Collar clamping robot, robot system, method for controlling a collar clamping robot, and program

Abstract

This invention provides a collar tightening robot that can automate the tightening of collars by determining whether the collar has been properly tightened to the zipper. [Solution] The collar tightening robot comprises a collar socket that advances the collar toward the workpiece while rotating it; a seating detection unit that detects when the collar has reached the seating surface of the workpiece; a peak torque detection unit that detects the peak torque of the tightening torque based on the measurement value of a torque sensor; a torque off detection unit that detects when the broken part of the collar has been twisted off and the tightening torque has fallen below a torque off determination value based on the measurement value of the torque sensor; a determination unit that determines whether the tightening of the collar has been completed normally; and an abnormality detection unit that detects an abnormality in the tightening state of the collar.

Description

Technical Field

[0001] The present disclosure relates to a collar fastening robot, a robot system, a control method for a collar fastening robot, and a program.

Background Art

[0002] For example, in an assembly method for structural members such as aircraft fuselage outer panel panels, first, the outer skin of the fuselage is set on a fixing jig, inner members (stringers, frames, shear ties, etc.) to be attached to the inner side of the outer skin are positioned, and then temporary attachment is performed. Thereafter, in order to fasten these inner members to the outer skin, the positions of fastener holes are marked using a Mylar jig or the like, and then drilling of each fastener hole, riveting (fastener insertion), and collar fastening are performed.

[0003] Conventionally, these processes have been performed manually by workers, which requires a great deal of work time. For this reason, in recent years, techniques for automating the assembly process using robots have been considered. For example, Patent Document 1 describes a technique in which each of a plurality of robots connects a single-function end effector such as a drilling tool or a fastener insertion tool, and each robot automatically executes a drilling process or a fastening process on a workpiece.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In conventional robot systems, there has been no means for determining whether or not a collar has been normally fastened. For this reason, it has been difficult to automate collar fastening by robots.

[0006] The purpose of this disclosure is to provide a collar fastening robot, a robotic system, a control method for the collar fastening robot, and a program that can automate the fastening of collars by determining whether the collar has been properly fastened to the fastener. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a collar tightening robot is a collar tightening robot for tightening a collar onto a fastener inserted into a workpiece, comprising: a collar socket that grips the base end of the collar and advances the collar toward the workpiece while rotating it; a seating detection unit that detects when the main body of the collar has reached the seating surface of the workpiece; a peak torque detection unit that detects the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the collar; a torque off detection unit that detects, based on the measurement value of the torque sensor, when the fracture portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below a torque off determination value; and a determination unit that determines whether the tightening of the collar has been completed normally based on the detection results of the seating detection unit, the peak torque detection unit, and the torque off detection unit.

[0008] According to one aspect of the present disclosure, the robot system comprises: a riveting robot positioned on the first member side of a workpiece formed by stacking a first member and a second member, for inserting a fastener into the workpiece; and a collar tightening robot positioned on the second member side of the workpiece, for tightening a collar onto the fastener inserted into the workpiece, wherein the riveting robot includes a first clamp control unit that controls the operation of a first member side end effector that presses the first member of the workpiece, and a third clamp control unit; the collar tightening robot includes a second clamp control unit that controls the operation of a second member side end effector that presses the second member of the workpiece; a collar socket that grips the base end of the collar and moves the collar forward toward the workpiece while rotating it; a seating detection unit that detects when the main body of the collar has reached the seating surface of the workpiece; and a torque sensor that measures the tightening torque of the collar, and the tightening The riveting robot includes a peak torque detection unit for detecting the peak torque, a torque-off detection unit for detecting, based on the measured value of the torque sensor, that the fractured portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below a torque-off determination value, and a determination unit for determining whether the tightening of the collar has been completed normally based on the detection results of the seating detection unit, the peak torque detection unit, and the torque-off detection unit. The first clamp control unit of the riveting robot presses the first member of the workpiece with a first force using the first member-side end effector and then holds the position of the first member-side end effector. The second clamp control unit of the collar tightening robot presses the second member of the workpiece with a second force greater than the first force using the second member-side end effector after the riveting robot has held the position of the first member-side end effector and then holds the position of the second member-side end effector. Furthermore, the third clamp control unit of the riveting robot presses the first member of the workpiece with a third force using the first member-side end effector, and then maintains the position of the first member-side end effector.

[0009] According to one aspect of the present disclosure, a method for controlling a collar fastening robot is a method for controlling a collar fastening robot that fastens a collar to a fastener inserted into a workpiece, comprising the steps of: grasping the base end of the collar and advancing the collar toward the workpiece while rotating it; detecting that the main body of the collar has reached the seating surface of the workpiece; detecting the peak torque of the fastening torque based on the measurement value of a torque sensor that measures the fastening torque of the collar; detecting, based on the measurement value of the torque sensor, that the fracture portion between the base end and the main body of the collar has been twisted off and the fastening torque has fallen below a torque-off determination value; and determining whether the fastening of the collar has been completed normally based on the detection results of the steps of detecting that the seating surface has been reached, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value.

[0010] According to one aspect of the present disclosure, the program causes a collar tightening robot, which tightens a collar onto a fastener inserted into a workpiece, to perform the steps of: grasping the base end of the collar and advancing the collar toward the workpiece while rotating it; detecting that the main body of the collar has reached the seating surface of the workpiece; detecting the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the collar; detecting, based on the measurement value of the torque sensor, that the fracture portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below a torque-off determination value; and determining whether the tightening of the collar has been completed successfully based on the detection results of the steps of detecting that the collar has reached the seating surface, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value. [Effects of the Invention]

[0011] According to the above embodiment, the tightening of the collar can be automated by determining whether the collar has been properly tightened to the zipper. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the overall configuration of the robot system according to the first embodiment. [Figure 2] This figure shows the configuration of the workpiece and workpiece holding jig according to the first embodiment. [Figure 3] This diagram shows the functional configuration of the hole-punching robot according to the first embodiment. [Figure 4] This figure shows the functional configuration of the backup robot according to the first embodiment. [Figure 5] This diagram shows the functional configuration of a rivet-driving robot according to the first embodiment. [Figure 6] This diagram shows the functional configuration of a color clamping robot according to the first embodiment. [Figure 7] This is the first figure showing an example of processing by a robot system according to the first embodiment. [Figure 8] This figure shows an example of a processing position according to the first embodiment. [Figure 9] This is a second figure showing an example of processing by the robot system according to the first embodiment. [Figure 10] This is a diagram illustrating the clamping process according to the first embodiment. [Figure 11] This is the third figure, which shows an example of the processing of the robot system according to the first embodiment. [Figure 12] This is the fourth figure, which shows an example of the processing of the robot system according to the first embodiment. [Figure 13] This is the fifth figure, which shows an example of the processing of the robot system according to the first embodiment. [Figure 14] This is a diagram illustrating the collar tightening process according to the first embodiment. [Figure 15] This is a schematic block diagram showing the configuration of a computer according to the first embodiment. [Modes for carrying out the invention]

[0013] <First Embodiment> Hereinafter, the first embodiment will be described in detail with reference to the drawings.

[0014] (Overall Configuration of Robot System) FIG. 1 is a schematic diagram showing the overall configuration of a robot system according to a first embodiment. As shown in FIG. 1, a robot system 1 includes a plurality of robots 100A to 100D, and a robot traveling device 40. The robot system 1 automatically executes each step of assembling a workpiece 30 by causing the plurality of robots 100A to 100D to cooperate with each other. In the present embodiment, a configuration in which the robot system 1 includes four robots: a drilling robot 100A, a backup robot 100B, a riveting robot 100C, and a collar fastening robot 100D will be described as an example. Note that the robot system 1 is not limited to the configuration example shown in FIG. 1, and may include any number of robots as long as there are two or more robots.

[0015] The workpiece 30 is formed by overlapping a first member 301 and a second member 302. One of the first member 301 and the second member 302 is a member arranged on the outer side of the product, and the other is a member arranged on the inner side of the product. Further, another member may be further arranged between the first member 301 and the second member 302. FIG. 1 shows an example in which the first member 301 is an outer skin of a fuselage outer panel of an aircraft, and the second member 302 is an inner member (a stringer, a frame, a shear tie, etc.) attached to an inner surface of the outer skin. In the following description, the longitudinal direction of the workpiece 30 is also referred to as the "width direction", the height direction as the "vertical direction", and the stacking direction of the workpiece 30 (the first member 301 and the second member 302) as the "depth direction".

[0016] The drilling robot 100A and the riveting robot 100C are positioned on the first member 301 side of the workpiece 30 (outside the fuselage outer panel). The backup robot 100B and the collar tightening robot 100D are positioned on the second member 302 side of the workpiece 30 (inside the fuselage outer panel). In the following description, the drilling robot 100A and the riveting robot 100C positioned on the first member 301 side may be referred to as "outside robots (first member side robots)," and the backup robot 100B and the collar tightening robot 100D positioned on the second member 302 side may be referred to as "inside robots (second member side robots)."

[0017] The hole-punching robot 100A, in cooperation with the backup robot 100B, performs the process of clamping the workpiece 30, and then performs the process of punching fastener holes in the workpiece 30. The clamping process is a process of pressing down on the workpiece 30 from both the first member 301 side and the second member 302 side so that there are no gaps between the overlapping members. The riveting robot 100C, in cooperation with the collar-tightening robot 100D, performs the process of clamping the workpiece 30, and then performs the process of riveting the fastener into the fastener holes punched by the hole-punching robot 100A. After the riveting of the fastener is finished, the collar-tightening robot 100D performs the process of tightening the collar onto the fastener while continuing to clamp the workpiece 30.

[0018] The robot travel device 40 is, for example, a travel rail, which allows each robot 100A to 100D to move along the width direction of the workpiece 30.

[0019] (Configuration of the workpiece holding jig) Figure 2 shows the configuration of the workpiece and workpiece holding jig according to the first embodiment. As shown in Figures 1 and 2, the workpiece 30 is fixed and held in the workpiece holding jig 20. The workpiece holding jig 20 is movable, for example, along a guide rail 22 provided in the work area. One or more jig positioning devices 23 may also be provided near the guide rail 22. The workpiece holding jig 20 is precisely installed in a predetermined position within the work area with the jig positioning device 23 as the reference position.

[0020] As shown in Figure 2, jig reference blocks 201 and 202 are provided at both ends of the workpiece holding jig 20 in the width direction to indicate the mounting reference position of the workpiece 30. For example, the jig reference block 201 provided on one side in the width direction has an L-shaped cross-section, and the jig reference block 202 provided on the other side has a rectangular cross-section. By aligning the lower corner of one side of the workpiece 30 in the width direction with the inner surface 201a of the jig reference block 201, and aligning the lower corner of the other side of the workpiece 30 in the width direction with the upper surface 202a of the jig reference block 202, the workpiece 30 can be accurately mounted to the specified position on the workpiece holding jig 20. Note that multiple workpiece holding jigs 20 with different positions and shapes of jig reference blocks 201 and 202 depending on the shape of the workpiece 30 may be provided. The workpiece holding jig 20 may also be provided with a clamper 203 to prevent the mounted workpiece 30 from falling off or shifting, and a faceplate 204 to reproduce the nominal shape of the workpiece 30.

