JP2000134903A - Motor and stage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a magnetic flux detecting coil hardly influenced by the relative variation of a stator and a mover by reducing the control residual of a current control system, by constituting the coil in such a way that the coil generates an induced voltage proportional to that of a driving coil when a magnet and the driving coil move relatively to each other. SOLUTION: The mover 30 of a linear motor is provided with a magnetic flux detecting coil 32 which is constituted so that the coil 32 may receive magnetic flux variation which is substantially equal to that of a driving coil 31 in addition to the coil 31. The coil 32 is coaxially provided inside the coil 31 (on a stator side) and is designed to have a larger number of turns that the coil 31 has a thinner thickness than the coil 31 has, and a length which is nearly equal to that of the coil 31, by using a thinner winding than that of the coil 31. Therefore, the induced voltage of the coil 32 becomes proportional to that of the coil 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor for use in a stage device or the like on which an object is mounted and high precision positioning performance and speed control are required. Further, the present invention relates to a stage device using the motor.

[0002]

2. Description of the Related Art FIG. 11 is a perspective view of a conventional linear motor.

A guide 102 is fixed on a base (not shown). The guide 102 guides the stage 101 reciprocally in a predetermined direction (hereinafter, referred to as a “scanning direction”). A linear motor stator 1 is provided on both sides along a traveling path of a stage 101 traveling along a guide 102.
Reference numeral 10 is provided to be vibrationally independent of a base (not shown). A linear motor stator 1 is provided on both sides of the stage 101.
A linear motor mover 130 is provided so as to be opposed to 10. The linear motor stator 110 and the linear motor mover 130 each constitute a linear motor 104 for moving the stage 101 in the scanning direction. The stage 101 is guided in a non-contact manner by a guide 102 by a hydrostatic bearing pad or the like (not shown).

Each linear motor stator 110 has a guide 1
02 includes a long loop-shaped yoke 111 disposed substantially along the entire length thereof and a long magnet 112 fixed to the inside thereof. Each magnet penetrates the drive coil 131 of the linear motor movable element 130. When a drive current is supplied from a power supply (not shown) to each linear motor mover 130 to be excited,
Thrust is generated along the magnet, which causes the stage 10
1 is accelerated or decelerated.

FIG. 12 shows a control system of a conventional linear motor.

The position command output by the position command pattern generator 150 and the stage 10 measured by the interferometer 151
The difference from the position 1 is input to the control calculator, and the calculation result is converted into an analog voltage to be a current command.
To enter. The current control system 154 includes an adder 155, a detection resistor 156, and an error amplifier 157. Detection resistor 1
Since 56 returns a voltage proportional to the current flowing through the drive coil 131 connected in series, the error amplifier 157 gives a voltage obtained by multiplying the gain between the current command value and the actual current to the drive coil and the detection resistor. .

[0007]

When the positions of the stator and the mover relatively change, an induced voltage proportional to the relative speed is generated in the drive coil. When the relative fluctuation between the stator and the mover increases, the control residual of the current also increases. For example, in a precision moving stage device used in a semiconductor manufacturing apparatus or the like, a base and a yoke (not shown) are separately fixed in order to reduce disturbance of a control system of a stage on which a workpiece is mounted. Therefore, when the support portion of the yoke is excited by the reaction force generated when the stage is accelerated and vibrates, a large induced voltage is generated in the drive coil according to the relative speed between the coil and the yoke / magnet.

Further, since the gain of the error amplifier of the current control system is finite, the induced voltage caused by the relative speed between the mover and the stator becomes a disturbance of the current control system of the driver, and only the current control residual difference becomes the force. And the position accuracy and speed uniformity of the driven object are deteriorated.

Accordingly, an object of the present invention is to provide a linear motor that reduces the control residual of the current control system and is less affected by relative fluctuations of the stator and the mover.

[0010]

According to a first aspect of the present invention, there is provided a motor having a magnet and a driving coil opposed to the magnet, wherein the magnet and the driving coil move relatively. In the motor, a magnetic flux detection coil is provided integrally with the drive coil so that when the magnet and the drive coil move relatively, an induced voltage proportional to the induced voltage generated in the drive coil is generated. It is characterized in that the magnetic flux detection coil is configured.

