Industrial robot and teaching method for industrial robot

Abstract

To provide an industrial robot capable of reducing load on an operator for performing calibration even when calibration for correcting positions automatically taught is performed.SOLUTION: An industrial robot 1 continuously and automatically executes: a teaching step of learning a hand position that is a position of hands 4, 5 when mounting a transported object to be placed in a predetermined position PP on a placing section 3; and a calibration step of correcting the hand position learned in the teaching step. In the calibration step, the hand 5 is moved to the hand position identified in the teaching step, and a transported object 32 for teaching placed in the predetermined position PP is mounted and taken out onto the hand 5. Thereafter, the hand 5 is moved again to the hand position identified in the teaching step and the transported object 32 for teaching is placed on the placing section 3. Afterward, the position of the transported object 32 for teaching is detected by second sensors 28 attached to the hand 4 and the hand position is corrected based on the detection result by the second sensors 28.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an industrial robot for transporting an object, and also to a teaching method for an industrial robot for transporting an object. [Background technology]

[0002] Conventionally, horizontal articulated industrial robots that transport workpieces are known (see, for example, Patent Document 1). The industrial robot described in Patent Document 1 carries workpieces onto a stage and carries them out of the stage. This industrial robot is subjected to automatic teaching, which causes the industrial robot to memorize the vertical and horizontal positions of the workpieces accommodated on the stage. When automatic teaching is performed, a teaching jig is attached to the hand of the industrial robot. The teaching jig is equipped with a first sensor for detecting the vertical position of the workpiece and a second sensor for detecting the horizontal position of the workpiece.

[0003] Before automatic teaching is performed in the industrial robot described in Patent Document 1, calibration is performed. When performing calibration, an operator first loads a workpiece in the ideal position of the hand. Then, the operator operates the industrial robot to transport and place the workpiece loaded on the hand on the stage. After that, the above-mentioned teaching jig is attached to the hand, and the industrial robot performs the same operations as in automatic teaching, and the second sensor detects the horizontal position of the workpiece. In addition, a correction value is calculated based on the detection result of the second sensor. When automatic teaching of the industrial robot is completed, the automatically taught position is corrected based on the correction value calculated during calibration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-102695 Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of the industrial robot described in Patent Document 1, the tasks and operations for automatic teaching and the tasks and operations for calibration are separate, and the operator must perform the tasks and operations for calibration in addition to the tasks and operations for automatic teaching. Furthermore, in the case of this industrial robot, the tasks for calibration include manual work by the operator, making the operator's work for calibration cumbersome. Therefore, in the case of the industrial robot described in Patent Document 1, the burden on the operator for performing calibration is heavy.

[0006] Therefore, an object of the present invention is to provide an industrial robot for transporting an object, which can reduce the burden on an operator for performing calibration even when performing calibration to correct an automatically taught position.An object of the present invention is to provide an industrial robot teaching method for transporting an object, which can reduce the burden on an operator for performing calibration even when performing calibration to correct an automatically taught position. [Means for solving the problem]

[0007] In order to solve the above problems, the industrial robot of the present invention is an industrial robot for transporting an object to be transported, and includes a hand on which the object to be transported is placed, an arm to which the hand is connected at its tip side so as to be rotatable about an axial direction of rotation in the vertical direction, and a control unit for controlling the industrial robot. the robot includes a first hand and a second hand as hands, one of the first hand and the second hand being disposed above the other of the first hand and the second hand, and when viewed from the top-bottom direction, the center of rotation of the first hand relative to the arm and the center of rotation of the second hand relative to the arm coincide with each other, and when the rotation angle of the first hand relative to the arm and the rotation angle of the second hand relative to the arm are equal, the transport object placed on the first hand and the transport object placed on the second hand overlap in the top-bottom direction;The control unit automatically and consecutively executes a teaching step for causing the industrial robot to memorize the hand position, which is the vertical and horizontal position of the hand when loading the transport object placed at a predetermined position on the loading unit where the transport object is placed, onto the hand and when placing the transport object loaded on the hand at the predetermined position, and a calibration step for correcting the hand position memorized in the teaching step after the teaching step.When the teaching step is executed, a dummy transport object formed to the same shape as the transport object, or a transport object placed at a predetermined position, and the transport object or dummy transport object placed at the predetermined position is used as the transport object for teaching, in the teaching step: No. 1 A first sensor attached to the hand detects the vertical position of the teaching transport object placed at a predetermined position, and No. 1 The second sensor attached to the hand detects the horizontal position of the teaching transport object placed at a predetermined position, and the control unit specifies and stores the hand position based on the detection results of the first sensor and the second sensor. In the calibration step, the control unit stores the hand position specified in the teaching step. No. 2 The hand is moved to carry the teaching object placed in the specified position. No. 2 After loading and unloading the hand, the hand position is specified in the teaching step. No. 2 The hand is moved again to place the teaching object on the placement section, and then No. 1 A second sensor attached to the hand detects the horizontal position of the teaching transport object placed on the placement section, and the control unit corrects the horizontal position of the hand position stored in the teaching step based on the detection result of the second sensor.

