Industrial robot and teaching method for industrial robot

Abstract

Provided is an industrial robot and a teaching method for an industrial robot, which can reduce the burden on an operator who performs correction even when correction for correcting a position of automatic teaching is performed. In the industrial robot, a teaching step for storing a position of a hand, i.e., a hand position, at the time of loading a carrying object configured at a prescribed position on a placement portion, and a correction step for correcting the hand position stored in the teaching step, are automatically performed in succession. In the correction step, the hand is moved to the hand position determined in the teaching step, a teaching-use carrying object configured at the prescribed position is loaded on the hand and taken out, and then the hand is moved again to the hand position determined in the teaching step, the teaching-use carrying object is placed on the placement portion, and then a position of the teaching-use carrying object is detected using a second sensor mounted on the hand, and the hand position is corrected based on a detection result of the second sensor.

Description

Technical Field

[0001] This invention relates to an industrial robot for transporting and handling objects. Additionally, this invention relates to a teaching method for an industrial robot for transporting and handling objects. Background Technology

[0002] Conventionally, a horizontally articulated industrial robot for handling workpieces is known (for example, see Patent Document 1). The industrial robot described in Patent Document 1 handles the loading and unloading of workpieces onto and from a worktable. This industrial robot performs automatic teaching to store the vertical and horizontal positions of the workpiece stored on the worktable. During automatic teaching, a teaching gripper is mounted on the robot's hand. The teaching gripper includes 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, the industrial robot described in Patent Document 1 undergoes calibration. During calibration, the operator first loads the workpiece into the ideal position on the hand. Then, the operator operates the industrial robot to move the workpiece from the hand and place it on the worktable. Next, the aforementioned teaching fixture is attached to the hand, and the industrial robot performs the same actions as during automatic teaching, detecting the horizontal position of the workpiece using a second sensor. Furthermore, a correction value is calculated based on the detection result from the second sensor. When the automatic teaching of the industrial robot ends, the automatically taught position is corrected according to the correction value calculated during calibration.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-102695 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In the case of the industrial robot described in Patent Document 1, the tasks of automatic teaching and operation / calibration are separate. The operator must perform both automatic teaching and calibration tasks. Furthermore, in this industrial robot, the calibration task includes manual work by the operator, making the operator's work during calibration cumbersome. Therefore, in the case of the industrial robot described in Patent Document 1, the burden on the operator performing calibration increases.

[0009] Therefore, the technical problem of the present invention is to provide an industrial robot that, even when performing corrections for the position of an automatic teaching device, reduces the burden on the operator performing the corrections. Furthermore, the technical problem of the present invention is to provide a teaching method for an industrial robot that, even when performing corrections for the position of an automatic teaching device, reduces the burden on the operator performing the corrections.

[0010] Technical solutions adopted to solve technical problems

[0011] To solve the above-mentioned technical problems, the present invention provides an industrial robot for transporting objects, characterized by comprising: a hand on which the object to be transported is loaded; an arm rotatably connected to the hand at its front end, the hand rotating along a vertical axis; and a control unit that controls the industrial robot, the control unit continuously and automatically executing teaching steps and correction steps. The teaching step stores the hand position in the industrial robot, the hand position being the vertical and horizontal position of the hand when the object to be transported is loaded onto the hand at a predetermined position on the loading part of the object-carrying unit, and when the object loaded onto the hand is placed at a predetermined position. The correction step corrects the hand position stored in the teaching step after the teaching step. During the teaching step, a virtual object to be transported, formed with the same shape as the object to be transported, or an object to be transported is placed at a predetermined position. If the object to be transported is placed at the predetermined position... Alternatively, if the virtual transport object is set as the teaching transport object, then in the teaching step, the vertical position of the teaching transport object positioned at a predetermined location is detected by a first sensor mounted on the hand, and the horizontal position of the teaching transport object positioned at the predetermined location is detected by a second sensor mounted on the hand. The control unit determines and stores the hand position based on the detection results of the first and second sensors. In the correction step, the hand is moved to the hand position determined in the teaching step, and the teaching transport object positioned at the predetermined location is loaded onto the hand and removed. Then, the hand is moved back to the hand position determined in the teaching step, and the teaching transport object is placed on the mounting unit. Then, the horizontal position of the teaching transport object placed on the mounting unit is detected by the second sensor mounted on the hand, and the control unit corrects the horizontal position in the hand position stored in the teaching step based on the detection result of the second sensor.