It is desirable that the induced voltage generated by the magnetic flux detecting coil be fed forward to a current error adder of a current control system.

Preferably, the magnetic flux detecting coil is configured to penetrate a magnetic flux substantially equal to a magnetic flux linked to the driving coil, and the size or shape of the magnetic flux detecting coil is determined by the size of the driving coil. Alternatively, it is preferable that the shape is substantially equal to the shape.

The motor is preferably a linear motor, and may be a rotary motor.

[0014]

<First Embodiment> FIG. 1 is a schematic perspective view of a stage device according to a first embodiment of the present invention.

A guide 2 is fixed on a base (not shown). The guide 2 moves the stage 1 in a predetermined direction (hereinafter, referred to as
It is called “scanning direction”. ) And guide it back and forth freely. Linear motor stators 10 are provided on both sides along a traveling path of the stage 1 traveling along the guide 2 so as to be vibrationally independent of a base (not shown). Linear motor movers 30 are provided on both side surfaces of the stage 1 so as to face the linear motor stator 10. The linear motor stator 10 and the linear motor mover 30
Constitute a linear motor 4 for moving in the scanning direction. The stage 1 is guided in a non-contact manner by a guide 2 by a hydrostatic bearing pad (not shown) or the like.

Each linear motor stator 10 has a long loop-shaped yoke 1 disposed substantially along the entire length of the guide 2.
1 and a long magnet 12 fixed to the inside thereof. Each magnet 12 penetrates a drive coil 31 of a linear motor mover 30. On both sides of the stage 1, a coil support 33 for holding the drive coil 31 is provided.
Is composed. When a drive current is supplied from a power supply (not shown) to the drive coil 31 of each linear motor mover 30 to excite it, a thrust is generated along the magnet 12, and the stage 1 is accelerated or decelerated.

Unlike the conventional linear motor, the linear motor mover 30 of the present invention is provided with a magnetic flux detecting coil 32 configured to receive substantially the same magnetic flux change as the driving coil 31 in addition to the driving coil 31. ing.

The magnetic flux detecting coil 32 is provided coaxially with the drive coil 31 (closer to the stator).
The number of turns is increased by using a thinner winding, and the thickness is made smaller than that of the drive coil 31. The length of the magnetic flux detection coil 32 is designed to be almost the same as that of the drive coil 31. Have been.

The length of the magnetic flux detecting coil 32 is
The reason for making the linear motor mover 30 approximately the same as
This is to make the change in magnetic flux due to the relative fluctuation of the linear motor stator 10 substantially equal to that of the drive coil 31 irrespective of the position, and to detect this. That is, even if the magnetic flux density created by the magnet 12 is not always uniform, the drive coil 31
And the length dimensions of the magnetic flux detection coil 32 are substantially the same,
Regardless of where the linear motor mover 30 is located, the magnetic flux passing through both coils is made substantially the same, so that when the drive coil 31 receives the same change in magnetic flux is received by the magnetic flux detection coil 32.

The reason why the thickness of the magnetic flux detecting coil 32 is designed to be thin is to prevent the distance between the linear motor stator 10 and the drive coil 31 from increasing. Since substantially no current flows through the magnetic flux detection coil 32, the magnetic flux detection coil 3
2 does not contribute to thrust. Therefore, the magnetic flux detection coil 32 is designed to be as thin as possible so that the magnetic flux penetrating through the drive coil 31 does not decrease.

The reason why the thin winding used for the magnetic flux detecting coil 32 is used and the number of windings is increased as much as possible is to increase the sensitivity of the magnetic flux detecting coil 32 for detecting the magnetic flux. Since the induced voltage generated in the coil is proportional to the number of turns of the coil, the greater the number of turns of the magnetic flux detection coil 32, the greater the induced voltage generated when the magnetic flux changes. If the sensitivity is sufficiently ensured, an appropriate gain can be applied to control thereafter.

FIG. 2 shows a control system of the linear motor of the present invention.

