JP2001125648A - 2D positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a two-dimensional positioning device which can be prevented from becoming uncontrollable owing to rotational deviation of a slider part. SOLUTION: The two-dimensional positioning device which positions an object in two dimensions converts the detection signals of a Y-axial sensor and two X-axial sensors into an X-axial position detection signal of the center of the slider part and a detection signal of the yawing angle θ of the slider part and provides feedback control independently as to the X-axial movement and θ-directional movement of the slider part according to the converted signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional positioning device used for a prober, a handler, a stepper, etc., for positioning a two-dimensional position of an object.

[0002]

2. Description of the Related Art As a two-dimensional positioning device, there is a device described in the specification of Japanese Patent Application No. 10-238149 filed by the present applicant. FIG. 7 is a schematic diagram of this device. FIG.
The lattice platen 10 is made of a magnetic material, and X
Teeth are formed at a constant pitch along the axial direction and the Y-axis direction. In the figure, only some teeth are shown for simplification. An object to be positioned is placed on the slider portion 11. The levitation means 12 connects the slider portion 11 to the grid platen 1.
Float above zero. Grid platen 10 of slider section 11
A nozzle is provided on the surface opposite to the nozzle, and the levitation means 12 ejects compressed air from the nozzle to obtain a levitation force.

The Y-axis motor 13 is mounted on the slider section 11 and has teeth 132 formed at a constant pitch in the Y-axis direction. The Y-axis motor 13 generates a magnetic attraction between the teeth 132 and the teeth 101 of the grid platen 10 to move the slider in the Y-axis direction. The X-axis motors 14 and 15 are respectively mounted at symmetrical positions with respect to the center of the slider section 11. The X-axis motors 14 and 15 have teeth 141 and 151 formed at a constant pitch in the X-axis direction. The X-axis motors 14 and 15 generate magnetic attraction between the teeth 141 and 151 and the teeth 101 to move the slider portion in the X-axis direction.

The connecting members 111 and 112 are connected to the Y-axis motor 13.
And the X-axis motors 14 and 15 are connected. X-axis mirror 16
Is mounted on the side surface of the lattice platen 10, and has a mirror surface in the Y-axis direction. The Y-axis mirror 17 is mounted on a side surface of the lattice platen 10, and has a mirror surface in the X-axis direction.

The Y-axis sensor 18 is mounted on the Y-axis motor 13, irradiates the Y-axis mirror 17 with light, receives the reflected light, and utilizes the light interference to adjust the Y-axis direction of the slider 11 in the Y-axis direction. This is a laser interferometer for detecting a position. X-axis sensor 19
And 20 are mounted on the X-axis motors 14 and 15, respectively, irradiate the X-axis mirror 16 with light, receive the reflected light, and use the interference of light to adjust the position of the slider portion 11 in the Y-axis direction. It is a laser interferometer to detect.

The Y-axis control section 21 performs feedback control of the position of the slider section 11 based on the deviation between the Y-axis command position and the detection position of the Y-axis sensor 18. X axis control units 22 and 23
Performs feedback control on the position of the slider unit 11 based on the deviation between the X-axis command position and the detection positions of the X-axis sensors 19 and 20.

[0007] The slider portion 10 may cause rotational displacement about an axis orthogonal to the X axis and the Y axis. This is called yawing. The angle of the rotational deviation is defined as θ.

In the conventional apparatus shown in FIG. 7, the X-axis controllers 22 and 2
By giving the same position command value to X, the position in the X-axis direction and the θ direction are controlled. It is assumed that θ = 0 when the yaw of the slider is removed. Y-axis sensor 18
In order for the light irradiated from the X-axis sensors 19 and 20 to the mirror to return to the sensor correctly, θ ≒ 0 must be maintained. When θ greatly swings, the irradiation light from the Y-axis sensor 18 and the X-axis sensors 19 and 20 does not return to the sensors, and the position of the slider becomes unknown. As a result, feedback control of the position and speed of the slider unit becomes impossible. In the conventional device shown in FIG. 7, since the position sensor is an optical sensor using a laser interferometer, control becomes impossible even with a slight rotational displacement of the slider portion.