[0008] In order to solve the above problems, the present invention provides a teaching method for an industrial robot, which includes a hand on which an object to be conveyed is placed, and an arm to which the hand is rotatably connected at its tip end with the vertical direction as the axis of rotation. and a first hand and a second hand are provided as the hands, one of the first hand and the second hand is disposed above the other of the first hand and the second hand, and when viewed from the top-bottom direction, the center of rotation of the first hand relative to the arm and the center of rotation of the second hand relative to the arm coincide with each other, and when the rotation angle of the first hand relative to the arm and the rotation angle of the second hand relative to the arm are equal, the transport object placed on the first hand and the transport object placed on the second hand overlap in the top-bottom direction.A teaching method for an industrial robot, comprising the steps of: a teaching step for causing the industrial robot to memorize the hand position, which is the vertical and horizontal position of the hand when loading the transport object, which is placed at a predetermined position on a loading section where the transport object is placed, onto the hand, and when placing the transport object loaded on the hand at the predetermined position; and a calibration step for correcting the hand position memorized in the teaching step after the teaching step; when the teaching step is executed, a dummy transport object formed to the same shape as the transport object, or a transport object placed at a predetermined position, is used as the transport object for teaching, and in the teaching step: No. 1 A first sensor attached to the hand detects the vertical position of the teaching transport object placed at a predetermined position, and No. 1 A second sensor attached to the hand detects the horizontal position of the teaching transport object placed at a predetermined position, and the hand position is specified and stored based on the detection results of the first sensor and the second sensor. In the calibration step, the hand position specified in the teaching step is stored. No. 2 The hand is moved to carry the teaching object placed in the specified position. No. 2 After loading and unloading the hand, the hand position is specified in the teaching step. No. 2 The hand is moved again to place the teaching object on the placement section, and then No. 1 A second sensor attached to the hand detects the horizontal position of the teaching transport object placed on the placement section, and based on the detection result of the second sensor, the horizontal position of the hand position stored in the teaching step is corrected.

[0009] In the present invention, a teaching step is performed continuously and automatically to memorize the hand position, which is the vertical and horizontal position of the hand when loading an object to be transported, which is placed at a predetermined position on a loading section where the object to be transported is placed, onto the hand, and when placing the object to be transported loaded onto the hand at the predetermined position, into the industrial robot, and after the teaching step, a calibration step is performed to correct the hand position memorized in the teaching step.

[0010] In the present invention, in the calibration step, the hand position specified in the teaching step is No. 2 The hand is moved to carry the teaching object placed in the specified position. No. 2 After loading and unloading the hand, the hand position is specified in the teaching step. No. 2 The hand is moved again to place the teaching object on the placement section, and then No. 1 A second sensor attached to the hand detects the horizontal position of the teaching transport object placed on the placement section, and based on the detection result of the second sensor, the horizontal position of the hand position stored in the teaching step is corrected.

[0011] Therefore, in the present invention, if the operator performs the work and operations for executing the teaching step, it is possible to automatically execute up to the calibration step without performing the work and operations for executing the calibration step. Therefore, in the present invention, even when calibration is performed to correct the position automatically taught in the teaching step, it is possible to reduce the burden on the operator for performing the calibration.

[0012] Also, The present invention SoThe industrial robot has a first hand and a second hand as hands, one of the first hand and the second hand is arranged above the other of the first hand and the second hand, when viewed from the top-bottom direction, the center of rotation of the first hand relative to the arm and the center of rotation of the second hand relative to the arm coincide with each other, and when the rotation angle of the first hand relative to the arm and the rotation angle of the second hand relative to the arm are equal, the transport object placed on the first hand and the transport object placed on the second hand overlap in the top-bottom direction, and in the teaching step, a first sensor attached to the first hand detects whether the first hand is rotated relative to the arm or not. The vertical position of the teaching object to be transported placed at a predetermined position is detected by the first sensor, and the horizontal position of the teaching object to be transported placed at a predetermined position is detected by the second sensor attached to the first hand. In the calibration step, the second hand is moved to the hand position specified in the teaching step, the teaching object to be transported placed at the predetermined position is loaded onto the second hand and removed, and then the second hand is moved again to the hand position specified in the teaching step and the teaching object to be transported is placed on the placement section. Thereafter, the horizontal position of the teaching object to be transported placed on the placement section is detected by the second sensor attached to the first hand. is doing .

[0013] Therefore In the calibration step, the teaching object can be transported by the second hand to which the first sensor and the second sensor are not attached. .therefore For example, even if the first sensor and the second sensor are positioned in a position that may cause interference with the transport of the teaching transport object by the hand, in the calibration step, it is possible to transport the teaching transport object by the second hand while the first sensor and the second sensor remain attached to the first hand.

