Position specification device, robot, and position specification method

Abstract

To conduct position specification of a rod-like member using a simple method.SOLUTION: A position specification device for specifying a position of a rod-like member (a first pipe P1) comprises: a sensor unit 21; a moving device (a robot arm 10); and a control unit. The sensor unit 21 comprises a plurality of transmission type optical sensors. The moving device moves the sensor unit 21 in an X-direction, and in a Y-direction orthogonal to the X-direction. The sensor unit 21 can form a frame F of light being polygonal when viewed from a Z-direction orthogonal to the X-direction and the Y-direction, which is a frame F of light capable of surrounding the rod-like member, according to light beams B1-B3 emitted from the plurality of transmission type optical sensors. The control unit moves the sensor unit in one direction out of the X-direction and the Y-direction, and positions the rod-like member in the frame F according to signals from the transmission type optical sensors, in order to specify an X-coordinate and a Y-coordinate of the rod-like member.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a position specifying device, a robot, and a position specifying method for specifying the position of a member. [Background technology]

[0002] Conventionally, a measurement device for identifying the position of the tip of a multi-tip fin of a steam turbine is known (see Patent Document 1). In this technology, the measurement device includes a rail arranged along the axial direction of the steam turbine, a device body movable on the rail, and a laser oscillator located at one end of the rail and emitting a laser beam in the axial direction toward the device body. The multi-tip fin is spaced apart from the rail in a radial direction perpendicular to the axial direction.

[0003] The device main body is equipped with an optical component that refracts laser light from a laser oscillator in a radial direction, an objective lens through which the light refracted by the optical component passes which is movable in the radial direction, and a light receiving element that receives light reflected from the multi-chip fin.

[0004] The rails are engraved with position information that can be read using a laser, allowing the device body to constantly recognize its position on the steam turbine shaft.

[0005] In this measuring device, the axial position of the tip of the multi-chip fin is determined by scanning the multi-chip fin with laser light refracted by an optical component of the device body moving on a rail, and the radial position of the tip of the multi-chip fin is determined by measuring the amount of reflected light from the multi-chip fin while moving the objective lens of the device body to move the focal position of the laser light. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-185717 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, when a workpiece loaded on a cart is grasped by a robot hand, it is required to detect the position of a rod-shaped member supporting the workpiece and align the position of the robot hand with the workpiece based on the detected position. Specifically, when the direction in which the rod-shaped member extends is the Z direction, it is necessary to grasp the position of the rod-shaped member in each of the X direction perpendicular to the Z direction and the Y direction perpendicular to the X direction and the Z direction.

[0008] However, in the conventional method, it is necessary to move the device body to specify the axial position of the detection target, and it is necessary to move the objective lens to specify the position of the detection target in a direction perpendicular to the axial direction. Therefore, it is desired to specify the position of the component by a simpler method.

[0009] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a simple method for identifying the position of a rod-shaped member. [Means for solving the problem]

[0010] In order to achieve the above object, the position identifying device according to the present invention is a device for identifying the position of a rod-shaped member, and includes a sensor unit, a moving device, and a control unit. The sensor unit includes a plurality of transmission type optical sensors. The moving device moves the rod-shaped member or the sensor unit in an X direction and a Y direction perpendicular to the X direction. The sensor unit is a frame of light capable of surrounding a rod-shaped member using light beams emitted from multiple transmissive optical sensors, and is capable of forming a polygonal frame of light when viewed from the Z direction perpendicular to the X and Y directions. The control unit moves the rod-shaped member or the sensor unit in at least one of the X and Y directions, and determines the X and Y coordinates of the rod-shaped member by positioning the rod-shaped member within the frame based on a signal from the transmissive optical sensor.

[0011] According to this configuration, the position of the rod-shaped member can be identified simply by positioning the rod-shaped member within the light frame, so that the position of the rod-shaped member can be identified in a simple manner.

[0012] The moving device may be capable of moving the rod-shaped member or the sensor unit in a Z direction perpendicular to the X and Y directions, and the control unit may identify a first X coordinate and a first Y coordinate which are the X and Y coordinates of a first portion of the rod-shaped member, identify a second X coordinate and a second Y coordinate which are the X and Y coordinates of a second portion different in position in the Z direction from the first portion of the rod-shaped member, and calculate an angle of the portion from the first portion to the second portion of the rod-shaped member with respect to the Z direction based on the first X coordinate, the first Y coordinate, the second X coordinate, and the second Y coordinate.

[0013] According to this configuration, the angle of the rod-shaped member with respect to the Z direction can be grasped, and therefore, for example, the degree of deformation of the rod-shaped member can be grasped based on the grasped angle.

[0014] In addition, the number of the transmissive optical sensors may be three, and the polygon may be a triangle.

[0015] According to this configuration, the number of transmission type optical sensors can be minimized, thereby reducing costs.

[0016] In addition, the base of the triangle is along the X direction, and the two hypotenuses of the triangle are located on one side in the Y direction relative to the base, and the control unit moves the sensor unit from one side in the Y direction to the other side, bringing it closer to the rod-shaped member, and when a light ray constituting the base of the triangle is blocked by the rod-shaped member and then leaves the rod-shaped member, stops the movement of the sensor unit in the Y direction to determine the Y coordinate of the rod-shaped member, and when a light ray constituting one of the two hypotenuses is blocked by the rod-shaped member when the movement of the sensor unit in the Y direction is stopped, moves the sensor unit in the X direction so that the light ray constituting the other hypotenuse approaches the rod-shaped member, and when a light ray constituting one of the hypotenuses leaves the rod-shaped member, stops the movement of the sensor unit in the X direction to determine the X coordinate of the rod-shaped member.