[0012] In addition, to solve the above-mentioned technical problems, the present invention provides a teaching method for an industrial robot. The industrial robot has a hand for loading and transporting objects and an arm connected to the hand at its front end in a manner rotatable along an axis with the vertical direction as the rotation direction. The method is characterized by continuously and automatically executing teaching and correction steps. The teaching step stores the hand position in the industrial robot, which is the vertical and horizontal position of the hand when the object to be transported is loaded onto the hand at a predetermined position on the loading part of the object-carrying unit, and when the object loaded onto the hand is placed in the predetermined position. The correction step corrects the hand position stored in the teaching step after the teaching step. During the teaching step, a virtual object to be transported, formed with the same shape as the object to be transported, or an object to be transported, is placed in the predetermined position. If the object to be transported or the virtual object to be transported is placed in the predetermined position... If the object to be transported for teaching is to be used as a teaching object, then in the teaching step, the vertical position of the teaching object to be transported at a predetermined position is detected by a first sensor mounted on the hand, and the horizontal position of the teaching object to be transported at the predetermined position is detected by a second sensor mounted on the hand. The hand position is determined and stored based on the detection results of the first and second sensors. In the correction step, the hand is moved to the hand position determined in the teaching step, the teaching object to be transported at the predetermined position is loaded onto the hand and then removed. The hand is then moved to the hand position determined in the teaching step again and the teaching object to be transported is placed on the mounting part. Then, the horizontal position of the teaching object to be transported placed on the mounting part is detected by the second sensor mounted on the hand, and the horizontal position of the hand position stored in the teaching step is corrected based on the detection result of the second sensor.

[0013] In this invention, teaching steps and correction steps are executed continuously and automatically. The teaching step is used to store the hand position in the industrial robot. The hand position is the vertical and horizontal position of the hand when the object to be transported is loaded onto the hand at a predetermined position on the loading part and when the object loaded onto the hand is placed at a predetermined position. The correction step is used to correct the hand position stored in the teaching step after the teaching step.

[0014] Furthermore, in this invention, during the correction step, after moving the hand to the hand position determined in the teaching step, loading the teaching object placed in the predetermined position onto the hand, and removing it, the hand is moved again to the hand position determined in the teaching step and the teaching object is placed on the mounting portion. Then, using a second sensor mounted on the hand, the horizontal position of the teaching object placed on the mounting portion is detected, and based on the detection result of the second sensor, the horizontal position of the hand position stored in the teaching step is corrected.

[0015] Therefore, in this invention, if the operator performs tasks and operations for executing the teaching steps, the correction steps can be executed automatically even if tasks or operations for performing the correction steps are not performed. Thus, in this invention, even when performing corrections to adjust the automatically taught position during the teaching steps, the burden on the operator performing the corrections can be reduced.

[0016] In this invention, preferably, the industrial robot has a first hand and a second hand as its hand. Either the first hand or the second hand is positioned higher than the other hand. When viewed from above, the rotation center of the first hand relative to the arm coincides with the rotation center of the second hand relative to the arm. Furthermore, when the rotation angles of the first hand relative to the arm and the second hand relative to the arm are equal, the object being transported loaded on the first hand overlaps with the object being transported loaded on the second hand in the vertical direction. During the teaching step, a first sensor installed on the first hand detects the object positioned at the specified... The position of the teaching object to be transported is determined in the vertical direction, and the position of the teaching object to be transported in the horizontal direction is detected by a second sensor installed on the first hand. In the calibration step, the second hand is moved to the hand position determined in the teaching step, the teaching object to be transported in the predetermined position is loaded onto the second hand and then removed. After that, the second hand is moved to the hand position determined in the teaching step again, the teaching object to be transported is placed in the mounting part, and then the position of the teaching object to be transported in the horizontal direction placed in the mounting part is detected by the second sensor installed on the first hand.

[0017] If configured in this way, since the teaching object can be moved using a second hand without the first and second sensors installed during the calibration step, even if the first and second sensors are configured in a position that may obstruct the movement of the teaching object using the hand, the teaching object can be moved using the second hand during the calibration step while the first and second sensors are installed on the first hand.

[0018] In this invention, it is preferable to mount a teaching gripper having a first sensor and a second sensor onto the first hand during the teaching and calibration steps. With this configuration, since the teaching gripper mounted on the first hand has both a first sensor and a second sensor, even if the first sensor or the second sensor is positioned in a location that might obstruct the handling of the object being transported 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, the first sensor and the second sensor can be easily mounted onto the first hand during the teaching of the industrial robot.

[0019] In this invention, it is preferable that the first hand is positioned above the second hand. This configuration makes it easier to install the teaching fixture compared to when the first hand is positioned below the second hand.