[0014] In the present invention, when the teaching step and the calibration step are performed, it is preferable that a teaching jig having the first sensor and the second sensor is attached to the first hand. With this configuration, since the teaching jig attached to the first hand includes the first sensor and the second sensor, even if the first sensor and the second sensor are located in a position that may cause interference with the transport of the transport object by the first hand, the first sensor and the second sensor can be easily removed from the first hand after teaching the industrial robot. Furthermore, when teaching the industrial robot, the first sensor and the second sensor can be easily attached to the first hand.

[0015] In the present invention, the first hand is preferably arranged above the second hand, which makes it easier to attach a teaching tool compared to when the first hand is arranged below the second hand.

[0016] In the present invention, for example, an industrial robot includes a first hand drive mechanism that rotates a first hand relative to an arm, a second hand drive mechanism that rotates a second hand relative to the arm, an arm drive mechanism that extends and retracts the arm, which is a multi-joint arm, and a lifting mechanism that raises and lowers the arm, the object to be transported is formed in a circular plate shape, the hand includes a gripping mechanism that contacts the end face of the object to be transported mounted on the hand from at least three directions and holds the object to be transported in a fixed position horizontally, and when the rotation angle of the first hand relative to the arm and the rotation angle of the second hand relative to the arm are equal, when viewed from above and below, the center of the object to be transported on the first hand held by the gripping mechanism and the center of the object to be transported on the second hand held by the gripping mechanism coincide. [Effects of the Invention]

[0017] As described above, the present invention makes it possible to reduce the burden on the operator for performing calibration in an industrial robot for transporting objects, even when performing calibration to correct an automatically taught position. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a side view of an industrial robot according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the industrial robot shown in FIG. [Figure 3] FIG. 2 is a block diagram for explaining the configuration of the industrial robot shown in FIG. [Figure 4] 2 is a plan view for explaining the configuration of a jig used when teaching the industrial robot shown in FIG. 1. FIG. [Figure 5] 2 is a plan view for explaining the operation of the industrial robot shown in FIG. 1 in a teaching step. FIG. [Figure 6] 2 is a plan view for explaining the operation of the industrial robot shown in FIG. 1 in a teaching step. FIG. [Figure 7] 2 is a plan view for explaining the operation of the industrial robot shown in FIG. 1 in a calibration step. FIG. [Figure 8] 2 is a plan view for explaining the operation of the industrial robot shown in FIG. 1 in a calibration step. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] (Configuration of industrial robots) Fig. 1 is a side view of an industrial robot 1 according to an embodiment of the present invention. Fig. 2 is a plan view of the industrial robot 1 shown in Fig. 1. Fig. 3 is a block diagram for explaining the configuration of the industrial robot 1 shown in Fig. 1.

[0021] The industrial robot 1 (hereinafter referred to as "robot 1") of this embodiment is a horizontal articulated robot for transporting a semiconductor wafer 2 (hereinafter referred to as "wafer 2"), which is an object to be transported. The wafer 2 is formed in a disk shape. The robot 1 is incorporated into a semiconductor manufacturing system for use. The robot 1 transports the wafer 2 to a wafer mounting section 3 (see FIG. 5, etc.) on which the wafer 2 is mounted. That is, the robot 1 loads the wafer 2 onto the wafer mounting section 3 and unloads the wafer 2 from the wafer mounting section 3. The wafer mounting section 3 is, for example, a stage on which the wafer 2 is mounted when a predetermined process is performed on the wafer 2. The wafer mounting section 3 is formed, for example, inside a FOUP (Front-Opening Unified Pod) that accommodates a plurality of wafers 2.

[0022] The robot 1 includes hands 4 and 5 on which the wafer 2 is placed, an arm 6 to which the hands 4 and 5 are rotatably connected at their tip ends and which moves horizontally, and a main body 7 to which the base end of the arm 6 is rotatably connected. The robot 1 also includes a control unit 8 that controls the robot 1. The robot 1 of this embodiment includes two hands 4 and 5. The hand 4 of this embodiment is the first hand, and the hand 5 is the second hand.

[0023] The arm 6 is composed of three arm sections 10 to 12 that are rotatably connected to one another. That is, the arm 6 is a multi-joint arm. The base end of the arm section 10 is rotatably connected to the main body section 7. The base end of the arm section 11 is rotatably connected to the tip end of the arm section 10. The base end of the arm section 12 is rotatably connected to the tip end of the arm section 11. The arm sections 10 to 12 rotate about the up-down direction (vertical direction) as the rotation axis. The main body section 7 includes a housing 13 and a pillar-shaped member (not shown) to which the base end of the arm section 10 is rotatably connected. The base end of the arm section 10 is rotatably connected to the upper end of the pillar-shaped member. The main body section 7, arm section 10, arm section 11, and arm section 12 are arranged in this order from the bottom up in the up-down direction.

