JP2001232585A - Robot control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot control device capable of automatically restoring the operation part of a robot controlled to be positioned via an absolute encoder to an original point at a site. SOLUTION: After the operation part of the robot is moved in a specified range provided in the stroke region of the operation part of the robot by using a detecting sensor, a distance up to a mechanical original point of the operation part of the robot is calculated as the manipulated variable of the rotating angle of the absolute encoder directly connected to a servo motor for automatically moving the operation part of the robot to the mechanical original point. Further, with a previously stored correcting angle as a manipulated variable, the operation part of the robot is automatically moved from the mechanical original point to an electrical original point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a robot that controls the positioning of the robot via an absolute encoder.

[0002]

2. Description of the Related Art Conventionally, in a wafer transfer robot used in a semiconductor manufacturing apparatus, an absolute encoder is directly connected to a servo motor which is a driving source of an operation unit of the wafer transfer robot, and a rotation angle of the absolute encoder is fed back. In addition, the servomotor is rotated and stopped so that the rotation angle of the absolute encoder always coincides with the target value, thereby controlling the positioning of the operation unit of the wafer transfer robot.

If the voltage of the primary battery for data backup drops abnormally for some reason, data such as the rotation speed of the absolute encoder is lost, and the current position of the operating part of the wafer transfer robot becomes unknown. Therefore, after that, before the wafer transfer robot is operated, the operation part of the wafer transfer robot is moved to the origin (referred to as “electrical origin” in the present application) for positioning control (“origin return” in the present application). Was called).

However, there are several types of methods for returning to the origin, such as a method using the pulse of the origin of a pulse encoder, a method using a fixed position sensor, and a method using a stop at the end of a stroke. Is mainly performed by a machine tool or the like using an incremental encoder, and performing the origin return by these methods is not suitable for a wafer transfer robot using an absolute encoder. Therefore, the return to the original point of the operation part of the wafer transfer robot has been performed by adjusting the robot manufacturer's factory using a special jig or the like.

[0005]

However, if the wafer transfer robot is adjusted at the factory of the robot maker, the production line on which the wafer transfer robot is installed must be stopped. Requires some time. On the other hand, in the semiconductor manufacturing field in which technological progress is remarkable, the performance of semiconductors tends to increase dramatically, so that the semiconductor manufacturing apparatus is characterized by a relatively short life cycle. Therefore, in the semiconductor manufacturing field, the loss time required for recovery and the like causes a large loss, and semiconductor manufacturers strongly desire that the operation unit of the wafer transfer robot automatically return to the home position on the spot. Was. For that purpose, it is necessary to newly develop a method of returning to the origin of the wafer transfer robot.

Accordingly, the present invention has been made to solve the above-mentioned problem, and an operation part of a robot whose positioning is controlled through an absolute encoder is provided.
It is an object of the present invention to provide a robot control device that can automatically return to the origin on site.

[0007]

Means for Solving the Problems According to a first aspect of the present invention, there is provided a servo motor which is a driving source of an operation unit of a robot, and an absolute encoder directly connected to the servo motor. In a robot control device for positioning the operation unit of the robot by rotating and stopping the servomotor with the rotation angle of the absolute encoder as an operation amount, the operation unit of the robot is within a specific range. And the position of the operating part of the robot at which the absolute encoder has only one zero angle is the mechanical origin of the operating part of the robot, and the mechanical origin of the operating part of the robot and the operation of the robot The distance from the electrical origin of the unit to the rotation angle of the absolute encoder is stored in advance as a correction angle. In advance, the operation unit of the robot is automatically moved to a mechanical origin by recognizing that the operation unit of the robot is within a specific range by a detection sensor, and then the operation unit of the robot is electrically connected. By automatically moving to the origin, the origin of the operating section of the robot is returned.

According to a second aspect of the present invention, in the robot control apparatus according to the first aspect, a detection plate to be detected by the detection sensor is provided in an operation section of the robot. .

According to a third aspect of the present invention, in the robot control device according to the first or second aspect, the robot is a wafer transfer robot.