In the conventional apparatus shown in FIG. 7, θ is set to 0 for the following reason.
It was difficult to approach. (Reason 1) The control characteristics in the θ direction and the X axis direction cannot be set independently. In order to control θ ≒ 0, the servo rigidity of θ may be increased. However, in the conventional apparatus shown in FIG. 7, if the control method and control band of the X-axis controllers 22 and 23 are determined, the servo rigidity in the θ direction is uniquely determined.

(Reason 2) At the time of maximum acceleration in the X-axis direction, θ
Control in the direction becomes impossible. The output torque T of the slider unit in FIG. T = Fx2 · Lx2-Fx1 · Lx1 Fx1: Thrust of X-axis motor 14, Fx2: X-axis motor 1
Lx1: Distance in the Y-axis direction from the center of gravity of the slider section to the center of the X-axis motor 14 Lx2: Distance in the Y-axis direction from the center of the X-axis motor 15 to the center of gravity of the slider section

The load on the slider section is large, and X
When the acceleration / deceleration command value in the axial direction is large, the X-axis motor 14
15 and thrusts Fx1 and Fx2 may reach the maximum value. Fx1max is the maximum value of Fx1 and Fx2, respectively.
And Fx2max. At this time, the output torque T of the slider section is as follows. T = Fx2max · Lx2−Fx1max · Lx1 At this time, Fx1max · Lx1 ≠ due to manufacturing variations.
When Fx2max · Lx2, θ increases. Fx1
Even if max · Lx1 = Fx2max · Lx2, if the disturbance torque Td is applied, θ increases and servo control becomes impossible.

As described above, in the conventional apparatus shown in FIG. 7, the thrust is used only for the control in the X-axis direction, and the thrust for controlling in the θ direction is not considered. Therefore, 2
Imbalance occurs in the maximum thrust of two X-axis motors,
When disturbance torque is applied, θ increases, and servo control may fail.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the control of the slider portion can be performed by performing control in the X-axis direction and control in the θ direction independently. It is an object of the present invention to realize a two-dimensional positioning device capable of preventing the control from being lost due to a deviation.

[0014]

SUMMARY OF THE INVENTION The present invention is a two-dimensional positioning device having the following configuration.

(1) In a two-dimensional positioning device for positioning an object in a two-dimensional direction, a lattice platen having teeth formed at a constant pitch along the X-axis direction and the Y-axis direction, and the object are mounted. A slider portion, a floating means for floating the slider portion on the lattice platen, a Y-axis motor mounted on the slider portion and moving the slider portion in the Y-axis direction, and a position symmetrical with respect to the center of the slider portion. And a first and a second X-axis motor for moving the slider portion in the X-axis direction, respectively, and a Y-axis motor for the slider portion.
A Y-axis sensor for detecting an axial position, the first and second sensors
The first and second X-axis sensors respectively mounted on the X-axis motor and detecting the position of the slider portion in the X-axis direction, and the position detection signals of the first and second X-axis sensors are received. A conversion circuit that generates a position detection signal in the X-axis direction of the center of the slider based on the sum of the signals, and generates a detection signal of the yawing angle θ of the slider based on the difference, and a signal converted by the conversion circuit. X.theta. Control unit that independently performs feedback control on the X axis direction movement and .theta. Direction movement of the slider unit based on the X axis direction thrust command value and the .theta. Direction thrust command value which are control outputs of the X.theta. The first
And a command value conversion circuit that converts a thrust command value to be given to the second X-axis motor, a Y control unit that receives a position detection signal of the Y-axis sensor, and performs feedback control in the Y-axis direction based on the signal. 2 characterized by having
Dimensional positioning device.

(2) The command value conversion circuit receives a thrust command value in the X-axis direction and a thrust command value in the θ direction output from the Xθ control unit, and calculates the first and second thrust command values based on the sum and difference of these thrust command values. (2) The two-dimensional positioning apparatus according to (1), wherein a thrust command value for the X-axis motor is generated.

(3) The limit value of the thrust command value Ir0 in the X-axis direction is limited to Imax- | Irθ | (Imax is the maximum thrust command value, Irθ is the thrust command value in the θ direction), and the thrust command value in the θ direction is limited. Thrust command value Ir0 according to the magnitude of Irθ
2. The two-dimensional positioning apparatus according to (1), further comprising a limiter for limiting the limit value of (1).