[0020] In this invention, for example, an industrial robot includes: a first hand drive mechanism for rotating a first hand relative to an arm; a second hand drive mechanism for rotating a second hand relative to an arm; an arm drive mechanism for extending and retracting an arm that is a multi-jointed arm; and a lifting mechanism for raising and lowering the arm, wherein the object to be transported is formed in the shape of a circular plate. The hand has a clamping mechanism that contacts the end face of the object being transported on the hand from at least three directions and holds the object in a fixed position in the horizontal direction. When the rotation angle of the first hand relative to the arm is equal to the rotation angle of the second hand relative to the arm, when viewed from above and below, the center of the object being transported on the first hand held by the clamping mechanism coincides with the center of the object being transported on the second hand held by the clamping mechanism.

[0021] Invention Effects

[0022] As described above, in the present invention, in an industrial robot used for transporting objects, even when making corrections for the position of the automatic teaching device, the burden on the operator performing the corrections can be reduced. Attached Figure Description

[0023] Figure 1 This is a side view of an industrial robot according to an embodiment of the present invention.

[0024] Figure 2 yes Figure 1 The image shows a top view of an industrial robot.

[0025] Figure 3 It is used for explanation Figure 1 The diagram shown is a block diagram of the structure of an industrial robot.

[0026] Figure 4A and Figure 4B It is used to explain the Figure 1The diagram shows a top view of the fixture used for teaching an industrial robot.

[0027] Figure 5 It is used for explanation Figure 1 A top view of the actions in the teaching steps of the industrial robot shown.

[0028] Figure 6A and Figure 6B It is used for explanation Figure 1 A top view of the actions in the teaching steps of the industrial robot shown.

[0029] Figure 7 It is used for explanation Figure 1 A top view of the actions during the calibration process of an industrial robot.

[0030] Figure 8A and Figure 8B It is used for explanation Figure 1 A top view of the actions during the calibration process of an industrial robot.

[0031] Explanation of reference numerals in the attached figures

[0032] 1…Robot (industrial robot); 2…Wafer (semiconductor wafer, object to be transported); 3…Wafer mounting section (mounting section); 4…Hand (first hand); 5…Hand (second hand); 6…Arm; 8…Control unit; 14…Clamping mechanism; 19…First hand drive mechanism; 20…Second hand drive mechanism; 21…Arm drive mechanism; 22…Lifting mechanism; 25…Gripper; 27…First sensor; 28…Second sensor; 32…Virtual wafer (virtual object to be transported, object to be transported for teaching purposes); PP…Specified position. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] (Structure of an industrial robot)

[0035] Figure 1 This is a side view of an industrial robot 1 according to an embodiment of the present invention. Figure 2 yes Figure 1 The top view of industrial robot 1 shown. Figure 3 It is used for explanation Figure 1 The diagram shows a block diagram of the structure of the industrial robot 1.

[0036] The industrial robot 1 (hereinafter referred to as "robot 1") of this method is a horizontal multi-joint robot used for handling semiconductor wafers 2 (hereinafter referred to as "wafer 2"), which are the objects to be handled. The wafer 2 is formed in a circular plate shape. Robot 1 is used in a semiconductor manufacturing system. Robot 1 moves to the wafer mounting section 3 (refer to...) which serves as the mounting section for placing the wafer 2. Figure 5 (etc.) Transporting wafer 2. That is, robot 1 performs the loading of wafer 2 into wafer placement section 3 and the unloading of wafer 2 from wafer placement section 3. Wafer placement section 3 is, for example, a worktable that holds wafer 2 during specified processing. In addition, wafer placement section 3 is, for example, formed inside FOUP (Front-Opening Unified Pod) that houses multiple wafers 2.

[0037] Robot 1 includes: hands 4 and 5 for loading wafer 2; an arm 6 rotatably connected to hands 4 and 5 at its front end and capable of horizontal movement; and a main body 7 rotatably connected to the base end of the arm 6. Additionally, robot 1 includes a control unit 8 for controlling robot 1. In this embodiment, robot 1 has two hands 4 and 5. Hand 4 in this embodiment is the first hand, and hand 5 is the second hand.

[0038] Arm 6 is composed of three arm sections 10 to 12 that are rotatably connected to each other. That is, arm 6 is a multi-joint arm. The base end of arm section 10 is rotatably connected to the main body 7. The base end of arm section 11 is rotatably connected to the front end of arm section 10. The base end of arm section 12 is rotatably connected to the front end of arm section 11. Arm sections 10 to 12 rotate along the vertical axis. The main body 7 has a housing 13 and a columnar member (not shown) rotatably connected to the base end of arm section 10. The base end of arm section 10 is rotatably connected to the upper end of the columnar member. The main body 7, arm section 10, arm section 11, and arm section 12 are arranged in this order from the bottom in the vertical direction.

[0039] Hands 4 and 5 are formed into a roughly Y-shape when viewed from above. Hands 4 and 5 are formed into the same shape. The base of hands 4 and 5 is rotatably connected to the front end of arm 12. Hands 4 and 5 rotate with the vertical direction as the axis of rotation. Hands 4 and 5 can rotate independently relative to arm 12. Hands 4 and 5 have a clamping mechanism 14, which contacts the end face (outer peripheral surface) of the wafer 2 mounted on hands 4 and 5 from three directions and holds the wafer 2 mounted on hands 4 and 5 in a fixed position in the horizontal direction. The clamping mechanism 14 includes: an end face abutment member 15 having an abutment surface for the end face of wafer 2 to abut; and a wafer pressing mechanism 16 that presses the wafer 2 by pressing the end face of wafer 2 against the abutment surface of the end face abutment member 15.

[0040] The end face abutment members 15 are disposed at two points on the front ends of the hands 4 and 5, which are approximately Y-shaped. The wafer pressing mechanism 16 includes a pressing part that presses the end face of the wafer 2 toward the front end side of the hands 4 and 5 and a cylinder that drives the pressing part. The pressing part has a roller that contacts the end face of the wafer 2. The wafer pressing mechanism 16 is electrically connected to the control unit 8. Specifically, a solenoid valve disposed on the piping path of the air cylinder is electrically connected to the control unit 8. Two wafer mounting members 17 that hold the wafer 2 are fixed on the hands 4 and 5, and the wafer 2 is mounted on the end face abutment members 15 and the wafer mounting members 17. In addition, the clamping mechanism 14 may also be configured to contact the end face of the wafer 2 mounted on the hands 4 and 5 from four or more directions to hold the wafer 2.

[0041] The base of hand 4 overlaps with the base of hand 5 in the vertical direction. In this configuration, hand 4 is positioned on the upper side and hand 5 on the lower side. That is, hand 4 is positioned higher than hand 5. Furthermore, hands 4 and 5 are positioned higher than arm 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 12) coincides with the rotation center of hand 5 relative to arm 6 (i.e., the rotation center of hand 5 relative to arm 12).

[0042] When the rotation angle of hand 4 relative to arm 6 is equal to the rotation angle of hand 5 relative to arm 6, hand 4 and hand 5 overlap in the vertical direction. That is, when the rotation angle of hand 4 relative to arm 6 is equal to the rotation angle of hand 5 relative to arm 6, the wafer 2 mounted on hand 4 overlaps with the wafer 2 mounted on hand 5 in the vertical direction. More specifically, when the rotation angle of hand 4 relative to arm 6 is equal to the rotation angle of hand 5 relative to arm 6, if viewed from the vertical direction, the center of wafer 2 on hand 4 held by clamping mechanism 14 coincides with the center of wafer 2 on hand 5 held by clamping mechanism 14.

[0043] Robot 1 includes: a first hand drive mechanism 19 for rotating hand 4 relative to arm 6; a second hand drive mechanism 20 for rotating hand 5 relative to arm 6; an arm drive mechanism 21 for extending and retracting arm 6, which is a multi-joint arm; and a lifting mechanism 22 for raising and lowering arm 6. The first hand drive mechanism 19, the second hand drive mechanism 20, the arm drive mechanism 21, and the lifting mechanism 22 are electrically connected to a control unit 8. Specifically, electric motors and the like, which serve as drive sources for the first hand drive mechanism 19, the second hand drive mechanism 20, the arm drive mechanism 21, and the lifting mechanism 22, are electrically connected to the control unit 8.

[0044] The arm drive mechanism 21 consists of a first drive mechanism that rotates the arms 10 and 11 to extend and retract a portion of the arm 6 formed by the arms 10 and 11, and a second drive mechanism that rotates the arm 12 relative to the arm 11. The lifting mechanism 22 raises and lowers the columnar component of the main body 7. The lifting mechanism 22 is housed inside the frame 13. The lifting mechanism 22 raises and lowers the hands 4 and 5, as well as the arm 6, together with the columnar component.

[0045] (Teaching methods for industrial robots)

[0046] Figure 4A and Figure 4B It is used to explain the process of... Figure 1 A top view of the structure of the gripper 25 used for teaching the robot 1 shown. Figure 5 , Figure 6A and Figure 6B It is used for explanation Figure 1 A top view of the actions during the teaching steps of robot 1 shown. Figure 7 , Figure 8A and Figure 8B It is used for explanation Figure 1 A top view of the actions during the calibration process of robot 1 shown.

[0047] The robot 1 is taught to properly transport the wafer 2 relative to the wafer mounting section 3. During the teaching of the robot 1, the control unit 8 continuously and automatically executes teaching steps and correction steps. The teaching steps are used to store the hand position HP in the robot 1. The hand position HP is the vertical and horizontal position of the hands 4 and 5 when the wafer 2, which is positioned at a predetermined position PP on the wafer mounting section 3, is loaded onto the hands 4 and 5, and when the wafer 2 loaded on the hands 4 and 5 is placed on the predetermined position PP on the wafer mounting section 3. The correction steps are used to correct the hand position HP stored in the teaching steps after the teaching steps.

[0048] During the teaching and calibration steps, the control unit 8 controls the wafer pressing mechanism 16, the first hand drive mechanism 19, the second hand drive mechanism 20, the arm drive mechanism 21, and the lifting mechanism 22 to make the robot 1 move. That is, during the teaching and calibration steps, the robot 1 moves automatically, and there is no manual operation performed by the operator who is teaching the robot 1 during the teaching and calibration steps.

[0049] During the teaching of robot 1, a virtual wafer 32, formed with the same shape as wafer 2, is used as the virtual transport object. Additionally, a teaching fixture 25 is used during the teaching of robot 1. The fixture 25 is mounted on the upper surface of hand 4. That is, the fixture 25 is mounted on hand 4 during the teaching and calibration steps. Figure 4A and Figure 4BAs shown, the fixture 25 has: a fixture body 26 formed as a thin flat plate; a first sensor 27 for detecting the position of the virtual wafer 32 in the vertical direction; and two second sensors 28 for detecting the position of the virtual 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 is handling the wafer 2.

[0050] The clamp body 26 is mounted on the upper surface of the hand 4 with its thickness direction aligned with the vertical direction. The clamp body 26 is formed into a roughly Y-shaped form when viewed from the vertical direction. A first sensor 27 and a second sensor 28 are mounted on the clamp body 26. The first sensor 27 is a transmissive optical sensor with a light-emitting part 27a and a light-receiving part 27b. Similarly, the second sensor 28 is a transmissive optical sensor with a light-emitting part and a light-receiving part. When the clamp 25 is mounted on 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 side of the hand 4. When the clamp 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.

[0051] The light-emitting portion 27a and the light-receiving portion 27b of the first sensor 27 are arranged opposite each other in the horizontal direction with a predetermined gap. When the clamp 25 is mounted on the upper surface of the hand 4, the light-emitting portion 27a is positioned near one of the two end-face abutment members 15, and the light-receiving portion 27b is positioned near the other end-face abutment member 15. The light-emitting portion and the light-receiving portion of the second sensor 28 are arranged opposite each other in the vertical direction with a predetermined gap. The second sensor 28 is mounted on the upper surface of the clamp body 26. When the clamp 25 is mounted on the upper surface of the hand 4, one of the two second sensors 28 is positioned near one of the two wafer mounting members 17, and the other second sensor 28 is positioned near the other wafer mounting member 17.

[0052] Before performing the teaching step, the fixture 25 is mounted on the hand 4. Additionally, before performing the teaching step, a virtual wafer 32 is positioned at a predetermined position PP in the wafer mounting section 3. That is, during the teaching step, the virtual wafer 32 is positioned at the predetermined position PP. The fixture 25 is mounted on the hand 4 by the operator performing the teaching of the robot 1. The virtual wafer 32 is placed by the operator at the predetermined position PP. In this configuration, the virtual wafer 32 is the object to be transported for teaching, positioned at the predetermined position PP. Furthermore, before performing the teaching step, the hand 4, on which the fixture 25 is mounted, is positioned on the front of the wafer mounting section 3 (see reference). Figure 5 ).

[0053] Subsequently, the control unit 8 receives a teaching start command signal from the robot 1. Upon receiving the teaching start command signal, the control unit 8 executes the teaching steps. During the teaching steps, the vertical position of the virtual wafer 32 positioned at the predetermined position PP is detected by the first sensor 27, and the horizontal position of the virtual wafer 32 positioned at the predetermined position PP is detected by the second sensor 28. Based on the detection results of the first sensor 27 and the second sensor 28, the control unit 8 determines the aforementioned hand position HP.

[0054] In the teaching process, firstly, the vertical position of the virtual wafer 32 positioned at the designated location PP is detected by the first sensor 27 mounted on the hand 4. Then, the horizontal position of the virtual wafer 32 positioned at the designated location PP is detected by the second sensor 28 mounted on the hand 4. Furthermore, the actions performed by the robot 1 in this teaching process are the same as those performed by the industrial robot described in Patent Document 1 during automatic teaching.

[0055] When the first sensor 27 detects the vertical position of the virtual wafer 32 positioned at the designated location PP, the hand 4 positioned on the front of the wafer carrier 3 is moved toward the virtual wafer 32. At this time, the hand 4 is moved back and forth in the vertical direction with a fixed amplitude. For example, the hand 4 is moved back and forth in the vertical direction to move in a rectangular wave pattern. If the hand 4 moves toward the virtual wafer 32 while simultaneously moving back and forth in the vertical direction, soon the light from the light-emitting portion 27a of the first sensor 27 toward the light-receiving portion 27b is blocked by the virtual wafer 32 (see reference). Figure 6A Therefore, it is possible to detect the vertical position of the virtual wafer 32 configured at the specified position PP.

[0056] When the vertical position of the virtual wafer 32 positioned at the designated location PP is detected, the hand 4 is temporarily moved back to the front of the wafer mounting section 3. Then, after setting the height of the hand 4 based on the detection result of the vertical position of the virtual wafer 32, the hand 4 is moved in a straight line toward the virtual wafer 32 in order to detect the horizontal position of the virtual wafer 32 positioned at the designated location PP by the second sensor 28.

[0057] As hand 4 moves toward virtual wafer 32, the light emanating from the light-emitting portion of the second sensor 28 toward the light-receiving portion is soon blocked by virtual wafer 32. When detecting the horizontal position of virtual wafer 32 positioned at a predetermined location PP, the position of hand 4 is adjusted in a direction orthogonal to the direction of movement of hand 4 so that the light emanating from the light-emitting portions of both second sensors 28 toward the light-receiving portion is simultaneously blocked by virtual wafer 32 (see reference). Figure 6B ).

[0058] For example, when only the light emanating from the light-emitting part of one of the two second sensors 28 towards the light-receiving part is blocked by the virtual wafer 32, the movement of hand 4 towards the virtual wafer 32 is stopped, and hand 4 is moved in a direction orthogonal to the direction of movement of hand 4 to a position where the light emanating from the light-emitting part of the other second sensor 28 towards the light-receiving part is blocked by the virtual wafer 32. Then, hand 4 is moved back to the front of the wafer mounting part 3, and then moves towards the virtual wafer 32 again.

[0059] If the light emanating from the light-emitting parts of the two second sensors 28 toward the light-receiving parts is simultaneously blocked by the virtual wafer 32 (see reference). Figure 6B The system can detect the horizontal position of the virtual wafer 32 positioned at the designated location PP. When the vertical and horizontal positions of the virtual wafer 32 positioned at the designated location PP are detected, the control unit 8 determines the hand position HP based on the detection results of the first sensor 27 and the second sensor 28, as described above.

[0060] Next, the control unit 8 performs a calibration step. The calibration step is performed after the teaching step; therefore, at the start of the calibration step, the virtual wafer 32 is positioned at the designated location PP of the wafer mounting unit 3. In the calibration step, firstly, as... Figure 7 As shown, hand 5 is automatically positioned on the front side of wafer mounting section 3. Then, hand 5 is moved to the hand position HP determined in the teaching step (refer to...). Figure 8A The virtual wafer 32, positioned at the designated location PP, is loaded into hand 5 and then removed (refer to...). Figure 8B For example, such as Figure 8B As shown, the virtual wafer 32 mounted on the hand 5 is removed to the front side of the wafer mounting section 3. The virtual wafer 32 mounted on the hand 5 is held in a fixed position by the clamping mechanism 14.

[0061] Then, move hand 5 back to the hand position HP determined in the teaching step (refer to...). Figure 8A The virtual wafer 32 is then placed on the wafer mounting section 3. Ideally, the virtual wafer 32 should be placed at the designated position PP, but in reality, the virtual wafer 32 is placed at a position on the wafer mounting section 3 that is slightly offset from the designated position PP. That is, the virtual wafer 32 is placed near the designated position PP.

[0062] Then, robot 1 performs the same action as when detecting the horizontal position of virtual wafer 32 in the teaching step, and detects the horizontal position of virtual wafer 32 placed on wafer mounting section 3 using second sensor 28. At this time, if the light from the light-emitting parts of both second sensors 28 towards the light-receiving parts is simultaneously blocked by virtual wafer 32, the horizontal position of virtual wafer 32 placed on wafer mounting section 3 can be detected. Afterwards, control unit 8 corrects the horizontal position in hand position HP stored in the teaching step based on the detection results of second sensor 28.

[0063] (The main effects of this method)

[0064] As explained above, in this method, the control unit 8 continuously and automatically executes a teaching step for storing the hand position HP in the robot 1, and a correction step after the teaching step for correcting the position of the hand position HP stored in the teaching step. Furthermore, in this method, during the correction step, the hand 5 is moved to the hand position HP determined in the teaching step, a virtual wafer 32 positioned at a predetermined position PP is loaded onto the hand 5 and removed, the hand 5 is moved again to the hand position HP determined in the teaching step, and the virtual wafer 32 is placed on the wafer mounting unit 3. Then, the horizontal position of the virtual wafer 32 placed on the wafer mounting unit 3 is detected by the second sensor 28, and based on the detection result of the second sensor 28, the horizontal position of the hand position HP stored in the teaching step is corrected.

[0065] Therefore, in this method, if the operator performs the tasks and operations for executing the teaching steps, the correction steps can be executed automatically even if the tasks or operations for performing the correction steps are not performed. Therefore, in this method, even when corrections are performed to correct the position automatically taught in the teaching steps, the burden on the operator performing the corrections can be reduced.

[0066] In this method, during the calibration step, the virtual wafer 32 is handled by hand 5 without the first sensor 27 and the second sensor 28 installed. Therefore, in this method, for example, even if the first sensor 27 and the second sensor 28 are positioned in a location that could obstruct the handling of the virtual wafer 32 using hand 4, the virtual wafer 32 can still be handled by hand 5 during the calibration step with the first sensor 27 and the second sensor 28 installed on hand 4.

[0067] In this configuration, the gripper 25 includes a first sensor 27 and a second sensor 28. Therefore, even if the first sensor 27 and the second sensor 28 are positioned in a location that could obstruct the handling 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, the first sensor 27 and the second sensor 28 can be easily mounted onto the hand 4 during robot 1 teaching. Additionally, in this configuration, since the hand 4 with the gripper 25 mounted is positioned higher than the hand 5, mounting the gripper 25 is easier compared to mounting it onto the hand 5.

[0068] (Other implementation methods)

[0069] The above-described method is an example of a preferred embodiment of the present invention, but it is not limited thereto. Various modifications can be made without changing the spirit of the present invention.

[0070] In the above method, during the calibration step, after the virtual wafer 32 is moved out and in, the horizontal position of the virtual wafer 32 placed on the wafer mount 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. Alternatively, during the calibration step, after the virtual wafer 32 is moved out and in, the vertical position of the virtual wafer 32 placed on the wafer mount 3 is detected by the first sensor 27, and the horizontal position of the virtual wafer 32 placed on the wafer mount 3 is detected by the second sensor 28, and the hand position HP stored in the teaching step is corrected based on the detection results of the first sensor 27 and the second sensor 28. That is, the vertical and horizontal positions of the hand position HP stored in the teaching step can also be corrected during the calibration step.

[0071] In the above-described manner, the gripper 25 can also be mounted on the hand 5. In this case, hand 5 is used in the teaching step. Hand 5 is the first hand, and hand 4 is the second hand. That is, the second hand can also be positioned higher than the first hand. Additionally, in the above-described manner, when teaching the robot 1, wafer 2 can be used instead of virtual wafer 32. In this case, wafer 2 becomes the object to be handled during teaching.

[0072] In the above-described manner, the first sensor 27 can also be directly mounted on the hand 4. Additionally, the second sensor 28 can also be directly mounted on the hand 4. When the first sensor 27 and the second sensor 28 are directly mounted on the hand 4, the clamp 25 is not required. Furthermore, if the first sensor 27 and the second sensor 28 are directly mounted on the hand 4, and if they are positioned in a location that could obstruct the handling of the wafer 2 by the hand 4, the first sensor 27 and the second sensor 28 are mounted on the hand 4 before the robot 1 begins teaching, and are removed from the hand 4 when the robot 1's teaching ends.

[0073] Furthermore, if the first sensor 27 and the second sensor 28 are directly mounted on the hand 4, and if the first sensor 27 and the second sensor 28 are positioned in a location that does not obstruct the handling of the virtual wafer 32 by the hand 4, the robot 1 may not need to have a hand 5. In this case, during the calibration step, the hand 4 is moved to the hand position HP determined in the teaching step, the virtual wafer 32 positioned at the designated position PP is loaded onto the hand 4 and removed, and then the hand 4 is moved back to the hand position HP determined in the teaching step to place the virtual wafer 32 on the wafer mounting section 3. Even in this case, if the operator performs the work and operations for performing the teaching step, the calibration step can be performed automatically even if the work and operations for performing the calibration step are not performed. Therefore, even when calibration is performed to correct the position automatically taught in the teaching step, the burden on the operator performing the calibration can be reduced.

[0074] In the above configuration, arm 6 can be composed of two arms or more than four arms. Furthermore, in the above configuration, robot 1 can also be a robot used to handle objects other than wafer 2.