[0021] Furthermore, above the workpiece holding jig 20, a plurality of first reference members 21 are provided at intervals in the width direction. The first reference members 21A to 21G are blocks or dot plates, etc., with holes indicating reference positions. Each robot 100A to 100D can set its robot coordinates to match the position and inclination of the workpiece 30 by detecting the reference positions (holes) of the first reference members 21 and the inclination of the surface of the first reference members 21 (the surface facing the robots 100A to 100D). Details of how to set the robot coordinates of robots 100A to 100D will be described later. The first reference members 21A to 21G are provided in positions detectable by robots 100A to 100D from both the first member 301 side (outside) and the second member 302 side (inside). Alternatively, the first reference members 21A to 21G may be provided in pairs on both the first member 301 side (outside) and the second member 302 side (inside) of the workpiece holding jig 20. In this case, the pair of first reference members 21A are installed facing each other across the workpiece holding jig 20 so that the widthwise and heightwise positions of the outer first reference member 21A and the inner first reference member 21A coincide. Although Figures 1 and 2 show an example in which seven first reference members 21A to 21G are provided, the number of first reference members 21 may be changed according to the size of the workpiece 30, etc.

[0022] In this embodiment, after the first member 301 and the second member 302 are temporarily attached by an operator, the robot system 1 performs the assembly process. In the temporary attachment, the first member 301 and the second member 302 of the workpiece 30 are overlapped and pilot holes are drilled, and these pilot holes are temporarily fastened with bolts 31 (the parts indicated by black circles in Figure 2). The robot system 1 then performs the following processes on the temporarily attached workpiece 30: drilling fastener holes at predetermined processing positions 32, inserting fasteners, and tightening collars.

[0023] If the widthwise length of the workpiece 30 is large, the robot system 1 may divide the workpiece 30 into multiple processing areas A1 to A6, as shown in the example in Figure 2, and move robots 100A to 100D to each processing area A1 to A6 before executing each process. In this case, the first reference member 21 indicating the reference position of the workpiece 30 is placed at both ends in the widthwise direction of each processing area A1 to A6.

[0024] (Functional configuration of a hole-punching robot) Figure 3 is a diagram showing the functional configuration of a drilling robot according to the first embodiment. As shown in Figures 1 and 3, the drilling robot 100A includes an arm 11, an end effector 12, a first sensor 13, a second sensor 14, and a control device 10A.

[0025] The arm 11 can change its posture through multiple rotatable joints, allowing the end effector 12 to be moved to the appropriate position and orientation.

[0026] The end effector 12 is a single-function end effector that performs the process assigned to each robot. The end effector 12 of the drilling robot 100A includes a drill 121 for drilling, a pressure foot 122 for pressing against the workpiece 30 (first member 301), a force sensor 123 for measuring the pressing force [N] of the pressure foot 122, and a drive unit 124 for rotating and moving the drill 121 back and forth. The pressure foot 122 of the drilling robot 100A is, for example, a cylindrical resin member and is arranged concentrically with the drill 121. The pressure foot 122 presses against the workpiece 30 (first member 301) with its end face 122a. The drive unit 124 includes, for example, a servo motor for rotating the drill 121 and an actuator for moving the drill back and forth.

[0027] The first sensor 13 is located on the tip side of the end effector 12 (the side facing the workpiece 30). The first sensor 13 is a 3D vision sensor capable of detecting the position and tilt of the object to be detected.

[0028] Multiple second sensors 14 are provided on the tip side (the side facing the workpiece 30) of the end effector 12. The second sensors 14 are laser distance sensors that measure the distance between the second sensors 14 and the surface of the workpiece 30 when the drilling robot 100A points the end effector 12 towards the workpiece 30. In this embodiment, as shown in Figures 1 and 2, the second sensors 14 include a pair of second sensors 14a and 14b provided above and below the end effector 12, and a pair of second sensors 14c and 14d provided on the left and right sides. In other words, the second sensors 14 include four sensors: the upper second sensor 14a, the lower second sensor 14b, the left second sensor 14c, and the right second sensor 14d.

[0029] The control device 10A controls the operation of the drilling robot 100A. The control device 10A includes a first reference position detection unit 1001, a coordinate setting unit 1002, a second reference position detection unit 1003, a machining position determination unit 1004, a first position control unit 1005, a first clamp control unit 1011, a third clamp control unit 1013, and a drilling control unit 1021.

[0030] The first reference position detection unit 1001 detects two first reference members 21, which are spaced apart in the width direction of the workpiece holding jig 20, using the first sensor 13.

[0031] The coordinate setting unit 1002 sets the robot coordinates based on the detection information of the first reference member 21. The detection information of the first reference member 21 includes information such as the position (3D coordinate) of the reference position (hole) of the two detected first reference members 21 and the inclination of the surface of the first reference member 21 (the surface facing the drilling robot 100A).

[0032] The second reference position detection unit 1003 detects a second reference member on the workpiece 30 using the first sensor 13. In this embodiment, the second reference member is a bolt 31 used for temporarily fastening the workpiece 30. In other embodiments, other components (such as marks marked on the workpiece 30) may be used as the second reference member.

[0033] The machining position determination unit 1004 determines the coordinates (3D coordinates) of the machining position 32 of the workpiece 30 in robot coordinates based on the detection information of the second reference member 31.

[0034] The first position control unit 1005 controls the posture of the drilling robot 100A (arm 11) based on the coordinates of the machining position 32 determined by the machining position determination unit 1004, and moves the end effector 12 of the drilling robot 100A to the machining position 32.

[0035] As shown in the example in Figure 1, the workpiece 30 may have various shapes, such as a curved shape that bulges outwards. For this reason, after moving the end effector 12 to the machining position 32, the first position control unit 1005 corrects the posture of the drilling robot 100A (arm 11) based on the distance measured by each of the second sensors 14a to 14d so that the end effector 12 faces in a direction perpendicular to the surface of the workpiece 30 at the machining position 32 (the outer surface 301a of the first member 301). When the first position control unit 1005 has performed the plane straightening correction, it corrects the coordinates of the machining position 32 based on the posture after the plane straightening correction.

[0036] The machining position transmission unit 1006 transmits the coordinates of the machining position 32 to the other robots 100B to 100D. If the first position control unit 1005 corrects the coordinates of the machining position 32, the machining position transmission unit 1006 transmits the corrected coordinates of the machining position 32 to the other robots 100B to 100D.

[0037] The first clamp control unit 1011 and the third clamp control unit 1013 control the operation of the clamping process of the workpiece 30 while monitoring the measured value of the force sensor 123 after the end effector 12 has moved to the processing position 32. In the clamping process, the first member-side robot and the second member-side robot work together to press the workpiece 30 from both sides. The first clamp control unit 1011 and the third clamp control unit 1013 of the drilling robot 100A control the pressing of the workpiece 30 from the first member 301 side (the outside in this embodiment).

[0038] After the first clamping control unit 1011 and the third clamping control unit 1013 have completed clamping the workpiece 30, the hole-punching control unit 1021 controls the drive unit 124 to punch fastener holes in the workpiece 30.

[0039] (Functional configuration of the backup robot) Figure 4 is a diagram showing the functional configuration of the backup robot according to the first embodiment. As shown in Figures 1 and 4, the backup robot 100B comprises an arm 11, an end effector 12, a first sensor 13, and a control device 10B. The functional configuration of the arm 11 and the first sensor 13 of the backup robot 100B is the same as that of the arm 11 and the first sensor 13 of the drilling robot 100A.

[0040] The end effector 12 of the backup robot 100B includes a pressure foot 122 that presses against the inside of the workpiece 30 (second member 302), a force sensor 123 that measures the pressing force [N] of the pressure foot 122, and the like. The pressure foot 122 of the backup robot 100B is a resin member having a shape that does not come into contact with the drill 121 of the drilling robot 100A, such as a U-shape with an open upper end.

[0041] The control device 10B controls the operation of the backup robot 100B. The control device 10B includes a first reference position detection unit 1001, a coordinate setting unit 1002, a processing position receiving unit 1007, a second position control unit 1008, and a second clamping control unit 1012. The functions of the first reference position detection unit 1001 and the coordinate setting unit 1002 of the backup robot 100B are the same as those of the first reference position detection unit 1001 and the coordinate setting unit 1002 of the drilling robot 100A.

[0042] The processing position receiving unit 1007 receives the coordinates of the processing position 32 from the drilling robot 100A.

[0043] The second position control unit 1008 moves the end effector 12 of the backup robot 100B to the coordinates of the processing position 32 received from the drilling robot 100A.

[0044] The second clamp control unit 1012 controls the operation of the clamping process for the workpiece 30 while monitoring the measured value of the force sensor 123 after the end effector 12 has moved to the processing position 32. The second clamp control unit 1012 of the backup robot 100B controls the pressing of the workpiece 30 from the second member 302 side (in this embodiment, the inside).

[0045] (Functional configuration of a riveting robot) Figure 5 shows the functional configuration of a riveting robot according to the first embodiment. As shown in Figure 5, the riveting robot 100C comprises an arm 11, an end effector 12, a first sensor 13, a second sensor 14, and a control device 10C. The functional configuration of the arm 11, the first sensor 13, and the second sensor 14 of the riveting robot 100C is the same as that of the arm 11, the first sensor 13, and the second sensor 14 of the hole-punching robot 100A.

[0046] The end effector 12 of the riveting robot 100C includes a pressure foot 122 that presses against the outside of the workpiece 30 (first member 301), a force sensor 123 that measures the pressing force [N] of the pressure foot 122, a fastener gripping part 125 that grips the fastener 50, and a hammering unit 126 into which the fastener 50 is inserted. The pressure foot 122 of the riveting robot 100C is, like that of the drilling robot 100A, a resin member having, for example, a cylindrical shape, and is arranged concentrically with the fastener gripping part 125. The pressure foot 122 presses against the outside of the workpiece 30 with its end face 122a. The hammering unit 126 inserts the fastener 50, which is gripped by the fastener gripping part 125, into the processing position 32 (fastener hole) of the workpiece 30.

[0047] The control device 10C controls the operation of the riveting robot 100C. The control device 10C includes a first reference position detection unit 1001, a coordinate setting unit 1002, a second reference position detection unit 1003, a processing position determination unit 1004, a processing position receiving unit 1007, a second position control unit 1008, a first clamp control unit 1011, a third clamp control unit 1013, and a riveting control unit 1031. The functions of the first reference position detection unit 1001, coordinate setting unit 1002, second reference position detection unit 1003, processing position determination unit 1004, first clamp control unit 1011, and third clamp control unit 1013 of the riveting robot 100C are the same as those of the first reference position detection unit 1001, coordinate setting unit 1002, second reference position detection unit 1003, processing position determination unit 1004, first clamp control unit 1011, and third clamp control unit 1013 of the drilling robot 100A. Furthermore, the functions of the processing position receiving unit 1007 and second position control unit 1008 of the riveting robot 100C are the same as those of the processing position receiving unit 1007 and second position control unit 1008 of the backup robot 100B.