(4) The first and second X-axis motors
A core having teeth formed at a constant pitch along the X-axis direction at a position facing the teeth of the lattice platen, wherein the core of the first X-axis motor and the core of the second X-axis motor are slider units. The two-dimensional positioning device according to (1), wherein the two-dimensional positioning device is arranged point-symmetrically with respect to the center of the image.

(5) The Y-axis sensor and the first and second Xs
The axis sensor is a sensor that optically detects the position of the slider using a laser interferometer. These sensors have a corner cube, and the corner cube of the Y-axis sensor is the center position of the slider in the Y-axis direction. And the corner cubes of the first and second X-axis sensors are X
The two-dimensional positioning device according to (1), wherein the two-dimensional positioning device is arranged at a position symmetrical with respect to the axial center axis.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In FIG. 1, the same components as those described above are denoted by the same reference numerals.
FIG. 1 is a configuration diagram of a servo control system. The lattice platen, slider section, levitation means, X-axis motor, Y-axis motor, X-axis sensor, Y-axis sensor, X-axis mirror, and Y-axis mirror have the same configuration as the conventional apparatus of FIG.

In FIG. 1, the X-axis sensor 19 determines the moving direction of the slider portion, and generates an up pulse or a down pulse according to the determined direction. The number of generated pulses is a number corresponding to the amount of movement of the slider unit. The up / down counter 30 counts up or down according to an up pulse or a down pulse. The count of the up / down counter 30 becomes the detection position of the slider.
The specific configuration of the X-axis sensor 19 will be described later.

The correction means 31 holds a correction table 32 in which the position of the slider depending on the bending of the mirror and the correction amount for removing yaw of the slider are associated. The correction means 31 reads the correction amount from the correction table 32 based on the given command position, and corrects the detection position of the up / down counter 30 with the read correction amount. The data in the correction table 32 is data obtained by calibration. The correcting means 31 is provided to correct the bending of the X-axis mirror 16 and the Y-axis mirror 17 due to a mechanical error in FIG. X-axis mirror 16 and Y
If the bend of the axis mirror 17 does not affect the position detection, the correction unit 31 may not be provided.

The X-axis sensor 20 is also
Similarly to the above, an up-down counter 33, a correction means 34, and a correction table 35 are provided. The conversion circuit 36 receives the signals of the detection positions X1 and X2 in the X-axis direction obtained from the correction means 31 and 34, and converts these signals into a signal x of the center of the slider portion in the X-axis direction and a signal of the yawing angle θ of the slider portion. Convert to The conversion formula is as follows. x = (X1 + X2) / 2, θ = (x2-x1) / 2Ld Ld: distance from the center of the slider to the optical axis of the X-axis sensors 19 and 20 (Ld is shown in FIG. 7)

The X-axis position control unit 37 has an X-axis position command value X
A control signal for feedback-controlling the position of the slider portion in the X-axis direction is output based on the deviation between i and the detection position x. The X-axis speed calculation circuit 38 detects the moving speed of the slider portion in the X-axis direction from the change speed of the detection position x. The X-axis conversion circuit 38 is, for example, an F / V converter. The X-axis speed controller 39 calculates the X-axis of the slider based on the deviation between the control signal of the X-axis position controller 37 and the speed detected by the X-axis speed calculator 38.
A control signal for feedback-controlling the moving speed in the axial direction is output. This control signal becomes a thrust command value Ir0 for moving the slider in the X-axis direction.

Similarly, for the control of θ, the θ position controller 4
A 0, θ speed calculation circuit 41 and a θ speed control unit 42 are provided. The control signal of the θ speed control unit 42 sets the slider unit to θ
The thrust command value Irθ to rotate in the direction is obtained. Limiter 4
3 is the limit value of the thrust command value Ir0 in the X-axis direction
ax− | Irθ | (Imax is the maximum thrust command value), and outputs the thrust command value Irx after the restriction. Thus, the limit value of the thrust command value Ir0 in the X-axis direction is limited according to the magnitude of the thrust command value Irθ in the θ direction.

The command value conversion circuit 44 calculates the thrust command value Irx in the X-axis direction and the thrust command value Irθ in the θ direction by the following equation.
They are converted into thrust command values Ir1 and Ir2 for the shaft motors 14 and 15. Ir1 = Irx−Irθ, Ir2 = Irx + Irθ The thrust command values Ir1 and Ir2 fall within the range of −Imax to Imax due to the action of the limiter 43.