[0017] Moreover, a robot according to the present invention includes the position identifying device, a gripping portion that holds a workpiece supported by a rod-shaped member, and a pressing portion that presses the workpiece along the rod-shaped member. The control unit exposes a portion of the rod-shaped member by pressing the workpiece with the pressing unit, and then positions the portion of the rod-shaped member within the frame, thereby identifying the X and Y coordinates of the portion of the rod-shaped member.

[0018] According to this configuration, before the position identification device identifies the position of a part of the rod-shaped member, the pressing portion presses the workpiece to expose a part of the rod-shaped member, so that the position identification device can accurately identify the position of the rod-shaped member.

[0019] The gripping portion may also hold the workpiece by magnetic force.

[0020] The robot according to the present invention also includes a position identifying device capable of calculating the angle of the rod-shaped member with respect to the Z direction, and a gripping unit that holds a workpiece supported by the rod-shaped member. The control unit obtains the X and Y coordinates of each portion of the rod-shaped member located at different positions in the Z direction, and calculates the angle between each portion, thereby calculating the shape of the rod-shaped member.

[0021] According to this configuration, the shape of the rod-shaped member can be calculated, so that, for example, the degree of deformation of the rod-shaped member can be grasped based on the calculated shape.

[0022] Moreover, a robot according to the present invention includes the position specifying device and a gripping unit. The gripping portion holds a workpiece supported by a rod-shaped member and a second rod-shaped member that is located at a different position from the rod-shaped member in a direction perpendicular to the Z direction. The robot is equipped with a sensing device. The detection device has at least one transmission type optical sensor and detects the second rod-shaped member. After identifying the X and Y coordinates of the rod-shaped member, the control unit rotates the detection device around the rod-shaped member and determines the orientation of the gripper by stopping the rotation of the detection device based on the detection result of the detection device.

[0023] If the rod-shaped member or the second rod-shaped member is deformed in the up-down direction, the workpiece supported by the rod-shaped member and the second rod-shaped member may tilt obliquely. In such a case, the control unit specifies the X and Y coordinates of the rod-shaped member, then rotates the detection device around the rod-shaped member and detects the second rod-shaped member with the detection device, thereby aligning the orientation of the gripping part with the workpiece, so that the gripping part can hold the workpiece firmly.

[0024] In addition, the detection device may have two transmissive optical sensors, and the two transmissive optical sensors of the detection device may be arranged so that two light beams are parallel to each other, and the control unit may stop the rotation of the detection device on condition that the second rod-shaped member is positioned between the two light beams.

[0025] According to this configuration, the time required to determine the orientation of the gripping portion can be shortened, as compared to a method in which the second rod-shaped member is detected by a single transmissive optical sensor, for example.

[0026] In addition, the position identification method of the present invention is a method for identifying the position of a rod-shaped member by using a sensor unit capable of forming a polygonal light frame when viewed from the Z direction, which is a light frame that can surround a rod-shaped member using light rays emitted from a plurality of transmissive optical sensors. In this method, the rod-shaped member or the sensor unit is moved in at least one of the X direction perpendicular to the Z direction and the Y direction perpendicular to the Z direction, and the X and Y coordinates of the rod-shaped member are determined by positioning the rod-shaped member within a frame based on a signal from a transmission type optical sensor.

[0027] According to this method, the position of the rod-shaped member can be identified simply by positioning the rod-shaped member within the light frame, so that the position of the rod-shaped member can be identified in a simple manner.

[0028] Furthermore, the position identification method may include identifying a first X coordinate and a first Y coordinate, which are the X coordinates and the Y coordinates of a first portion of the rod-shaped member, identifying a second X coordinate and a second Y coordinate, which are the X coordinates and the Y coordinates of a second portion located at a position different from the first portion of the rod-shaped member in the Z direction, and calculating an angle of a portion from the first portion to the second portion of the rod-shaped member with respect to the Z direction based on the first X coordinate, the first Y coordinate, the second X coordinate, and the second Y coordinate.

[0029] According to this method, it is possible to grasp the angle of the rod-shaped member with respect to the Z direction, and therefore, for example, it is possible to grasp the degree of deformation of the rod-shaped member based on the grasped angle.

[0030] In addition, the number of the transmissive optical sensors may be three, and the polygon may be a triangle.

[0031] According to this method, the number of transmission type optical sensors can be minimized, thereby reducing costs.

[0032] In addition, the base of the triangle is along the X direction, and the two hypotenuses of the triangle are located on one side in the Y direction relative to the base, and in the position identification method, the sensor unit is moved from one side in the Y direction to the other side to approach the rod-shaped member, and when a light ray constituting the base of the triangle is blocked by the rod-shaped member and then deviates from the rod-shaped member, the movement of the sensor unit in the Y direction is stopped to determine the Y coordinate of the rod-shaped member, and when a light ray constituting one of the two hypotenuses is blocked by the rod-shaped member when the movement of the sensor unit in the Y direction is stopped, the sensor unit may be moved in the X direction so that the light ray constituting the other hypotenuse approaches the rod-shaped member, and when a light ray constituting one of the hypotenuses deviates from the rod-shaped member, the movement of the sensor unit in the X direction is stopped to determine the X coordinate of the rod-shaped member. Effect of the Invention

[0033] According to the present invention, the position of a rod-shaped member can be specified simply by positioning the rod-shaped member within the light frame, so that the position of the rod-shaped member can be specified in a simple manner.

