JPH11156768A - Conveying device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the acceleration and to reduce the original point returning time, in order to reduce the conveying time, in a conveying device. SOLUTION: In order to make equal the angular speeds of two driving motors, the signals of the position detectors of both driving motors are compared, and the difference of both motors is feedbacked to a motor controller at one side, so as to correct the delay or the advance, and the synchronism of the two driving motors is made possible to take constantly. A sensor to detect the existence of a wafer cassette 4 is installed to the carrier 3 of a conveying device, and when the wafer cassette 4 is loaded, the acceleration of the conveyance is suppressed to a limited value, and when there is no wafer cassette 4, the acceleration is carried out to the maximum output of the driving system. In order to reduce the time to return to an original point, sensors are provided to the detecting plates of the driving shaft to drive the first arm 1a and the driving shaft to drive the first arm 1b respectively, the forms of the detecting plates are made in a semicircular form, it is classified into four patterns by the detecting conditions of two sensors, the rotating direction of the arm is defined in respective pattern, and the rotation is carried out depending on the difinision respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly, to a transfer apparatus used for unmanned transfer of a wafer cassette containing a wafer as an object to be transferred, and a control method thereof.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, various types of robots called transfer robots or transfer devices are used as means for handling wafers. Among them,
A robot that transports a substrate such as a wafer, has a pair of two connected arms, supports one carrier with a pair of arms, drives a pair of arms simultaneously, and the fulcrum of the arm supporting the carrier is Japanese Patent Application No. Hei 8 for a robot that can pass on the drive shaft
No. -8,491 (see application).

[0003]

SUMMARY OF THE INVENTION In a conventional transfer device,
An A drive motor for driving the first arm A, a B drive motor for driving the first arm B, and a Z-axis drive motor for driving in the normal direction of the surface on which the arm operates are connected to respective motor drivers. The controller is connected to a controller for controlling the motor driver, and is connected to a CPU of a computer for controlling the operation of the entire transfer apparatus.

In the conventional transport device, when the B drive motor is rotated in the reverse direction with respect to the A drive motor, the carrier moves in a linear direction, and when the B drive motor is rotated in the same direction, the carrier moves in the rotational direction. Now, consider the case where the carrier is moved in a linear direction. As described above, it is sufficient to rotate the A drive motor and the B drive motor in opposite directions.
At this time, if you do not make the angular velocity of the two motors equal,
The movement of the carrier includes not only a linear component but also a rotational component. In other words, focusing on the acceleration of the carrier, if the time for the carrier to move from the X point to the Y point is the same,
Than the acceleration when the movement of the carrier is only a linear component,
The acceleration when the linear component and the rotational component are included increases.

A wafer contained in a wafer cassette placed on a carrier of a transfer device has an acceleration value obtained from a friction coefficient between the wafer and the wafer cassette because the wafer is stationary in the wafer cassette. Good if not exceeded. If the wafer moves in the wafer cassette without being stationary, dust is generated and contaminates the wafer, which is not allowed.

[0006] In other words, if the acceleration under the condition that the wafer is stationary in the wafer cassette is indicated, the moving time of the carrier is longer than the acceleration including the linear component and the rotating component.
Naturally, the movement time is shorter when the acceleration is only the linear component. However, conventionally, since the load viewed from the A drive motor and the load viewed from the B drive motor cannot be completely equalized, the angular velocities of the two motors cannot be equalized, and the carrier includes a linear component and a rotational component. Acceleration was occurring.

Next, when the wafer cassette is mounted on the carrier of the transfer device, the acceleration is limited as described above, but when nothing is mounted on the carrier, the acceleration is at the full capacity of the drive motor. Acceleration reduces the overall work time. However, the conventional transfer device has always been operated at the maximum acceleration with the wafer cassette mounted on the carrier, so that the working time could not be shortened.

Next, when the transport device is operated, an accident may occur in which the carrier or the arm contacts an obstacle for some reason. At this time, some protection means is provided to protect the carrier and the arm from damage. Conventionally, an A drive motor for driving the first arm A and a B drive motor for driving the first arm B are provided.
A mechanical torque limiter is installed between the drive motor and the output shaft of the Z-axis drive motor for driving the arm in the direction normal to the working surface, and the load. When a certain value was exceeded, a torque limiter was activated to disconnect from the motor so as not to damage the carrier or arm.

