JPH029596A - Handling device - Google Patents

Abstract

PURPOSE:To provide practicability of sensing abnormal motion of a holder by locating that part of track to be sensed, which represents the track on which the holder is to travel, in the fixation position near transfer of an object to be transferred, and by installing a sensor to sense this track in an appropriate position of the holder. CONSTITUTION:When any cause has tracked off a holder 3 at the tip of a hand arm 2, a photo-sensor 5 mounted on this holder 3 is set off from a reflex plate 6, and the reflected light from a light emitting element can no more be sensed, and now the motion of the hand arm 2 is emergency stopped. After this stopping, the hand arm 2 is returned till the position where the photo-sensor 5 is sensitive for the light from reflex plate 6, and thereafter the hand arm 2 is operated while the photo-sensor 5 is sensing the position of the holder 3. This avoids the holder 3 and object 1 held thereby from touching other object 7 when the holder 3 traveling goes out of specified track, which ensures that the handling device concerned operates safely.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a handling device.

(Conventional technology) In a handling device with two degrees of freedom.

There are cases where it is necessary to control the movement of the holding part that holds the object to be transferred so that it passes along a certain trajectory6. The arm is installed.

A handling device is attached to the tip of this hand arm with a carrier holding portion that holds a wafer carrier containing a plurality of semiconductor wafers. When using this handling device to move a wafer carrier between a loading/unloading table and a holding section in a clean stocker.

In order to make the space in which the wafer carrier moves as small as possible, it is necessary to drive the vertical axis and the rotation axis synchronously to move the carrier holder up and down as well as rotate it, thereby moving the wafer carrier horizontally.

One way to meet this need is usually by means of encoders on the vertical and rotational axes.

A method is adopted in which the increment from the initial position of each drive shaft is detected and the synchronous drive of the vertical axis and rotary axis is controlled based on this increment.

(Problem to be Solved by the Invention) However, since such conventional handling devices are controlled by encoders provided on each drive shaft,
If the motion of the recarrier holder deviates from a predetermined trajectory due to a hardware or software malfunction, there is a good possibility that it will come into contact with or collide with other equipment.

In addition, each drive axis is controlled based on increments from the initial position of each drive axis, so if the current position is lost due to a stop in the middle of operation, etc., the subsequent operation of the handling device itself will be There are problems such as it becoming impossible.

The present invention has been made in response to the above-mentioned problems, and is capable of immediately stopping an emergency stop when the handling mechanism deviates from the trajectory.
Therefore, it is an object of the present invention to provide a handling device that can operate safely and can operate safely and reliably even after stopping.

[Structure of the invention]

(Means for Solving the Problems) The present invention is a handling device that holds an object to be transferred in a holding part and moves the object, in which the holding part detects a trajectory of the object to be transferred, which represents the trajectory to be moved. The object of the present invention is to obtain a handling device characterized in that the handling device is disposed at a fixed position near the transfer and loading portion, and a sensor for detecting the trajectory is provided at an appropriate position on the holding portion.

(Function) Therefore, according to the present invention, when the handling device is driven, the holding part that holds the transferred object moves in the transfer orbit area, and along with this movement, the sensor provided in the holding part moves. The robot moves along a stationary trajectory detection section that is placed separately from the drive system. In this state, the drive system of the handling device is
Although normal movement can be confirmed, once the sensor deviates from the trajectory detection section, the handling device comes to an emergency stop. Thereafter, the holding part is moved under control to a position where the trajectory detecting part is detected by the sensor, and a normal pulling out operation of the holding part is performed.

(Example) The following is an example in which the apparatus of the present invention is applied to a case where a carrier storing a semiconductor wafer is transferred.

This will be explained with reference to the drawings.

As shown in FIGS. 1A and 1B, a case will be considered in which an object 1 to be transferred is transferred from position A to position B using a hand arm 2. As shown in FIG. First, grasp the transferred object 1 on the table at position A with the holding part 3 at the tip of the hand arm 2. Next, after lifting it slightly, the hand arm 2 is rotated around the rotation axis 4. Expand and contract.

When the transferred object 1 reaches position B after passing through a predetermined trajectory, nine rotations and expansion/contraction are stopped, and the transferred object 1 is lowered and placed on the table at position B.

In this case, the holding part 3 needs to pass along a predetermined trajectory. However, if it deviates from the orbit for some reason, the transferred object 1 or the holding part 3 may come into contact with other members 7, or the position B
The transferred object 1 may be transported to a different position. To avoid such situations.

An optical sensor 5 is provided at a predetermined location on the hand arm 2.

