JP2008039543A - Planar positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a planar positioning device capable of acquiring the origin absolute position information of a rider without arranging absolute position measuring means such as a laser length measuring device outside.
In a planar positioning device for controlling positioning by sliding a slider having a thrust generating motor core multiplexed in the X-axis direction and the Y-axis direction in the X-axis direction or the Y-axis direction on the upper surface of the platen.
When returning to the origin of the slider, the core winding of the multiplexed motor core is used as a sensor of a resolver type position detecting means for detecting a relative position between a tooth formed on the platen and a tooth formed on the motor core. To do.
[Selection] Figure 1

Description

  The present invention relates to a planar positioning device that controls positioning by sliding a slider having a thrust generating motor core multiplexed in the X-axis direction and the Y-axis direction on the upper surface of a platen in the X-axis direction or the Y-axis direction. .

  Patent Document 1 discloses a structure of a planar positioning device (XY stage) having a flat platen and a slider whose position is controlled by sliding the upper surface in the X-axis direction and the Y-axis direction, and a slider position feedback control technique. It is disclosed in detail.

  FIG. 5 is a plan view illustrating a general configuration example of the planar positioning device. Multi-axis Y-axis laser interferometers Ly1, Ly2, Ly3, Ly4 and X-axis laser interferometers Lx1, Lx2 fixedly arranged along the edges in the adjacent X-axis direction and Y-axis direction of the flat platen 1 are switched. Thus, the position of the slider 2 is detected.

  An interferometer in which the position of the slider 2 on the platen 1 is fixedly arranged along the X-axis direction and the Y-axis direction of the platen, and a Y-axis bar mirror 21 mounted on the slider and reflecting the irradiation beam of this interferometer. And a plane positioning device that uses the X-axis bar mirror 22 for detection is disclosed in Patent Document 2.

  As optical sensors for moving the slider 2 to the initial position on the platen 1, Y-axis area sensors Ay1, Ay2 and X-axis area sensors Ax1, Ax2 are arranged.

  Further, the absolute position of the origin in the initial state when the slider S is returned to the origin is measured by the laser length measuring devices Fy1, Fx1, and Fx2 fixedly disposed along the adjacent X-axis direction and Y-axis direction edges of the platen 1. Is done.

  In a planar positioning device that uses a laser interferometer that can measure only the relative position as a position detector, although its accuracy is high, the absolute position is unknown at the time of initialization, so the absolute position information is acquired by the initialization operation. There is a need.

The initialization operation is executed by the following procedures (1) to (5).
(1) The slider 1 is moved in the -X and -Y directions in the figure.
(2) The movement is stopped by the detection signal of the area sensor in each movement direction.
(3) The laser length measuring device output confirms that it is within the measurable range of absolute position measurement by the laser length measuring device using the trigonometric method.
(4) If necessary, move to a region where the measurement error by the laser length measuring device is reduced.
(5) The origin absolute position information of the slider 2 is acquired by the laser length measuring device.

JP 2000-65970 A JP 2005-9952 A JP 2001-125658 A

The conventional initialization method for returning the slider to the origin has the following problems.
(1) It is necessary to arrange a laser length measuring device for measuring the absolute position of the origin of the slider in the X-axis direction and the Y-axis direction, which causes an increase in the cost of the apparatus.

(2) Since a space for arranging the laser length measuring device is required, the apparatus becomes large.

(3) When replacing the laser length measuring device, it is necessary to adjust the mounting position, which is a cause of deterioration in maintainability.

  The present invention has been made to solve the above-described problems, and is a planar positioning that can acquire the absolute position information of the slider without arranging an absolute position measuring means such as a laser length measuring device outside. The purpose is to realize the device.

In order to achieve such a subject, the present invention has the following configuration.
(1) In a planar positioning device that controls positioning by sliding a slider having a thrust generating motor core multiplexed in the X-axis direction and the Y-axis direction in the X-axis direction or the Y-axis direction on the upper surface of the platen.
When returning to the origin of the slider, the core winding of the multiplexed motor core is used as a sensor of a resolver type position detecting means for detecting a relative position between a tooth formed on the platen and a tooth formed on the motor core. A planar positioning device characterized by:

(2) The resolver type position detecting means detects the relative position based on a detected current value flowing through the core winding when a sinusoidal excitation voltage is applied to the core winding used as a sensor. The planar positioning device according to (1).

(3) The origin position of the slider is calculated by combining the resolver type position detecting means and an area sensor for detecting the origin coarse position on the platen of the slider (1) or (2) The flat surface positioning device according to (1).

