to the surfaces of the first marker 47a and the second marker 47b, multiple cameras equipped with image sensors that can detect and recognize the colored paint can be used.

[0055] In this embodiment, the first marker 47a and the second marker 47b have spherical shapes that respectively constitute parts of virtual spheres 48a and 48b centered on the rotation axis of the shaft portion 44. Therefore, when the rotating shaft portion 44 is photographed, the first marker 47a and the second marker 47b are recognized as spheres from any direction regardless of the position of the detection unit, and the first marker 47a and the second marker 47b can be detected with high accuracy. The virtual spheres 48a and 48b are preferably as close to perfect spheres as possible. However, in the present invention, the surface shapes of the first marker 47a and the second marker 47b are not particularly limited as long as they are continuously arranged circumferentially around the rotation axis of the shaft portion 44. In the present invention, the position information detection markers 25 may include at least two markers, but may also include three or more markers spaced apart from each other. Increasing the number of markers allows the posture of the welding tool 23 to be calculated with even higher accuracy.

[0056] Furthermore, in this embodiment, the information on the tip position and orientation of the welding tool 23 calculated with high accuracy as described above is compared with the information on the estimated position and orientation of the welding tool 23 output from the manipulator 15, thereby determining the amount of correction to correct the position and orientation of the welding tool 23. Therefore, at any timing before or during welding, the manipulator 15 can be driven using this amount of correction to correct the position and orientation of the welding tool 23.

[0057] The operation of detecting the accurate position of the position information detection marker 25 by the detectors CAM1 and CAM2 and calculating the position and orientation of the welding tool 23, as well as the method of correcting the position and orientation of the welding tool 23, will be briefly described below.

[0058] The detection units CAM1 and CAM2 capture images of the first marker 47a and the second marker 47b at instructed timing during construction and output the resulting captured images to the position calculation unit 31. The position calculation unit 31 determines the positions of the first marker 47a and the second marker 47b from the input captured images by image processing and generates position information in the camera coordinate system of the xy plane as marker position information. In other words, the marker detection device 19 calculates the position of each position information detection marker 25 for each captured image of the first marker 47a and the second marker 47b. The position calculation unit 31 outputs the marker position information calculated for each captured image to the control device 17.

[0059] Thereafter, the estimated position and orientation of the welding tool 23 are calculated based on the position and orientation information of the robot arm 27 output from the manipulator 15. Meanwhile, the position and orientation calculation unit calculates the position and orientation of the welding tool 23 using the marker position information detected by the marker detection device 19 and the corresponding position table stored in the storage unit. Thereafter, the correction amount of the position and orientation of the welding tool 23 is calculated according to the difference between the estimated position and orientation of the welding tool 23 and the position and orientation of the welding tool 23 calculated by the position and orientation calculation unit. Thereafter, the control device 17 controls the welding tool 23 based on the drive data based on the welding plan stored in the storage unit, the correction amount, and the like.

[0060] As described above, in this embodiment, the accurate position and orientation of the welding tool 23 can be easily calculated, and therefore it is possible to accurately correct the drive of the manipulator 15. Note that by repeatedly performing this correction, it is possible to achieve even more accurate drive.

[0061] In the above embodiment, a welding tool 23 for friction stir welding and a position and attitude calculation method and system for this welding tool have been described, but the present invention is not limited to the above embodiment. That is, the present invention can be applied to all rotary tools that rotate about a rotation axis, and specifically, to cutting tools, drills, etc. Furthermore, the present invention also contemplates the mutual combination of the configurations of the embodiments, and modifications and applications by those skilled in the art based on the description in the specification and well-known technology, and these modifications and applications are within the scope of the protection sought. [Explanation of symbols]

[0062] 11,13 Parts to be joined 15 Manipulator 17 Control device 19 Marker detection device 23 Joining Tools 23a Probe 23b Shoulder 25 Position detection marker 27 Robot Arm 31 Position calculation section 44 Shaft 46 Rotation axis 47a First marker 47b Second marker 57a First marker image 57b Second marker image 100 Friction Stir Welding System CAM1, CAM2 detection section

Claims

1. A rotary tool having a rotating shaft, the shaft portion has a position information detection marker on a surface thereof for detecting position information of the rotary tool, the position information detection markers include a first marker provided continuously in a circumferential direction of the shaft portion around the rotation axis of the shaft portion, and a second marker provided continuously in a circumferential direction of the shaft portion around the rotation axis of the shaft portion at a position spaced from the first marker in the axial direction of the shaft portion, The rotary tool, wherein the first marker and the second marker are used to calculate a tip position and an attitude of the rotary tool based on the position information.

2. The rotary tool according to claim 1 , wherein the first marker and the second marker each have a spherical shape that constitutes a part of a sphere centered on a point on the rotation axis of the shaft portion.

3. The rotary tool according to claim 1 , wherein the first marker and the second marker are coated with a colored paint or a reflective paint.

4. A method for calculating a position and orientation of a rotary tool, which calculates a tip position and orientation of the rotary tool according to any one of claims 1 to 3 using a marker detection device, comprising: a detecting step of detecting positions of the first marker and the second marker by the marker detection device; a position and orientation calculation step of calculating a tip position and orientation of the rotary tool based on the position information of the first marker and the second marker detected in the detection step.

5. a corresponding position table is previously obtained, which associates the position information of the first marker and the second marker with the tip position and attitude of the rotary tool; 5. The method for calculating the position and orientation of a rotary tool according to claim 4, wherein in the position and orientation calculation step, the position and orientation of the rotary tool corresponding to the position information are calculated by referring to the corresponding position table.

6. A rotary tool position and orientation calculation system for calculating a position and orientation of the rotary tool according to any one of claims 1 to 3, a control device for controlling the position and attitude of the rotary tool on which the position information detection marker is formed; a marker detection device having a plurality of detection units that detect the position information detection marker from different directions; the control device has a position and orientation calculation unit that calculates the tip position and orientation of the rotary tool based on the position information of the first marker and the second marker detected by the marker detection device.

7. the control device includes a storage unit that stores a corresponding position table that associates the position information of the first marker and the second marker with a tip position and an attitude of the rotary tool, 7. The system for calculating the position and orientation of a rotary tool according to claim 6, wherein the position and orientation calculation unit calculates the position and orientation of the rotary tool corresponding to the position information by referring to the corresponding position table.

8. 7. The rotary tool position and orientation calculation system according to claim 6, wherein the plurality of detection units are a plurality of cameras arranged to capture images of the first marker and the second marker from different directions.

9. The first marker and the second marker are coated with a colored paint, 7. The system for calculating the position and orientation of a rotary tool according to claim 6, wherein the detection unit is a camera that captures an image of the colored paint.

10. The first marker and the second marker are coated with a reflective paint that reflects infrared rays, the marker detection device includes an infrared irradiator that irradiates the first marker and the second marker with infrared rays; 7. The system for calculating the position and attitude of a rotary tool according to claim 6, wherein the detection unit is a camera that captures infrared light reflected by the first marker and the second marker.

Images