The difference between the position command output from the position command pattern generator 50 and the position of the stage 1 measured by the interferometer 51 is input to the control calculator 52, and the calculation result is converted into an analog voltage to be a current command. , To the current control system 54. The current control system 54 includes an adder 55, a detection resistor 56, and an error amplifier 57 (current amplifier). Detection resistor 5
6 returns a voltage proportional to the current flowing through the drive coil 31 connected in series, the error amplifier 57 applies a voltage obtained by multiplying the gain between the error between the current command value and the actual current by the drive coil 31 and the detection resistor 56. Give to. When the positions of the linear motor stator 10 and the linear motor mover 30 relatively change, an induced voltage is generated in the drive coil 31 in proportion to the relative speed, but the induced voltage of the magnetic flux detecting coil 32 is adjusted by an appropriate gain adjuster 58. The signal is feed-forwarded to the adder 55 of the current control system 54 via the control circuit 54.

Since the induced voltage generated in the magnetic flux detecting coil 32 is designed to be proportional to the induced voltage generated in the drive coil 31, it is output to the adder 55 of the current control system 54 via an appropriate gain. If so, the induced voltages of the two can be almost canceled. For this reason, the linear motor of the present invention hardly causes a current error from the beginning, as compared with the case where the voltage is changed after a current error occurs as in the conventional case. Can be very small.

Embodiment 2 FIG. 3 is a schematic perspective view of a stage device according to a second embodiment of the present invention.

The guide 2 is fixed on a base (not shown). The guide 2 guides the stage 1 reciprocally along the scanning direction. A linear motor stator 10 is mounted on both sides along the travel path of the stage 1 traveling along the guide 2.
Are arranged independently of the base (not shown) in terms of vibration.
Linear motor movers 30 are provided on both side surfaces of the stage 1 so as to face the linear motor stator 10. The linear motor stator 10 and the linear motor mover 30 each constitute a linear motor 4 for moving the stage 1 in the scanning direction. The stage 1 is guided in a non-contact manner by a guide 2 by a hydrostatic bearing pad (not shown) or the like.

Each linear motor mover 30 has a magnet holding frame 36 provided on both sides of the stage and a movable magnet 35 held by the magnet holding frame 36.

Each linear motor stator 10 includes an upper yoke 16 and a lower yoke 16 having a length extending over the entire stroke of the stage, and a single-phase drive coil wound coaxially around each yoke 16 and extending over the entire stroke. 14, a magnetic flux detection coil 15 wound coaxially with the drive coil 14 over the entire length of the stroke, and a spacer 17 for coupling the upper yoke 16 and the lower yoke 16. The movable magnet 35 of the linear motor movable element 30 is disposed so as to be sandwiched between a coil wound around the upper yoke 16 (a drive coil and a magnetic flux detection coil) and a coil wound around the lower yoke 16.

Also in this embodiment, the magnetic flux detecting coil 15 is designed so that the number of turns is increased by using a thin winding and the thickness of the magnetic flux detecting coil 15 is made as thin as possible, as in the above-described embodiment. It is designed to be almost the same as the drive coil 14. These reasons are the same as in the first embodiment.

The control system is the same as in the above embodiment.

According to this embodiment, the same effects as those of the above-described embodiment can be obtained, and the thickness of the yoke 16 does not need to be increased even if the stroke for moving the stage 1 is extended.

<Embodiment 3> FIG. 4 is a schematic perspective view of a stage device according to a third embodiment of the present invention.

The guide 2 is fixed on a base (not shown). The guide 2 guides the stage 1 reciprocally along the scanning direction. A workpiece 3 is mounted on the stage 1. Linear motor stators 10 are provided on both sides along a traveling path of the stage 1 traveling along the guide 2 so as to be vibrationally independent of a base (not shown). Linear motor movers 30 are provided on both side surfaces of the stage 1 so as to face the linear motor stator 10. The linear motor stator 10 and the linear motor mover 30 each constitute a linear motor 4 for moving the stage 1 in the scanning direction. The stage 1 is guided in a non-contact manner by a guide by an unshown hydrostatic bearing pad or the like.