[0010] The robot controller of the present invention having the above-described features, by using the rotation angle of the absolute encoder as an operation amount, to rotate and stop the servo motor, which is the drive source of the operation unit of the robot, to operate the robot. The position of the unit is used as the control amount, and the operation amount is commanded by an absolute (absolute value) command method.

Further, in the robot control device of the present invention,
In the stroke area of the operating part of the robot, a specific range is provided in which only one zero angle of the absolute encoder is included. Further, only the position of the robot operating unit within a specific range where the absolute encoder is at a zero angle is defined as the mechanical origin of the robot operating unit.

In the robot control apparatus according to the present invention, when the operating portion of the robot is returned to the origin, the servomotor is rotated and stopped in the CCW direction or the CW direction by the recognition of the detection sensor, and the operation of the robot is started. Part once within the specified range. In addition, the operation amount from the current rotation angle position of the absolute encoder to the zero angle of the absolute encoder corresponding to the mechanical origin of the robot's operating part is calculated, and the servo motor is rotated and stopped based on the calculated operation amount. Move the operating part of the robot to the mechanical origin. Thereafter, the correction angle stored in advance is read as an operation amount, and the servomotor is rotated / stopped according to the read operation amount, and the operating part of the robot is moved to the electrical origin.

That is, the robot controller of the present invention controls the positioning of the operating part of the robot by rotating and stopping the servomotor, which is the drive source of the operating part of the robot, using the rotation angle of the absolute encoder as an operation amount. By using a specific range provided in the stroke area of the operating part of the robot, a detection sensor, etc., the operating part of the robot can be automatically moved to the mechanical origin, and furthermore, Using the stored correction angle, the robot's operating part can be automatically moved from the mechanical origin to the electrical origin, so the robot's operating part, whose positioning is controlled via an absolute encoder, Home return can be performed automatically on site.

Further, by using the rotation angle of the absolute encoder as an operation amount, the servomotor, which is the drive source of the operation unit of the robot, is rotated and stopped to move the operation unit of the robot to the mechanical origin or the electric origin. Therefore, the robot operating unit can automatically return to the home position with the accuracy of the positioning control of the operating unit of the robot.

Further, in the robot control device of the present invention,
When moving the operating part of the robot to the mechanical origin,
Since it is not necessary to stop the operation part of the robot at the stroke end and stop it, the balance between the mechanical system and the control system of the robot is unlikely to be lost.

In the field of semiconductor manufacturing equipment, the loss time required for restoring a manufacturing line or the like causes a large loss. Therefore, when the robot to be controlled is a wafer transfer robot, the above-described effects are greatly increased. Can be demonstrated.

The positioning control of the robot via the absolute encoder may be either feedback control or feedforward control.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. The robot control device according to the present embodiment controls a part of the wafer transfer robot as a control target. Therefore, the wafer transfer robot will be described first with reference to FIG. As shown in FIG. 2, the wafer transfer robot 32 moves the open cassette 30 to each processing apparatus or from each processing apparatus to the open cassette 3.
In this case, the wafer 31 is automatically transferred to one or more wafers at a time.

The wafer transfer robot 32 includes a slide portion 34 for horizontally moving a hand 36 holding the wafer 31, a turn portion 35 for rotating the slide portion 34 on a horizontal plane, a slide portion 34 and a turn portion. 35
And a lift unit 33 for moving the vertical direction. Then, the robot control device of the present embodiment includes the hand 36 of the slide portion 34 of the wafer transfer robot 32.
Is controlled.

Next, a hand 36 for holding the wafer 31 is provided on the slide portion 34 of the wafer transfer robot 32.
An outline of a mechanism for moving the in the horizontal direction will be described with reference to FIG. As shown in FIG. 3, in the slide portion 34, a belt 4 is stretched by pulleys 2 and 3 provided on the base plate 1. A servo motor (not shown) is connected to the pulley 2 on the back side of the base plate 1. On the other hand, a block 6 which slidably holds a rail 7 is fixedly provided in the groove 5 provided in the base plate 1. The rail 7 is connected to the above-described belt 4 via a block 8.