[0048] After the first clamping control unit 1011 and the third clamping control unit 1013 have completed clamping the workpiece 30, the riveting control unit 1031 controls the hammering unit 126 to insert the fastener 50 into the processing position 32 (fastener hole drilled by the drilling robot 100A) received from the drilling robot 100A. As described above, since the fastener size differs for each processing position 32, the riveting control unit 1031 refers to the design information of the workpiece 30 and selects and inserts the fastener 50 corresponding to the fastener size of the processing position 32. The design information of the workpiece 30, including the fastener size instruction, may be stored in advance by the riveting robot 100C, or the riveting robot 100C may acquire it from a design information database (not shown) at a predetermined timing before the assembly of the workpiece 30 is performed.

[0049] As a backup for the coordinate sharing function from the drilling robot 100A, a second sensor 14 is provided to enable the riveting robot 100C to perform positioning independently, and to enable more precise alignment with the collar tightening robot 100D described later, allowing for independent plane alignment correction.

[0050] (Functional configuration of a color-tightening robot) Figure 6 shows the functional configuration of a collar clamping robot according to the first embodiment. As shown in Figure 6, the collar clamping robot 100D includes an arm 11, an end effector 12, a first sensor 13, a second sensor 14, and a control device 10D. The functional configuration of the arm 11, the first sensor 13, and the second sensor 14 of the collar clamping robot 100D is the same as that of the arm 11, the first sensor 13, and the second sensor 14 of the drilling robot 100A.

[0051] The end effector 12 of the collar fastening robot 100D includes a pressure foot 122 that presses against the inside of the workpiece 30 (second member 302), a force sensor 123 that measures the pressing force [N] of the pressure foot 122, a collar socket 127 that grips the collar 51, a drive unit 128 that rotates and moves the collar socket 127 back and forth, a torque sensor 129, and the like. The pressure foot 122 of the collar fastening robot 100D is a resin member having a shape that does not come into contact with the fastener 50 into which the riveting robot 100C is inserted, such as a U-shape with an open upper end. Also, as shown in the example in Figure 6, the collar 51 has a main body portion 511 that is fastened to the fastener 50, a base end portion 512, and a break portion 513 between the main body portion 511 and the base end portion 512. The collar socket 127 of the end effector 12 is a vacuum chuck that holds, for example, the base end 512 of the collar 51 by suction. The collar 51 is tightened to the fastener 50 by the rotation and forward movement of the collar socket 127. When the collar seating surface 511a, which is the end face of the collar 51 facing the workpiece 30, sits on the surface (seating surface) of the workpiece 30, the break portion 513 is twisted off, leaving only the main body portion 511 on the fastener 50. The drive unit 128 includes a servo motor for rotating the collar socket 127 and a servo motor for moving the collar socket 127 forward and backward. The torque sensor 129 measures the tightening torque [Nm] of the collar 51.

[0052] To provide a backup for the coordinate sharing function from the drilling robot 100A, and to enable the collar tightening robot 100D to perform positioning independently, as well as to enable more precise alignment with the riveting robot 100C, a second sensor 14 is provided to allow for independent plane alignment correction.

[0053] The control device 10D controls the operation of the collar clamping robot 100D. The control device 10D includes a first reference position detection unit 1001, a coordinate setting unit 1002, a second reference position detection unit 1003, a processing position determination unit 1004, a processing position receiving unit 1007, a second position control unit 1008, a second clamp control unit 1012, a collar clamping control unit 1041, a seating detection unit 1042, a peak torque detection unit 1043, a torque off detection unit 1044, a determination unit 1045, and an abnormality detection unit 1046. The functions of the first reference position detection unit 1001, coordinate setting unit 1002, second reference position detection unit 1003, and processing position determination unit 1004 of the color clamping robot 100D are the same as those of the first reference position detection unit 1001, coordinate setting unit 1002, second reference position detection unit 1003, and processing position determination unit 1004 of the drilling robot 100A. Furthermore, the functions of the processing position receiving unit 1007, second position control unit 1008, and second clamp control unit 1012 of the color clamping robot 100D are the same as those of the processing position receiving unit 1007, second position control unit 1008, and second clamp control unit 1012 of the backup robot 100B.

[0054] The collar tightening control unit 1041 grips a collar 51 of a size corresponding to the fastener 50 inserted by the riveting robot 100C with the collar socket 127, and controls the drive unit 128 to rotate and advance the collar socket 127. The design information of the workpiece 30, including the fastener size, may be stored in advance by the collar tightening robot 100D, or the collar tightening robot 100D may acquire it from a design information database (not shown) at a predetermined timing before performing the assembly of the workpiece 30.

[0055] The seating detection unit 1042 detects that the main body 511 of the collar 51 has reached the seating surface of the workpiece 30 (the inner surface 302a of the second member 302). The seating detection unit 1042 detects from the amount of movement of the collar socket 127 of the end effector 12 that the main body 511 of the collar 51 has advanced to a set position, that is, that it has reached the seating surface.

[0056] The peak torque detection unit 1043 detects the peak torque of the tightening torque of the collar 51 based on the measurement value of the torque sensor 129.

[0057] The torque-off detection unit 1044 detects, based on the measurement value from the torque sensor 129, that the broken portion 513 of the collar 51 has been twisted off and the tightening torque has fallen below the torque-off judgment value.

[0058] The determination unit 1045 determines whether the tightening of the collar 51 has been completed successfully based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque-off detection unit 1044.

[0059] If the abnormality detection unit 1046 determines that the tightening of the collar 51 has not been completed normally, it detects an abnormality in the collar tightening state based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque-off detection unit 1044.

[0060] (Example of robot system processing 1) Figures 7 and 9 show an example of the processing of the robot system according to the first embodiment. Figure 8 shows an example of the processing position according to the first embodiment. Figure 10 is a diagram illustrating the clamping process according to the first embodiment. Hereinafter, the flow of a series of processes of the robot system 1, including (1) robot coordinate setting process, (2) positioning process, (3) clamping process, and (4) drilling process, will be described with reference to Figures 7 to 10.

[0061] In these processes, the drilling robot 100A and the backup robot 100B work in coordination. During this time, the riveting robot 100C and the collar tightening robot 100D are waiting in their retracted positions (step S301).

[0062] The drilling robot 100A moves to processing area An (step S101). At this time, the drilling robot 100A instructs the backup robot 100B to move to processing area An. Then, the backup robot 100B moves to processing area An as instructed by the drilling robot 100A (step S201). Processing area An is one of several processing areas A1 to A6 (Figure 2). For example, the drilling robot 100A and the backup robot 100B first move to processing area A1.

[0063] When the drilling robot 100A and the backup robot 100B move to the processing area A1, they each execute the robot coordinate setting process (1) in Figure 7 in parallel. Specifically, the first reference position detection unit 1001 of the drilling robot 100A detects the first reference members 21 provided at both ends in the width direction of the processing area An using the first sensor 13 (step S102). Similarly, the first reference position detection unit 1001 of the backup robot 100B detects the first reference members 21 provided at both ends in the width direction of the processing area An using the first sensor 13 (step S202). When the drilling robot 100A and the backup robot 100B move to the processing area A1, the first reference position detection unit 1001 of each robot 100A and 100B detects the first reference members 21A and 21B (Figure 2) provided at both ends in the width direction of the processing area A1.

[0064] The coordinate setting unit 1002 of the drilling robot 100A sets the robot coordinates of the drilling robot 100A based on the detection information of the first reference member 21 (step S103). The detection information includes the coordinates of the reference positions of each of the two first reference members 21 (for example, the position of the hole provided in the center), the inclination of the robot-facing surface of each of the two first reference members 21, and the distance between the reference positions of the two first reference members. Taking the processing area A1 as an example, the coordinate setting unit 1002 of the drilling robot 100A sets one of the two detected reference positions of the first reference members 21A and 21B (for example, the reference position of the first reference member 21A) as the origin of the robot coordinates. The coordinate setting unit 1002 of the drilling robot 100A also performs a correction to match the inclination of the surfaces of the first reference members 21A and 21B with the inclination of the robot coordinate plane. Furthermore, the coordinate setting unit 1002 of the drilling robot 100A may correct the robot coordinates based on the difference between the design distance from the reference position of one first reference member 21A to the reference position of the other first reference member 21B and the distance between the reference positions included in the detection information. The coordinate setting unit 1002 of the backup robot 100B performs the same processing as the coordinate setting unit 1002 of the drilling robot 100A, and sets (corrects) the robot coordinates of the backup robot 100B with the same reference position of the first reference member 21A as the origin (step S203). This makes it possible to align the origin of the robot coordinates of the drilling robot 100A (upper right origin), the origin of the robot coordinates of the backup robot 100B (upper left origin), and the design coordinate origin of the workpiece 30 with the same reference position of the first reference member 21A. Note that the coordinate setting by the first reference member 21 only needs to be done once for each processing area A1 to A6.

[0065] Once the robot coordinates are set, the drilling robot 100A and the backup robot 100B begin the positioning process shown in Figure 7 (2). At this time, the backup robot 100B waits at a predetermined standby position until it receives the coordinates of the machining position 32 from the drilling robot 100B (step S204).

[0066] In the positioning process, the drilling robot 100A detects the second reference member 31 (step S104) and determines the coordinates of the processing position 32 (step S105) for each target area (for example, a rectangular area with sides of 30 to 50 cm) within the processing area An.

[0067] Figure 8 is an enlarged view of a part of the processing area A1 in Figure 2. Specifically, using the processing area A1 in Figure 8 as an example, the second reference position detection unit 1003 detects two second reference members 31a and 31b in order from the one closest to the origin of the robot coordinates (step S104). For example, the design information of the workpiece 30 includes the position of the second reference member 31, and the second reference position detection unit 1003 may move the first sensor 13 to the coordinates indicated in the design information to detect the second reference member 31. The design information of the workpiece 30 may be stored in advance by each robot 100A to 100D, or each robot 100A to 100D may acquire it from a design information database (not shown) at a predetermined timing before the start of work on the workpiece 30.

[0068] The machining position determination unit 1004 determines the coordinates of the machining position 32 of the fastener hole using the machining pitch set for each of the detected second reference members 31a and 31b (step S105). The design information of the workpiece 30 further includes, for example, the pitch of the fastener hole based on the second reference members 31a and 31b. The machining position determination unit 1004 determines the coordinates of the machining positions 32a to 32f in the target range R1 below the second reference members 31a and 31b using the pitch defined in the design information (step S105).

[0069] Furthermore, since other target ranges R2, R3, R4, ... remain in the processing area A1 besides the second reference members 31a, 31b (step S106; NO), the same processing steps S104 to S105 are performed for the other target ranges as well. For example, the second reference position detection unit 1003 then detects the second reference members 31b, 31c (step S104), and the processing position determination unit 1004 determines the coordinates of the processing position 32 in the target range R2 below the second reference members 31b, 31c at the pitch specified in the design information (step S105). The coordinates of the processing position 32 are similarly determined for target ranges R3, R4, ... If the coordinates of the processing position 32 for all target ranges have been determined (step S106; YES), the process proceeds to the next step S107.

[0070] Next, the first position control unit 1005 moves the end effector 12 to the machining position i where the hole will be drilled (step S107).