[0034] Furthermore, according to the present invention, by calculating the angle of the portion from the first portion to the second portion from the X, Y coordinates of the first portion and the second portion of the rod-shaped member which are at different positions in the Z direction, it is possible to grasp the angle of the rod-shaped member with respect to the Z direction, and therefore, for example, it is possible to grasp the degree of deformation of the rod-shaped member based on the grasped angle.

[0035] Furthermore, according to the present invention, by setting the number of transmission type optical sensors to three and forming a polygon in a triangular shape, the number of transmission type optical sensors can be minimized, thereby reducing costs.

[0036] Furthermore, in the robot of the present invention, by configuring it to have a pressing unit that presses the workpiece along the rod-shaped member, the workpiece can be pressed with the pressing unit to expose part of the rod-shaped member before the position of that part of the rod-shaped member is identified by the position identification device, so that the position of the rod-shaped member can be accurately identified by the position identification device.

[0037] Furthermore, in the robot according to the present invention, by calculating the shape of the rod-shaped member from the angle of a specified portion of the rod-shaped member, it is possible to grasp, for example, the degree of deformation of the rod-shaped member based on the calculated shape.

[0038] Furthermore, in the robot of the present invention, by configuring it to include a detection device that detects the second rod-shaped member, the control unit can detect the second rod-shaped member using the detection device that rotates the rod-shaped member, and align the orientation of the gripping part with the workpiece, thereby enabling the gripping part to firmly hold the workpiece.

[0039] Furthermore, in the robot of the present invention, by configuring it to have two transmissive optical sensors arranged so that two light beams are parallel to each other, the time required to determine the orientation of the gripping part can be shortened compared to a method in which the second rod-shaped member is detected using, for example, a single transmissive optical sensor. [Brief description of the drawings]

[0040] [Figure 1] 1 is a perspective view showing a robot equipped with a position specifying device according to an embodiment. [Diagram 2] FIG. 2 is an enlarged perspective view of a robot hand. [Diagram 3] FIG. 2 is a rear view of the sensor unit and the detection device. [Figure 4] 11(a) to 11(d) are diagrams showing a method for identifying the position of the first pipe. [Diagram 5] 13(a) and 13(b) are diagrams showing a method for rotating the robot hand in accordance with the vertical misalignment of two pipes. [Figure 6] FIG. 1A shows the process of moving the pressing part from the retracted position to the advanced position, FIG. 1B shows the process of pressing the workpiece with the pressing part, and FIG. 1C shows the process of moving the robot hand to the measurement start position. [Figure 7] FIG. 11 is a diagram showing a process of identifying the position of a first pipe. [Figure 8] FIG. 13 is a diagram showing a process of gripping a workpiece with a robot hand. [Figure 9] FIG. 13 is a diagram showing the first half of a flowchart illustrating the operation of a control unit. [Figure 10] FIG. 13 shows the second half of the flowchart illustrating the operation of the control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the robot 1 is a robot that grasps a workpiece W on a cart C that has been brought to an installation area A, and transports it to the next process.

[0042] In the following description, directions will be described using the X, Y, and Z directions shown in the drawings. The Y direction is perpendicular to the X direction. The Z direction is perpendicular to the X and Y directions. The arrows indicating each direction in the drawings will point to one side in each direction.

[0043] In this embodiment, the Y direction is along the up-down direction. In the following description, one side of the Y direction is also referred to as "upper", and the other side of the Y direction is also referred to as "lower". One side of the X direction is also referred to as "right", and the other side of the X direction is also referred to as "left". One side of the Z direction is also referred to as "front", and the other side of the Z direction is also referred to as "rear".

[0044] The cart C has a plurality of sets each consisting of a first pipe P1 as an example of a rod-shaped member and a second pipe P2 as an example of a second rod-shaped member. The workpiece W is supported by one set of the first pipe P1 and the second pipe P2. The first pipe P1 and the second pipe P2 of one set each extend in the Z direction, have different positions in the X direction, and are approximately the same in the Y direction. In the one set of the first pipe P1 and the second pipe P2, the first pipe P1 is located on one side of the second pipe P2 in the X direction, i.e., on the right side.

[0045] The workpiece W is a back frame that serves as the skeleton of the seat back, and has a U-shaped pipe W1. The workpieces W are arranged in the same orientation in the Z direction on a pair of a first pipe P1 and a second pipe P2.

[0046] The robot 1 includes a robot arm 10 as an example of a moving device, a robot hand 20 provided at the tip of the robot arm 10, and a control unit 30. The robot arm 10 has a plurality of joints, for example six joints, and moves the robot hand 20 in the X-direction, Y-direction, and Z-direction.

[0047] As shown in FIG. 2, the robot hand 20 includes a sensor unit 21, a detection device 22, three gripping parts 24, and a pressing part .

[0048] The sensor unit 21 has a function of detecting the first pipe P1. The detection device 22 has a function of detecting the second pipe P2. The sensor unit 21 and the detection device 22 are arranged side by side in the X direction with a gap therebetween. The sensor unit 21 is located to the right of the detection device 22. The structures of the sensor unit 21 and the detection device 22 will be described in detail later.