(4) The planar positioning device according to any one of (1) to (3), further comprising position detection value correction means for executing linearity correction on the detection value of the resolver type position detection means.

As is apparent from the above description, the present invention has the following effects.
(1) Since the winding of the motor core is used as a sensor for measuring the absolute position of the origin of the slider, there is no need to place an absolute position measuring means such as a laser length measuring instrument outside, which reduces the cost of the device and saves space. Can contribute.

(2) Since the area sensor is used for collision prevention in a multi-slider system in addition to returning to the origin of the slider, it is not necessary to add a new configuration on the platen only for returning to the origin.

(3) Since the motor core winding is used as a sensor, it is not necessary to replace the sensor until the end of the motor life, thus realizing a long-life and maintenance-free system.

  The present invention will be described in detail below with reference to the drawings. FIG. 1 is a functional block diagram showing an embodiment of a planar positioning device having resolver type position detecting means to which the present invention is applied. FIG. 2 is a plan view of a planar positioning device to which the present invention is applied.

  As shown in FIG. 2, in the planar positioning device to which the present invention is applied, the X-axis and the Y-axis of the thrust generating motor core 3 mounted on the slider 2 are multiplexed (doubled in the figure). The duplicated motor core is disclosed in Patent Document 3 and has a general configuration.

  The difference between the planar positioning apparatus to which the present invention is applied and the conventional apparatus shown in FIG. 5 is that, in the planar positioning apparatus to which the present invention is applied, the X-axis laser length measuring devices Fx1, Fx2 and Y-axis of the conventional apparatus. The laser length measuring device Fy1 is unnecessary.

  In the illustrated motor coil 3, the X-axis motor core is duplexed into a set of X1-1 and X2-1 and a set of X1-2 and X2-2, and the core windings of each set are connected in series. Similarly, the Y-axis motor core is duplexed into a set of Y1-1 and Y2-1 and a set of Y1-2 and Y2-2, and the core windings of each set are connected in series.

  In FIG. 1, a core winding 31 represents a core winding of X-axis motor cores X1-1 and X2-1 and Y-axis motor cores Y1-1 and Y2-1. Similarly, the core winding 32 represents a core winding of the X-axis motor cores X1-2 and X2-2 and the Y-axis motor cores Y1-2 and Y2-2.

  The current amplifier 41 inputs the thrust generation command Vp1 and supplies the exciting current Im1 to the core winding 31. The current amplifier 42 receives the thrust generation command Vp2 and supplies the exciting current Im2 to the core winding 32 via the changeover switch 5 in the normal operation mode.

  The change-over switch 5 disconnects the core winding 32 from the current amplifier 42 and connects to the resolver type position detecting means 100 which is a feature of the present invention in the origin return operation mode. At the time of this switching connection, the core winding 32 is used as a sensor of the resolver type position detecting means 100.

  The resolver is well known as a classic displacement sensor, and it detects the change in the inductance of the coil, which changes due to the displacement of the magnetic substance in the magnetic field generated by the alternating current flowing through the coil, and detects the change in position. This is the principle of measurement.

  FIG. 3 is an image diagram when the core winding 32 is used as a sensor of the resolver type position detecting means 100.

  In FIG. 3A, the relative mechanical angle between the teeth formed on the platen 1 and the teeth formed on the motor core 3 is 0 °, and the inductance of the core winding 32 is maximized. In FIG. 3B, the relative mechanical angle between the teeth formed on the platen 1 and the teeth formed on the motor core 3 is 180 °, and the inductance of the core winding 32 is minimized.

  If this change in inductance is detected by a change in the current Is that flows when a sinusoidal voltage having a constant amplitude is applied to the core winding 32, within one pitch between the teeth formed on the platen 1 and the teeth formed on the motor core 3. It is possible to detect the relative positional displacement.

  In FIG. 1, the relative position information Ps of the resolver type position detecting means 100 and the coarse position information Pr by the area sensor 200 similar to the conventional apparatus are passed to the origin position calculating means 300 to calculate the origin absolute position information Pa.

  The area sensor 200 to which the present invention is applied has sufficiently small detection accuracy with respect to one pitch of the platen teeth. When an optical area sensor is used as in the embodiment, it can be realized by designing the light spot diameter to be small.

Next, the procedure up to the calculation of the origin absolute position information Pa during the initialization operation will be described.
(1) The position detected by the area sensor 200 is measured in advance, and the coarse position information Pr is measured.