[0071] The order of drilling is predetermined by the program of the drilling robot 100A. Depending on the type and position of the first member 301 and the second member 302 used in the workpiece 30, different sizes of fasteners may be used. For this reason, the design information of the workpiece 30 specifies the fastener size for each processing position, and the drilling robot 100A needs to drill fastener holes of the specified size. For example, suppose the fastener size at processing positions 32a to 32d and 32g to 32h in Figure 8 is diameter D1, the fastener size at the other processing positions 32e to 32f, 32i, and 32j to 32o is diameter D2, and the drill 121 attached to the end effector 12 of the drilling robot 100A has a diameter of D1. In this case, the drilling robot 100A, following the program, drills holes in the order of machining positions 32a, 32b, 32c, 32d, 32g, and 32h, then switches to a drill 121 with a diameter of D2 and drills holes in the order of machining positions 32e, 32f, 32i, 32j, 32k, 32l, 32m, 32n, and 32o. In this example in Figure 8, the first position control unit 1005 first moves the end effector 12 to machining position i = machining position 32a in step S107.

[0072] After moving the end effector 12 to the processing position 32a, the first position control unit 1005 performs the following: Surface orientation correction is performed using the second sensor 14 (step S108). Surface orientation correction is the process of correcting the posture of the drilling robot 100A (arm 11) so that the end effector 12 (drill 121) is oriented perpendicular to the outer surface of the workpiece 30 (outer surface 301a of the first member). Specifically, the first position control unit 1005 corrects the posture of the drilling robot 100A so that the measured distances to the outer surface 301a of the workpiece 30 by the second sensors 14a and 14b, which are positioned in the vertical direction of the end effector 12, are the same, and the measured distances to the outer surface 301a of the workpiece 30 by the second sensors 14c and 14d, which are positioned in the horizontal direction of the end effector 12, are the same. The measurement distances being the same means that the error in the measurement distances of the two sensors is within an acceptable range. Once the plane alignment correction is complete, the first position control unit 1005 corrects the coordinates of the machining position 32a based on the orientation of the drilling robot 100A after the plane alignment correction.

[0073] Next, the machining position transmission unit 1006 of the drilling robot 100A transmits the coordinates of the machining position 32a to the other robots 100B, 100C, and 100D (step S109). The coordinates of the machining position 32a transmitted here are the coordinates after surface perpendicularity correction.

[0074] When the processing position receiving unit 1007 of the riveting robot 100C and the collar fastening robot 100D receives the coordinates of the processing position 32a, they are stored in the memory devices of each robot (step S302).

[0075] Furthermore, when the processing position receiving unit 1007 of the backup robot 100B receives the coordinates of the processing position 32a, the second position control unit 1008 of the backup robot 100B moves the end effector 12 of the backup robot 100B to the received coordinates of the processing position 32a (step S205).

[0076] As described above, the drilling robot 100A and the backup robot 100B set their robot coordinates based on the same reference position (reference position of the first reference member 21), so the robot coordinates of the drilling robot 100A and the backup robot 100B each start from the same origin (however, since the backup robot 100B is facing in the opposite direction to the drilling robot 100A, the robot coordinates of the drilling robot 100A and the robot coordinates of the backup robot 100B are reversed left and right). For this reason, the position of the processing position 32a of the workpiece 30 can be made to coincide with the same coordinates in the robot coordinates of the drilling robot 100A and the robot coordinates of the backup robot 100B. However, as in the example in Figure 1, if the workpiece 30 has a curved shape that bulges outwards, the inclination of the workpiece 30 as seen from the outer drilling robot 100A and the inclination of the workpiece 30 as seen from the inner backup robot 100B will not match. Therefore, the second position control unit 1008 of the backup robot 100B transforms the coordinates of the machining position 32a based on the design shape included in the design information of the workpiece 30 so that the end effector 12 of the backup robot 100B is oriented perpendicular to the inner surface of the workpiece 30 (inner surface 302a of the second member), and moves the end effector 12 to the transformed coordinates of the machining position 32a. At this time, since the coordinates of the machining position 32a are precisely determined by the drilling robot 100A based on the second reference member 31 and after surface orientation correction, the second position control unit 1008 of the backup robot 100B can accurately approach the machining position 32a by performing only a simple coordinate transformation based on the design shape. In other words, the backup robot 100B can omit time-consuming processes such as detection of the second reference member 31, determination of the machining position coordinates, and surface orientation correction.

[0077] Next, the drilling robot 100A and the backup robot 100B perform the clamping process (3) in Figure 7 (steps S110, S210).

[0078] The processing flow of the clamping process will be explained with reference to Figure 9. In Figure 9, the outer robot OML corresponds to the drilling robot 100A, and the inner robot IML corresponds to the backup robot 100B.

[0079] First, the first clamp control unit 1011 of the drilling robot 100A starts measuring with the force sensor 123 (step S1101). Also, the second clamp control unit 1012 of the backup robot 100B starts measuring with the force sensor 123 (step S2101) and waits with the end effector 12 positioned in a standby position just before the machining position 32a of the workpiece 30 (for example, 5 mm before the inner surface 302a of the workpiece 30).

[0080] Next, the first clamp control unit 1011 of the drilling robot 100A moves the end effector 12 to a standby position in front of the machining position 32a of the workpiece 30 (for example, 5 mm in front of the outer surface 301a of the workpiece 30), and then starts a force control mode in which the pressure foot 122 presses against the outer surface 301a of the workpiece 30 with a first force F1 (step S1102).

[0081] The first force F1 is set to a pressure less than the pressure at which plastic deformation of the workpiece 30 occurs, for example. For example, an aircraft fuselage panel may undergo plastic deformation if a pressure greater than 50 N is applied from one side. Therefore, the first force F1 is set to a pressure less than 50 N (e.g., 20 N).

[0082] Figure 10 illustrates the time series of measured values ​​(pressing force [N]) from the force sensors 123 of the drilling robot 100A and the backup robot 100B, respectively. In Figure 10, OML represents the drilling robot 100A and IML represents the backup robot 100B. In the example in Figure 10, the first clamp control unit 1011 of the drilling robot 100A starts pressing with a first force F1 at time t1 (step S1102).

[0083] Furthermore, the first clamp control unit 1011 of the drilling robot 100A presses the outer surface 301a with a first force F1 for a predetermined pressing time Tp (for example, 1 second), and then switches to a position-holding mode that holds the position of the end effector 12 in its current position (step S1103). In the example in Figure 10, the first clamp control unit 1011 of the drilling robot 100A switches to the position-holding mode at time t2 (step S1103).

[0084] Next, the second clamp control unit 1012 of the backup robot 100B starts a force control mode in which it presses the pressure foot 122 against the inner surface 302a of the workpiece 30 with a second force F2 at the processing position 32a of the workpiece 30 after the drilling robot 100A has switched to position holding mode (step S2103). For example, the second clamp control unit 1012 of the backup robot 100B may execute step S2013 after a predetermined time (pressing time Tp+α) after the start of the clamping process, or it may receive notification from the drilling robot 100A that it has switched to position holding mode. In the example in Figure 10, the second clamp control unit 1012 of the backup robot 100B starts pressing at time t3 (step S2103). The second force F2 is set to a pressing force (e.g., 150N, 300N, etc.) that can suppress the formation of gaps between the members of the workpiece 30.

[0085] Furthermore, the second clamp control unit 1012 of the backup robot 100B presses the inner surface 302a with a second force F2 for a predetermined pressing time Tp (e.g., 1 second), and then switches to a position-holding mode that holds the position of the end effector 12 in its current position (step S2103). In the example in Figure 10, the second clamp control unit 1012 of the backup robot 100B switches to the position-holding mode at time t4 (step S2104).

[0086] When the backup robot 100B presses the workpiece 30 with a second force F2 at time t3, the drilling robot 100A maintains the position of the end effector 12. As shown in the example in Figure 10, the force sensor 123 of the drilling robot 100A detects the same pressing force as the second force F2 due to the pressing by the backup robot 100B. Therefore, the clamping process of the workpiece 30 may be terminated at this point (time t4).

[0087] However, in the drilling robot 100A, the control command value to the end effector 12 (first force F1) and the measured value of the force sensor 123 (second force F2) do not match. If the control command value and the measured value remain in this mismatch, problems may occur in the control of the drilling robot 100A. For this reason, the third clamp control unit 1013 of the drilling robot 100A may start a force control mode in which the pressure foot 122 is pressed against the outer surface 301a of the workpiece 30 with a third force F3 after the backup robot 100B switches to position holding mode in step S2104 (step S1104). In this case, the value of the third force F3 is set to the value obtained by subtracting the first force F1 from the second force F2. For example, the first clamp control unit 1011 of the drilling robot 100A switches to position holding mode in step S1103. Subsequently, the third clamp control unit 1013 of the drilling robot 100A receives notification from the backup robot 100B that it has switched to position holding mode, and then executes step S1104. After executing step S1104, the third clamp control unit 1013 of the drilling robot 100A switches to position holding mode, which holds the position of the end effector 12 at its current position after a predetermined pressing time Tp (step S1105). In this way, the control command value and the measured value in the drilling robot 100A can be matched.

[0088] Once the clamping process is complete, the drilling robot 100A continues to clamp the workpiece 30 and performs the drilling process shown in Figure 7 (4). At this time, the backup robot 100B continues to clamp the workpiece 30 and backs up the drilling robot 100A (step S220). In the drilling process, first, the drilling control unit 1021 of the drilling robot 100A performs drilling at the processing position 32a using the end effector 12 (step S120).

[0089] Once drilling is complete, the first clamp control unit 1011 of the drilling robot 100A lowers the end effector 12 to a position a certain distance away from the workpiece 30, releasing the clamp on the workpiece 30 (step S121). Similarly, the second clamp control unit 1012 of the backup robot 100B lowers the end effector 12 to a position a certain distance away from the workpiece 30, releasing the clamp on the workpiece 30 (step S221). Steps S112 and S212 may be performed simultaneously.

[0090] Next, the drilling robot 100A determines whether it has completed drilling at all machining positions 32 in the machining area A1 (step S130). If drilling at machining position 32a is completed, drilling at the other machining positions 32b, 32c, ... is not yet complete (step S130; NO). In this case, the drilling robot 100A returns to step S107 and repeatedly executes the following processes for each of the next machining positions 32b, 32c, ...: (2) positioning process (steps S107-S109), (3) clamping process (step S110), and (4) drilling process (steps S120-S121). Similarly, if drilling at other machining positions 32 is not completed (step S230; NO), the backup robot 100B returns to step S204 and, based on the hole position coordinate transmission information from the drilling robot 100A (the coordinates of the machining position 32 transmitted by the drilling robot 100A in step S109), repeatedly performs the following processes for each of the next machining positions 32b, 32c, ...: (2) positioning process (steps S204~S205), clamping process (step S210), and (4) backup drilling process (steps S220~S221).

[0091] If the drilling robot 100A has completed drilling at all machining positions 32 in machining area A1 (step S130; YES), it determines whether it has completed drilling in all machining areas A1 to A6 of the workpiece 30 (step S131). If, at the time that drilling in machining area A1 is complete, drilling in the other machining areas A2 to A6 is not yet complete (step S131; NO), the drilling robot 100A returns to step S101, moves to the next machining area An, and then repeatedly executes the following processes: (1) robot coordinate setting process (steps S102 to S103), (2) positioning process (steps S104 to S109), (3) clamping process (step S110), and (4) drilling process (steps S120 to S121). If the backup robot 100B has completed drilling at all machining positions 32 in machining area A1 (step S230; YES), it waits for instructions from the drilling robot 100A (step S231). When the drilling robot 100A returns to step S101 and sends an instruction to move to the next machining area An, the backup robot 100B returns to step S201 and moves to the next machining area An as instructed by the drilling robot 100A, and then repeatedly performs the following processes: (1) robot coordinate setting process (steps S202-S203), (2) positioning process (steps S204-S205), clamping process (step S210), and (4) backup of the drilling process (steps S220-S221).

[0092] When the drilling robot 100A has completed drilling holes in all machining positions 32 in the entire machining area A1 to A6 (step S131; YES), it finishes drilling holes in the workpiece 30 and moves to a predetermined retraction position (step S132). At this time, the drilling robot 100A instructs the backup robot 100B to move to the retraction position. Then, the backup robot 100B finishes backing up the drilling robot 100A and moves to the predetermined retraction position (step S232).

[0093] (Example of robot system processing 2) Figures 11 to 13 show an example of the processing of the robot system according to the first embodiment. Figure 14 is a diagram illustrating the collar tightening process according to the first embodiment. Hereinafter, the flow of a series of processes of the robot system 1, including (5) robot coordinate setting process, (6) positioning process, (7) clamping process, (8) riveting process, and (9) collar tightening process, will be described with reference to Figures 11 to 14.

[0094] In these processes, the riveting robot 100C and the collar tightening robot 100D work in coordination. During this time, the drilling robot 100A and the backup robot 100B remain in a retracted position (step S601). Alternatively, they may work in other processing areas.

[0095] The riveting robot 100C moves to processing area An (step S401). At this time, the riveting robot 100C instructs the collar tightening robot 100D to move to processing area An. Then, the collar tightening robot 100D moves to processing area An as instructed by the riveting robot 100C (step S501). Processing area An is one of several processing areas A1 to A6 (Figure 2). For example, the riveting robot 100C and the collar tightening robot 100D first move to processing area A1.

[0096] When they move to processing area A1, the riveting robot 100C and the collar tightening robot 100D each execute the robot coordinate setting process (5) in Figure 11 in parallel. This robot coordinate setting process is the same as the process executed by the drilling robot 100A and the backup robot 100B (steps S102-S103 and S202-S203 in Figure 7). That is, in processing area A1, the riveting robot 100C detects the first reference members 21A and 21B with the first sensor 13 via the first reference position detection unit 1001 (step S402), and the coordinate setting unit 1002 sets the robot coordinates of the riveting robot 100C based on the detection information of the first reference members 21A and 21B (step S403). Similarly, in the processing area A1, the collar fastening robot 100D detects the first reference members 21A and 21B with the first sensor 13 via the first reference position detection unit 1001 (step S502), and the coordinate setting unit 1002 sets the robot coordinates of the collar fastening robot 100D based on the detection information of the first reference members 21A and 21B (step S503). As a result, the riveting robot 100C and the collar fastening robot 100D can each align the origin of their robot coordinates with the same reference position of the first reference member 21A as the origin of the robot coordinates of the drilling robot 100A.

[0097] Once the robot coordinates are set, the riveting robot 100C and the collar tightening robot 100D begin the positioning process (6) in Figure 11. In step S302 in Figure 7, the riveting robot 100C and the collar tightening robot 100D receive and store the coordinates (coordinates after surface perpendicularity correction) of each machining position i in the machining area A1 from the drilling robot 100A. Therefore, the second position control unit 1008 of the riveting robot 100C reads the coordinates of the machining positions i to be riveted and collar tightened (step S404) and moves the end effector 12 to the read-out machining position i coordinates (step S405). Similarly, the second position control unit 1008 of the collar tightening robot 100D reads the coordinates of the machining positions i to be riveted and collar tightened (step S504) and moves the end effector 12 to the read-out machining position i coordinates (step S505).

[0098] As described above, the riveting robot 100C and the collar tightening robot 100D set their robot coordinates based on the same reference position (reference position of the first reference member 21) as the drilling robot 100A, so the robot coordinates of each robot 100A, 100B, 100C, and 100D start from the same origin (however, since the collar tightening robot 100D faces in the opposite direction to the drilling robot 100A, the robot coordinates of the drilling robot 100A and the robot coordinates of the collar tightening robot 100D are reversed left and right). For this reason, the position of the processing position 32a of the workpiece 30 can be made to coincide with the robot coordinates of the drilling robot 100A and the robot coordinates of the riveting robot 100C and the collar tightening robot 100D, respectively, at the same coordinate. As a result, the riveting robot 100C, located on the outside of the workpiece 30 (on the first member 301 side) of the same workpiece 30 as the drilling robot 100A, can use the coordinates of the processing position 32a received from the drilling robot 100A to accurately position the end effector 12 in a direction perpendicular to the outer surface 301a of the workpiece 30 relative to the fastener hole at the processing position 32a drilled by the drilling robot 100A. In other words, the riveting robot 100C can omit time-consuming processes such as detecting the second reference member 31, determining the coordinates of the processing position, and correcting for perpendicularity. Furthermore, the collar fastening robot 100D, located on the inside of the workpiece 30 (on the second member 302 side) opposite the drilling robot 100A, transforms the coordinates of the processing position 32a based on the design shape included in the design information of the workpiece 30, so that the end effector 12 is oriented perpendicular to the inner surface 302a of the workpiece 30, similar to the backup robot 100B, and moves the end effector 12 to the transformed coordinates of the processing position 32a. Therefore, the color-fastening robot 100D can accurately position the end effector 12 perpendicular to the inner surface of the workpiece 30 relative to the fastener hole at the processing position 32a drilled by the drilling robot 100A, simply by performing a simple coordinate transformation based on the design shape. In other words, the color-fastening robot 100D can omit time-consuming processes such as detecting the second reference member 31, determining the coordinates of the processing position, and correcting for perpendicularity to the surface.In other embodiments, the riveting robot 100C and the collar tightening robot 100D may each perform plane alignment correction using the second sensor 14 (the same process as step S108 in Figure 7), and further correct the coordinates of the processing position 32 shared from the drilling robot 100A to match their own orientation. This makes it possible to align the fasteners and collars with higher precision.

[0099] The order of riveting and collar tightening is predetermined by the programs of the riveting robot 100C and the collar tightening robot 100D. Similar to the hole-punching robot 100A described above, the riveting robot 100C and the collar tightening robot 100D may be programmed to perform riveting and collar tightening according to the fastener size based on the design information of the workpiece 30. For example, here we assume that the riveting robot 100C and the collar tightening robot 100D are positioned at the processing position 32a in Figure 8.

[0100] Next, the riveting robot 100C and the collar tightening robot 100D perform the clamping process shown in Figure 11 (7) (steps S410, S510). The clamping process of the riveting robot 100C and the collar tightening robot 100D performs the same series of processes as shown in Figure 9, as performed by the drilling robot 100A and the backup robot 100B, so a detailed explanation is omitted. In Figure 9, the outer robot OML corresponds to the riveting robot 100C, and the inner robot IML corresponds to the collar tightening robot 100D. In other words, the processes in steps S410 and S510 of Figure 11 are the same as the clamping processes of the drilling robot 100A and the backup robot 100B described above (S110, S210), but with the drilling robot 100A replaced by the riveting robot 100C and the backup robot 100B replaced by the collar tightening robot 100D.

[0101] Once the clamping process is complete, the riveting robot 100C continues to clamp the workpiece 30 and executes the riveting process shown in Figure 11 (8) (step S420). At this time, the collar clamping robot 100D continues to clamp the workpiece 30 and backs up the riveting robot 100C (step S520).

[0102] The riveting process of the riveting robot 100C will be explained with reference to Figure 12. As shown in Figure 12, in the riveting process, the riveting control unit 1031 of the riveting robot 100C inserts the fastener 50 into the processing position 32a using the end effector 12 (step S4201). Furthermore, once the insertion of the fastener 50 is complete, the riveting control unit 1031 of the riveting robot 100C outputs an insertion completion signal to the collar tightening robot 100D (step S4202).

[0103] Once the riveting process is complete, the collar clamping robot 100D continues to clamp the workpiece 30 and performs the collar clamping process (S530) shown in Figure 11 (9). At this time, the riveting robot 100D continues to clamp the workpiece 30 and provides backup for the collar clamping robot 100D (step S430).

[0104] The collar tightening process of the collar tightening robot 100D will be explained with reference to Figure 13. First, when the collar tightening control unit 1041 of the collar tightening robot 100D receives an insertion completion signal from the riveting robot 100C (step S5301), it pre-grabs a collar 51 corresponding to the fastener size at the processing position 32a with the collar socket 127, and rotates and advances the collar socket 127 according to the collar tightening conditions corresponding to this collar 51 (step S5302). For example, the design information of the workpiece 30 includes information such as the fastener size and collar type at each processing position 32. The collar tightening control unit 1041 calculates and sets the collar tightening conditions according to the collar type at the processing position 32a from the design information of the workpiece 30. The collar tightening conditions include the amount of movement from the collar seating surface 511a to the seating surface (inner surface 302a) at the standby position before the processing position 32a of the end effector 12, the tightening torque value (upper limit UL and lower limit LL), etc. In this case, since the workpiece 30 is clamped from both the inside and outside so that there are no gaps, the amount of movement from the collar seating surface 511a to the seating surface calculated by the collar clamping control unit 1041 can be accurately matched with the actual distance from the collar seating surface 511a to the inner surface 302a of the workpiece 30.

[0105] Figure 14 illustrates the time series of tightening torque [Nm] and the amount of movement [mm] of the collar socket 127 measured by the torque sensor 129 of the collar tightening robot 100D when the collar 51 is tightened correctly. In Figure 14, "UL" is the upper limit of the tightening torque set as a collar tightening condition, "LL" is the lower limit of the tightening torque set as a collar tightening condition, and "OFF" is the torque off judgment value. The torque off judgment value indicates the torque value required only for the rotation of the collar socket 127 after the fracture portion 513 of the collar 51 has been twisted off. Also, the seating position in Figure 14 indicates the distance (amount of movement) from the collar seating surface 511a to the seating surface of the workpiece 30, which is set as a collar tightening condition. Due to the rotation and forward movement of the collar socket 127, the collar 51 is screwed into the threaded portion of the fastener 50 at the processing position 32a. The seating detection unit 1042 detects that the collar 51 has reached the seating position when it has moved by the amount set by the collar tightening conditions, and turns on the seating position arrival signal (time t11 in Figure 14). Also, when the collar 51 reaches the seating position, the tightening torque reaches the peak torque. At this time, the peak torque detection unit 1043 detects the peak value of the tightening torque (peak torque value) and turns on the peak torque detection signal. If a tightening torque exceeding the specified amount is applied to the collar 51, the breaking portion 513 of the collar 51 will twist off. In this case, the tightening torque will fall below the torque off judgment value OFF, and the torque off detection unit turns on the torque off detection signal (time t12 in Figure 14).

[0106] The determination unit 1045 of the collar tightening robot 100D determines whether the collar 51 has been properly tightened based on the seating position arrival signal, peak torque detection signal, torque off detection signal, and peak torque value.

[0107] As shown in the example in Figure 14, if the seating position arrival signal turns ON (step S5303; YES), the peak torque detection signal turns ON (step S5304), the torque off detection signal turns ON within a predetermined time after the seating position arrival signal turns ON (step S5305; YES), and the peak torque value is within the normal range (tightening torque lower limit LL or higher and tightening torque upper limit UL or lower) (step S5306), then the collar 51 It is determined that the part has been tightened correctly, i.e., in the correct seating position and with the appropriate tightening torque (step S5308).

[0108] Furthermore, if the determination unit 1045 does not determine that the process has completed normally (steps S5303, S5305, and S5306 are not YES), the abnormality detection unit 1046 can detect a tightening abnormality of the collar based on the seating position arrival signal, peak torque detection signal, torque off detection signal, and peak torque value, as follows.

[0109] For example, if the tightening torque of collar 51 is not appropriate, it may cause damage such as fatigue failure during product use. For this reason, even if the seating position arrival signal, peak torque detection signal, and torque off detection signal are correctly turned ON (step S5303; YES, step S5304, step S5305; YES), if the peak torque value is less than the tightening torque lower limit LL or exceeds the tightening upper limit UL (step S5306; NO), the abnormality detection unit 1046 determines that it has detected a tightening abnormality of collar 51 (a torque abnormality indicating "over-torque" or "under-torque") (step S5309).

[0110] Furthermore, there are cases where the zipper 50 rotates together with the collar 51, resulting in a phenomenon called "joint rotation." For this reason, even if the seating position arrival signal and the peak torque detection signal are correctly turned ON (step S5303; YES, step S5304), the abnormality detection unit 1046 determines that it has detected a tightening abnormality of the collar 51 ("joint rotation") if the torque off signal does not turn ON even after a predetermined time has elapsed since the seating position arrival signal turned ON (step S5306; NO) (step S5310).

[0111] Furthermore, there are cases where "premature breakage" occurs, where the fracture portion 513 of the collar 51 breaks off before the collar 51 reaches the seating position. For this reason, the abnormality detection unit 1046 determines that it has detected a tightening abnormality of the collar 51 ("premature breakage") when the peak torque detection signal and the torque off detection signal are turned ON (step S5307; YES) while the seating position arrival signal is not ON (step S5303; NO).

[0112] If the abnormality detection unit 1046 detects a tightening abnormality in any of the collars 51 (steps S5309, S5310, S5311), it records an abnormality log related to the processing position 32 where the abnormality was detected (step S5312). The operator later checks the location recorded in the abnormality log.

[0113] Furthermore, if the determination unit 1045 determines that the collar 51 has been properly tightened (step S5308), the process returns to Figure 11, and the riveting robot 100C and the collar tightening robot 100D release the clamps. Specifically, the first clamp control unit 1011 of the riveting robot 100C lowers the end effector 12 to a position a certain distance away from the workpiece 30, releasing the clamp on the workpiece 30 (step S431). Similarly, the second clamp control unit 1012 of the collar tightening robot 100D lowers the end effector 12 to a position a certain distance away from the workpiece 30, releasing the clamp on the workpiece 30 (step S531). Steps S431 and S531 may be performed simultaneously.

[0114] Next, the riveting robot 100C determines whether it has completed riveting and collar tightening at all processing positions 32 in processing area A1 (step S440). If riveting and collar tightening at processing position 32a is completed, the work at the other processing positions 32b, 32c, ... is not yet complete (step S440; NO). In this case, the riveting robot 100C and the collar tightening robot 100D go to the supply shelf to retrieve the fasteners and collars corresponding to the next indicated holes. After that, the riveting robot 100C returns to step S404 and repeatedly performs the following processes for each of the next processing positions 32b, 32c, ...: (6) positioning process (steps S404-S405), (7) clamping process (step S410), (8) riveting process (step S420), and (9) collar tightening process backup (steps S430-S431). Similarly, if the work at other processing positions 32 is not completed (step S540; NO), the collar clamping robot 100D returns to step S504 and repeatedly performs the following processes for each of the next processing positions 32b, 32c, ...: (6) positioning process (steps S504-S505), (7) clamping process (step S510), (8) rivet driving process backup (step S520), and (9) collar clamping process (steps S530-S531).

[0115] If the riveting robot 100C has completed work at all processing positions 32 in processing area A1 (step S440; YES), it determines whether it has completed work in all processing areas A1 to A6 of the workpiece 30 (step S441). If the work in processing area A1 is finished, the work in the other processing areas A2 to A6 is not yet completed (step S441; NO). In this case, the riveting robot 100C returns to step S401, moves to the next processing area An, and then repeatedly executes the following processes: (5) robot coordinate setting process (steps S402 to S403), (6) positioning process (steps S404 to S405), (7) clamping process (step S410), (8) riveting process (step S420), and (9) collar tightening process backup (steps S430 to S431). Similarly, when the collar clamping robot 100D has completed drilling holes at all machining positions 32 in machining area A1 (step S540; YES), it waits for instructions from the riveting robot 100C (step S541). When the riveting robot 100C returns to step S401 and sends an instruction to move to the next machining area An, the collar clamping robot 100D returns to step S501 and moves to the next machining area An as instructed by the riveting robot 100C, and then repeatedly executes the following processes: (5) robot coordinate setting process (steps S502-S503), (6) positioning process (steps S504-S505), (7) clamping process (step S510), (8) backup of the riveting process (step S520), and (9) collar clamping process (steps S530-S531).

[0116] When the riveting robot 100C has completed work at all processing positions 32 in the entire processing area A1 to A6 (step S441; YES), it finishes working on the workpiece 30 and moves to a predetermined retraction position (step S442). At this time, the riveting robot 100C instructs the collar clamping robot 100D to move to the retraction position. Then, the collar clamping robot 100D finishes working on the workpiece 30 and moves to a predetermined retraction position (step S542).

[0117] (Computer configuration) Figure 15 is a schematic block diagram showing the configuration of a computer according to the first embodiment. The computer 900 comprises a processor 901, main memory 902, auxiliary memory 903, and interface 904. The control devices 10A to 10D of each of the robots 100A to 100D described above are each implemented in the computer 900. The operation of each of the above-described processing units is stored in the auxiliary memory 903 in the form of a program. The processor 901 reads the program from the auxiliary memory 903, loads it into the main memory 902, and executes the above processing according to the program. The processor 901 also allocates memory area in the main memory 902 to be used for the above processing according to the program.

[0118] The program may be for implementing a part of the functions to be performed by the computer 900. For example, the program may perform functions in combination with other programs already stored in the auxiliary storage device 903, or in combination with other programs implemented in other devices. In other embodiments, the computer may be equipped with a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to, or in place of, the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array), etc. In this case, some or all of the functions implemented by the processor may be implemented by the integrated circuit.

[0119] Examples of auxiliary storage devices 903 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. The auxiliary storage device 903 may be an internal medium directly connected to the bus of the computer 900, or it may be an external medium (external storage device 910) connected to the computer 900 via an interface 904 or a communication line. Furthermore, if this program is distributed to the computer 900 via a communication line, the computer 900 that receives the distribution may expand the program into the main memory 902 and execute the above processing. In at least one embodiment, the auxiliary storage device 903 is a tangible storage medium that is not temporary.

[0120] (Effect 1) As described above, the robot system 1 according to this embodiment includes a first robot that positions the processing position and a second robot that performs positioning using the processing position determined by the first robot. In this embodiment, the first robot is a drilling robot 100A, and the second robots are a backup robot 100B, a riveting robot 100C, and a collar tightening robot 100D. The first and second robots include a first reference position detection unit 1001 that detects two first reference members 21 spaced apart in the width direction of a workpiece holding jig 20 that holds a workpiece 30 using a first sensor 13 attached to the end effector 12, and a coordinate setting unit 1002 that sets robot coordinates based on the detection information of the first reference members 21. The first robot further includes a second reference position detection unit 1003 that detects a second reference member 31 on the workpiece 30 using a first sensor 13, a machining position determination unit 1004 that determines the coordinates of the machining position 32 of the workpiece 30 in robot coordinates based on the detection information of the second reference member 31, a first position control unit 1005 that moves the end effector 12 of the first robot to the coordinates of the machining position 32 and corrects the coordinates of the machining position 32 by plane perpendicularity correction using a second sensor 14 attached to the end effector 12, and a machining position transmission unit 1006 that transmits the coordinates of the machining position 32 to the second robot. The second robot further includes a machining position receiving unit 1007 that receives the coordinates of the machining position 32 from the first robot, and a second position control unit 1008 that moves the end effector 12 of the second robot to the coordinates of the machining position 32.

[0121] In conventional robot systems, as described above, it is necessary to correct and position the robot coordinates of each robot performing each process to meet the required accuracy, which results in a problem of increased overall work time. In contrast, in the robot system 1 of this embodiment, both the first robot and the second robot have robot coordinates with the same position on the workpiece holding jig 20 (position of the first reference member 21) as the origin, and by sharing the coordinates of the processing position 32 determined by the first robot's precise positioning process with the second robot, the precise positioning process in the second robot can be omitted. In other words, the robot system 1 can share the coordinates of the processing position among multiple robots and perform highly accurate positioning in a short time. As a result, the work time required for the entire assembly of the workpiece 30 can be reduced.

[0122] Furthermore, the first reference position detection unit 1001 moves the end effector 12 to detect the two first reference members 21, and the coordinate setting unit 1002 corrects the robot coordinates based on the design distance between the two first reference members and the amount of movement of the end effector 12 from the detection of the first first reference member 21 to the detection of the second first reference member 21.

[0123] In this way, the robot system 1 can accurately correct the scale of each robot's robot coordinates based on the distance between the first reference members 21. This further improves the positioning accuracy of each robot and allows the end effector 12 to be precisely moved to the machining position 32.

[0124] Furthermore, the coordinate setting unit 1002 detects the inclination of the surface of the first reference member 21 and corrects the robot coordinates.

[0125] In this way, the robot system 1 can match the inclination of the workpiece holding jig 20 and the workpiece 30 with the inclination of the robot coordinates. This further improves the positioning accuracy of each robot and allows the end effector 12 to be precisely moved to the machining position 32.

[0126] Furthermore, the first position control unit 1005 of the first robot corrects the posture of the first robot so that the end effector 12 faces in a direction perpendicular to the surface of the workpiece at the machining position 32, based on the distance measured by each of the second sensors 14 of the end effector. Based on the corrected posture of the first robot, it corrects the coordinates of the machining position 32, and the machining position transmission unit 1006 transmits the corrected coordinates of the machining position 32 by the first position control unit 1005 to the second robot.

[0127] In this way, the first robot can orient the end effector 12 to the workpiece 30 according to its shape. Furthermore, the first robot transmits the coordinates of the machining position 32 after orientation correction to the second robot, allowing each robot to share the coordinates of the machining position 32 that can be precisely oriented according to the shape of the workpiece 30.

[0128] The second sensor 14 of the first robot includes a pair of second sensors 14a and 14b located above and below the end effector 12, and a pair of second sensors 14c and 14d located on the left and right sides of the end effector 12. The first position control unit 1005 corrects the posture of the first robot so that the distances measured by the pair of second sensors 14a and 14b located above and below are the same, and the distances measured by the pair of second sensors 14c and 14d located on the left and right are the same.

[0129] In this way, the first robot can more precisely orient the end effector 12 to the workpiece 30 in accordance with its shape. This further improves positioning accuracy.

[0130] The second reference member is a bolt 31 used for temporary fastening, which is attached during the temporary assembly of the workpiece 30.

[0131] In this way, the robot system 1 can eliminate the need for the operator to separately mark the processing position 32 for positioning. This reduces the overall time required for assembling the workpiece 30.

[0132] (Effect 2) Furthermore, the robot system 1 according to this embodiment is a robot system 1 that clamps a workpiece 30 by a first member-side robot positioned on the first member 301 side of the workpiece 30, which is formed by stacking a first member 301 and a second member 302, and a second member-side robot positioned on the second member 302 side. In this embodiment, the first member-side robot is either a drilling robot 100A or a riveting robot 100C. Also, if the first member-side robot is a drilling robot 100A, the second member-side robot is a backup robot 100B, and if the first member-side robot is a riveting robot 100C, the second member-side robot is a collar clamping robot 100D. The first member-side robot includes a first clamp control unit 1011 that controls the operation of the first member-side end effector 12 that presses the first member 301 of the workpiece 30. The second member-side robot includes a second clamp control unit 1012 that controls the operation of the second member-side end effector 12 that presses against the second member 302 of the workpiece 30. The first clamp control unit 1011 of the first member-side robot presses against the first member 301 of the workpiece 30 with a first force F1 using the first member-side end effector 12, and then holds the position of the first member-side end effector 12. After the first member-side robot has held the position of the first member-side end effector 12, the second clamp control unit 1012 of the second member-side robot presses against the second member 302 of the workpiece 30 with a second force F2 which is greater than the first force F1 using the second member-side end effector 12, and then holds the position of the second member-side end effector 12.

[0133] In this way, the robot system 1 can prevent gaps from forming between the first member 301 and the second member 302 by pressing the workpiece 30 from both sides to ensure close contact. Furthermore, when pressing the workpiece with the same force simultaneously from both sides, misalignment or deformation of the first and second members may occur if the pressing timing is not perfectly synchronized. In contrast, in this embodiment, by sequentially pressing from the first member 301 side and then from the second member 302 side, misalignment or deformation due to timing mismatch can be suppressed.

[0134] Furthermore, the first force F1 is set to a pressure less than the pressing force that causes plastic deformation of the workpiece 30.

[0135] In this way, the robot system 1 can suppress plastic deformation of the workpiece 30 when the first part-side robot presses the workpiece 30 with a first force F1.

[0136] Furthermore, the first clamp control unit 1011 of the first member-side robot holds the position of the second member-side end effector 12 after the second member-side robot has held the position of the second member-side end effector 12, presses the first member-side end effector 12 against the first member 301 of the workpiece 30 with a third force F3, and then holds the position of the first member-side end effector 12.

[0137] When the robot on the second member side presses with a second force F2, the robot on the first member side maintains the position of the first member side end effector 12, so that the same pressing force as the second force F2 is applied to the workpiece 30 from the first member side end effector 12. On the other hand, the control command value given by the robot on the first member side to the first member side end effector 12 remains the first force F1. If the control command value for the first member side end effector 12 and the pressing force that the first member side end effector 12 applies to the workpiece 30 differ significantly, problems may arise in other controls of the robot on the first member side. For this reason, in this embodiment, as described above, by further executing the process of the robot on the first member side pressing the workpiece 30 with a third force F3, it is possible to suppress the large difference between the control command value for the first member side end effector 12 and the pressing force that the first member side end effector 12 applies to the workpiece 30.

[0138] Furthermore, the third force F3 is set to be the value obtained by subtracting the first force F1 from the second force F2.

[0139] In this way, the robot on the first member side can match the control command value of the first member side end effector 12 with the pressing force that the first member side end effector 12 applies to the workpiece 30.

[0140] (Effect 3) Furthermore, the collar tightening robot 100D according to this embodiment includes a collar socket 127 that grips the base end portion 512 of the collar 51 and advances the collar 51 toward the workpiece 30 while rotating it; a seating detection unit 1042 that detects when the main body portion 511 of the collar 51 has reached the seating surface of the workpiece 30; a peak torque detection unit 1043 that detects the peak torque of the tightening torque based on the measurement value of a torque sensor 129 that measures the tightening torque of the collar 51; a torque-off detection unit 1044 that detects when the fracture portion 513 between the base end portion 512 and the main body portion 511 of the collar 51 has been twisted off and the tightening torque has fallen below the torque-off determination value based on the measurement value of the torque sensor 129; and a determination unit 1045 that determines whether the tightening of the collar 51 has been completed normally based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque-off detection unit 1044.

[0141] In this way, the collar tightening robot 100D can accurately determine whether the collar 51 has correctly reached the seating surface of the workpiece 30, whether the broken portion 513 has been twisted off and the main body 511 of the collar 51 has been tightened to the fastener 50. Therefore, the collar tightening robot 100D can automate the tightening of the collar 51. Furthermore, for example, when a worker tightens the collar manually, it is difficult to precisely determine whether the collar has correctly reached the seating surface of the workpiece, and to detect the peak torque and torque off. This can lead to variations in tightening accuracy depending on the worker, and an inspection process to check the collar tightening state in a later process is necessary. In contrast, the collar tightening robot 100D according to this embodiment can guarantee that at each processing position 32, the collar is tightened to a position where there is no gap on the seating surface of the collar and within the specified tightening torque range.

[0142] Furthermore, the determination unit 1045 determines that the tightening state of the collar 51 is abnormal if it detects a peak torque and the tightening torque falls below the torque-off determination value before it is detected that the collar 51 has reached the seating surface.

[0143] In this way, the collar clamping robot 100D can detect an abnormality called "premature breakage," where the fracturing portion 513 breaks off before the collar 51 reaches the seating surface.

[0144] Furthermore, the determination unit 1045 determines that the tightening state of the collar 51 is abnormal if, after a predetermined time has elapsed since the collar 51 reached the seating surface and the peak torque was detected, the tightening torque has not fallen below the torque-off determination value.

[0145] In this way, the collar tightening robot 100D can detect an abnormality called "rotation together" where the breaking portion 513 of the collar 51 does not break, and the fastener 50 rotates together with the collar 51.

[0146] Furthermore, the determination unit 1045 determines that the tightening state of the collar 51 is abnormal if the peak torque exceeds the upper limit of the tightening torque UL, or if it is less than the lower limit of the tightening torque LL.

[0147] In this way, the collar tightening robot 100D can detect abnormalities such as "over-torque," where the tightening torque of collar 51 is excessive, or "under-torque," where the tightening torque of collar 51 is insufficient.

[0148] <Other Embodiments> Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to that described above, and various design changes are possible. In other embodiments, the order of the above-described processes may be changed as appropriate. Also, some processes may be executed in parallel.

[0149] For example, in the above-described embodiment, an example was explained in which the drilling robot 100A and the backup robot 100B work together to perform the clamping and drilling processes, and the riveting robot 100C and the collar tightening robot 100D work together to perform the clamping, riveting, and collar tightening processes. However, the embodiment is not limited to this. In other embodiments, for example, the backup robot 100B may be omitted, and the collar tightening robot 100D may work together with the drilling robot 100A to back up the clamping and drilling processes.

[0150] Furthermore, in addition to the drilling robot 100A, backup robot 100B, riveting robot 100C, and collar fastening robot 100D, the robot system 1 may further include robots having other functions.

[0151] <Note> The above-described embodiment can be understood, for example, as follows:

[0152] (1) According to the first embodiment, the collar tightening robot 100D is a collar tightening robot 100D that tightens a collar 51 onto a fastener 50 inserted into a workpiece 30, and includes a collar socket 127 that grips the base end 512 of the collar 51 and advances the collar 51 toward the workpiece 30 while rotating it, a seating detection unit 1042 that detects when the main body 511 of the collar 51 has reached the seating surface of the workpiece 30, a peak torque detection unit 1043 that detects the peak torque of the tightening torque based on the measured value of a torque sensor 129 that measures the tightening torque of the collar 51, and based on the measured value of the torque sensor 129 The system includes a torque-off detection unit 1044 that detects when the fractured portion 513 between the base end portion 512 and the main body portion 511 of the collar 51 has been twisted off and the tightening torque has fallen below the torque-off determination value; a determination unit 1045 that determines whether the tightening of the collar 51 has been completed normally based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque-off detection unit 1044; and an abnormality detection unit 1046 that detects an abnormality in the tightening state of the collar 51 based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque-off detection unit 1044 if the tightening of the collar 51 has not been completed normally.

[0153] In this way, the collar tightening robot 100D can accurately determine whether the collar 51 has correctly reached the seating surface of the workpiece 30, whether the broken portion 513 has been twisted off and the main body 511 of the collar 51 has been tightened to the fastener 50. Therefore, the collar tightening robot 100D can automate the tightening of the collar 51. Furthermore, for example, when a worker tightens the collar manually, it is difficult to precisely determine whether the collar has correctly reached the seating surface of the workpiece, and to detect the peak torque and torque off. This can lead to variations in tightening accuracy depending on the worker, and an inspection process to check the collar tightening state in a later process is necessary. In contrast, the collar tightening robot 100D according to this embodiment can guarantee that at each processing position 32, the collar is tightened to a position where there is no gap on the seating surface of the collar and within the specified tightening torque range.

[0154] (2) According to the second embodiment, in the collar tightening robot 100D according to the first embodiment, the abnormality detection unit 1046 determines that the tightening state of the collar 51 is abnormal if a peak torque is detected and the tightening torque is found to be less than the torque-off determination value before it is detected that the collar 51 has reached the seating surface.

[0155] In this way, the collar clamping robot 100D can detect an abnormality called "premature breakage," where the fracturing portion 513 breaks off before the collar 51 reaches the seating surface.

[0156] (3) According to the third embodiment, in the collar tightening robot 100D according to the first or second embodiment, the abnormality detection unit 1046 determines that the tightening state of the collar 51 is abnormal if, after a predetermined time has elapsed since the collar 51 reached the seating surface and the peak torque was detected, the tightening torque has not fallen below the torque-off determination value.

[0157] In this way, the collar tightening robot 100D can detect an abnormality called "rotation together" where the breaking portion 513 of the collar 51 does not break, and the fastener 50 rotates together with the collar 51.

[0158] (4) According to the fourth embodiment, in the collar tightening robot 100D according to any one of the first to third embodiments, the abnormality detection unit 1046 determines that the tightening state of the collar 51 is abnormal if the peak torque exceeds the upper limit of the tightening torque UL or is less than the lower limit of the tightening torque LL.