[0049] The pressing portion 23 is a member for pressing the workpiece W along the first pipe P1 and the second pipe P2. The pressing portion 23 is disposed between the sensor unit 21 and the detection device 22. The pressing portion 23 is movable between a retracted position indicated by a solid line and an advanced position indicated by a two-dot chain line. When the pressing portion 23 is located at the retracted position, it is retracted behind the front faces 21A, 22A of the sensor unit 21 and the detection device 22. When the pressing portion 23 is located at the advanced position, it is located in front of the front faces 21A, 22A.

[0050] The gripping portion 24 is a portion that holds the workpiece W supported by the first pipe P1 and the second pipe P2 by magnetic force. The gripping portion 24 has an electromagnet. The gripping portion 24 has a recess that is V-shaped in cross section into which the U-shaped pipe W1 can fit.

[0051] 3, the sensor unit 21 includes a U-shaped plate 40, a first optical sensor 51, a second optical sensor 52, and a third optical sensor 53. The sensor unit 21 can form a triangular light frame F when viewed from the Z direction, which is a light frame F that can surround the first pipe P1 by light rays emitted from the three optical sensors 51 to 53. The base of the triangular frame F is aligned in the left-right direction, and the two oblique sides of the triangular frame F are positioned above the base.

[0052] The U-shaped plate 40 has a first portion 41 extending in the left-right direction, a second portion 42 extending downward from the left end of the first portion 41, and a third portion 43 extending downward from the right end of the first portion 41.

[0053] The first optical sensor 51, the second optical sensor 52, and the third optical sensor 53 are transmissive optical sensors. Each of the optical sensors 51 to 53 has a light-emitting portion L1 that emits light and a light-receiving portion L2 that receives light from the light-emitting portion L1. The light-emitting portion L1 of the first optical sensor 51 is provided at the lower end of the second portion 42. The light-receiving portion L2 of the first optical sensor 51 is provided at the lower end of the third portion 43. The light-emitting portion L1 of the first optical sensor 51 emits light along the left-right direction.

[0054] The light-emitting portion L1 of the second optical sensor 52 is provided at the lower end of the second portion 42. More specifically, the light-emitting portion L1 of the second optical sensor 52 is located below the light-emitting portion L1 of the first optical sensor 51. The light-receiving portion L2 of the second optical sensor 52 is provided at the right portion of the first portion 41. The light-emitting portion L1 of the second optical sensor 52 emits light diagonally upward to the right.

[0055] The light-emitting portion L1 of the third optical sensor 53 is provided on the left side of the first portion 41. The light-receiving portion L2 of the third optical sensor 53 is provided on the lower end of the third portion 43. More specifically, the light-receiving portion L2 of the third optical sensor 53 is located below the light-receiving portion L2 of the first optical sensor 51. The light-emitting portion L1 of the third optical sensor 53 emits light diagonally downward to the right.

[0056] The detection device 22 includes a U-shaped plate 60 , a fourth optical sensor 54 , and a fifth optical sensor 55 .

[0057] The U-shaped plate 60 has a first portion 61 extending in the left-right direction, a second portion 62 extending downward from the left end of the first portion 61, and a third portion 63 extending downward from the right end of the first portion 61.

[0058] The fourth optical sensor 54 and the fifth optical sensor 55 are transmissive optical sensors. The fourth optical sensor 54 and the fifth optical sensor 55 are arranged so that two light beams are parallel to each other. Specifically, the fourth optical sensor 54 and the fifth optical sensor 55 each have a light-emitting unit L1 that emits light and a light-receiving unit L2 that receives light from the light-emitting unit L1.

[0059] The light-emitting portion L1 of the fourth optical sensor 54 is provided at approximately the center in the up-down direction of the second portion 62. The light-receiving portion L2 of the fourth optical sensor 54 is provided at approximately the center in the up-down direction of the third portion 63. The light-emitting portion L1 of the fourth optical sensor 54 emits light along the left-right direction.

[0060] The light-emitting portion L1 of the fifth optical sensor 55 is provided at a position in the second portion 62 that is a predetermined distance below the light-emitting portion L1 of the fourth optical sensor 54. The light-receiving portion L2 of the fifth optical sensor 55 is provided at a position in the third portion 63 that is a predetermined distance below the light-receiving portion L2 of the fourth optical sensor 54. The predetermined distance is greater than the diameter of the second pipe P2. The light-emitting portion L1 of the fifth optical sensor 55 emits light in the left-right direction. The fifth optical sensor 55 is located at approximately the same position as the first optical sensor 51 in the up-down direction.

[0061] 1 is a device that controls the robot 1, and is configured to include, for example, a CPU, a RAM, a ROM, an input / output circuit, etc. The control unit 30 has a function of identifying the position of the first pipe P1 by using the sensor unit 21. In this embodiment, the sensor unit 21, the robot arm 10, and the control unit 30 configure a position identifying device that identifies the position of the first pipe P1.

[0062] 4(a)-(d), the control unit 30 determines the X and Y coordinates of the first pipe P1 by moving the sensor unit 21 in at least one of the left-right and up-down directions and positioning the first pipe P1 within the light frame F based on signals from the optical sensors 51-53. In more detail, as shown in FIG. 4(a), the control unit 30 moves the sensor unit 21 from top to bottom, thereby bringing the triangular frame F closer to the first pipe P1.