Each linear motor stator 10 is constituted by fixing six flat driving coils 19 to a stator frame 21, and is fixed by a fixing member (not shown). The linear motor mover 30 has a four-pole magnet 3 magnetized in the vertical direction.
The linear motor 8 and the yoke 39 are integrally formed, are disposed above and below the linear motor stator 10, and are fixed to the stage 1 in a non-contact manner with the linear motor stator 10.

The six drive coils 19 of the linear motor stator 10 are arranged in the drive direction at a pitch 1.5 times the magnetic pole pitch of the quadrupole magnet 38. Since the magnetic pole pitch corresponds to a half cycle of the fundamental wave of the magnetic flux density, the pitch of the six coils corresponds to 0.75 cycle of the fundamental wave of the magnetic flux density, and the electrical angle is 270 degrees or -90 degrees.

A magnetic flux detecting coil 20 is provided on the upper surface of each drive coil 19. In the present embodiment, similarly to the above-described embodiment, the magnetic flux detection coil 20 is designed so that the number of turns is increased by using a thin winding and the thickness of the magnetic flux detection coil 20 is reduced as much as possible. These reasons are the same as in the first embodiment. The flat surface of the magnetic flux detecting coil 20 and the flat surface of the drive coil 19 are designed to have substantially the same shape. This is because, regardless of where the linear motor mover 30 is located, the magnetic flux detection coil 20 and the drive coil 19
And the drive coil 19
Is received by the magnetic flux detection coil 20.

In the present embodiment, the magnetic flux detecting coil 20 is provided on the upper surface of the drive coil 19. However, since the magnet 38 of the linear motor mover 30 is arranged so as to sandwich the drive coil 19, the drive coil 19 A magnetic flux detection coil may be provided on the lower surface, or a magnetic flux detection coil 20 may be provided on both surfaces of the drive coil 19.

FIG. 5 shows a drive sequence of the linear motor mover of this embodiment.

The relative position between the drive coil 19 and the magnet 38 is detected by a sensor (not shown), and the two drive coils 19 at positions separated by 270 degrees or -90 degrees from the detection result.
And drives in the same direction by supplying a current proportional to a sine wave corresponding to the phase of each drive coil 19 (two-phase sine wave drive). In the figure, selected coils are indicated by symbols A and B. Although the coil has six phases, it is a two-phase motor in the sense that the coils whose electrical angles are orthogonal are sequentially switched.

FIG. 6 shows a control system of the linear motor of this embodiment.

As compared with the above-described embodiment, the control arithmetic unit 52 issues two current commands of the A phase and the B phase, and the two current commands are transmitted to the six current control systems 54 via the switch means 59. The difference is that they are connected to

The configuration of the current control system 54 having the drive coil 19 and the magnetic flux detection coil 20 is the same as that of the above-described embodiment. By making the shape of the flat surface of the magnetic flux detecting coil 20 substantially the same as the shape of the flat surface of the drive coil 19, the change of the magnetic flux linked to the magnetic flux detecting coil 20 can be changed. It is designed to be proportional to a change in magnetic flux linking the coil 19.
Therefore, if the current is returned to the adder 55 of the current control system 54 via an appropriate gain, the induced voltage caused by the relative movement between the linear motor stator 10 and the linear motor mover 30 can be almost cancelled, and as a result, the current control The residual becomes extremely small.

As shown in FIG. 7, the switching for achieving the sequence of FIG. 5 is performed by using the detection resistor 56, the adder 55, and the current error amplifier 57 in common, and thereafter providing the switch means 59. Only the drive coil 19 and the magnetic flux detection coil 20 may be switched.

In this embodiment, the same effects as in the above-described embodiment can be obtained.

<Embodiment 4> Next, a fourth embodiment of the present invention will be described. FIG. 8 is a schematic diagram of a stage device, FIG. 9 is an exploded view of a drive coil and a magnetic flux detection coil, and FIG. 10 is a diagram illustrating a drive sequence. Note that the same reference numerals as those in the third embodiment denote the same members, and a description of overlapping parts will be omitted.

In this embodiment, the linear motor stator 10
Is composed of seven coil units 23 per one side. The linear motor stator 10 includes an A-phase drive coil 24A.
And the B-phase drive coils 24B are alternately arranged along the traveling path. In other words, the two drive coils 24A and 24B of the A-phase and the B-phase are shifted in phase along the drive direction to form the coil unit 23, and the linear motor stator 10 includes seven sets of the coil units 23 along the drive direction. It is fixed side by side.