Also, the current of the driver connected to the motor is monitored, and when the carrier or arm comes into contact with an obstacle and the generated torque of the motor increases, naturally the current flowing to the motor also increases. When a certain value was exceeded, the driver was stopped and protected.

However, a disadvantage of the method described above is that both the torque and the current are limited to a certain value. The torque current varies not only with the magnitude of the load but also with the position of the carrier.
It also changes depending on the operation elapsed time of the transfer device. That is, in order to cope with these changes, a value having a sufficient margin with respect to the peak value of the torque or the current must be set as the limit value. As a result, the protection was not instantaneously activated upon contact with the obstacle, so that the carrier, the arm, and the contacted person also became more damaged.

Next, in the case where the power is cut off due to a power failure or the contact of a carrier or an arm to activate the protection circuit as described above, the A drive is performed to prevent the current position of the transport device from being known when the power is restored. Absolute encoders were used for the motor, the B drive motor, and the Z axis drive motor. However, the absolute encoder is very expensive as compared with the incremental encoder, and has been one of the causes for increasing the cost of the transfer device.

Next, as for the operation of the transfer device, the carrier can perform a linear motion, a rotary motion, and an up-and-down motion. As an example of the conventional operation, the carrier is moved straight by extending the arm and moved up. Receiving the wafer cassette, retracting the arm and moving the carrier straight, turning the carrier, extending the arm and moving the carrier straight, descending and passing the wafer cassette, contracting the arm and moving the carrier straight and reversing the carrier I turned around and went back to work. However, there was a demand to further reduce the operation time.

Next, an origin signal when an inexpensive incremental encoder is used for the A drive motor and the B drive motor will be described. As described above, when the power is cut off due to a power failure or a protection circuit, the current position of the transport device cannot be determined when the power is restored. Therefore, it is necessary to first find the origin position and restart from there. In the conventional transfer device, a detection plate and a sensor, each of which is cut out at one location on the circumference, are attached to the drive shaft for driving the first arm A and the drive shaft for driving the first arm B, respectively. Signal was detected. Therefore, when the power is restored and the origin position is searched, both the A drive motor and the B drive motor rotate only in a predetermined rotation direction, and in some cases, it is necessary to rotate the motor by 350 degrees or more. I was

[0014]

In order to equalize the angular velocities of the A drive motor and the B drive motor, a signal of a position detector of the A drive motor is compared with a signal of a position detector of the B drive motor. Take the difference based on one,
Feedback is made to the non-reference motor controller to correct the delay or advance so that the A drive motor and the B drive motor can always be synchronized.

As means for giving an appropriate acceleration to the carrier, a sensor for detecting the presence or absence of a wafer cassette is provided on the carrier of the transfer device, and when the wafer cassette is mounted, the transfer acceleration is suppressed to a value which is limited. When there is no drive, it accelerates to the maximum output of the drive system.

As a protection means when the carrier or the arm comes into contact with an obstacle, a current flowing through the motors of the A drive motor, the B drive motor, and the Z axis drive motor is detected for one cycle of the conveyance.
The protection circuit is activated by comparing the current value with the limit value of the current value recorded for one cycle in advance.

As a means for providing the same function as an absolute encoder by using an incremental encoder, a motor provided with a speed detector and a position detector is provided with a negative operation brake which is released when the power is supplied and is activated when the power is turned off. In addition, the signal of the position detector was recorded in a memory backed up by a battery through a computer. As a result, even when the power is cut off, the signal of the position detector is stored in the memory, and the position of the motor is also fixed by the negative operation brake. Therefore, even if the power is turned on again, the relationship between the position of the motor and the position signal of the incremental encoder does not change, so that the same effect as when the absolute encoder is used can be obtained.

As means for shortening the transport time, control is performed by combining two or more of the linear motion, the rotary motion, and the vertical motion of the carrier.