[0063] The control unit 30 stops the downward movement of the sensor unit 21 and determines the Y coordinate of the first pipe P1 on the condition that the light ray B1 constituting the base of the triangular frame F is blocked by the first pipe P1 as shown in FIG. 4(b) and then the light ray B1 leaves the first pipe P1 as shown in FIG. 4(c). When the downward movement of the sensor unit 21 is stopped and the light ray constituting one of the two hypotenuses is blocked by the first pipe P1, the control unit 30 moves the sensor unit 21 in the left-right direction so that the light ray constituting the other hypotenuse approaches the first pipe P1. After that, the control unit 30 stops the left-right movement of the sensor unit 21 and determines the X coordinate of the first pipe P1 on the condition that the light ray constituting one hypotenuse leaves the first pipe P1.

[0064] For example, as shown in Fig. 4(c), if the light ray B3 constituting the right-side oblique side is blocked by the first pipe P1 when the downward movement of the sensor unit 21 is stopped, the control unit 30 moves the sensor unit 21 to the right so that the light ray B2 constituting the left-side oblique side approaches the first pipe P1. After that, as shown in Fig. 4(d), the control unit 30 stops the rightward movement of the sensor unit 21 and determines the X coordinate of the first pipe P1 on the condition that the light ray B3 constituting the right-side oblique side has deviated from the first pipe P1.

[0065] Conversely, when the downward movement of the sensor unit 21 is stopped and the light ray B2 constituting the left hypotenuse is blocked by the first pipe P1, the control unit 30 moves the sensor unit 21 to the left and determines the X coordinate of the first pipe P1 on the condition that the left light ray B2 has left the first pipe P1. When the downward movement of the sensor unit 21 is stopped and the light rays B2 and B3 constituting the two hypotenuses are not blocked by the first pipe P1, the control unit 30 keeps the sensor unit 21 stopped and determines the X coordinate of the first pipe P1. The X and Y coordinates of the first pipe P1 can be, for example, the X and Y coordinates of the center of gravity of the triangular frame F.

[0066] The control unit 30 has a function of identifying the X-coordinate and the Y-coordinate for each portion of the first pipe P1 in the Z direction by the method described above. Specifically, as shown in Fig. 2, the control unit 30 identifies a first X-coordinate and a first Y-coordinate, which are the X-coordinate and the Y-coordinate of a first portion P11 of the first pipe P1. The control unit 30 also identifies a second X-coordinate and a second Y-coordinate, which are the X-coordinate and the Y-coordinate of a second portion P12 that is located in a different position in the Z direction from the first portion P11 of the first pipe P1.

[0067] Furthermore, the control unit 30 has a function to calculate the angle of the portion of the first pipe P1 from the first portion P11 to the second portion P12 with respect to the Z direction based on the first X coordinate, the first Y coordinate, the second X coordinate, and the second Y coordinate. The control unit 30 also has a function to calculate the shape of the first pipe P1 by acquiring the X coordinate and the Y coordinate of each portion of the first pipe P1 located at a different position in the Z direction and calculating the angle between each portion.

[0068] 5(a) and (b), the control unit 30 has a function of determining the orientation of the gripper 24 by rotating the detection device 22 around the first pipe P1 after identifying the X and Y coordinates of the first pipe P1 and stopping the rotation of the detection device 22 based on the detection result of the detection device 22. In this embodiment, after rotating the detection device 22, the control unit 30 stops the rotation of the detection device 22 on the condition that the second pipe P2 is positioned between the two light beams B4 and B5 emitted from the fourth optical sensor 54 and the fifth optical sensor 55.

[0069] Specifically, the control unit 30 determines whether or not one of the two light beams B4, B5 is blocked by the second pipe P2 after identifying the X and Y coordinates of the first pipe P1. As shown in Fig. 5(a), the control unit 30 rotates the detection device 22 downward when the light beam B5 from the lower fifth optical sensor 55 is blocked by the second pipe P2. The control unit 30 stops the rotation of the detection device 22 on the condition that the light beam B5 has deviated from the second pipe P2 as shown in Fig. 5(b).

[0070] When the light beam B4 from the upper fourth optical sensor 54 is blocked by the second pipe P2, the control unit 30 rotates the detection device 22 upward, and when the light beam B4 leaves the second pipe P2, the control unit 30 stops the rotation of the detection device 22. In other words, when one of the two light beams B4, B5 is blocked, the control unit 30 rotates the detection device 22 so that the other light beam approaches the second pipe P2. After that, the control unit 30 stops the rotation of the detection device 22 when one of the light beams leaves the second pipe P2.

[0071] When the robot 1 initially transports multiple workpieces W supported by a pair of a first pipe P1 and a second pipe P2, the control unit 30 has a function of exposing a part of the first pipe P1 and a part of the second pipe P2 by pressing the workpiece W with the pressing unit 23 of the robot hand 20 as shown in Figures 6(a) and 6(b) before identifying the X, Y coordinates of the first pipe P1. Note that in Figures 6 to 8, only the workpiece W that is closest to the robot 1 among the multiple workpieces W is shown, and the other workpieces W are not shown.

[0072] In detail, the control unit 30 moves the pressing unit 23 from the retracted position to the advanced position as shown in Fig. 5(a), and then, as shown in Fig. 5(b), moves the robot hand 20 forward to press the workpiece W. After pressing the workpiece W, the control unit 30 returns the pressing unit 23 to the retracted position.

[0073] After that, the control unit 30 moves the robot hand 20 so that the sensor unit 21 is positioned above the exposed portion of the first pipe P1 and the detection device 22 is positioned above the exposed portion of the second pipe P2. In the following description, this position, i.e., the position where measurement of the X and Y coordinates starts, is also referred to as the "measurement start position."