In the above-described embodiment, the drive coils are arranged in the drive direction so as not to overlap with each other. Therefore, the drive coils are arranged in the drive direction at a pitch 1.5 times the magnetic pole pitch. One in which two coils of A-phase and B-phase are overlapped so that their phases are shifted along the driving direction is 1
Since one coil unit is arranged along the driving direction, the magnetic poles of each coil are arranged at a pitch of 0.5 times. That is, adjacent A-phase drive coils 24A and B-phase drive coils 24B are arranged at a pitch 0.5 times the magnetic pole pitch, and A-phase drive coils or B-phase drive coils are arranged at a pitch equal to the magnetic pole pitch. . Here, since the distance between the centers of the sides contributing to the thrust of each drive coil is equal to the magnetic pole pitch, the adjacent A-phase drive coil and B-phase drive coil are separated by 0.5 magnetic pole pitch.
In order to arrange at a double pitch, the A-phase drive coil and the B-phase drive coil may be arranged to be shifted by half the magnetic pole pitch.

However, if the displacement is simply performed, the drive coils overlap in the vertical direction, so that an air gap corresponding to the thickness of the drive coil in the vertical direction is generated. As a result, the thrust decreases, and the overall vertical dimension also increases. Therefore, in the present embodiment, as shown in FIG. 9, a bent portion is formed in a portion of the B-phase drive coil facing the movable magnet, and the side facing the magnet is raised or recessed with respect to the side not facing the movable magnet 41. By doing so, the portion of the B-phase drive coil 24B facing the movable magnet 41 is made flush with the A-phase drive coil 24A. Thereby, the movable magnet 41
It is possible to keep the gap as viewed from below small, the thrust does not decrease, and the overall vertical dimension does not increase.

Also in this embodiment, each drive coil 24
A magnetic flux detecting coil 25 (A-phase magnetic flux detecting coil 25A) is provided on the upper surface of the (A-phase driving coil 24A and B-phase driving coil 24B).
-A B-phase magnetic flux detection coil 25B) is provided. Also in the present embodiment, similarly to the above-described embodiment, the magnetic flux detection coil 25 is designed so that the number of turns is increased by using a thin winding and the thickness of the magnetic flux detection coil is reduced as much as possible. These reasons are the same as in the first embodiment. In addition, the magnetic flux detection coil and the drive coil are designed to have substantially the same shape. This is because, regardless of where the linear motor mover is located, the magnetic flux passing through the magnetic flux detection coil and the drive coil is made substantially the same, so that the magnetic flux detection coil receives the same change in magnetic flux as the drive coil receives. .

The magnetic pole pitch is １ ／ of the fundamental wave of the magnetic flux density.
Since this corresponds to (0.5) cycle, the pitch of each coil corresponds to 1/4 (0.25) cycle of the fundamental wave of the magnetic flux density, which is 90 degrees in terms of electrical angle. As shown in the drive sequence of FIG. 10, while detecting the relative positions of the A-phase coil, the B-phase coil and the movable magnet by the position sensor, the coils at positions separated by 90 degrees are selected, and the current is sequentially applied in an appropriate direction. And drive in the same direction.

In this embodiment, the driving method is basically a two-phase sine wave drive. Therefore, the control system may have substantially the same configuration as that of the third embodiment. However, it goes without saying that the control system is designed in consideration of the difference in the number of coils and the sequence of coil selection.

According to the present embodiment, in addition to the functions and effects of the third embodiment, there is an excellent effect that the efficiency can be improved and the heat generation can be further reduced.

As can be seen from the above four embodiments,
The magnetic flux detection coil of the linear motor according to the present invention is configured to have a portion common in size or shape to the drive coil so as to receive substantially the same flux change as the drive coil. Also, the mounting position of the magnetic flux detecting coil is arranged so as to include the same position coordinates as the drive coil. The first and second embodiments are examples in which the magnetic flux detection coil and the drive coil include common dimensions, and the third and fourth embodiments are examples in which the magnetic flux detection coil and the drive coil include common shapes.