[0159] In this way, the collar tightening robot 100D can detect abnormalities such as "over-torque," where the tightening torque of collar 51 is excessive, or "under-torque," where the tightening torque of collar 51 is insufficient.

[0160] (5) According to the fifth aspect, the robot system 1 comprises a riveting robot 100C positioned on the first member 301 side of a workpiece 30 formed by stacking a first member 301 and a second member 302, which inserts a fastener 50 into the workpiece 30, and a collar tightening robot 100D positioned on the second member 302 side of the workpiece 30, which tightens a collar 51 onto the fastener 50 inserted into the workpiece 30, wherein the riveting robot 100C controls the operation of a first member side end effector 12 that presses the first member 301 of the workpiece 30. The collar clamping robot 100D comprises a first clamp control unit 1011 and a third clamp control unit 1013, a second clamp control unit 1012 that controls the operation of the second member-side end effector 12 that presses the second member 302 of the workpiece 30, a collar socket 127 that grips the base end 512 of the collar 51 and moves the collar 51 forward toward the workpiece 30 while rotating it, a seating detection unit 1042 that detects when the main body 511 of the collar 51 has reached the seating surface of the workpiece 30, and a torque sensor 129 that measures the clamping torque of the collar 51. The riveting robot 100C includes a peak torque detection unit 1043 that detects the peak torque of the tightening torque based on the measured value of the torque sensor 129, a torque off detection unit 1044 that detects that the fractured portion 513 between the base end 512 and the main body 511 of the collar 51 has been twisted off and the tightening torque has fallen below the torque off determination value based on the measured value of the torque sensor 129, and a determination unit 1045 that determines whether the tightening of the collar 51 has been completed normally based on the detection results of the seating detection unit 1042, the peak torque detection unit 1043, and the torque off detection unit 1044, and the number The clamp control unit 1011 presses the first member 301 of the workpiece 30 with a first force F1 using the first member-side end effector 12, and then holds the position of the first member-side end effector 12. The second clamp control unit 1012 of the collar clamping robot 100D presses the second member 302 of the workpiece 30 with a second force F2 which is greater than the first force F1 using the second member-side end effector 12, after the riveting robot 100C has held the position of the first member-side end effector 12, and then holds the position of the second member-side end effector 12.Furthermore, the third clamp control unit of the riveting robot presses the first member of the workpiece with a third force using the first member-side end effector, and then maintains the position of the first member-side end effector.

[0161] The robot system 1 clamps the workpiece 30 from both sides in this manner, ensuring no gaps are left between them, and then tightens the collar 51. This allows the amount of movement from the collar seating surface 511a to the seating surface to accurately match the actual distance from the collar seating surface 511a to the inner surface 302a of the workpiece 30. As a result, the seating detection unit 1042 of the collar tightening robot 100D can accurately detect that the collar 51 has seated on the seating surface of the workpiece 30 and tighten the collar 51 appropriately. Therefore, the tightening accuracy of the collar tightening robot 100D can be improved.

[0162] (6) According to the sixth aspect, the control method for the collar fastening robot 100D is a control method for the collar fastening robot 100D that fastens a collar 51 to a fastener 50 inserted into a workpiece 30, comprising the steps of: grasping the base end portion 512 of the collar 51 and moving the collar 51 forward toward the workpiece 30 while rotating it; detecting that the main body portion 511 of the collar 51 has reached the seating surface of the workpiece 30; detecting the peak torque of the fastening torque based on the measured value of a torque sensor 129 that measures the fastening torque of the collar 51; and based on the measured value of the torque sensor 129, the base end portion 512 and the main body portion 51 The process includes: detecting that the fractured portion 513 between 1 and 1 has been twisted off and the tightening torque has fallen below a torque-off determination value; determining whether the tightening of the collar 51 has been completed normally based on the detection results of the steps of detecting that the seating surface has been reached, detecting the peak torque, and detecting that the torque has fallen below a torque-off determination value; and, if the tightening of the collar 51 has not been completed normally, detecting an abnormality in the tightening state of the collar 51 based on the detection results of the steps of detecting that the seating surface has been reached, detecting the peak torque, and detecting that the torque has fallen below a torque-off determination value.

[0163] (7) According to the seventh aspect, the program includes the steps of: having a collar tightening robot 100D that tightens the collar 51 onto a fastener 50 inserted into a workpiece 30 grasp the base end 512 of the collar 51 and move the collar 51 forward toward the workpiece 30 while rotating it; detecting that the main body 511 of the collar 51 has reached the seating surface of the workpiece 30; detecting the peak torque of the tightening torque based on the measurement value of a torque sensor 129 that measures the tightening torque of the collar 51; and detecting that the broken portion 513 between the base end 512 and the main body 511 of the collar 51 is fastened based on the measurement value of the torque sensor 129. The system is configured to perform the following steps: detect when the tightening torque has broken and fallen below the torque-off threshold; detect when the seating surface has been reached; detect the peak torque; and determine whether the tightening of the collar 51 has been completed successfully based on the detection results of the steps for detecting when the torque has fallen below the torque-off threshold; and, if the tightening of the collar 51 has not been completed successfully, to detect an abnormality in the tightening state of the collar 51 based on the detection results of the steps for detecting when the seating surface has been reached; detect the peak torque; and detect when the torque has fallen below the torque-off threshold. [Explanation of Symbols]

[0164] 1. Robot System 100A Hole-Drilling Robot 100B Backup Robot 100C Nail-driving robot 100D Color Tightening Robot 10A, 10B, 10C, 10D control devices 1001 First reference position detection unit 1002 Coordinate setting section 1003 Second reference position detection unit 1004 Processing position determination section 1005 First position control unit 1006 Processing position transmission unit 1007 Processing position receiving unit 1008 Second position control unit 1011 First Clamp Control Unit 1012 Second clamp control unit 1013 Third Clamp Control Unit 1021 Hole drilling control unit 1031 Rivet Control Unit 1041 Color clamping control unit 1042 Seating detection unit 1043 Peak Torque Detection Unit 1044 Torque-off detection unit 1045 Judgment section 1046 Anomaly detection unit 11 Arms 12 End Effects 121 Drill 122 Pressure Foot 122a End face 123 Force Sensor 124 Drive Unit 125 Fastener gripping part 126 Hammering Unit 127 Color Sockets 128 Drive Unit 129 Torque Sensor 13. First Sensor 14. Second Sensor 20 Workpiece holding fixture 21. First reference member 30 Work 301 First Member 302 Second Member 31 Bolts (Second standard member) 32 Processing position 50 zippers 51 Colors 511 Main body 511a Colored seat 512 Proximal end 513 Fracture section

Claims

1. A collar tightening robot that tightens a collar onto a fastener inserted into a workpiece, A collar socket that grips the base end of the collar and advances the collar toward the workpiece while rotating it, A seating detection unit that detects when the main body of the colored part reaches the seating surface of the workpiece, A peak torque detection unit detects the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the aforementioned collar, A torque-off detection unit detects, based on the measured value of the torque sensor, that the fractured portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below the torque-off determination value. A determination unit that determines whether the tightening of the collar has been completed successfully based on the detection results of the seating detection unit, the peak torque detection unit, and the torque-off detection unit, If the tightening of the aforementioned collar is not completed normally, an abnormality detection unit detects an abnormality in the tightening state of the collar based on the detection results of the seating detection unit, the peak torque detection unit, and the torque-off detection unit, A color-matching tightening robot equipped with these features.

2. The abnormality detection unit determines that the tightening state of the collar is abnormal if, before it is detected that the collar has reached the seating surface, the peak torque is detected and the tightening torque is detected to be less than the torque-off determination value. The color clamping robot according to claim 1.

3. The abnormality detection unit determines that the tightening state of the collar is abnormal if, after a predetermined time has elapsed since the collar reached the seating surface and the peak torque was detected, the tightening torque has not fallen below the torque-off determination value. The color clamping robot according to claim 1 or 2.

4. The abnormality detection unit determines that the tightening state of the collar is abnormal if the peak torque exceeds the upper limit of the tightening torque or falls below the lower limit of the tightening torque. The color clamping robot according to claim 1 or 2.

5. A riveting robot is positioned on the first member side of a workpiece formed by stacking the first and second members, and inserts a fastener into the workpiece. A collar tightening robot is positioned on the second member side of the workpiece and tightens the collar onto a fastener inserted into the workpiece, A robotic system equipped with, The aforementioned riveting robot, The system includes a first clamp control unit and a third clamp control unit that control the operation of the first member-side end effector that presses the first member of the workpiece, The aforementioned color clamping robot, A second clamp control unit controls the operation of the second member-side end effector that presses the second member of the workpiece, A collar socket that grips the base end of the collar and advances the collar toward the workpiece while rotating it, A seating detection unit that detects when the main body of the colored part reaches the seating surface of the workpiece, A peak torque detection unit detects the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the aforementioned collar, A torque-off detection unit detects, based on the measured value of the torque sensor, that the fractured portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below the torque-off determination value. A determination unit that determines whether the tightening of the collar has been completed successfully based on the detection results of the seating detection unit, the peak torque detection unit, and the torque-off detection unit, Equipped with, The first clamp control unit of the riveting robot presses the first member of the workpiece with a first force using the first member-side end effector, and then maintains the position of the first member-side end effector. The second clamp control unit of the collar clamping robot, after the riveting robot has held the position of the first member-side end effector, presses the second member of the workpiece with a second force greater than the first force using the second member-side end effector, and then holds the position of the second member-side end effector. The third clamp control unit of the riveting robot presses the first member of the workpiece with a third force using the first member-side end effector, and then maintains the position of the first member-side end effector. Robot system.

6. A control method for a collar tightening robot that tightens a collar onto a fastener inserted into a workpiece, The steps include: grasping the base end of the collar and moving the collar forward toward the workpiece while rotating it; The steps include detecting when the main body of the color reaches the seating surface of the workpiece, The steps include detecting the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the collar, The steps include detecting, based on the torque sensor's measurement value, that the fractured portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below the torque-off threshold, A step of determining whether the tightening of the collar has been completed successfully based on the detection results of the steps of detecting that the seating surface has been reached, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value, If the tightening of the collar is not completed normally, the steps include detecting an abnormality in the tightening state of the collar based on the detection results of the steps of detecting that the collar has reached the seating surface, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value, A control method for a color-tightening robot.

7. A collar tightening robot that tightens a collar onto a fastener inserted into a workpiece, The steps include: grasping the base end of the collar and moving the collar forward toward the workpiece while rotating it; The steps include detecting when the main body of the color reaches the seating surface of the workpiece, The steps include detecting the peak torque of the tightening torque based on the measurement value of a torque sensor that measures the tightening torque of the collar, The steps include detecting, based on the torque sensor's measurement value, that the fractured portion between the base end and the main body of the collar has been twisted off and the tightening torque has fallen below the torque-off threshold, A step of determining whether the tightening of the collar has been completed successfully based on the detection results of the steps of detecting that the seating surface has been reached, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value, If the tightening of the collar is not completed normally, the steps include detecting an abnormality in the tightening state of the collar based on the detection results of the steps of detecting that the collar has reached the seating surface, detecting the peak torque, and detecting that the torque has fallen below the torque-off determination value, A program that executes the command.

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