[0074] The control unit 30 moves the robot hand 20 downward from the measurement start position, thereby identifying the X, Y coordinates of the first pipe P1, as shown in Fig. 7. If the portion to be measured of the first pipe P1 and the portion to be measured of the second pipe P2 are misaligned in the Y direction, the control unit 30 rotates the detection device 22, more specifically the robot hand 20, around the first pipe P1, using the method described above.

[0075] 8, the control unit 30 causes each gripping portion 24 of the robot hand 20 to face the U-shaped pipe W1 of the workpiece W in the Z direction with reference to the identified X, Y coordinates. Note that the movement amounts of the robot hand 20 in the X, Y, and Z directions from the X, Y coordinates of the first pipe P1 are set in advance according to the shape of the workpiece W. Also, each movement amount is set to a value according to the inclination of the robot hand 20 about the first pipe P1.

[0076] Thereafter, the control unit 30 energizes the electromagnets of each gripping unit 24 to hold the workpiece W at each gripping unit 24. Finally, the control unit 30 sends the workpiece W gripped by the robot hand 20 to the next process.

[0077] Next, the operation of the control unit 30 will be described in detail with reference to FIG. 9 and FIG. When the user turns on the switch for starting the operation of the robot 1, the control unit 30 starts the transport process shown in Figures 9 and 10. In the following description, the first optical sensor 51 is also referred to as the "bottom sensor", the second optical sensor 52 and the third optical sensor 53 are also referred to as the "oblique sensor", and the fourth optical sensor 54 and the fifth optical sensor 55 are also referred to as the "parallel sensor".

[0078] In the transport process, the control unit 30 first energizes each of the optical sensors 51 to 55 (S1). After step S1, the control unit 30 moves the robot hand 20 so that the pressing unit 23 faces the workpiece W to be transported (S2). Here, information on the initial position of the robot hand 20, the position of the installation area A, the shape of the cart C, and the shape of the workpiece W is pre-stored in the storage unit, and the control unit 30 knows the approximate position of the workpiece W based on this information.

[0079] After step S2, the control unit 30 moves the pressing unit 23 from the retreated position to the advanced position, and then advances the robot hand 20 to push the workpiece W forward (S3). After step S3, the control unit 30 moves the robot hand 20 so that the robot hand 20 is positioned at the measurement start position (S4).

[0080] After step S4, the control unit 30 moves the robot hand 20 downward (S5). After step S5, the control unit 30 determines whether the bottom sensor (first optical sensor 51) turns ON after turning OFF, thereby determining whether the light beam B1 of the bottom sensor is blocked by the first pipe P1 and then moves off the first pipe P1 (S6).

[0081] The control unit 30 repeats the process of step S6 until the bottom sensor turns ON after it turns OFF (S6: No). In step S6, if the control unit 30 determines that the bottom sensor turns ON after it turns OFF (Yes), it stops the downward movement of the robot hand 20 (S7).

[0082] After step S7, the control unit 30 determines whether or not any of the two oblique side sensors (the second optical sensor 52 and the third optical sensor 53) is OFF (S8). If it is determined in step S8 that any of the oblique side sensors (e.g., the third optical sensor 53) is OFF (Yes), the control unit 30 moves the robot hand 20 in the left-right direction so that the light beam of the ON oblique side sensor (e.g., the second optical sensor 52) approaches the first pipe P1 (S9).

[0083] After step S9, the control unit 30 determines whether or not the oblique sensor in the OFF state (e.g., the third optical sensor 53) has been turned ON (S10). The control unit 30 repeats the process of step S10 until the oblique sensor in the OFF state is turned ON (S10: No).

[0084] When it is determined in step S10 that the oblique side sensor in the OFF state has become ON (Yes), the control unit 30 stops the left-right movement of the robot hand 20 (S11). After step S11, the control unit 30 determines the X, Y, and Z coordinates of the center of gravity of the light frame F at that time as the X, Y, and Z coordinates of the measurement target portion of the first pipe P1 (S12).

[0085] If it is determined in step S8 that both of the hypotenuse sensors are ON (No), the control unit 30 does not move the robot hand 20 in the left-right direction, and determines the X, Y, and Z coordinates of the center of gravity of the light frame F at that time as the X, Y, and Z coordinates of the measurement target portion of the first pipe P1 (S12).

[0086] After step S12, the control unit 30 determines whether or not either of the two parallel sensors (the fourth optical sensor 54 and the fifth optical sensor 55) is OFF (S13), as shown in Fig. 10. If it is determined in step S13 that either of the two parallel sensors (e.g., the fifth optical sensor 55) is OFF (Yes), the control unit 30 rotates the robot hand 20 about the first pipe P1 so that the light beam of the parallel sensor in the ON state (e.g., the fourth optical sensor 54) approaches the second pipe P2 (S14).

[0087] After step S14, the control unit 30 determines whether or not a parallel sensor (e.g., the fifth optical sensor 55) that is in the OFF state has been turned ON (S15). The control unit 30 repeats the process of step S15 until the parallel sensor that is in the OFF state is turned ON (S15: No).

[0088] If it is determined in step S15 that the parallel sensor in the OFF state has turned ON (Yes), the control unit 30 moves the robot hand 20 based on the position of the first pipe P1 so that each gripper 24 faces the U-shaped pipe W1 of the workpiece W (S17). If it is determined in step S13 that both of the two parallel sensors are ON (No), the control unit 30 executes the process of step S17 without rotating the robot hand 20.