The current sensor 45 detects a current flowing through the coil of the X-axis motor 14. Commutation / current control circuit 46
Controls the commutation of the X-axis motor 14 and the current flowing through the coil. The commutation angle calculation circuit 47 stores s in which the count of the up / down counter 30 and the sin value are stored correspondingly.
I have an in table. When the X-axis motor 14 is a three-phase motor, when the count of the up / down counter 30 is given, the commutation angle calculation circuit 47 reads out the values of sinφ and sin (φ + 120 °) from the sin table. φ is an angle that changes according to the count of the up / down counter 30.

The multiplying digital-to-analog converters (MDA) 48, 49 provide a thrust command value Ir1
Is an analog input signal, s read from the sin table
Ir1 sinφ and Ir1 sin (φ + 120 °) using the values of inφ and sin (φ + 120 °) as gain setting signals
Output a current command value. Here, the phase of the two command values is shifted by 120 ° because the motor is a three-phase motor. When the number of phases is different, the phase shift takes another value.

The X-axis current control circuit 50 outputs a current command value Ir
The current flowing through the coil of the X-axis motor 14 is controlled based on the deviation between 1 sinφ, Ir1 sin (φ + 120 °) and the current detection value of the current sensor 45.

The X-axis motor 15 is also provided with a current sensor 51 and a commutation / current control circuit 52. Y
As for the servo control system in the axial direction, similarly to the servo control systems in the X-axis direction and the θ direction, the up-down counter 53,
Correction unit 54, correction table 55, Y-axis position control unit 5
6, a Y-axis speed calculation circuit 57, a Y-axis speed control unit 58, and a commutation / current control circuit 59 are provided. In the Y-axis direction servo control system, the control is performed without converting the control amount as performed by the conversion circuit 36.

FIG. 2 is a simplified diagram of the control system of FIG. In FIG. 2, the conversion circuit 36 includes the X-axis sensors 19, 2
0 and the detection values X1, X2, and Y of the Y-axis sensor 18 are converted into a position x in the X-axis direction at the center of the slider portion, a yawing angle θ of the slider portion, and a position Y in the Y-axis direction. The X-axis position / speed control unit 60 feedback-controls the position and speed of the slider unit in the X-axis direction using the signal of the position x as a feedback signal. The control signal of the X-axis position / speed controller 60 is output as a thrust command value Irx in the X-axis direction. The θ position / speed control unit 61 performs feedback control of the position and speed of the slider unit in the θ direction using the signal of the yawing angle θ as a feedback signal.
The control signal of the θ position / speed control unit 61 is output as a thrust command value Irθ in the θ direction.

Here, the thrust command values Irx, Irθ are
By converting into x-Irθ and Irx + Irθ, X
This is converted into a thrust command value for the shaft motors 14 and 15. In this way, the control in the X-axis direction and the control in the θ direction are performed independently. The Y-axis position / speed controller 62 feedback-controls the position and speed of the slider unit in the Y-axis direction using the signal of the position Y as a feedback signal. The control signal of the Y-axis position / speed controller 62 is output as a thrust command value Iry in the Y-axis direction.

FIG. 3 is a diagram showing an example of the arrangement of cores in the X-axis motor and the Y-axis motor. As shown in FIG. 3, teeth 72 and 73 are formed on the cores 70 and 71 of the X-axis motors 14 and 15 at a constant pitch along the X-axis direction.
The cores 70 and 71 are arranged point-symmetrically with respect to the center O of the slider portion 11. Cores 74 and 7 of Y-axis motor 13
5 has teeth 76 and 77 at a constant pitch along the Y-axis direction.
Are formed. These teeth are arranged at positions facing the teeth of the lattice platen 10.

When the cores 70 and 71 generate a thrust Fx,
The slider section 11 moves in the f direction. Core 70 is thrust-
When Fx is generated and the core 71 generates a thrust Fx, the slider 11 rotates in the θ1 direction. When the cores 73 and 74 generate a thrust Fy, the slider portion 11 moves in the g direction.

FIG. 4 is a diagram showing a configuration example of the cores in the X-axis motor and the Y-axis motor. In FIG. 4, motor cores 81 and 82 are arranged with a permanent magnet 83 interposed therebetween. The permanent magnets 83 are magnetized along the direction in which the motor cores are arranged. The motor core 81 has salient poles 84A, 84B, 84C.
A-phase coil 85A and B-phase coil 85 according to the arrangement order of
A B and C phase coil 85C is wound. These coils are wound over salient poles of two motor cores 81 and 82. Teeth are formed at the tip of each salient pole at a pitch P. The teeth of the salient poles 84A, 84B, 84C are P /
The phases are shifted by three. Sine-wave currents whose phases are shifted by 120 ° flow through the A-phase coil 84A, the B-phase coil 84B, and the C-phase coil 84C.

The motor core 82 has the same configuration as the motor core 81. The motor core 82 is arranged with the phase of the teeth of the salient pole shifted from the motor core 81 by P / 2. By supplying a three-phase sine wave current to the A-phase coil 84A, the B-phase coil 84B, and the C-phase coil 84C, the motor cores 81 and 82 move in the aa 'direction. The core shown in FIG. 4 corresponds to one core in FIG.

FIG. 5 is a diagram showing a configuration example of the sensor of FIG. The Y-axis sensor 18 and the X-axis sensors 19 and 20 in FIG. 1 have the same configuration. The X-axis sensor 19 will be described as an example. In FIG. 5, a laser light source 191 emits a laser beam.
In the optical path of the light emitted from the laser light source 191, mirrors 192 and 192 are provided.
193, a half mirror 194, a deflecting beam splitter (referred to as PBS) 195, a λ / 4 plate 196, and a corner cube 197 are arranged.

Light emitted from the laser light source 191 includes light that travels along the path of the half mirror 194, the mirror 193, the mirror 192, and the half mirror 194, and travels in the direction b in FIG.
This light is referred to as light. Further, the light emitted from the laser light source 191 includes a half mirror 194, a PBS 195, a λ / 4
Plate 196, X-axis mirror 16, λ / 4 plate 196, PBS1
95, a corner cube 197, a λ / 4 plate 196, an X-axis mirror 16, a λ / 4 plate 196, a PBS 195, and a half mirror 194, and there is light traveling in the direction b in the drawing.
This light is referred to as light.

The mirror 193 is arranged at an angle of 45 ° with the optical axis of the laser light source 191. On the contrary,
The mirror 194 is at 45 ° + θa with respect to the optical axis of the laser light source 191.
Are arranged at an angle. Since the arrangement angle of the mirror 194 is shifted by θa, the wavefront of the light is shifted from the wavefront of the light by θa. by this,
The light and the light interfere with each other to form an interference fringe S. A photodiode array (referred to as a PDA) 198 detects the interference fringes S. The PDA 198 has four photodiodes 198A-
198D. Four photodiodes 198A-
198D is arranged within one pitch of the interference fringes S. The photodiodes 198A to 198D are arranged so as to be shifted by p / 4 (p is the pitch of interference fringes). The pitch of interference fringes is p = λ / θa (λ is the wavelength of the laser beam).

The subtractor 199 has the (photodiode 19
An operation of (detection signal of 8A)-(detection signal of photodiode 198C) is performed. The subtractor 200 calculates (detection signal of the photodiode 198B)-(photodiode 19
8D detection signal).

When the slider moves, X
The axis sensor 19 moves, and the interference fringes move in the direction dd ′ in FIG. When the interference fringes move, each photodiode 198A-1
The light and dark portions of the interference fringe corresponding to 98D move, and the detection values of the photodiodes 198A to 198D change. Based on this, the position of the slider section 11 is detected.

[0042] When the interference fringe is moved in the direction d, the output V _A ~V _D of the photodiode is as follows. V _A = K [1 + msin {xe · 2π / (λ / 4)}] + K _n V _B = K [1 + m cos ｛xe · 2π / (λ / 4)}] + K _n V _C = K [1-msinｓxe 2π / (λ / 4)｝] + K _n V _D = K [1-mcos ｛xeｅ2π / (λ / 4)｝] + K _n xe: distance to be detected, K, m: coefficient, K _n : Noise component

The subtraction signals of the subtracters 199 and 200 are as follows. _{V A -V C = 2mKsin {xe} · 2π / (λ / 4)} V B -V D = 2mKcos {xe · 2π / (λ / 4)} the result of the subtraction, the DC noise component K generated by ambient light
_n is canceled. Signal V _A -V _C and V _B -V _D is converted into the A-phase pulse and the B-phase pulse described above. Interference fringe is d
'When moved in the direction, the phase relationship between the signal V _A -V _C and V _B -V _D is reversed.