On one side surface of the rail 7, pulleys 11 are provided at both ends, and a belt 12 is stretched by the pulleys 11. The belt 12 is connected via a block 15 to a guide 14 that slides on the rail 7. In addition, the guide 14
This serves as a base for a hand 36 holding the wafer 31 shown in FIG.

Accordingly, when the servo motor (not shown) rotates, the belt 4 moves by the pulley 2 connected to the servo motor (not shown), so that the rail 7 also moves via the block 8 fixed to the belt 4. Then, the linear motion of the rail 7 is converted into the rotational motion of the belt 12 by the block 13 fixed to the base plate 1, so that the guide 14 also moves via the block 15 fixed to the belt 12. . This allows the hand 36 (see FIG. 2) provided on the guide 14 to move in the horizontal direction.

At this time, the position of the rail 7, the position of the guide 14 that slides on the rail 7, and the position of the hand 36 (see FIG. 2) provided on the guide 14 correspond one-to-one. Further, an absolute encoder (not shown) is directly connected to a servo motor (not shown), and rotation and stop of the servo motor (not shown) are performed by a digital servo having a closed loop. Location, and thus
The position of the hand 36 (see FIG. 2) can be controlled via an absolute encoder (not shown).

That is, as shown in FIGS. 2 and 3, the robot controller of the present embodiment uses a servomotor (not shown) to move the rail 7 (see FIG. 2) on the slide portion 34 of the wafer transfer robot 32 (see FIG. 2). 3), Guide 1
4 (see FIG. 3) and the drive source of the hand 36 (see FIG. 2), and the rotation angle of an absolute encoder (not shown) is used as an operation amount to rotate and stop a servo motor (not shown) which is a drive source, thereby obtaining a wafer. The positions of the rail 7 (see FIG. 3), the guide 14 (see FIG. 3), and the hand 36 (see FIG. 2) in the slide portion 34 of the transfer robot 32 (see FIG. 2) are used as control amounts. Value) The operation amount is instructed by a command method.

The base plate 1 is provided with a pair of the above-described servo mechanisms.
The two hands 36 holding 1 can be individually moved in the horizontal direction (positioning control).

The robot controller of the present embodiment is provided with a slide unit 34 of the wafer transfer robot 32 shown in FIG.
Is to control the position of the hand 36,
The positions of both the rail 7 (see FIG. 3) and the guide 14 (see FIG. 3) are controlled. Accordingly, the rail 7 (see FIG. 3), the guide 14 (see FIG. 3), and the hand 36 (see FIG. 2) all correspond to the "operating portion of the robot". , Rail 7
Only (see FIG. 3) will be described as “the operation part of the robot”.

Next, a description will be given of an outline of the return to the original point in the slide portion 34 of the wafer transfer robot 32 in FIG. 2 with reference to FIG. In the robot controller of the present embodiment, the sliding portion 34 of the wafer transfer robot 32 shown in FIG.
In the stroke region of the rail 7 (see FIG. 3), a specific range is provided so that the absolute encoder (not shown) makes one rotation and only one zero angle of the absolute encoder (not shown) is included. Therefore, when the rail 7 (see FIG. 3) of the slide section 34 of the wafer transfer robot 32 shown in FIG. 2 moves within a specific range, the data of the rotation angle of the absolute encoder (not shown) always differs.

Specifically, as shown in FIG. 3, a detection plate 9 is provided on a block 8 connecting the belt 4 and the rail 7, and a detection sensor 10 for detecting the detection plate 9 is fixed to the base plate 1. As shown in FIG. 1, the range in which the detection sensor 10 detects the detection plate 9 is defined as a specific range.

Then, the only position of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 within a specific range where an absolute encoder (not shown) is at a zero angle is set to the wafer transfer robot shown in FIG. 32
The mechanical origin of the rail 7 (see FIG. 3) of the slide portion 34 of FIG. Further, the distance between the mechanical origin and the electric origin of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. 2 is determined by the rotation angle of an absolute encoder (not shown), and is not shown as a correction angle. It is stored in the controller in advance.

In the robot controller according to the present embodiment, when returning the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. Until the plate 9 is detected, the servo motor (not shown) is rotated and stopped, and the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 is once moved within a specific range.

Further, based on the current rotational angular position of the absolute encoder (not shown), the absolute encoder (not shown) corresponding to the mechanical origin of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. The operation amount up to the zero angle is calculated, and the servo motor (not shown) is rotated by the calculated operation amount.
After stopping, the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 is moved to the mechanical origin.

Thereafter, a correction angle stored in advance in a controller (not shown) is read as an operation amount, and a servo motor (not shown) is rotated / stopped according to the read operation amount, so that the sliding portion of the wafer transfer robot 32 shown in FIG. The rail 7 (see FIG. 3) is moved to the electrical origin.

This is the wafer transfer robot 32 shown in FIG.
This operation is executed by a program stored in a controller (not shown) in advance. Therefore, next, the return to the original point in the slide portion 34 of the wafer transfer robot 32 in FIG. 2 will be described based on the flowcharts in FIGS.

In order to return to the original position at the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2, as shown in FIG.
In S1, a controller (not shown) receives a home return command. Then, in the next S2, the search processing of the mechanical origin of FIG. 5 is performed.

In the process of searching for the mechanical origin shown in FIG.
At 1, it is determined whether the detection sensor 10 is on. When it is determined that the detection sensor 10 is on (S11: Yes), the process proceeds to S15 described later. on the other hand,
If it is determined that the detection sensor 10 is not turned on (S11: No), the process proceeds to S12, and a servo motor (not shown) is rotated at a constant speed in a predetermined direction (the left direction in FIG. 3). At this time, the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. 2 also moves.

Thereafter, in S13, the detection sensor 1
0 is ON, and the determination in S13 is repeated until it is determined that the detection sensor 10 is ON (S13).
13: No). If it is determined that the detection sensor 10 is on (S13: Yes), the process proceeds to S14, and the rotation of a servo motor (not shown) is stopped by a dynamic brake or the like. At this time, the movement of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. 2 also stops.

The next step S15 is executed when it is determined in step S11 that the detection sensor 10 is turned on (S11: Yes) or after step S14, and the rotation speed counter of the absolute encoder (not shown) is set to "1". 0 ". Then, in S16, the data of the current rotational angle position of the absolute encoder (not shown) is read.

Further, in S17, the slide unit 3 of the wafer transfer robot 32 of FIG.
The rotation angle of the absolute encoder (not shown) up to the zero angle corresponding to the mechanical origin of the rail 7 (see FIG. 3) is calculated. The calculation may be performed using a calculation formula or a matrix.

Next, in S18, a servo motor (not shown) is rotated and stopped using the rotation angle calculated in S17 as an operation amount. This completes the mechanical origin search process of FIG. 5, and the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 of FIG. 2 also moves to the mechanical origin.

Thereafter, returning to FIG. 4, in S3, the servo motor (not shown) is rotated and stopped using the correction angle stored in the controller (not shown) as an operation amount. Next, in S6, it is confirmed that the rotation of the servo motor (not shown) has been stopped (S6: Ye).
s) Proceeding to S7, control initialization is performed for an absolute encoder (not shown). This allows
The rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 can be moved to the electrical origin.

As described in detail above, in the robot controller of the present embodiment, when returning to the origin of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 of FIG. Upon recognition of the detection sensor 10 (S11: Yes or S13: Yes in FIG. 5), a servo motor (not shown) is rotated and stopped in a predetermined direction (leftward in FIG. 3) (S12 in FIG. 5), and the wafer shown in FIG. Rail 7 of slide section 34 of transfer robot 32 (see FIG. 3)
Is once moved into a specific range (see FIG. 1). Further, the wafer transfer robot 32 of FIG.
The operation amount of the absolute encoder (not shown) corresponding to the mechanical origin of the rail 7 (see FIG. 3) of the slide portion 34 up to zero angle is calculated (S17 of FIG. 5), and the servo amount (not shown) is calculated based on the calculated operation amount. Rotate motor
After stopping, the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 is moved to the mechanical origin (S18 in FIG. 5). Thereafter, the correction angle stored in advance is read as an operation amount, and a servo motor (not shown) is rotated / stopped by the read operation amount,
The rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 is moved to the electrical origin (S4 in FIG. 4).

That is, the control device of the robot according to the present embodiment uses the rotation angle of an absolute encoder (not shown) as an operation amount, and
By rotating and stopping a servo motor (not shown), which is a driving source of the rail 7 (see FIG. 3) of the slide portion 34, the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. The positioning control is performed by using a specific range (see FIG. 1) provided in the stroke area of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. The rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 can be automatically moved to the mechanical origin (see FIG. 5), and the correction angle stored in advance can be changed. The rail 7 of the slide section 34 of the wafer transfer robot 32 shown in FIG.
(See FIG. 3) can be automatically moved from the mechanical origin to the electrical origin (see FIG. 4), so that the slide of the wafer transfer robot 32 of FIG. 2 whose position is controlled through an absolute encoder (not shown) is controlled. Part 34
Rail 7 (see FIG. 3) can be automatically returned to the origin on site.

Also, using a rotation angle of an absolute encoder (not shown) as an operation amount, a servo motor (not shown), which is a drive source of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. By doing so, the wafer transfer robot 32 of FIG.
Since the rail 7 (see FIG. 3) of the slide portion 34 is moved to the mechanical origin or the electrical origin (see FIGS. 4 and 5), the slide portion 3 of the wafer transfer robot 32 shown in FIG.
With the accuracy of the positioning control of the rail 7 (see FIG. 3), the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG.

Further, in the robot controller according to the present embodiment, the sliding portion 3 of the wafer transfer robot 32 shown in FIG.
When moving the rail 7 (see FIG. 3) to the mechanical origin, it is not necessary to stop the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. 2 (see FIG. 5), the rail 7 of the slide portion 34 of the wafer transfer robot 32 in FIG.
The balance between the mechanical system and the control system (see FIG. 3) is unlikely to be lost.

Further, in the field of semiconductor manufacturing equipment, the loss time required for restoring the manufacturing line or the like causes a large loss. Therefore, as in this embodiment, the robot to be controlled is the wafer transfer robot shown in FIG. When the number is 32, the above-described effect can be exerted greatly.

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the present invention. For example, in the present embodiment, as shown in FIG. 3, the detection sensor 10 is provided at one end of the stroke of the rail 7 of the slide portion 34 of the wafer transfer robot 32 (see FIG. 2). A specific range is provided near the beginning of the stroke of the rail 7 of the slide portion 34 of the transfer robot 32 (see FIG. 2). For this reason, in S12 of the mechanical origin search process in FIG. 5, a servo motor (not shown) is rotated and stopped only in a predetermined direction (the left method in FIG. 3).

However, the wafer transfer robot 32
A specific range may be provided near the middle of the stroke of the rail 7 of the slide portion 34 (see FIG. 2). However,
In this case, in the process of searching for the mechanical origin in FIG. 5, a process for rotating / stopping a servo motor (not shown) in the CCW direction or the CW direction is added, and the slide portion 34 of the wafer transfer robot 32 (see FIG. 2) is added. It is necessary to provide a pair of position sensors near the stroke end of the rail 7 so that the rail 7 of the slide portion 34 of the wafer transfer robot 32 (see FIG. 2) does not collide with the stroke end.

In this embodiment, the rail 7 of the slide portion 34 of the wafer transfer robot 32 shown in FIG.
Although (FIG. 3) was immediately moved from the mechanical origin to the electrical origin (S5 in FIG. 4), the wafer transfer robot 32 in FIG. Rail 7 of slide part 34 of robot 32
(See FIG. 3) may be moved from the mechanical origin to the adjustment absolute position, and then to the electrical origin.

The positioning control of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 shown in FIG. 2 through an absolute encoder (not shown) is performed as follows.
Feedback control or feedforward control may be used.