[0089] After step S17, the control unit 30 adsorbs the workpiece W by each gripper 24 (S18). After step S18, the control unit 30 moves the robot hand 20 to transport the workpiece W to the next process (S19).

[0090] After step S19, the control unit 30 judges whether or not the transfer of all of the workpieces W supported by the pair of the first pipe P1 and the second pipe P2 has been completed (S20). If it is judged in step S20 that the transfer of all of the workpieces W has not been completed (No), the control unit 30 moves the robot hand 20 to a position forward in the Z direction from the previous measurement start position (S21). After step S21, the control unit 30 returns to the process of step S5 and measures the position of a portion of the first pipe P1 that has shifted forward from the previous measurement target portion.

[0091] If it is determined in step S20 that the transfer of all the workpieces W is completed (Yes), the control unit 30 calculates the angle of each portion of the first pipe P1 based on the X, Y, and Z coordinates of the measured portions (S22). After step S22, the control unit 30 calculates the shape of the first pipe P1 based on the X, Y, and Z coordinates of each portion and the angle of each portion (S23).

[0092] If the shape of the first pipe P1 calculated in the process of step S23 is significantly different from the normal shape, the control unit 30 may notify the user to replace the first pipe P1. For example, the control unit 30 may notify the user to replace the first pipe P1 when the angle of a predetermined portion is equal to or greater than a threshold value, or may calculate the overall inclination of the first pipe P1 from the angle of a straight line connecting the tip end and base end of the first pipe P1, and may notify the user to replace the first pipe P1 when the overall inclination is equal to or greater than a threshold value.

[0093] After step S23, the control unit 30 turns off the power supply to each of the optical sensors 51 to 55, returns the robot hand 20 to the initial position (S24), and ends this process.

[0094] As described above, according to this embodiment, the following effects can be obtained. Since the position of the first pipe P1 can be specified simply by positioning the first pipe P1 within the light frame F, the position of the first pipe P1 can be specified in a simple manner.

[0095] Since the angle and shape of the first pipe P1 can be grasped, the degree of deformation of the first pipe P1 can be grasped based on the grasped angle and shape.

[0096] Since the number of optical sensors in the sensor unit 21 is set to three, the number of optical sensors in the sensor unit 21 can be minimized, leading to cost reduction.

[0097] Before the position of the first pipe P1 is identified, the workpiece W is pressed by the pressing portion 23 to expose the first pipe P1, so that the position of the first pipe P1 can be identified with high accuracy.

[0098] If the first pipe P1 or the second pipe P2 is deformed in the vertical direction, the control unit 30 determines the X and Y coordinates of the first pipe P1, then rotates the detection device 22 around the first pipe P1 and detects the second pipe P2 with the detection device 22, thereby aligning the orientation of the gripping portion 24 with the workpiece W, so that the gripping portion 24 can firmly hold the workpiece W.

[0099] Since the rotation of the detection device 22 is stopped on the condition that the second pipe P2 is located between the two light beams B4, B5, the time required to determine the orientation of the grip part 24 can be shortened compared to, for example, a method in which the second pipe P2 is detected with a single transmission type light sensor. Here, when detecting the second pipe P2 with a single transmission type light sensor, the light sensor is positioned so that the light beam passes either above or below the second pipe P2, so it is necessary to move the detection device 22 up and down within a predetermined range so that deformation of the second pipe P2 on the side where the light beam does not pass can be detected, which takes time.

[0100] The present invention is not limited to the above-described embodiment, but can be used in various forms as exemplified below. The rod-shaped member is not limited to a cylindrical pipe, but may be, for example, a rectangular pipe, a cylinder, a prism, a wire, or the like.

[0101] The number of optical sensors in the sensor unit may be four or more. The light frame may be any polygonal shape, such as a square or a pentagon.

[0102] The moving device may be one that moves the sensor unit at least in the X direction and the Y direction. The moving device may also be one that moves the rod-shaped member relative to the stationary sensor unit. In this case, the X coordinate and the Y coordinate of the rod-shaped member may be identified by moving the rod-shaped member in at least one of the X direction and the Y direction and positioning the rod-shaped member within the frame based on a signal from the transmission type optical sensor.

[0103] The gripping portion is not limited to one that attracts the workpiece by magnetic force, and may be, for example, a mechanism in which two members are movable between a gripping position where they clamp the workpiece and a separated position where they are separated from the workpiece.

[0104] The pressing portion does not need to move in the Z direction relative to the sensor unit. The workpiece may have any shape as long as it is supported by at least one rod-shaped member.

[0105] The detection device may include at least one transmissive optical sensor.

[0106] The elements described in the above-mentioned embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0107] 1. Robot 10 Robot Arm 21 Sensor unit 30 Control section 51 First optical sensor 52 Second optical sensor 53 Third optical sensor B1 Ray B2 Ray B3 Ray F frame P1 First pipe

Claims

1. A position identifying device for identifying a position of a rod-shaped member, A sensor unit including a plurality of transmission type optical sensors; a moving device that moves the rod-shaped member or the sensor unit in an X direction and a Y direction perpendicular to the X direction; A control unit, the sensor unit is a light frame capable of surrounding the rod-shaped member by light beams emitted from the plurality of transmission type optical sensors, and is capable of forming a polygonal light frame when viewed from a Z direction perpendicular to the X direction and the Y direction; The control unit is a position determining device for determining the X and Y coordinates of a rod-shaped member by moving the rod-shaped member or the sensor unit in at least one of the X and Y directions and positioning the rod-shaped member within the frame based on a signal from the transmission type optical sensor.