(2) In the normal operation mode, the slider 2 is moved to a position crossing the beams of the X-axis area sensors Ax1 and Ax2 and the beams of the Y-axis area sensors Ay1 and Ay2.

(3) Switch the selector switch 5 to the home return operation mode. At this time, if necessary, switching is performed after the operation of the current amplifier 42 is stopped to avoid a rapid current change in the core winding.

(4) The resolver type position detecting means 100 detects the relative position information Ps within one pitch of the tooth, and passes it to the origin position calculating means 300 together with the coarse position information Pr detected by the area sensor 200.

(5) Since the resolver type position detection means has non-linearity in the inductance change with respect to the displacement of the detection target, the position detection value correction means 400 for correcting linearity is provided according to the position detection accuracy to be obtained.

  FIG. 4 is a functional block diagram showing another embodiment of a planar positioning device having resolver type position detecting means to which the present invention is applied.

  The feature of this embodiment is that the current amplifier of the position feedback control system and the current detector of the core winding in the normal operation mode are commonly used in a part of the configuration of the resolver type position detecting means, and the resolver type position detecting means The configuration is simplified.

  In this embodiment, the changeover switch 5 is provided on the input side of the current amplifier 4. When the changeover switch 5 is in the normal operation mode, the current Im of the core winding 3 is detected by the current detector 6 as a voltage value.

  The deviation between the voltage value Vf and the current command Vp is amplified by the error amplifier, and the output Vm is given to the input of the current amplifier 4 via the changeover switch 5 to constitute a position feedback control system.

  When the changeover switch 5 is in the origin return operation mode, a sinusoidal voltage Vs of several KHz with a constant amplitude is applied from the oscillator 500 to the input of the current amplifier 4. The current Is output from the current amplifier 4 to which the voltage is input to the core winding 3 is detected by the current detector 6 with the voltage value Vi, and is input to the resolver type position detector 100 to calculate the relative position information Ps. The

  The sine wave voltage Vs of the oscillator 500 is guided to the resolver type position detection means 100 and a ratio with the voltage value Vi from the current detector 6 is calculated, and the fluctuation of the relative position detection value Ps due to the fluctuation of the sine wave voltage Vs. It is corrected.

  The current amplifier 4 commonly used in both modes in this embodiment needs to pass a current Is proportional to a sinusoidal voltage Vs of several KHz through the core winding, and is not an inverter type current amplifier that is normally used. A class D amplifier that converts the output current into an analog by an analog amplifier or an LC filter is employed.

  In the embodiment described above, the case where the present invention is applied to the planar positioning device in which the motor core is duplicated has been described. However, the planar positioning device may have a motor core multiplexed more than duplexed.

It is a functional block diagram which shows one Embodiment of the plane positioning apparatus which has a resolver type position detection means to which this invention is applied. It is a top view of the plane positioning device to which the present invention is applied. It is an image figure at the time of using a core winding as a sensor of a resolver type position detection means. It is a functional block diagram which shows other embodiment of the plane positioning apparatus which has a resolver type position detection means to which this invention is applied. It is a top view which shows the general structural example of a plane positioning device.

Explanation of symbols

1 Platen 2 Slider 21 Y-axis Bar Mirror 22 X-axis Bar Mirror
Ly1, Ly2, Ly3, Ly4 Y-axis laser interferometer
Lx1, Lx2 X-axis laser interferometer
Ay1, Ay2 Y-axis area sensor
Ax1, Ax2 X-axis area sensor 3 Motor core 31, 32 Core winding 41, 42 Current amplifier 5 Changeover switch 100 Resolver type position detection means 200 Area sensor 300 Origin position calculation means 400 Position detection value correction means

Claims (4)

In a planar positioning device that controls positioning by sliding a slider having a thrust generating motor core multiplexed in the X-axis direction and the Y-axis direction in the X-axis direction or the Y-axis direction on the upper surface of the platen.
When returning to the origin of the slider, the core winding of the multiplexed motor core is used as a sensor of a resolver type position detecting means for detecting a relative position between a tooth formed on the platen and a tooth formed on the motor core. A planar positioning device characterized by:   The resolver type position detecting means detects the relative position based on a detected current value flowing in the core winding when a sinusoidal excitation voltage is applied to the core winding used as a sensor. 2. A planar positioning device according to 1.   3. The absolute position of the origin of the slider is calculated by combining the resolver type position detection unit and an area sensor that detects a rough origin position of the slider on the platen. Planar positioning device. 4. The planar positioning device according to claim 1, further comprising position detection value correction means for executing linearity correction on the detection value of the resolver type position detection means.

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