JPH08111998A - Positioning device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a low-cost, highly durable and highly reliable positioning device equipped with a long-stroke polyphase motor in which dozens of coils are connected. A positioning device for moving a table 1 by selecting a coil to be energized in a linear motor coil 4 according to a detection position of a position detector 7 is provided with first and second current amplifiers 15, and Relay 1 of odd-numbered coils in the coil array to the first current amplifier
9, and even-numbered coil groups in the coil array are connected to the second current amplifier via relays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a positioning device that can be used in semiconductor manufacturing equipment, machine tools, etc., and more particularly, it has a multi-phase motor for selectively switching coils to be energized according to the detection position of a movable body. The present invention relates to a positioning device.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a conventional positioning device. The apparatus in this figure includes a linear motor coil 104 in which four-phase coils are arranged in a straight line. The coil support member 103 supports the linear motor coil 104,
The linear motor coil 1 is provided on both sides of the coil support member 103.
A pair of guides 102 are provided in parallel with the arrangement direction of the coils constituting 04.

A table top plate 101 is attached to a guide 102 via a bearing 106, and the table top plate 101 is freely guided by a guide 102 in the coil arrangement direction. Further, the table top plate 101 has a permanent magnet 10
5 are attached, and the permanent magnets 105 are arranged in four pairs with their polarities alternating in the coil arrangement direction.

A position detector (linear scale) 107 for detecting the position of the table top plate 101 is provided on the side of the guide 102. Up / down from the position detector 107 according to the movement amount and direction of the table top 101.
A down signal is output and taken into the counter unit 110 to obtain the position information of the table top 101. The counter unit 110 is initialized when the light blocking plate 108 attached to the table top plate 101 passes through the origin photo switch 109.

A servo controller 111 is connected to the counter unit 110, and a difference between the target position of the table 101 and the current position of the table 101 obtained from the counter unit 110 is calculated by PID, for example, and the control output obtained by this calculation is obtained. Output as a command value to the D / A converter 113.

FIG. 4 shows an energization pattern of the linear motor coil in the positioning device having the polyphase type linear motor. In the figure, symbols A and B indicate the directions of the currents flowing through the coils, symbol A indicates the current that is facing backward when viewed from the front of the drawing, and symbol B indicates the current that is facing forward when viewed from the front of the drawing. As shown in (Case 0) to (Case 9) of FIG. 4, the direction of the coil to be energized and the current flowing through the coil are switched at a certain pitch (every 10 mm in this figure) depending on the position of the movable magnet 105, and thrust in the same direction. Is generated to move the movable magnet 105 in a predetermined direction,
Along with this, the top plate 101 is moved.

Each coil is connected to each switch 114 through a current amplifier 115, and the switch switching is controlled by an amplifier switching signal output from the phase switching controller 112 so that each coil is appropriately energized. Be seen.

The details of the current amplifier portion of this device are shown in FIG. The current flowing through the motor coil 104 is detected by the detection resistor 11
The voltage between both ends of 6 is measured by the differential amplifier 117, and the difference from the command is amplified by the power operational amplifier 118 to form a current feedback circuit. In this example, a current feedback circuit is provided for each coil. Further, the configuration of the current amplifier portion as shown in FIG. 6 is also known. Instead of switching the control command, the relay 119 connected to each coil is sequentially switched.

[0009]

However, each of the above-mentioned conventional examples has the following problems. In the conventional current amplifier configuration shown in FIG. 5, since a current feedback circuit is provided for each coil, in the case of a long-stroke polyphase motor in which several tens of coils are connected, it is expensive (tens of thousands of yen). ) Power operational amplifiers, detection resistors, and differential amplifiers are required for the number of coils, resulting in a large number of parts. As a result, there are problems that the current amplifier itself becomes expensive and the device becomes large.

Since the current amplifier of the conventional example shown in FIG. 6 has a structure in which the coil to be energized is switched by an inexpensive (several hundred yen) relay, an expensive power operational amplifier, a detection resistor, and a differential amplifier are shared by all the coils. As a result, it is possible to suppress an increase in cost even when configuring a long-stroke polyphase motor in which several tens of coils are connected, but the following disadvantages occur. That is, in this conventional example, the relay is turned on / off while a current of several amperes (A) is flowing.
Since it will be turned off, the contact of the relay is severely worn,
When applied to an apparatus such as a semiconductor manufacturing apparatus that requires highly accurate positioning, it lacks durability and reliability.

SS without mechanical contacts instead of relays
It is conceivable to use R (solid state relay), but at the present time, it is not possible to flow several amperes and to be inexpensive.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an inexpensive, durable and highly reliable multi-phase motor having a long stroke in which several tens of coils are connected. It is to provide a positioning device.