The comparators 201 and 202 are connected to the subtractor 19
An A-phase pulse and a B-phase pulse are generated from the subtraction signals of 9 and 200. The direction determination circuit 203 determines the moving direction of the slider unit from the phase relationship between the A-phase pulse and the B-phase pulse, and generates an up pulse or a down pulse according to the determination result.

The up / down counter 30 counts up or down according to an up pulse or a down pulse. The count of the up / down counter 30 becomes the detection position of the slider. In the initial state, it is known in advance how much the phases of the teeth of the rotor and the stator of the motor are shifted when a known current is applied to each phase coil of the X-axis motor 14. At this time, the value of the up / down counter 30 is set to a reference value, for example, 0. As the slider moves, the up / down counter 30 counts up or down from the reference value to detect the position. In this way, the position is detected in an incremental manner.

FIG. 6 is a diagram showing another example of the structure of the sensor shown in FIG. In FIG. 6, the laser light source 90 is a Y-axis sensor 18,
The light source is common to the X-axis sensors 19 and 20. Y-axis interference unit 91 and X-axis interference units 92 and 93 are Y
These units constitute the axis sensor 18 and the X-axis sensors 19 and 20. The Y-axis interference unit 91 and the X-axis interference units 92 and 93 irradiate laser light in the Y-axis direction and the X-axis direction, and receive light reflected by the Y-axis mirror 17 and the X-axis mirror 16 to optically position. To detect.

The Y-axis sensor 18 and the X-axis sensors 19 and 20 have corner cubes 94, 95 and 96, respectively.
The corner cube 94 of the Y-axis sensor 18 has the slider 1
1 at the center position in the Y-axis direction. The corner cubes 95 and 96 of the X-axis sensors 19 and 20 are arranged at symmetrical positions with respect to the center axis of the slider portion 11 in the X-axis direction. By arranging the corner cubes in this manner, when thermal expansion occurs in the slider portion, the positional shift amounts of the corner cubes become substantially equal. As a result, the influence of the thermal expansion on the sensor can be reduced.

[0048]

According to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, the Y-axis sensor and the
The detection signals of the two X-axis sensors are converted into a position detection signal in the X-axis direction at the center of the slider portion and a detection signal of the yawing angle θ of the slider portion.
Feedback control is performed independently on the axial movement and the θ movement. For this reason, the control method and servo gain of the θ-direction control can be set independently of those in the X-axis direction. This improves the servo rigidity in the θ direction,
It is possible to prevent the control unit from becoming uncontrollable due to the rotational displacement of the slider unit. Further, the positioning accuracy in the yawing direction can be remarkably improved.

According to the second aspect of the present invention, a thrust command value in the X-axis direction and a thrust command value in the θ direction are received, and the thrust of the first and second X-axis motors is determined by the sum and difference of these thrust command values. Command value is being generated. Thus, the thrust command value can be given to the two X-axis motors while satisfying the condition that the control of the X-axis direction movement and the control of the θ-direction movement do not interfere with each other.

According to the third aspect of the present invention, the limit value of the thrust command value Ir0 in the X-axis direction is set to Imax- | Irθ | (I
(max is the maximum thrust command value), the limit value of the thrust command value Ir0 in the X-axis direction is limited according to the magnitude of the thrust command value Irθ in the θ direction. As a result, the control in the θ direction can be performed prior to the control in the X axis direction, and the control in the θ direction is not affected by the control in the X axis direction even under heavy load or high acceleration / deceleration. Characteristics can be maintained.

According to the fourth aspect of the present invention, since the teeth of the two X-axis motors are arranged point-symmetrically with respect to the center of the slider portion, the two X-axis motors are generated when the slider portion is thermally expanded. Are substantially equal. As a result, the influence of the temperature change on the motor can be reduced.