In addition, a reflecting plate 6 is installed at a fixed position corresponding to the trajectory of the optical sensor 5 when the hand arm 2 moves. That is, while the hand arm 2 is in operation, the position of the hand arm 2 is constantly detected by the optical sensor 5, and when the hand arm 2 goes off track, the position of the optical sensor 5 is removed from the reflector 6 and away from the light emitting element 1. When the reflected light cannot be detected, the operation of the hand arm 2 is brought to an emergency stop. After stopping.

The hand arm 2 is returned to a position where the optical sensor 5 can detect the light from the reflection plate 6, and then the hand arm 2 is operated while the optical sensor 5 detects the position.

The above is the basic operating principle of the present invention.

The handling device of the present invention is characterized in that a trajectory detected portion is provided at a fixed position that is not driven by a drive system, and is operated while constantly being detected by a sensor. When such a handling device of the present invention is operated, the holding means for holding the transferred object moves in a predetermined area, and the sensor moves along the trajectory detected part in accordance with this movement. In this state, it can be confirmed that the drive system is operating normally. On the other hand, if the sensor deviates from the detected part of the trajectory, the drive system is brought to an emergency stop. After that, the holding means is controlled and moved to a position where the orbit detection target part can be detected by the sensor,
The holding means is then returned to its initial position.

FIG. 2 is a partially cutaway perspective view showing a clean stocker that stores wafer carriers and incorporates the above-mentioned handling device.

A ball screw 18 is disposed within the vertical shaft frame 11 , and the ball screw 18 is rotationally driven by the vertical drive shaft 15 . A nut 21 is attached to the ball screw 18, and a rotating shaft 14 is attached to the base 13 attached to the nut 21.

A caster 12 disposed between the upper and lower guides 11 is attached to the tip of the vertical axis frame 11, and a horizontal drive shaft 16 is attached to this caster 12. The guide 17 and the caster 12 are connected by a rack-and-binion, and by transmitting torque from the horizontal drive shaft 16 to the caster 12, the vertical shaft frame 11 is moved horizontally.

The rotating shaft 14 and the vertical drive shaft 15 described above. By the operation of the horizontal drive shaft 16, the wafer carriers placed on the loading/unloading table 19 are sequentially stored in the storage section 20.

FIG. 3 is an enlarged perspective view of a part of the handling device shown in FIG. 2.

The output from the motor (not shown) is transmitted to the rotating output shaft 28 via a reducer such as Harmonic Drive 29 (product name).
is transmitted to. This rotation output shaft 28 has a hand arm 2.
2 is fixed, and three carrier holding parts 23a, 23 that hold a wafer carrier at the tip of the hand arm 22.
b, 23c are attached.

A trajectory confirmation sensor 25 on the loading/unloading table 19 side is provided at the end of the carrier holding section 23a. Further, a sensor arm 30 is attached to the hand arm 22, and a trajectory confirmation sensor 24 on the storage section side is provided at the tip of the sensor arm 30.

A reflection plate 26 is attached to a fixed member other than the drive system, such as the storage unit 20, facing the sensor arm 30.The reflection plate 26 has a notch that is a non-reflection area at the end. along which the sensor 2
The trajectory detection line 27, which is the light reflecting area traced by 4.

FIG. 4 is a diagram showing the trajectory confirmation sensors 24 and 25.

The orbit confirmation sensor 24.25 is provided with three reflective optical sensors 31, 32, and 33, each consisting of a light emitting sensor and a light receiving sensor.

FIG. 5 is a diagram showing the state in which the wafer carrier is handled.

In the storage section 20, a plurality of stands 34 on which wafer carriers are placed are vertically arranged. The storage section 20 is provided with the reflective plate 26 as described above, and similarly the loading/unloading table 1
On the 9 side, there is a reflector 3 facing the sensor 25 shown in FIG.
A cutout is formed in the zero reflection plate 35 to which the sensor 5 is attached, and the outline of the cutout forms a trajectory detection line 36 along which the sensor 25 follows.

The wafer carrier 37 is moved onto the loading/unloading table 1 by vertical movement along the vertical axis of the hand arm and rotation around the rotary output shaft 28 in synchronization therewith.
9 and the storage section 20 as appropriate.