[0024] The hands 4 and 5 are formed so that their shape when viewed from the top and bottom is approximately Y-shaped. The hands 4 and 5 are formed with the same shape. The base ends of the hands 4 and 5 are rotatably connected to the tip ends of the arm unit 12. The hands 4 and 5 rotate about the vertical direction as their axis of rotation. The hands 4 and 5 are rotatable independently relative to the arm unit 12. The hands 4 and 5 are equipped with a gripping mechanism 14 that contacts the edge face (outer peripheral surface) of the wafer 2 loaded on the hands 4 and 5 from three directions to hold the wafer 2 loaded on the hands 4 and 5 at a fixed position in the horizontal direction. The gripping mechanism 14 is equipped with an edge face contacting member 15 having an abutment surface against which the edge face of the wafer 2 abuts, and a wafer pressing mechanism 16 that presses the wafer 2 so that the edge face of the wafer 2 is pressed against the abutment surface of the edge face contacting member 15.

[0025] The edge surface contact members 15 are disposed at two locations at the tips of the roughly Y-shaped hands 4 and 5. The wafer pressing mechanism 16 includes a pressing unit that presses the edge surface of the wafer 2 toward the tips of the hands 4 and 5, and an air cylinder that drives the pressing unit. The pressing unit includes a roller that contacts the edge surface of the wafer 2. The wafer pressing mechanism 16 is electrically connected to the control unit 8. Specifically, an electromagnetic valve disposed in the piping path of the air cylinder is electrically connected to the control unit 8. Two wafer placement members 17 on which the wafer 2 is placed are fixed to the upper surfaces of the hands 4 and 5, and the wafer 2 is placed on the edge surface contact members 15 and the wafer placement members 17. The gripping mechanism 14 may be configured to contact the edge surface of the wafer 2 placed on the hands 4 and 5 from four or more directions to hold the wafer 2.

[0026] The base end of hand 4 and the base end of hand 5 overlap in the vertical direction. In this embodiment, hand 4 is arranged on the upper side, and hand 5 is arranged on the lower side. That is, hand 4 is arranged above hand 5. Furthermore, hands 4 and 5 are arranged above arm unit 12. When viewed from the vertical direction, the rotation center of hand 4 relative to arm 6 (i.e., the rotation center of hand 4 relative to arm unit 12) and the rotation center of hand 5 relative to arm 6 (i.e., the rotation center of hand 5 relative to arm unit 12) coincide with each other.

[0027] When the rotation angle of hand 4 relative to arm 6 and the rotation angle of hand 5 relative to arm 6 are equal, hand 4 and hand 5 overlap in the vertical direction. In other words, when the rotation angle of hand 4 relative to arm 6 and the rotation angle of hand 5 relative to arm 6 are equal, wafer 2 loaded on hand 4 and wafer 2 loaded on hand 5 overlap in the vertical direction. More specifically, when the rotation angle of hand 4 relative to arm 6 and the rotation angle of hand 5 relative to arm 6 are equal, the center of wafer 2 on hand 4 held by gripping mechanism 14 and the center of wafer 2 on hand 5 held by gripping mechanism 14 coincide when viewed from the vertical direction.

[0028] Robot 1 includes a first hand drive mechanism 19 that rotates hand 4 relative to arm 6, a second hand drive mechanism 20 that rotates hand 5 relative to arm 6, an arm drive mechanism 21 that extends and retracts arm 6, which is a multi-joint arm, and a lifting mechanism 22 that raises and lowers arm 6. First hand drive mechanism 19, second hand drive mechanism 20, arm drive mechanism 21, and lifting mechanism 22 are electrically connected to control unit 8. Specifically, motors and the like that serve as drive sources for first hand drive mechanism 19, second hand drive mechanism 20, arm drive mechanism 21, and lifting mechanism 22 are electrically connected to control unit 8.

[0029] The arm drive mechanism 21 is composed of a first drive mechanism that rotates the arm sections 10 and 11 to extend and retract a portion of the arm 6 consisting of the arm sections 10 and 11, and a second drive mechanism that rotates the arm section 12 relative to the arm section 11. The lifting mechanism 22 raises and lowers the pillar-shaped member of the main body section 7. The lifting mechanism 22 is housed inside the housing 13. The lifting mechanism 22 raises and lowers the hands 4 and 5 and the arm 6 together with the pillar-shaped member.

[0030] (Industrial robot teaching method) Fig. 4 is a plan view illustrating the configuration of a jig 25 used when teaching the robot 1 shown in Fig. 1. Figs. 5 and 6 are plan views illustrating the operation of the robot 1 shown in Fig. 1 in a teaching step. Figs. 7 and 8 are plan views illustrating the operation of the robot 1 shown in Fig. 1 in a calibration step.

[0031] The robot 1 is taught how to properly transport the wafer 2 to the wafer placement unit 3. When teaching the robot 1, the control unit 8 automatically and consecutively executes a teaching step for causing the robot 1 to memorize the hand positions HP, which are the vertical and horizontal positions of the hands 4 and 5 when the wafer 2 to be placed at the predetermined position PP of the wafer placement unit 3 is placed on the hands 4 and 5, and when the wafer 2 placed on the hands 4 and 5 is placed at the predetermined position PP of the wafer placement unit 3, and a calibration step for correcting (calibrating) the hand positions HP memorized in the teaching step after the teaching step.