Claims

1. An industrial robot for transporting objects, characterized in that, have: The first hand and the second hand, the first hand and the second hand, load the object to be transported, and either the first hand or the second hand is positioned above the other hand. An arm, wherein the arm is rotatably connected to the first hand and the second hand at the front end, and the first hand and the second hand rotate with the up-down direction as the axis of rotation; The control unit controls the industrial robot. The control unit continuously and automatically executes teaching and correction steps. The teaching step stores the hand position in the industrial robot. The hand position is the vertical and horizontal position of the first hand when the object to be transported is loaded onto the first hand at a predetermined position on the loading unit, and when the object loaded onto the first hand is placed back into the predetermined position. The correction step corrects the hand position stored in the teaching step after the teaching step. When viewed from the vertical direction, if the rotation center of the first hand relative to the arm coincides with the rotation center of the second hand relative to the arm, and the rotation angle of the first hand relative to the arm is equal to the rotation angle of the second hand relative to the arm, then the object being transported loaded on the first hand and the object being transported loaded on the second hand overlap in the vertical direction. During the teaching step, a virtual transport object is formed with the same shape as the transport object, or the transport object is positioned at the specified location. If the transport object or the virtual transport object configured at the specified location is set as a teaching transport object. In the teaching step, a first sensor mounted on the first hand detects the vertical position of the teaching object positioned at the predetermined location, and a second sensor mounted on the first hand detects the horizontal position of the teaching object positioned at the predetermined location. The control unit determines and stores the hand position based on the detection results from the first and second sensors. In the correction step, the second hand is moved to the hand position determined in the teaching step, and the teaching object to be transported, which is positioned at the predetermined position, is loaded onto the second hand and then removed. The second hand is then moved back to the hand position determined in the teaching step and the teaching object to be transported is placed on the mounting unit. Then, the horizontal position of the teaching object to be transported placed on the mounting unit is detected by the second sensor mounted on the first hand, and the control unit corrects the horizontal position in the hand position stored in the teaching step based on the detection result of the second sensor.

2. The industrial robot according to claim 1, characterized in that, During the teaching and correction steps, a teaching fixture having the first sensor and the second sensor is mounted on the first hand.

3. The industrial robot according to claim 2, characterized in that, The first hand is positioned above the second hand.

4. The industrial robot according to any one of claims 1 to 3, characterized in that, have: A first hand drive mechanism, which causes the first hand to rotate relative to the arm; a second hand drive mechanism, which causes the second hand to rotate 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 being transported is formed in the shape of a circular plate. The first hand and the second hand are equipped with clamping mechanisms, which contact the end faces of the transported object loaded on the first hand and the second hand from at least three directions and hold the transported object in a fixed position in the horizontal direction. When the rotation angle of the first hand relative to the arm is equal to the rotation angle of the second hand relative to the arm, when viewed from above and below, the center of the object being transported on the first hand held by the clamping mechanism is consistent with the center of the object being transported on the second hand held by the clamping mechanism.

5. A teaching method for an industrial robot, the industrial robot having a first hand and a second hand for loading and transporting objects, and an arm at the front end connecting the first hand and the second hand in a manner rotatable along an axis with the up-down direction as the rotation direction, characterized in that, The robot continuously and automatically executes teaching and correction steps. The teaching step stores the hand position in the industrial robot, which is the vertical and horizontal position of the first hand when the object to be transported is loaded onto the first hand at a predetermined position on the loading part, and when the object loaded onto the first hand is placed at the predetermined position. The correction step corrects the hand position stored in the teaching step after the teaching step. When viewed from the vertical direction, if the rotation center of the first hand relative to the arm coincides with the rotation center of the second hand relative to the arm, and the rotation angle of the first hand relative to the arm is equal to the rotation angle of the second hand relative to the arm, then the object being transported loaded on the first hand and the object being transported loaded on the second hand overlap in the vertical direction. During the teaching step, a virtual transport object is formed with the same shape as the transport object, or the transport object is positioned at the specified location. If the transport object or the virtual transport object configured at the specified location is set as a teaching transport object. In the teaching step, a first sensor mounted on the first hand detects the vertical position of the teaching object positioned at the predetermined location, and a second sensor mounted on the first hand detects the horizontal position of the teaching object positioned at the predetermined location. The hand position is determined and stored based on the detection results of the first and second sensors. In the correction step, the second hand is moved to the hand position determined in the teaching step, and the teaching object to be transported, positioned at the predetermined position, is loaded onto the second hand and then removed. The second hand is then moved again to the hand position determined in the teaching step, and the teaching object to be transported is placed on the mounting portion. Then, the horizontal position of the teaching object to be transported, placed on the mounting portion, is detected by the second sensor mounted on the first hand, and the horizontal position in the hand position stored in the teaching step is corrected based on the detection result of the second sensor.

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