According to the fifth aspect of the present invention, the corner cube of the Y-axis sensor is disposed at the center position of the slider in the Y-axis direction, and the corner cubes of the first and second X-axis sensors are located at the X-axis of the slider. It is arranged at a position symmetrical with respect to the central axis of the direction. Therefore, when thermal expansion occurs in the slider portion, the positional shift amounts of the corner cubes become substantially equal. As a result, the influence of the thermal expansion on the sensor can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a control system of FIG. 1;

FIG. 3 is a configuration diagram of a main part of the present invention.

FIG. 4 is a configuration diagram of a main part of the present invention.

FIG. 5 is a configuration diagram of a main part of the present invention.

FIG. 6 is a configuration diagram of a main part of the present invention.

FIG. 7 is a diagram showing a configuration example of a conventional two-dimensional positioning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lattice platen 11 Slider part 12 Levitation means 13 Y axis motor 14, 15 X axis motor 18 Y axis sensor 19, 20 X axis sensor 36 Conversion circuit 37 X axis position control part 39 X axis speed control part 40 θ position control part 42 θ speed control unit 43 limiter 44 command value conversion circuit 56 Y-axis position control unit 58 Y-axis speed control unit 94 to 96 Corner cube

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Fumio Kaiho 2-9-32 Nakamachi, Musashino-shi, Tokyo F-term in Yokogawa Electric Corporation (reference) 2F078 CA08 CA10 CB05 CB09 CB12 5H303 AA04 BB02 BB08 BB17 CC10 DD04 DD12 EE03 EE07 FF06 GG13 HH01 HH07 JJ02 KK02 KK08 KK18 QQ06

Claims (5)

[Claims] 1. A two-dimensional positioning device for positioning an object in a two-dimensional direction, a lattice platen having teeth formed at a constant pitch along the X-axis direction and the Y-axis direction, and a slider on which the object is mounted A floating unit for floating the slider on the lattice platen; a Y-axis motor mounted on the slider and moving the slider in the Y-axis direction; and a symmetrical position with respect to the center of the slider. First and second X-axis motors respectively mounted and for moving the slider portion in the X-axis direction, Y-axis sensors for detecting the Y-axis direction position of the slider portion, and the first and second X-axis motors And a first and a second X-axis sensor for detecting a position of the slider portion in the X-axis direction, respectively, and receiving position detection signals of the first and the second X-axis sensors,
A conversion circuit that generates a position detection signal in the X-axis direction of the center of the slider based on the sum of these signals, and generates a detection signal of the yawing angle θ of the slider based on the difference. An Xθ control unit that independently performs feedback control on the X-axis movement and the θ-direction movement of the slider unit based on the obtained signal, a thrust command value in the X-axis direction and a thrust in the θ direction that are control outputs of the Xθ control unit. A command value conversion circuit for converting a command value into a thrust command value to be applied to the first and second X-axis motors; receiving a position detection signal of the Y-axis sensor; and performing feedback control in the Y-axis direction based on the signal. A two-dimensional positioning device, comprising: 2. The command value conversion circuit receives a thrust command value in the X-axis direction and a thrust command value in the θ direction output from the Xθ control unit, and calculates first and second thrust command values based on the sum and difference of these thrust command values.
2. The two-dimensional positioning apparatus according to claim 1, wherein a thrust command value for said X-axis motor is generated. 3. The limit value of the thrust command value Ir0 in the X-axis direction is limited to Imax− | Irθ | (Imax is the maximum thrust command value, Irθ is the thrust command value in the θ direction), and the thrust command value Irθ in the θ direction 2. The two-dimensional positioning apparatus according to claim 1, further comprising a limiter for limiting a limit value of the thrust command value Ir0 according to the magnitude of the thrust command value Ir0. 4. The first and second X-axis motors each have a core having teeth formed at a constant pitch along the X-axis direction at a position opposed to the teeth of the lattice platen. The two-dimensional positioning apparatus according to claim 1, wherein the core of the X-axis motor and the core of the second X-axis motor are arranged point-symmetrically with respect to the center of the slider portion. 5. The Y-axis sensor and the first and second X-axis sensors are sensors that optically detect the position of a slider unit using a laser interferometer, and these sensors have a corner cube. , The corner cube of the Y-axis sensor is disposed at the center position of the slider portion in the Y-axis direction,
2. The two-dimensional positioning apparatus according to claim 1, wherein the corner cube of the X-axis sensor is disposed symmetrically with respect to the center axis of the slider in the X-axis direction.