In the present embodiment, the rail 7 of the slide portion 34 of the wafer transfer robot 32 shown in FIG.
The position control (see FIG. 3) is performed by a servo mechanism, and at the same time, the speed control of the rail 7 (see FIG. 3) of the slide portion 34 of the wafer transfer robot 32 in FIG. 2 is performed by the servo mechanism. You may.

[0051]

According to the robot control apparatus of the present invention, the positioning control of the robot operating unit is performed by rotating and stopping the servo motor which is the drive source of the robot operating unit using the rotation angle of the absolute encoder as an operation amount. By using a specific range provided in the stroke area of the operating part of the robot, a detection sensor, etc., the operating part of the robot can be automatically moved to the mechanical origin, and furthermore, Using the stored correction angle, the operating part of the robot can be automatically moved from the mechanical origin to the electrical origin,
The operating part of the robot whose positioning is controlled via the absolute encoder can automatically return to the origin on site.

Also, by using the rotation angle of the absolute encoder as an operation amount, the servomotor, which is the drive source of the robot operation unit, is rotated and stopped, thereby moving the robot operation unit to the mechanical origin or the electric origin. Therefore, the robot operating unit can automatically return to the home position with the accuracy of the positioning control of the operating unit of the robot.

Further, in the robot controller according to the present invention,
When moving the operating part of the robot to the mechanical origin,
Since it is not necessary to stop the operation part of the robot at the stroke end and stop it, the balance between the mechanical system and the control system of the robot is unlikely to be lost.

In the field of semiconductor manufacturing equipment, the loss time required for restoring a manufacturing line or the like causes a large loss. Therefore, when the robot to be controlled is a wafer transfer robot, the above-described effects are greatly increased. Can be demonstrated.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of origin return performed by a robot control device of the present invention.

FIG. 2 is a perspective view of a wafer transfer robot to be controlled by the robot control device of the present invention.

FIG. 3 is a diagram showing an outline of a mechanism of a slide unit of a wafer transfer robot which is a control target of the robot control device of the present invention.

FIG. 4 is a flowchart of origin return performed by the robot control device of the present invention.

FIG. 5 is a flowchart of a mechanical origin search process performed by the robot control device of the present invention in origin return.

[Explanation of symbols]

 2 Pulley directly connected to servo motor 9 Detection plate 10 Detection sensor 32 Wafer transfer robot 34 Sliding part of wafer transfer robot

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shigeru Hayashimoto 850 Horinouchi-cho, Kasugai-shi, Aichi F-term (reference) in Kasugai Works 3F059 AA01 BA04 DA10 DD01 DE01 FB26 5F031 CA02 DA08 FA01 FA07 FA13 GA47 GA48 GA50 GA51 GA54 JA14 JA22 JA36 JA51 KA06 KA08 KA10 PA02 PA10 5H303 AA10 BB01 BB06 DD01 EE03 EE07 FF01 FF07 FF20 GG02 GG20 HH05 HH09

Claims (3)

[Claims] 1. A servo motor which is a drive source of an operation part of a robot, and an absolute encoder directly connected to the servo motor, wherein the rotation of the servo motor is controlled by using a rotation angle of the absolute encoder as an operation amount.
In the robot control device for positioning the operating part of the robot by stopping, the position of the operating part of the robot such that the operating part of the robot is within a specific range and the absolute encoder has only one zero angle. Is the mechanical origin of the operating part of the robot, and the distance between the mechanical origin of the operating part of the robot and the electrical origin of the operating part of the robot is determined in advance as a correction angle by the rotation angle of the absolute encoder. Remembering, by automatically recognizing the operating part of the robot to a mechanical origin by recognizing by a detection sensor that the operating part of the robot is within a specific range, the operating part of the robot is The robot automatically moves to an electrical origin, thereby performing a return to the origin of the operation part of the robot. Control device. 2. The robot control device according to claim 1, wherein a detection plate to be detected by the detection sensor is provided in an operation part of the robot. 3. The robot control device according to claim 1, wherein the robot is a wafer transfer robot.