[0032] In the teaching step and the calibration step, the control unit 8 controls the wafer pressing mechanism 16, the first hand driving mechanism 19, the second hand driving mechanism 20, the arm driving mechanism 21, and the lifting mechanism 22 to operate the robot 1. That is, in the teaching step and the calibration step, the robot 1 operates automatically, and no manual work is performed by an operator who teaches the robot 1 in the teaching step and the calibration step.

[0033] When teaching the robot 1, a dummy wafer 32 formed in the same shape as the wafer 2 is used as a dummy transport object. A teaching jig 25 is also used when teaching the robot 1. The jig 25 is attached to the upper surface of the hand 4. That is, when the teaching step and the calibration step are performed, the jig 25 is attached to the hand 4. As shown in FIG. 4 , the jig 25 includes a jig body 26 formed in the shape of a thin flat plate, a first sensor 27 for detecting the position of the dummy wafer 32 in the vertical direction, and two second sensors 28 for detecting the position of the dummy wafer 32 in the horizontal direction. The first sensor 27 and the second sensor 28 are used when teaching the robot 1, but are not used when the robot 1 transports the wafer 2.

[0034] The jig body 26 is attached to the upper surface of the hand 4 so that the thickness direction of the jig body 26 coincides with the up-down direction. The jig body 26 is formed so that its shape when viewed from the up-down direction is approximately Y-shaped. The first sensor 27 and the second sensor 28 are attached to the jig body 26. The first sensor 27 is a transmission-type optical sensor having a light-emitting portion 27a and a light-receiving portion 27b. Like the first sensor 27, the second sensor 28 is also a transmission-type optical sensor having a light-emitting portion and a light-receiving portion. When attaching the jig 25 to the hand 4, the wiring of the first sensor 27 and the wiring of the second sensor 28 are connected to the wiring on the hand 4 side. When the jig 25 is attached to the upper surface of the hand 4, the first sensor 27 and the second sensor 28 are electrically connected to the control unit 8.

[0035] The light-emitting unit 27a and the light-receiving unit 27b of the first sensor 27 are arranged to face each other in the horizontal direction with a predetermined gap between them. When the jig 25 is attached to the upper surface of the hand 4, the light-emitting unit 27a is arranged near one of the two end surface abutting members 15, and the light-receiving unit 27b is arranged near the other end surface abutting member 15. The light-emitting unit and the light-receiving unit of the second sensor 28 are arranged to face each other in the vertical direction with a predetermined gap between them. The second sensor 28 is attached to the upper surface of the jig body 26. When the jig 25 is attached to the upper surface of the hand 4, one of the two second sensors 28 is arranged near one of the two wafer mounting members 17, and the other second sensor 28 is arranged near the other wafer mounting member 17.

[0036] Before the teaching step is performed, the jig 25 is attached to the hand 4. Also, before the teaching step is performed, a dummy wafer 32 is placed at a predetermined position PP on the wafer placement unit 3. That is, when the teaching step is performed, the dummy wafer 32 is placed at the predetermined position PP. The jig 25 is attached to the hand 4 by an operator who teaches the robot 1. The dummy wafer 32 is placed at the predetermined position PP by the operator. In this embodiment, the dummy wafer 32 is a teaching transport object that is placed at the predetermined position PP. Also, before the teaching step is performed, the hand 4 to which the jig 25 is attached is placed in front of the wafer placement unit 3 (see FIG. 5).

[0037] Thereafter, the control unit 8 receives a teaching start command signal for the robot 1. Having received the teaching start command signal, the control unit 8 executes a teaching step. In the teaching step, the first sensor 27 detects the vertical position of the dummy wafer 32 placed at the predetermined position PP, and the second sensor 28 detects the horizontal position of the dummy wafer 32 placed at the predetermined position PP, and the control unit 8 identifies the above-mentioned hand position HP based on the detection results of the first sensor 27 and the second sensor 28.

[0038] In the teaching step, first, the first sensor 27 attached to the hand 4 detects the vertical position of the dummy wafer 32 placed at the predetermined position PP, and then the second sensor 28 attached to the hand 4 detects the horizontal position of the dummy wafer 32 placed at the predetermined position PP. Note that the operations performed by the robot 1 in the teaching step of this embodiment are the same as the operations performed by the industrial robot described in the above-mentioned Patent Document 1 when this industrial robot is automatically taught.

[0039] When the first sensor 27 detects the vertical position of the dummy wafer 32 placed at the predetermined position PP, the hand 4 placed in front of the wafer placement unit 3 is moved toward the dummy wafer 32. At this time, the hand 4 is moved up and down reciprocatingly with a constant amplitude. For example, the hand 4 is moved up and down reciprocatingly so as to move in a rectangular wave pattern. As the hand 4 moves up and down reciprocatingly toward the dummy wafer 32, the light directed from the light-emitting portion 27a to the light-receiving portion 27b of the first sensor 27 is eventually blocked by the dummy wafer 32 (see FIG. 6(A)), and the vertical position of the dummy wafer 32 placed at the predetermined position PP is detected.