[0013]

In order to achieve the above-mentioned object, the present invention has a position detector for detecting the position of a movable body and a coil array having at least three coils, and the position In a positioning device that moves and positions the movable body by selecting a coil to be energized in the coil array according to a detection position of a detector, the first and second current amplifiers are provided and the first current is provided. An odd-numbered coil group in the coil array is connected to the amplifier via a relay, and an even-numbered coil group in the coil array is connected to the second current amplifier via a relay.

In the present invention, while the coil in the coil array is energized via one of the first and second current amplifiers, the relay of the coil to be energized next is switched on the other side. It is more preferable to do so.

Further, according to the present invention, there is provided a position detector for detecting the position of the movable body and a coil array having at least three coils, and the coil array in the coil array is provided in accordance with the detection position of the position detector. In a positioning device for moving and positioning the movable body by selecting a coil to be energized, a plurality of current amplifiers are provided, and the current amplifiers are provided for each coil in a coil group in the coil row. It is characterized in that they are alternately connected via.

In the present invention, while the desired coil in the coil array is energized via one of the current amplifiers, the relay of the coil to be energized next via the other current amplifier is switched. Is more preferable.

[0017]

According to the present invention as described above, it is possible to switch the relay of the coil to be energized next time on the side of the other current amplifier while energizing via one current amplifier. Become. Therefore, according to the present invention, it is possible to eliminate the ON / OFF state of the relay in the energized state,
The durability and reliability of the relay are improved.

Further, even when a long stroke polyphase type motor in which several tens of coils are connected is provided, for example, even-numbered coils and odd-numbered coils are sequentially added together with relays to each current amplifier. Therefore, it is possible to suppress an increase in device cost.

[0019]

1 is a diagram showing the schematic construction of an embodiment of a positioning apparatus of the present invention. The positioning device of the present invention shown in this figure includes a linear motor coil (motor coil array) 4 in which four-phase coils are arranged in a straight line. The coil support member 3 supports the linear motor coil 4, and a pair of guides 2 are provided on both sides of the coil support member 3 in parallel with the arrangement direction of the coils forming the linear motor coil 4.

A table top plate (or stage) 1 which is a movable body is attached to the guide 2 via a bearing 6, and the table top plate 1 is guided by the guide 2 freely in the coil arrangement direction. Here, the bearing 6 is well known, and is of a non-contact type such as an air bearing. Further, one set of bearings 6 is provided at each of the four corners of the table top 1, and restrains the movement of the top 1 along a plane perpendicular to the moving direction of the top 1. Permanent magnets 5 are further attached to the table top plate 1 as movable magnets, and the permanent magnets 5 are arranged in four pairs in the coil arrangement direction with their polarities alternating.

The table top plate 1 is provided on the side of the guide 2.
A position detector (linear scale) 7 for detecting the position of is provided. In a semiconductor manufacturing apparatus that requires high positioning accuracy, a laser interferometer-type length measuring device is used as the position detector 7. The position detector 7 outputs an up / down signal each time the table top 1 moves by a unit movement amount according to the moving direction. The counter unit 10 takes in the up / down signal and obtains the position information of the table top 1. The counter unit 10 is the table top 1
It is initialized when the shading plate 8 attached to the optical disc passes the origin photo switch 9.

A servo controller 11 is connected to the counter unit 10, and the servo controller 11 sets the preset target position of the table 1 and the counter unit 10 in advance.
The difference from the current position in Table 1 obtained from
ID calculation is performed, and the control output obtained by this calculation is D /
Output as a command value to the A converter 13. A current amplifier 15 is provided to each of a plurality (two in this embodiment) of switches 14 to which command values are input via the D / A converter 13.
Is connected. As shown in FIG. 2, an odd-numbered coil group (coil1, coil3, coil5, ...) Of the linear motor 4 is provided at the output stage of the current amplifier 15 on one side, and an output stage of the other current amplifier 15 is provided on the output stage of the other current amplifier 15. Even numbered coil group (coil2, c
oil4, coil6, ...) are connected. In this embodiment, the number of the current amplifiers 15 is two, which is the same as the number of the switches 14, but two current amplifiers 15 are provided for one switch 14 and these are odd number (or even number) of the linear motor 4. It may be connected to half of the second coil group. After all, if the number of current amplifiers 15 is smaller than the number of coil groups of the linear motor 4, the object of the present invention can be achieved.