2. the moving device is capable of moving the rod-shaped member or the sensor unit in a Z direction perpendicular to the X direction and the Y direction, The control unit is Identifying a first X-coordinate and a first Y-coordinate, which are the X-coordinate and the Y-coordinate of a first portion of the rod-shaped member; identifying a second X-coordinate and a second Y-coordinate, which are the X-coordinate and the Y-coordinate of a second portion of the rod-shaped member that is located at a position different from that of the first portion in the Z direction; 2. The position identification device according to claim 1, further comprising: a position determining unit that determines an angle of a portion of the rod-shaped member from the first portion to the second portion with respect to the Z direction based on the first X-coordinate, the first Y-coordinate, the second X-coordinate, and the second Y-coordinate.

3. the number of the transmissive optical sensors is three; The position determining device according to claim 1 , wherein the polygon is a triangle.

4. The base of the triangle is aligned along the X direction, two hypotenuses of the triangle are located on one side in the Y direction with respect to the base, The control unit is The sensor unit is moved from one side to the other side in the Y direction to approach the rod-shaped member, stopping the movement of the sensor unit in the Y direction and determining a Y coordinate of the rod-shaped member when the light ray constituting the base of the triangle is blocked by the rod-shaped member and then leaves the rod-shaped member; when the movement of the sensor unit in the Y direction is stopped and, in a case where a light beam constituting one of the two oblique sides is blocked by the rod-shaped member, the sensor unit is moved in the X direction so that a light beam constituting the other oblique side approaches the rod-shaped member; 4. The position determining device according to claim 3, wherein the movement of the sensor unit in the X direction is stopped and the X coordinate of the rod-shaped member is determined on the condition that the light beam constituting the one of the hypotenuses has deviated from the rod-shaped member.

5. A position specifying device according to any one of claims 1 to 4, A gripping portion for holding a workpiece supported by the rod-shaped member; a pressing unit that presses the workpiece along the rod-shaped member, The control unit is a pressing portion of the rod-shaped member that is pressed into the workpiece by the pressing portion, and then the pressing portion of the rod-shaped member is positioned within the frame, thereby determining an X coordinate and a Y coordinate of the part of the rod-shaped member.

6. 6. The robot according to claim 5, wherein the gripping portion holds the workpiece by magnetic force.

7. The position specifying device according to claim 2 ; a gripping unit that holds a workpiece supported by the rod-shaped member, The control unit is A robot comprising: a robot body having a rod-shaped member; a robot body having a rod-shaped member; a robot body having a rod-shaped member;

8. A position specifying device according to any one of claims 1 to 4, a gripping unit for holding a workpiece supported by the rod-shaped member and a second rod-shaped member located at a different position from the rod-shaped member in a direction perpendicular to the Z direction, a detection device having at least one transmission type optical sensor and configured to detect the second rod-shaped member; The control unit is a detection device that detects the X and Y coordinates of the rod-shaped member, rotates the detection device around the rod-shaped member, and stops the rotation of the detection device based on the detection result of the detection device, thereby determining the orientation of the gripping part.

9. The detection device includes two of the transmission type optical sensors, The two transmission type optical sensors of the detection device are arranged so that two light beams are parallel to each other, 9. The robot according to claim 8, wherein the control unit stops the rotation of the detection device on condition that the second rod-shaped member is positioned between two light beams.

10. A position identification method for identifying a position of a rod-shaped member using a sensor unit capable of forming a polygonal light frame as viewed in a Z direction, the method comprising the steps of: a position determining method for determining the X and Y coordinates of the rod-shaped member by moving the rod-shaped member or the sensor unit in at least one of an X direction perpendicular to the Z direction and a Y direction perpendicular to the Z direction and the X direction, and positioning the rod-shaped member within the frame based on a signal from the transmission type optical sensor.

11. Identifying a first X-coordinate and a first Y-coordinate, which are the X-coordinate and the Y-coordinate of a first portion of the rod-shaped member; Identifying a second X-coordinate and a second Y-coordinate, which are the X-coordinate and the Y-coordinate of a second portion located at a position different from the first portion of the rod-shaped member in the Z-direction; 11. The position identification method according to claim 10, further comprising calculating an angle of a portion of the rod-shaped member from the first portion to the second portion with respect to the Z direction based on the first X-coordinate, the first Y-coordinate, the second X-coordinate, and the second Y-coordinate.

12. the number of the transmissive optical sensors is three; The method of claim 10, wherein the polygon is a triangle.

13. The base of the triangle is aligned along the X direction, two hypotenuses of the triangle are located on one side in the Y direction with respect to the base, The sensor unit is moved from one side to the other side in the Y direction to approach the rod-shaped member, stopping the movement of the sensor unit in the Y direction and determining a Y coordinate of the rod-shaped member when the light ray constituting the base of the triangle is blocked by the rod-shaped member and then leaves the rod-shaped member; when the movement of the sensor unit in the Y direction is stopped and, in a case where a light beam constituting one of the two oblique sides is blocked by the rod-shaped member, the sensor unit is moved in the X direction so that a light beam constituting the other oblique side approaches the rod-shaped member; 13. The position identification method according to claim 12, further comprising the step of stopping the movement of the sensor unit in the X direction and determining the X coordinate of the rod-shaped member when the light ray constituting the one of the hypotenuses deviates from the rod-shaped member.

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