[0040] When the vertical position of the dummy wafer 32 placed at the predetermined position PP is detected, the hand 4 is temporarily retracted to the front of the wafer placement part 3. Thereafter, the height of the hand 4 is set based on the detection result of the vertical position of the dummy wafer 32, and then the hand 4 is moved linearly toward the dummy wafer 32 in order to detect the horizontal position of the dummy wafer 32 placed at the predetermined position PP with the second sensor 28.

[0041] As the hand 4 moves toward the dummy wafer 32, the light traveling from the light-emitting portions to the light-receiving portions of the second sensors 28 is eventually blocked by the dummy wafer 32. When detecting the horizontal position of the dummy wafer 32 placed at the predetermined position PP, the position of the hand 4 in a direction perpendicular to the direction of movement of the hand 4 is adjusted so that the light traveling from the light-emitting portions to the light-receiving portions of the two second sensors 28 is simultaneously blocked by the dummy wafer 32 (see FIG. 6(B)).

[0042] For example, when only the light traveling from the light-emitting portion to the light-receiving portion of one of the two second sensors 28 is blocked by the dummy wafer 32, the movement of the hand 4 toward the dummy wafer 32 is stopped, and the hand 4 is moved in a direction perpendicular to the movement direction of the hand 4 to a position where the light traveling from the light-emitting portion to the light-receiving portion of the other second sensor 28 is blocked by the dummy wafer 32. Thereafter, the hand 4 is retreated to the front of the wafer placement unit 3, and then moved toward the dummy wafer 32 again.

[0043] When the light beams from the light-emitting portions to the light-receiving portions of the two second sensors 28 are simultaneously blocked by the dummy wafer 32 (see FIG. 6(B)), the horizontal position of the dummy wafer 32 placed at the predetermined position PP is detected. When the vertical and horizontal positions of the dummy wafer 32 placed at the predetermined position PP are detected, the control unit 8 identifies the hand position HP based on the detection results of the first sensor 27 and the second sensor 28, as described above.

[0044] Thereafter, the control unit 8 executes a calibration step. Since the calibration step is executed following the teaching step, at the start of the calibration step, a dummy wafer 32 is placed at a predetermined position PP on the wafer placement unit 3. In the calibration step, first, as shown in FIG. 7, the hand 5 is automatically placed in front of the wafer placement unit 3. Then, the hand 5 is moved to the hand position HP specified in the teaching step (see FIG. 8(A)), and the dummy wafer 32 placed at the predetermined position PP is loaded onto the hand 5 and removed (see FIG. 8(B)). For example, as shown in FIG. 8(B), the wafer 2 loaded on the hand 5 is removed to the front of the wafer placement unit 3. The dummy wafer 32 loaded on the hand 5 is held at a fixed position by the gripping mechanism 14.

[0045] Thereafter, the hand 5 is again moved to the hand position HP specified in the teaching step (see FIG. 8(A)), and the dummy wafer 32 is placed on the wafer mounting part 3. At this time, it is ideal that the dummy wafer 32 is placed at the predetermined position PP, but in reality, the dummy wafer 32 is placed at a position slightly shifted from the predetermined position PP on the wafer mounting part 3. In other words, the dummy wafer 32 is placed near the predetermined position PP.

[0046] Thereafter, the robot 1 is made to perform the same operation as that performed when detecting the horizontal position of the dummy wafer 32 in the teaching step, and the second sensors 28 detect the horizontal position of the dummy wafer 32 placed on the wafer placement part 3. At this time, when the light from the light-emitting parts to the light-receiving parts of the two second sensors 28 is simultaneously blocked by the dummy wafer 32, the horizontal position of the dummy wafer 32 placed on the wafer placement part 3 is detected. Thereafter, the control unit 8 corrects the horizontal position of the hand position HP stored in the teaching step based on the detection results of the second sensors 28.

[0047] (Main effect of this form) As described above, in this embodiment, the control unit 8 automatically and consecutively executes a teaching step for storing the hand position HP in the robot 1 and a calibration step for correcting the hand position HP stored in the teaching step after the teaching step. Also, in this embodiment, in the calibration step, the hand 5 is moved to the hand position HP specified in the teaching step, the dummy wafer 32 placed at the predetermined position PP is loaded onto the hand 5 and removed, and then the hand 5 is moved again to the hand position HP specified in the teaching step and the dummy wafer 32 is placed on the wafer placement unit 3. Thereafter, the second sensor 28 detects the horizontal position of the dummy wafer 32 placed on the wafer placement unit 3, and the horizontal position of the hand position HP stored in the teaching step is corrected based on the detection result of the second sensor 28.

[0048] Therefore, in this embodiment, if the operator performs the work and operation for executing the teaching step, it is possible to automatically execute up to the calibration step without performing the work and operation for executing the calibration step. Therefore, in this embodiment, even when calibration is performed to correct the position automatically taught in the teaching step, it is possible to reduce the burden on the operator for performing the calibration.