Further, in this embodiment, the ON / OFF of each switch 14 is controlled to be switched by the phase switching signal output from the phase switching controller 12, and the linear motor 4 is controlled.
The coils are energized. Linear motor coil 4
The energization pattern of is similar to that of the conventional example described above and is shown in FIG.

Next, details of the current amplifier 15 of this embodiment will be described with reference to FIG. For the current flowing through the motor coil 4, the voltage across the detection resistor 16 is measured by the differential amplifier 17,
The difference from the command is amplified by the power operational amplifier 18 to form a current feedback circuit. The odd-numbered coil groups (coil1, coil3, coil5, ...) Are relays 19 (relay 1,
Are connected to the power operational amplifier 18 via the relays 3, 5 ..., and even-numbered coil groups (coil2, coil4, coil6 ,.
.. is connected to the power operational amplifier 18 via the relay 19 (relay 2, relay 4, relay 6 ...).

The phase switching controller 12 outputs an amplifier switching signal and a relay switching signal as shown in FIG. The control sequence by these signals is shown as a table in FIG. Odd numbered coil group (coil1, coil
3, coil5, ...) and even-numbered coil groups (coil2, coil
4, coil6, ...) are alternately used as shown in FIG. 4, so that the amplifier switching signal from the phase switching controller 12 alternately turns ON / OFF the two switches 14 (sw1, sw2).

At this time, the phase switching controller 12
Relay switching signal from the coil group (coil1, coil
2, coil3, ...) Relay 1 of the coil you want to energize
9 is turned on and the current amplifier 1 on the side not energized
In the relay group connected to 5, turn ON * the relay corresponding to the coil to be energized next. At the position indicated by “∇” in the table of FIG. 3, the coil (coil 2) is energized via the amplifier 18 on the sw2 side, but the relay of the output stage of the amplifier 18 on the sw1 side that is not used is turned ON / OFF. OF
Switch F while referring to the position of the movable magnet (table), and switch the coil (coil1 OR coil3) appropriately. As a result, the relay is turned ON / O while the current is still flowing.
FF does not occur, wear of the relay contacts can be suppressed to a minimum, and durability and reliability are improved.

Further, in the case of constructing a long stroke polyphase type motor in which several tens of coils are connected, it is sufficient to add coils to the output stage of each current amplifier together with the relay in sequence. It is possible to suppress an increase in the cost of the device and also to reduce the size of the device.

[0028]

As described above, according to the present invention,
Even in a positioning device equipped with a long-stroke polyphase motor in which several tens of coils are connected, an inexpensive and highly reliable positioning device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a positioning table device of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a current amplifier of the present embodiment.

FIG. 3 is a diagram showing a control sequence of the present embodiment.

FIG. 4 is a diagram showing an energization pattern of a polyphase linear motor.

FIG. 5 is a diagram showing a schematic configuration of a conventional example of a current amplifier.

FIG. 6 is a diagram showing a schematic configuration of another conventional example of a current amplifier.

FIG. 7 is a diagram showing a schematic configuration of a conventional positioning device.

[Explanation of symbols]

 1 table top plate 2 guide 3 coil support member 4 linear motor coil 5 movable magnet 6 bearing 7 position detector 8 light shield 9 origin photo switch 10 counter unit 11 servo controller 12 phase switching controller 13 D / A converter 14 switch 15 current amplifier 16 Detection Resistor 17 Operational Amplifier 18 Power Operational Amplifier 19 Relay

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/027 21/68 K H02K 41/02 Z // B60L 13/03 9235-3H B60L 13 / 02 V

Claims (4)

[Claims] 1. A position detector for detecting the position of a movable body,
A coil array having at least three coils,
A positioning device for moving and positioning the movable body by selecting a coil to be energized in the coil array according to a detection position of the position detector, the first and second current amplifiers are provided, and the first and second current amplifiers are provided. An odd-numbered coil group in the coil array is connected to one current amplifier via a relay, and an even-numbered coil group in the coil array is connected to the second current amplifier via a relay. Positioning device. 2. While the coil in the coil array is energized through one of the first and second current amplifiers, the relay of the next energized coil is switched in the other. The positioning device according to claim 1. 3. A position detector for detecting the position of a movable body,
A coil array having at least three coils,
In a positioning device that moves and positions the movable body by selecting a coil to be energized in the coil array according to a detection position of the position detector, a plurality of current amplifiers are provided and the current amplifier is A positioning device characterized by being alternately connected to a coil group in a coil array via a relay provided for each coil. 4. A relay of a coil to be subsequently energized via the other current amplifier is switched while energizing a desired coil in the coil array via one of the current amplifiers. The positioning device according to claim 3.