As means for shortening the time for returning to the origin, a detection plate is provided on each of the drive shaft for driving the first arm A and the drive shaft for driving the first arm B, and a sensor is attached to the drive shaft. Is divided into four patterns according to the detection state of the sensors of the first arm A and the first arm B, and the rotation direction of the arm is defined in each pattern, and the arm is rotated according to the direction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2 and 3 show an embodiment of a transfer apparatus to which the present invention is applied. However, as described in the "prior art", holding two connected arms, supporting one carrier with a pair of arms, simultaneously driving a pair of arms,
The structure of the robot that allows the fulcrum of the arm supporting the carrier to pass on the drive shaft of the arm is described in detail in Japanese Patent Application No. 8-84841 (refer to the application), and the overlapping part of the structure is omitted. .

FIG. 1 is a bird's-eye view of this transfer device, in which a first arm A1a and a first arm B1b connected to a coaxial drive shaft.
Is arranged, and the second is provided via rotatable bearings 6a and 6b.
Arm A2a and the second arm B2b are connected to each other. The carrier 3 is connected to the second arm A2a and the second arm B2b via joint mechanisms 7a and 7b such that the opening angles of the arms are the same. A wafer cassette 4 is mounted on the carrier 3. The wafer cassette 4 is movable in a rectilinear direction 8, a rotational direction 9 about the axis 5 as a center of rotation, and a vertical direction 10.

FIG. 2 is a top view of the transfer device. FIG.
(A) is the rotation direction 1 of the first arm A1a and the first arm B1b.
1a and 11b, and a second arm A2a and a second arm B2b
Are rotated in the direction in which the arm is extended, and are moved in the straight traveling direction 8. FIG. 2B shows the rotation directions 11a and 11b and the rotation directions 12a and 12b.
Is rotated in the direction to shrink the arm, and is moved to the origin position. At this time, the arm joint mechanisms 7a and 7b supporting the carrier 3 pass through the axis 5 of the drive shaft of the arm.

FIG. 3 is a sectional view of the transfer device. The first arm A1a is coupled to a coaxial drive shaft 13a and meshes with a gear 15a coupled to a drive motor 16a via a gear 14a. Similarly, the first arm B1b has a coaxial drive shaft 13
b, and meshes with a gear 15b connected to a drive motor 16b via a gear 14b. As is apparent from this figure, when the drive motors 16a and 16b are rotated, the first arms A1a and 1b rotate around the axis of the coaxial drive shafts 13a and 13b. By rotating the driving motors 16a and 16b in the opposite directions, the carrier 3 moves in the rectilinear direction 8;
Make the move. These mechanisms are supported by rectilinear guides 20a and 20b, and are vertically moved by a ball screw shaft 18 and a ball screw nut 19 connected to a Z-axis drive motor 17.
It has a structure that can be moved to zero.

FIG. 4 shows a control system of the transfer device. FIG. 4A is an overall configuration diagram of a control system, in which a drive motor 16a of a first arm A1a, a drive motor 16b of a first arm B1b,
The Z-axis drive motor 17 includes drivers 31a, 31
b, 31c, the driver is connected to the controller 32, and above it is connected to the CPU 33 of the computer. FIG. 4 (b) explains in detail the system of one drive motor. The inside of the drive motor 16 includes a motor body 34, a speed detector 35, and a position detector 36. The speed signal 37 of the speed detector 35 is
1 is fed back. The position signal 38 of the position detector 36 is fed back to the controller. Then, the zero-phase signal 39 of the position detector 36 is fed back to the computer. FIG. 4B shows an example of a general digital servo, but the configuration is almost the same even when software servo is used.

In FIG. 4, the drive motor 16a of the first arm A1a, the drive motor 16b of the first arm B1b, and the Z-axis drive motor 17 are drivers 31a, 31b, 31 respectively.
When the drive motor 16b of the first arm B1b is rotated in the same direction as the rotation direction of the drive motor 16 of the first arm A1a, the carrier becomes a plane perpendicular to the drive shaft. When the carrier moves in the radial direction of the circle with the drive shaft as the origin and rotates in the opposite direction, the carrier moves in the plane perpendicular to the drive shaft in the rotation direction with the drive shaft as the origin.
At this time, by controlling the rotation direction and the rotation speed of the drive motor 16a of the first arm A1a and the drive motor 16b of the first arm B1b by the CPU 33, the drive of the carrier is performed in the radial direction and the rotational direction. Can be done simultaneously. In addition, since the Z-axis drive motor 17 can be driven at the same time, the work time can be reduced.

FIG. 5 shows the driving motor 16 of the first arm A1a.
This shows an embodiment in which a is driven in synchronization with the drive motor 16b of the first arm B1b. Drive motor 16a
The configuration in which the driving motor 16b is driven is basically the same as that shown in FIG.
The same as (b), except that the position signals 38a and 38b of the position detectors 36a and 36b are input to the correction controller 41, the difference between 38a and 38b is obtained, and the difference is used as the correction signal 42, which is used as the controller 32. Feedback to Then, the advance of the delay is determined by the sign of the compensation signal 42. In the example of this figure, the number of input pulses of the drive motor 16a is increased based on 16b. The drive motor 16a and the drive motor 16b are synchronized by reducing the number of pulses.

FIG. 6 is an embodiment showing a method of providing a detecting means for the wafer cassette 4 on the carrier 3 to change the acceleration of the transfer. FIG. 6A is a configuration diagram of the control system, in which the carrier 3
Is mounted with a wafer cassette 4. A sensor 51 is attached to the carrier 3 and detects the presence or absence of the wafer cassette 4. The signal is sent to the CPU 3 through the A / D converter 52.
3 is input. Here, if the sensor 51 is an on / off switch, the A / D converter 52 is not required and the CPU 3
3 can be entered. FIG. 6B shows the angular velocities of the drive shafts 13a and 13b and the linear direction 8 or the rotational direction 9 or the vertical direction 1.
FIG. 9 is a diagram showing a relationship between a movement of a movement of 0 and a driving time. As shown in this figure, when the wafer cassette 4 which is the object to be transported is on board, the angular velocity is suppressed to a certain value and the driving time is determined, but when there is no wafer cassette 4, the maximum angular velocity that can be output by this driving system is set. By doing so, the startup time can be shortened.

FIG. 7 shows the carrier 3 and the first arms 1a and 1b.
An example of protection in the case where the second arm 2a, 2b or the like comes into contact with an obstacle is shown. FIG. 7A is a configuration diagram of a control system, in which a drive motor 16a includes a driver 31a and a drive motor 1
6b is connected to the driver 31b, and the Z-axis drive motor 17 is connected to the driver 31c. Current measuring devices 61a, 61b, 61c are connected between the driver and the motor. The current values measured by the current measuring devices 61a, 61b, 61c are
And compared with the current limit value recorded in the memory 62.

FIG. 7B shows one system of the drive motor.
FIG. 4 is a diagram illustrating a relationship between a driving time of one cycle of conveyance and a current flowing through a motor at that time. The actual measured value of the current at the time of driving is compared with the current limit value recorded in the memory. If the current limit value is exceeded, the protection program is activated to stop the transport device. The actual measured value of the current at the time of driving changes depending on the temperature of the installation location of the transfer device, the elapsed drive time of the transfer device, and the like. Therefore, as a method of optimizing the current limit value, one cycle of driving is repeated several times, an average of the chart at that time is obtained, and a certain coefficient is multiplied to obtain a new current limit chart. This enables protection against malfunctions due to temperature and aging as described above.

FIG. 8 shows an embodiment in which an inexpensive incremental encoder is used for the position detector 36 of the drive motor and the same function as when an expensive absolute encoder is used. Although this diagram shows only one drive motor system, there are actually three systems. The drive motor includes a motor body 34, a speed detector 35, a negative operation brake 71, and a position detector 36. Here, the brake of the negative operation brake 71 is released when a current is flowing through the brake, and the brake is in a braking state when the current is cut off. Position detector 36
Is not only fed back to the controller 32 but also passes through the CPU 33 to the control bus 7.
4 is recorded in the memory 62. The memory 62 is backed up by a battery 73 so that information in the memory 62 is not erased even when the power is turned off. Controller 3
2 controls the negative operation brake 71 through the driver 72. Now, consider the case where the power supply of the transfer device is turned off. At the moment when the power is turned off, the negative operation brake 71 operates to fix the shaft of the motor. On the other hand, the position signal 38 of the position detector 36 immediately before the power is turned off is recorded in the memory 62. That is, the mechanical position of the motor at the moment when the power is turned off and the position signal 38 of the position detector 36 at that time.
Since the relationship is stored, the state immediately before the power is turned off can be reproduced when the power is turned on again.

[0031]

[Table 1]

FIGS. 9 and 10 and Table 1 show that although the inexpensive incremental encoder is used for the position detector 36 of the drive motor, the home return time when the countermeasure shown in FIG. 8 is not taken is shortened. An example for performing the above will be described.

FIG. 9 is a cross-sectional view of the transfer device, in which the coaxial drive shaft 13a is connected to the first arm A1a and the detection plate A81a, and the coaxial drive shaft 13b is connected to the first arm B1b and the detection plate B8.
1b. The detection plate A81a is a sensor A82.
The position is detected by a, and the detection plate B81b detects the position by the sensor B82b.

FIG. 10 is a plan view of the transfer device, showing a state at the origin position. FIG.
This is the same state as (b). FIG. 10 (b) is the same as FIG.
3 shows the relationship between the detection plate 81 and the sensor 82 in a plan view in a state where the detection plate 81 is stopped at the origin. The detection plate is semicircular, and is configured such that the semicircular diameter line coincides with the position of the sensor at the origin position. Here, the center of the semicircle of the detection plate coincides with the detection plate A81a and the detection plate B81b. If the transport device stops at an arbitrary position, the drive motor 1 is turned on according to the on / off state of the sensor shown in Table 1.
By moving 6a and 16b, it is possible to return to the origin in a short time.

In the embodiments described above, the servo motors are used as drive motors. However, the same effects can be obtained by replacing these motors with pulse motors.

[0036]

By using the transfer apparatus and the transfer method described above, the acceleration of the transfer apparatus can be increased, and the transfer time can be reduced. In addition, since the home return time can be shortened, the overall working time including the transport time can be shortened.

Since the carrier and the arm are hardly damaged even if they come into contact with the obstacle, the maintenance stop time can be reduced and the cost can be reduced.

Further, since the same performance can be obtained with an inexpensive incremental encoder without using an expensive absolute encoder, it was possible to contribute to a reduction in the manufacturing cost of the transfer device.

[Brief description of the drawings]

FIG. 1 is a perspective view of a transport device according to an embodiment of the present invention.

FIG. 2 is a plan view of a transfer device to which the present invention is applied.

FIG. 3 is a sectional view of a transfer device to which the present invention is applied.

FIG. 4 is a block diagram of a control system of the transport device of the present invention.

FIG. 5 is a block diagram of a control system for synchronizing drive motors according to the present invention.

6A and 6B are a block diagram of a control system for changing an acceleration depending on the presence or absence of a transferred object according to the present invention, and a characteristic diagram showing a relationship between an angular velocity of a driving shaft and a driving time.

7A is a block diagram of a control system for protecting a drive system according to the present invention, and FIG. 7B is a characteristic diagram showing a relationship between a driver current and a drive time.

FIG. 8 is a block diagram of a control system using the incremental encoder of the present invention.

FIG. 9 is a cross-sectional view of a transport device for shortening the time required to return to the original position according to the present invention.

FIG. 10 is an explanatory view of a transfer device for shortening the time required for returning to the original position according to the present invention.

[Explanation of symbols]

1a, 1b: first arm, 2: second arm, 3: carrier,
4 wafer cassette, 5 shaft center, 6 a, 6b bearing, 7
... joint mechanism, 8 ... straight direction, 9 ... rotation direction, 10 ... vertical direction, 11 ... rotation direction of first arm, 12a, 12b ... rotation direction of second arm, 13a, 13b ... drive shaft, 14 ... Gears, 15 ... Gears, 16a, 16b ... Drive motors, 17 ...
Z-axis drive motor, 18: Ball screw shaft, 19: Ball screw nut, 20: Straight guide, 31a, 31b: Driver, 32: Controller, 33: CPU, 34: Motor body, 35: Speed detector, 36: Position detector 37, speed signal, 38, position signal, 39, zero-phase signal, 41, correction controller, 42, correction signal, 51, sensor, 52,
A / D converter, 61: current measuring device, 62: memory, 71
... Negative operation brake, 72 ... Driver, 73 ... Battery, 74
... a control bus, 81 ... a detection plate, 82 ... a sensor.

Continued on the front page (72) Inventor, Tsutomu Fujimoto 800, Tomita, Ohira-machi, Shimotsuga-gun, Tochigi Pref.Hitachi, Ltd.Cooling Division, (72) Inventor Kiyoji Iizuka 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Within the Cooling and Heating Business Division (72) Inventor Hironao Kamagai 800, Tomita, Odaicho, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling and Heating Business Division Hitachi, Ltd. (72) Inventor Kazuichi Sugiyama 709-2, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi In electronics

Claims (11)

[Claims] 1. A drive system comprising: two drive shafts arranged coaxially; a drive system for rotating the shafts at one end on the same side of each drive shaft;
The other end of the drive shaft is a pair of first arms that can be driven by being connected to the shaft, and the other end of the first arm is rotatable on a plane perpendicular to the drive shaft with respect to the first arm. A pair of second arms having the same configuration, and the other end of the second arm is provided with a joint having a mechanism to make the opening angle of the second arm the same, and each is supported by the rotation center axis of the joint. In a transport device having a carrier on which the transported object is placed, and a joint that supports the carrier can pass on the rotation center axis of the drive shaft, a drive system for rotating the two drive shafts is provided. A transport device comprising means for synchronizing rotation of two axes. 2. A drive system comprising: two drive shafts arranged coaxially; a drive system for rotating the shafts at one end on the same side of each drive shaft;
The other end of the drive shaft is a pair of first arms that can be driven by being connected to the shaft, and the other end of the first arm is rotatable on a plane perpendicular to the drive shaft with respect to the first arm. A pair of second arms having the same configuration, and the other end of the second arm is provided with a joint having a mechanism to make the opening angle of the second arm the same, and each is supported by the rotation center axis of the joint. In a transport device having a carrier on which the transported object is placed, and a joint supporting the carrier can pass on the rotation center axis of the drive shaft, a drive system for rotating the two drive shafts is provided. A control method of a transport device, wherein the control is performed while synchronizing the rotation of two axes. 3. The transport device according to claim 1, wherein a means for detecting the presence or absence of an object to be transported is provided on the carrier, or a means for detecting the mass of the object to be transported is provided on the carrier, and a signal from the detecting means is provided. A transport device comprising means for driving by changing the angular velocity or angular acceleration of the drive system, or the angular velocity and angular acceleration. 4. The transfer device according to claim 1, wherein a means for detecting the presence or absence of an object to be transferred is provided on the carrier, or a means for detecting the mass of the object to be transferred is provided on the carrier, and a signal from the detection means is provided. A control method for a transport device, comprising: performing control of driving by changing an angular velocity or an angular acceleration of a drive system or an angular velocity and an angular acceleration. 5. The transfer device according to claim 1, further comprising means for detecting a current supplied to the drive motor of the drive system and means for recording the current value, and driving the transfer device at an arbitrary time to obtain the current value. Is recorded as a reference value, and the current value is detected and compared with the reference value when the transport device is driven thereafter, and when the ratio with the reference value deviates from a preset value, an abnormality is detected. And a means for performing a predetermined process by determining that an abnormal driving state has occurred. 6. The transfer apparatus according to claim 1, further comprising means for detecting a current supplied to a drive motor of a drive system and means for recording the current value, and driving the transfer apparatus at an arbitrary time and controlling the current value. Is recorded as a reference value, and the current value is detected and compared with the reference value when the transport device is driven thereafter, and when the ratio with the reference value deviates from a preset value, an abnormality is detected. A control method for a transport device, comprising: determining that a special driving state has occurred; and performing a predetermined process. 7. The transfer device according to claim 1, further comprising a brake and an incremental encoder coupled to a drive motor of a drive system, wherein the brake is released when the motor is driven, and when no current is supplied to the motor or when a power supply of the control device is supplied. When the power supply is interrupted, the brake is activated and the motor and the incremental encoder do not move.The counter connected to the incremental encoder is provided with a means for preventing the counted value from being erased even when power is not supplied. A method for controlling a transport device, comprising controlling a motor using a value of an encoder. 8. The transfer device according to claim 1, further comprising a brake and an incremental encoder coupled to a drive motor of a drive system, wherein the brake is released when the motor is driven, and when no current is supplied to the motor or a power supply of the control device. When the power supply is interrupted, the brake is activated and the motor and the incremental encoder do not move.The counter connected to the incremental encoder is provided with a means for preventing the counted value from being erased even when power is not supplied. A transport device comprising means for controlling a motor using a value of an encoder. 9. The transfer device according to claim 1, further comprising two drive motors for driving a series of mechanical systems in which the two drive shafts and the first arm, the second arm, the joint, and the carrier are connected. The carrier is driven on a plane perpendicular to the drive shaft by the rotation of the two drive motors, and the rotation of the two drive motors is set to the same direction or the opposite direction, so that the carrier is perpendicular to the drive shaft. A drive motor that drives a mechanical system capable of driving the mechanical system having the above-described configuration in a direction parallel to the drive shaft, while performing a radial movement or a rotational movement of a circle with the drive shaft as the origin within a simple plane. Equipped, the carrier performs a normal movement in a plane perpendicular to the drive shaft, the radial movement, the rotational movement, and the normal movement in the plane each move independently, or two movements Happen at the same time, and three The method of conveying apparatus movement of and controls to occur simultaneously. 10. The transfer device according to claim 1, wherein
A detection plate is provided on the drive shaft for driving the arm A, and a B detection plate is provided on the drive shaft for driving the first arm B. The A detection plate and the B detection plate have a semicircular shape, and each detection plate is If one sensor is provided for each detection, and the A detection plate and the B detection plate both sense the sensor when the transport device stops abnormally, the drive shaft for driving the first arm A is rotated in the forward direction. And the drive shaft for driving the first arm B is rotated in the opposite direction. If neither the A detection plate nor the B detection plate has detected the sensor, the first
The drive shaft for driving the arm A of the first
The drive shaft for driving the first arm A is rotated by rotating the drive shaft for driving the arm B in the forward direction, and if the sensor on the A detection plate senses and the sensor on the B detection plate does not sense. One arm B
And the drive shaft for driving the first arm A, if the sensor of the B detection plate does not sense and the sensor of the B detection plate senses, A means for rotating the drive shaft for driving the first arm B in the opposite direction and stopping the drive shaft when the state of each sensor is reversed to return to the home position is provided. Characteristic transport device. 11. The transfer device according to claim 1, wherein
A detection plate is provided on the drive shaft for driving the arm A, and a B detection plate is provided on the drive shaft for driving the first arm B. The A detection plate and the B detection plate have a semicircular shape, and each detection plate is If one sensor is provided for each detection, and the A detection plate and the B detection plate both sense the sensor when the transport device stops abnormally, the drive shaft for driving the first arm A is rotated in the forward direction. And the drive shaft for driving the first arm B is rotated in the opposite direction. If neither the A detection plate nor the B detection plate has detected the sensor, the first
The drive shaft for driving the arm A of the first
The drive shaft for driving the first arm A is rotated by rotating the drive shaft for driving the arm B in the forward direction, and if the sensor on the A detection plate senses and the sensor on the B detection plate does not sense. One arm B
And the drive shaft for driving the first arm A, if the sensor of the B detection plate does not sense and the sensor of the B detection plate senses, A transport device, comprising: rotating a drive shaft for driving the first arm B in the opposite direction, and performing control to return to the origin position by stopping the drive shaft when the state of each sensor is reversed. Control method.