[0049] In this embodiment, in the calibration step, the dummy wafer 32 is transported by the hand 5 to which the first sensor 27 and the second sensor 28 are not attached. Therefore, in this embodiment, even if the first sensor 27 and the second sensor 28 are disposed in a position that may cause an obstruction to the transport of the dummy wafer 32 by the hand 4, the dummy wafer 32 can be transported by the hand 5 in the calibration step with the first sensor 27 and the second sensor 28 still attached to the hand 4.

[0050] In this embodiment, the jig 25 is equipped with the first sensor 27 and the second sensor 28. Therefore, in this embodiment, even if the first sensor 27 and the second sensor 28 are disposed in a position where they may interfere with the transfer of the wafer 2 by the hand 4, the first sensor 27 and the second sensor 28 can be easily removed from the hand 4 after teaching the robot 1. Furthermore, when teaching the robot 1, the first sensor 27 and the second sensor 28 can be easily attached to the hand 4. Furthermore, in this embodiment, the hand 4 to which the jig 25 is attached is disposed above the hand 5, making it easier to attach the jig 25 compared to a case in which the jig 25 is attached to the hand 5.

[0051] (Other embodiments) The above-described embodiment is one example of a preferred embodiment of the present invention, but the present invention is not limited to this embodiment and various modifications can be made without departing from the spirit of the present invention.

[0052] In the embodiment described above, in the calibration step, after the dummy wafer 32 is carried in and out, the horizontal position of the dummy wafer 32 placed on the wafer placement unit 3 is detected by the second sensor 28, and the horizontal position of the hand position HP stored in the teaching step is corrected based on the detection result of the second sensor 28. However, in the calibration step, after the dummy wafer 32 is carried in and out, the vertical position of the dummy wafer 32 placed on the wafer placement unit 3 may be detected by the first sensor 27, and the horizontal position of the dummy wafer 32 placed on the wafer placement unit 3 may be detected by the second sensor 28, and the hand position HP stored in the teaching step may be corrected based on the detection results of the first sensor 27 and the second sensor 28. That is, in the calibration step, the vertical and horizontal positions of the hand position HP stored in the teaching step may be corrected.

[0053] In the above-described embodiment, the jig 25 may be attached to the hand 5. In this case, the hand 5 is used in the teaching step. In this case, the hand 5 is the first hand, and the hand 4 is the second hand. That is, the second hand may be positioned above the first hand. Also, in the above-described embodiment, when teaching the robot 1, the wafer 2 may be used instead of the dummy wafer 32. In this case, the wafer 2 becomes the transport object for teaching.

[0054] In the above-described embodiment, the first sensor 27 may be directly attached to the hand 4. Also, the second sensor 28 may be directly attached to the hand 4. When the first sensor 27 and the second sensor 28 are directly attached to the hand 4, the jig 25 is not necessary. Furthermore, when the first sensor 27 and the second sensor 28 are directly attached to the hand 4 and the first sensor 27 or the second sensor 28 is located in a position that may cause an obstruction to the transportation of the wafer 2 by the hand 4, the first sensor 27 or the second sensor 28 is attached to the hand 4 before teaching of the robot 1 begins, and when teaching of the robot 1 is completed, the first sensor 27 or the second sensor 28 is detached from the hand 4.

[0055] Furthermore, if the first sensor 27 and the second sensor 28 are directly attached to the hand 4 and are positioned so as not to interfere with the transfer of the dummy wafer 32 by the hand 4, the robot 1 may not be provided with the hand 5. In this case, in the calibration step, the hand 4 is moved to the hand position HP specified in the teaching step, the dummy wafer 32 placed at the predetermined position PP is loaded onto the hand 4, and then the hand 4 is moved again to the hand position HP specified in the teaching step to place the dummy wafer 32 on the wafer placement unit 3. Even in this case, as long as the operator performs the tasks and operations required to execute the teaching step, the robot 1 can be automatically executed up to the calibration step without performing the tasks and operations required to execute the calibration step. Therefore, even when calibration is performed to correct the position automatically taught in the teaching step, the burden on the operator for performing the calibration can be reduced.

[0056] In the above-described embodiment, the arm 6 may be configured with two arm portions, or may be configured with four or more arm portions. Also, in the above-described embodiment, the robot 1 may be a robot for transporting an object to be transported other than the wafer 2. [Explanation of symbols]

[0057] 1. Robots (industrial robots) 2. Wafers (semiconductor wafers, transported objects) 3 Wafer placement section (placement section) 4th hand (1st hand) 5th Hand (2nd Hand) 6 Arm 8 Control Unit 14 Grip mechanism 19 First hand drive mechanism 20 Second hand drive mechanism 21 Arm drive mechanism 22 Lifting mechanism 25 Jig 27 First Sensor 28 Second Sensor 32 Dummy wafer (dummy transport object, teaching transport object) PP in place

Claims

1. An industrial robot for transporting an object to be transported, a hand on which the transport object is placed, an arm to which the hand is rotatably connected at its tip end with the vertical direction as the axis of rotation, and a control unit for controlling the industrial robot, and the hand includes a first hand and a second hand, one of the first hand and the second hand is disposed above the other of the first hand and the second hand, when viewed from the up-down direction, a rotation center of the first hand relative to the arm and a rotation center of the second hand relative to the arm are coincident, and when a rotation angle of the first hand relative to the arm and a rotation angle of the second hand relative to the arm are equal, the transported object placed on the first hand and the transported object placed on the second hand overlap in the up-down direction, the control unit continuously and automatically executes a teaching step for causing the industrial robot to memorize hand positions, which are vertical and horizontal positions of the hand when the transport object to be placed at a predetermined position on a placement unit on which the transport object is placed, is loaded onto the hand and when the transport object loaded on the hand is placed at the predetermined position, and a calibration step for correcting the hand positions memorized in the teaching step after the teaching step; When the teaching step is performed, a dummy object to be transferred that is formed to have the same shape as the object to be transferred or the object to be transferred is placed at the predetermined position, When the object to be conveyed or the dummy object to be conveyed that is placed at the predetermined position is a teaching object to be conveyed, In the teaching step, a first sensor attached to the first hand detects the vertical position of the teaching transport object placed at the predetermined position, and a second sensor attached to the first hand detects the horizontal position of the teaching transport object placed at the predetermined position, and the control unit specifies and stores the hand position based on the detection results of the first sensor and the second sensor, In the calibration step, the second hand is moved to the hand position specified in the teaching step, and the teaching transport object placed at the predetermined position is loaded onto the second hand and removed, and then the second hand is moved again to the hand position specified in the teaching step to place the teaching transport object on the placement section, and then the second sensor attached to the first hand detects the horizontal position of the teaching transport object placed on the placement section, and the control unit corrects the horizontal position of the hand positions stored in the teaching step based on the detection result of the second sensor.

2. 2. The industrial robot according to claim 1, wherein a teaching jig having the first sensor and the second sensor is attached to the first hand when the teaching step and the calibration step are performed.

3. 3. The industrial robot according to claim 2, wherein the first hand is disposed above the second hand.

4. a first hand drive mechanism that rotates the first hand relative to the arm, a second hand drive mechanism that rotates the second hand relative to the arm, an arm drive mechanism that extends and retracts the arm, which is a multi-joint arm, and an elevation mechanism that elevates and lowers the arm, The object to be conveyed is formed in a disk shape, the hand includes a gripping mechanism that contacts an end surface of the object to be transported mounted on the hand from at least three directions and holds the object to be transported at a fixed position in a horizontal direction; 4. The industrial robot according to claim 1, wherein when the rotation angle of the first hand relative to the arm and the rotation angle of the second hand relative to the arm are equal, the center of the transported object on the first hand held by the gripping mechanism and the center of the transported object on the second hand held by the gripping mechanism are aligned when viewed from above and below.

5. a hand on which an object to be transported is placed, and an arm to which the hand is rotatably connected at its tip end with the vertical direction as the axis of rotation, and the hand includes a first hand and a second hand; one of the first hand and the second hand is disposed above the other of the first hand and the second hand, A teaching method for an industrial robot, wherein, when viewed from the top-bottom direction, a rotation center of the first hand relative to the arm and a rotation center of the second hand relative to the arm are coincident, and when a rotation angle of the first hand relative to the arm and a rotation angle of the second hand relative to the arm are equal, the transport object loaded on the first hand and the transport object loaded on the second hand overlap in the top-bottom direction, a teaching step for causing the industrial robot to memorize hand positions, which are vertical and horizontal positions of the hand when the transport object to be placed at a predetermined position on a placement section on which the transport object is placed, is loaded onto the hand and when the transport object loaded on the hand is placed at the predetermined position, and a calibration step for correcting the hand position memorized in the teaching step after the teaching step, When the teaching step is performed, a dummy object to be transferred that is formed to have the same shape as the object to be transferred or the object to be transferred is placed at the predetermined position, When the object to be conveyed or the dummy object to be conveyed that is placed at the predetermined position is a teaching object to be conveyed, In the teaching step, a first sensor attached to the first hand detects the vertical position of the teaching transport object placed at the predetermined position, and a second sensor attached to the first hand detects the horizontal position of the teaching transport object placed at the predetermined position, and the hand position is identified and stored based on the detection results of the first sensor and the second sensor; In the calibration step, the second hand is moved to the hand position specified in the teaching step, and the teaching transport object placed at the predetermined position is loaded onto the second hand and removed, and then the second hand is moved again to the hand position specified in the teaching step to place the teaching transport object on the placement section, and then the second sensor attached to the first hand detects the horizontal position of the teaching transport object placed on the placement section, and based on the detection result of the second sensor, the horizontal position of the hand positions stored in the teaching step is corrected.

Images