FIG. 6 shows the locus of movement of the hand arm 22 and the wafer carrier 37 when the wafer carrier is placed on the stand 34 in the storage section 20. Since the upper space of the stand 34 is narrow, the wafer carrier 37 is It must be moved horizontally and in a straight line to avoid contact with other stands above. Further, after placing the wafer carrier on the stand 34, it is necessary to pull out the carrier holding portion of the hand arm horizontally and linearly. When performing such an operation, the center portion of the trajectory confirmation sensor 24 must be moved along the trajectory detection line 27 that forms the outline of the notch in the first reflecting plate 26. To do this, it is necessary to control the synchronous drive of the vertical axis along which the hand arm 22 moves up and down and the rotation axis around which the hand arm 22 rotates. An encoder provided on the shaft detects the increment of each drive shaft from its initial position, and based on this increment, the synchronous drive of the vertical axis and the rotary shaft is controlled.

7A and 7B show the positional relationship between the trajectory confirmation sensor 24 and the reflector 26 when the vertical axis and the rotation axis are driven synchronously. FIG. 7A shows that the hand arm 22 is normal. Fig. 7B shows the case where the hand arm 2 is moving.
In FIG. 7A, the trajectory detection line 27 is located between 31 and 32 of the 1 reflection type optical sensor. On the other hand, in Figure 7B, 1
Both of the reflective optical sensors 31 and 32 are on the reflecting plate 26 side or the notch side, and the trajectory detection line 27 is not located between the reflective optical sensors 31 and 32. In this case, one reflective optical sensor 31. The trajectory detection line 27 is always detected by 32 and 33, and if the trajectory confirmation sensor 24 deviates from the trajectory detection line 27 due to some abnormality, the drive of the vertical axis and rotary axis is urgently stopped as a safety measure. will be stopped.

Each drive shaft detects the increment from its initial position, and its drive is controlled based on this increment, so if the current position is lost due to an emergency stop, etc., the hand arm 22 from the storage section 20 The pulling operation is performed as follows.

That is, the current position is detected by the trajectory confirmation sensor 24.

The hand arm 22 returns the position of the trajectory confirmation sensor 24 to the trajectory detection line 27 of the reflection plate 26 so that it does not come into contact with other parts in the storage section 2o, and then moves the trajectory confirmation sensor 24 back to the trajectory detection line 27 of the reflection plate 26.
4 while detecting the trajectory detection line 27.
6. In other words, by providing a reflector having a trajectory detection line 27 and a sensor for detecting the trajectory detection line 27 separately from the drive system, the operation of the hand arm can be controlled. It is possible to confirm safety and to pull out the hand arm without any trouble if you lose track of your current position.

Above, an example using a reflector having a notch to form a light reflective area and a non-reflective area has been described, but the present invention is not limited to this. For example, a reflector having a predetermined shape without a cutout may be used.

Alternatively, the reflector may have two regions with different reflectances.

Furthermore, although a case has been described in which an optical sensor is used as the sensor, the present invention is not limited to this, and it is also possible to use an ultrasonic sensor or the like.

〔Effect of the invention〕

As explained above, according to the handling device of the present invention, when the holding means moves deviating from the predetermined trajectory,
It is possible to detect abnormal movement of the holding means by a trajectory detection portion provided at a fixed position different from that of the driving means and a sensor provided on the holding means. When abnormal movement of the holding means is detected, the driving means can be stopped urgently, thereby preventing the holding means from coming into contact with other parts, etc., and as a result, the operation of the handling device can be made safer. I can do it. Further, after stopping, it is possible to return to the normal position and then operate along a predetermined trajectory. In this way, it is possible to safely and reliably perform a series of operations when the handling means operates abnormally, while detecting the position using the sensor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a handling device for explaining the operating principle of the apparatus of the present invention, FIG. 2 is a block diagram of a clean stocker for explaining an embodiment of the apparatus of the present invention, and FIG. 3 is a block diagram of the 21ii! Fig. 4 is an explanatory diagram of the handling device in Fig. 3, Fig. 4 is an explanatory diagram of the trajectory confirmation sensor in Fig. 3, Fig. 5 and Fig. 6 are explanatory diagrams of the operation of the handling device in Fig. 3, and Fig. 7 is an illustration of the trajectory in Fig. FIG. 3 is an explanatory diagram of the positional relationship between a confirmation sensor and a reflection plate. 22...Hand arm 23...Holding part 24.25...Trajectory confirmation sensor 27.36...Trajectory detection line 37...Wafer carrier Patent applicant Tokyo Electron Ltd. Figure A Figure Figure Figure A Figure B Figure

Claims (1)

[Claims] In a handling device that holds an object to be transferred in a holding part and moves it, a trajectory detected part representing the trajectory in which the holding part should move is disposed at a fixed position near the transfer of the object to be transferred, and this A handling device characterized in that a sensor for detecting a trajectory is provided at an appropriate position on the holding portion.