The linear motor of the present invention is not limited to a single-phase / two-phase driven linear motor, but can be applied to a polyphase linear motor. Further, the present invention can be similarly applied to those having an iron core and those having inductor teeth. Further, the configuration of the linear motor is not limited to the mover in which the magnet and the yoke are integrated, and the linear motor mover may be a magnet only or a coil only.

In addition, the present invention is not limited to a linear motor, but may be applied to a rotary motor.

[0056]

According to the motor of the first aspect of the present invention, the magnetic flux detecting coil can generate an induced voltage proportional to the induced voltage generated in the drive coil.

According to the motor of the second aspect, even if the magnet and the drive coil move relative to each other, almost no current error occurs, so that a highly accurate motor can be provided.

According to the third aspect of the present invention, since the magnetic flux linking the magnetic flux detection coil and the drive coil are substantially equal, the magnetic flux detection coil generates an induced voltage proportional to the induced voltage generated in the drive coil. Can be easily configured.

According to the motor of the fourth aspect, since the magnetic flux detecting coil and the driving coil have substantially the same size or shape, the magnetic flux detecting coil generates an induced voltage proportional to the induced voltage generated in the driving coil. It can be easily configured.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a stage device according to a first embodiment.

FIG. 2 is an explanatory diagram of a control system according to the first embodiment.

FIG. 3 is a schematic perspective view of a stage device according to a second embodiment.

FIG. 4 is a schematic perspective view of a stage device according to a third embodiment.

FIG. 5 is a drive sequence according to a third embodiment;

FIG. 6 is an explanatory diagram of a control system according to a third embodiment.

FIG. 7 is a modified example of the control system of the third embodiment.

FIG. 8 is a schematic perspective view of a stage device according to a fourth embodiment.

FIG. 9 is an exploded view of a coil used in the fourth embodiment.

FIG. 10 shows a drive sequence according to a fourth embodiment.

FIG. 11 is a schematic perspective view of a conventional stage device.

FIG. 12 is a control system of a conventional stage device.

[Explanation of symbols]

 Reference Signs List 1 stage 2 guide 3 workpiece 4 linear motor 10 linear motor stator 11 yoke 12 magnet 14 drive coil 15 magnetic flux detection coil 16 yoke 17 spacer 19 drive coil 20 magnetic flux detection coil 21 stator frame 23 coil unit 24 drive coil 25 magnetic flux detection Coil 30 Linear motor mover 31 Drive coil 32 Magnetic flux detection coil 33 Coil support 35 Magnet 36 Magnet holding frame 38 Magnet 39 Yoke 41 Magnet 42 Yoke 43 Side plate 50 Position command pattern generator 51 Interferometer 52 Control calculator 53 D / A conversion Device 54 current control system 55 adder 56 detection resistor 57 error amplifier 58 gain adjuster 59 switch means

Claims (10)

[Claims] 1. A motor having a magnet and a drive coil facing the magnet, wherein the magnet and the drive coil move relatively, a magnetic flux detection coil being provided integrally with the drive coil, A motor configured to generate the induced voltage proportional to the induced voltage generated in the drive coil when the drive coil and the drive coil relatively move. 2. The motor according to claim 1, wherein the induced voltage generated by the magnetic flux detection coil is fed forward to a current error adder of a current control system. 3. The motor according to claim 1, wherein the magnetic flux detection coil is configured to penetrate a magnetic flux substantially equal to a magnetic flux linked to the drive coil. 4. The motor according to claim 1, wherein the size or shape of the magnetic flux detection coil is substantially equal to the size or shape of the drive coil. 5. The motor according to claim 1, wherein the motor is a linear motor. 6. The motor according to claim 5, wherein the linear motor has the drive coil on a mover and the magnet on a stator. 7. The motor according to claim 5, wherein the linear motor has the magnet on a mover and the drive coil on a stator. 8. The motor according to claim 7, wherein the linear motor is a polyphase linear motor. 9. The motor according to claim 1, wherein the motor is a rotary motor. 10. A stage device comprising the motor according to claim 1. Description: