JPH06138947A - Attitude error controller for linear motion object - Google Patents

Abstract

PURPOSE:To ensure the high accuracy of motion over a stroke of a long distance, i.e., several tens of centimeters in regard of an attitude control table itself. CONSTITUTION:An arithmetic unit 13 calculates a 5-axis motion error by combining the 3-axis measurement results of the 3-axis measurement controllers 11 and 12 based on the measurement results of two 3-axis masurement units 8 and 9. Then the unit 13 applies the operational output to a 5-axis attitude control table 15 set on a slide table 3 for the 5-axis attitude control so that the 5-axis motion error is eliminated. Furthermore the 5-axis motion error caused by the motion of the table 3 is corrected so that the attitude of the table 15 is kept with high accuracy while the table 15 itself is moved in a long distance, i.e., several tens of centimeters. Furthermore the 5-axis error can also be precisely corrected in a submicron range for a long stroke except the traveling direction of a linear motion object.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a posture error control device for a linear moving body used for a sensor moving mechanism of a precision measuring machine, a micro-cutting stand of a precision machine tool, or the like.

[0002]

2. Description of the Related Art Conventionally, a posture control table for a linear moving body has been used as an aligner for silicon wafers or a work table for ultra-precision grinding, but each of them only served as a posture control table at a fixed position. .

[0003]

SUMMARY OF THE INVENTION In the above conventional configuration,
It was difficult to precisely maintain the posture while moving the posture control table itself over a long distance of several tens of cm. For example, in a work flow work line, precise realignment is required, and precise measurement and processing cannot be performed while moving over a long distance. Also, two displacements perpendicular to the traveling direction, excluding the traveling direction of the linear moving body,
The 5-axis motion error correction technology for pitching, rolling, and yawing inclination angles has been extremely difficult to measure in a submicron precision range over a long stroke.

The present invention solves the above-mentioned problems of the related art, and the attitude error control of a linear moving body which can improve the accuracy of the motion of the attitude control table itself over a long stroke of several tens of centimeters. The purpose is to provide a device.

[0005]

In order to solve the above-mentioned problems, a posture error control device for a linear moving body according to the present invention uses a scale provided on a base for measuring a linear scale provided on a slide table. 3 of the movement position of the slide table that moves linearly on the base by reading, the displacement and the inclination angle as the movement error of the slide table.
Two 3-axis measurement units capable of axis measurement are provided in parallel, and by performing calculation based on the measurement results of the two 3-axis measurement units, the movement position of the slide table and the vertical direction with respect to the traveling direction are set. 2 displacements, pitching,
A motion error measuring unit that measures a 5-axis motion error of the tilt angle of rolling and yawing, a 5-axis attitude control table that is mounted on the slide table and is capable of 5-axis attitude control, and the motion error measuring unit. And a control unit for correcting and controlling the 5-axis motion error associated with the movement of the slide table with respect to the 5-axis attitude control table, based on the 5-axis motion error measured in (4).

[0006]

With the above structure, the motion error measuring unit can be
The 5-axis motion error is calculated and measured based on the measurement result from the 3-axis measurement unit of the stand, and the motion error for all possible motion degrees of freedom of the linear motion body is measured. The posture is controlled so that there is no motion error with respect to the mounted 5-axis posture control table, so it is possible to maintain the posture precisely while moving the posture control table itself over a long distance of several tens of centimeters. Also, submicron precision error correction is possible over a long distance.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a schematic configuration diagram of a posture error control device for a linear moving body according to an embodiment of the present invention, and FIG.
FIG. 6 is a perspective view of a table portion in which the 6-axis measurement unit in FIG. In FIGS. 1 and 2, a slide table 3 is mounted on the upper surface of a linear guide portion 2 of a base 1 extending in the front-rear direction so as to be slidable in the front-rear direction. At one end of the base 1 in the width direction, a glass scale 4 having a coded scale on its upper surface is provided with a linear guide portion 2.
It is arranged in parallel with. In addition, an inclined surface inclined by a predetermined angle θ is provided at the other end of the base 1, and the side surface of the glass scale 5 is placed on the inclined surface and arranged in parallel with the linear guide portion 2 and the glass scale 4. ing. Further, a CCD camera 6 is attached to one side surface of the slide table 3 so that the upper surface of the glass scale 4 and the measuring section face each other. Further, the end surface portion connected to the lower portion of the other side surface of the slide table 3 is formed as an inclined surface inclined by a predetermined angle θ, and the CCD camera 7 is arranged on the inclined surface so that the upper surface of the glass scale 5 and the measuring unit face each other. It is installed. The glass scale 4 and the CCD camera 6 compose a first triaxial measurement unit 8, and the glass scale 5 and the CCD camera 7 compose a second triaxial measurement unit 9. A 6-axis measuring unit 10 is constituted by the first 3-axis measuring unit 8 and the second 3-axis measuring unit 9 described above.

Further, the three-axis measurement controller 11 connected to the CCD camera 6 calculates the measured value from the CCD camera 6 and calculates the coordinate position X of the slide table 3 as a linear moving body and the CCD camera 6 as a movement error. Then, the displacement amount Z ₁ between the glass scale 4 and the upper surface of the glass scale 4 and the inclination angle α ₁ are obtained. Similarly, the three-axis measurement controller 12 connected to the CCD camera 7 calculates the measurement value from the CCD camera 7 and calculates the coordinate position X of the slide table 3 as a linear moving body and the CCD camera 7 as a movement error. A displacement amount Z _{2 from} the upper surface of the glass scale 5 and an inclination angle α ₂ are obtained.

The arithmetic unit 13 to which these three-axis measuring controllers 11 and 12 are connected combines the calculated values from the three-axis measuring controllers 11 and 12 to calculate the coordinate position X of the slide table 3 as a linear moving body and the movement. As the error, a total of 6 axes including a vertical displacement amount Z, a horizontal displacement amount Y, a vertical plane Pitching angle along the front-rear direction, a vertical plane Rolling angle along the horizontal direction, and a horizontal Yawing angle. Find the displacement of. Further, the arithmetic unit 13 is connected to the actuator 17 of the posture control table 15 placed on the slide table 3 via the actuator driver 14, and the actuator 17 is connected via the actuator driver 14 according to the motion error of the 6-axis displacement. The posture control is performed so as to eliminate the motion error of the 5-axis displacement except the coordinate position X of the slide table 3 that occurs when the slide table 3 slides and moves on the linear guide portion 2 of the base 1.

FIG. 3 is a perspective view showing the assembly of the attitude control table 15 in FIG. 1 to the slide table 3. Figure 3
In the above, the posture control table 15 is supported by four supports 16 constituted by an elastic hinge mechanism, and five actuators 17 are provided between the supports 16 so that the posture can be controlled. Insert bolts 19 into the long holes 18 of the flanges provided on the left and right of this attitude control table 15,
The attitude control table 15 is fixed by screwing 19 into the bolt hole 20 on the slide table 3.

FIG. 4 is a perspective view of the attitude control table 15 in FIG. 1, and A and B are mirrors for viewing the back side of the attitude control table 15. In FIG. 4, among the five actuators 17, the actuators 17a, 17b and 17c vertically arranged on the side surface where the collar is provided are provided with vertical displacement amount Z and traveling direction as motion error correction. Pitching angle in the vertical plane along the front-back direction that is G, and
The actuators 16d and 16e arranged to drive the three axes of the Rolling angle in the vertical plane along the left-right direction are provided with the actuators 16d and 16e arranged in the horizontal direction. The displacement amount Y in the left-right direction and the Yawing in the horizontal plane. It controls the drive of the three axes of the corner.

FIG. 5A is a perspective view of the support 16 in the attitude control table 15 of FIG. 1, and FIG.
FIG. 6 is a perspective view of the support 16 showing a state of being displaced in the −Y direction, and c is a cross-sectional perspective view of the support 16 showing a state of being displaced in the Z direction from the state of the support 16 of a. In FIGS. 5A, 5B, and 5C, the four supports 16 of the attitude control table 15 are respectively
It is composed of an integral elastic hinge mechanism composed of a parallel spring structure and a radial spring structure. The parallel spring controls the displacement in the XY directions, and the radial spring controls the displacement in the Z direction.

With the above structure, the linear guide portion 2 of the base 1 is provided.
When the slide table 3 slides and moves on the upper side, the CCD cameras 6 and 7 fixed on both sides of the slide table 3 do not always move vertically while being kept perpendicular to the glass scales 4 and 5, respectively. , Fig. 6
For example, as shown in the error explanatory diagram of the triaxial element in the triaxial measuring unit 8, as shown in the diagram of FIG.
The camera 6 moves. Therefore, the slide table 3 as a linear moving body has a vertical displacement amount Z excluding its motion coordinate position X, a horizontal displacement amount Y, a pitching angle in a vertical plane along the front-rear direction, and a vertical direction along the left-right direction. Rolling angle in the plane and Ywi in the horizontal plane
A 5-axis ng angle motion error occurs.

These 5-axis motion errors are calculated by the 3-axis measurement controllers 10 and 11 and the arithmetic unit 12 based on the measured values from the 3-axis measurement units 8 and 9. That is, in the triaxial measurement unit 8, the glass scale 4
The coded scale engraved on the upper surface of the table is read by the CCD camera 6, the measured values from the CCD camera 6 are calculated by the 3-axis measurement controller 11, and the coordinate position X of the slide table 3 as a linear moving body and the movement error. As the displacement amount Z ₁ between the CCD camera 6 and the upper surface of the glass scale 4 and the inclination angle α
_{Get one} . Similarly, for the triaxial measurement unit 9 and the triaxial measurement controller 12, the coordinate position X of the slide table 3 as a linear moving body and the motion error CC
A displacement amount Z ₂ between the D camera 7 and the upper surface of the glass scale 5 and an inclination angle α ₂ are obtained. Based on these, in the calculating means 13, the coordinate position X of the slide table 3 as a linear moving body, the displacement amount Z in the vertical direction, the displacement amount Y in the left-right direction, the Pitching angle in the vertical plane along the front-back direction, and the left-right direction. Angle in the vertical plane along Y, and Y in the horizontal plane
Obtain the displacement of 6 axes of the awing angle.

Here, there are two kinds of three-axis measuring unit in which a bar code is engraved at right angles to the length direction of the linear scale, and three-axis measuring unit in which the bar code is engraved at a predetermined angle β as shown in FIG. By mounting as shown in FIG. 1, 6-axis measurement can be performed. The measurement specifications at this time are shown in the following (Table 1).

[0016]

[Table 1]Hereinafter, the 6-axis displacement calculation method in the calculation means 13 will be described.
To do. Make the bar code diagonal to the linear scale (βr
ad) The engraved 3-axis measuring unit 8 with SPACER1
Then, S the 3-axis measuring unit 9 with a bar code engraved at right angles
When PACER2 is set, the coordinate of each X axis is ξ₁, Ξ
₂, Z axis displacement is η₁, Η₂, Tilt angle α ₁, Α₂Tosu
It In addition, the space between SPACER1 and SPACER2
Let θ be the mounting angle of L and SPACER2.

At this time, the displacement of the stage in the X, Y, and Z directions can be expressed by the following equation (1).

[0018]

[Equation 1] In addition, the Roll angle, the Yaw angle, and the Pitch angle of the stage can be expressed by the following equation (2).

[0019]

[Equation 2] As described above, by using two three-axis measuring units with one side inclined by a predetermined angle θ, the displacements of the six axes can be accurately measured simultaneously.

Next, how the plane of the posture control table 15 is posture-controlled by the five actuators 17a to 17e will be described below. First, the driving of the vertical displacement amount Z as the motion error correction is performed by expanding and contracting the vertical actuators 17a, 17b, 17c in the same manner.
For driving in ng angle, vertical actuator 17
The difference between the expansion and contraction of a and 17b is used, and the driving of the Rolling angle in the vertical plane along the left-right direction is performed by the difference between the expansion and contraction of the actuators 17a and 17b and the actuator 17c in the vertical direction.

That is, the vertical actuator 17a,
The spatial coordinates of the tips of 17b and 17c are (X _a ,
_{Y a, Z a), (} X b, Y b, Z b), (X c, Y c,
Z _c ) and the direction cosine of the table top is (l, m, n)
If the center coordinates of the table top surface are (0, 0, z ₀ ), the equation of the table top surface is lx + my + nz = p 2, p = z ₀ / n, and the command to be given to each actuator 17a, 17b, 17c The values can be expressed in Z coordinate values as follows:

[0022]

[Equation 3]Here, since the x and y coordinates are fixed, the table
Center coordinate Z of displacement in the Z direction on the upper surface of the bull₀And Pitchi
l of the direction cosine indicating the ng angle and the Rolling angle,
When m and n are specified, the vertical actuators 17a and 17a
Displacement Z of b and 17c _a, Z_b, Z_cIs required.

Further, for driving the lateral displacement Y as a motion error correction, the lateral actuator 16 is used.
d is extended and the lateral actuator 16e is contracted, and the driving of the yawing angle in the horizontal plane is performed by simultaneously extending the lateral actuators 16d and 16e.

On the other hand, the signals from the two 3-axis measuring units are
Each (ξ₁, Η₁, Α₁), (Ξ ₂, Η₂, Α₂)When
To do. In addition, the quantity to be measured on the 6 axes is (x, y, z,
θ_x, Θ _y, Θ_z), There exists a matrix A,

[0025]

[Equation 4] become that way. However,

[0026]

[Equation 5] Is. Here, the obtained (x, y, z, θ _x , θ _y ,
θ _z ) is respectively subjected to PI calculation, and the signals are further used to calculate the signals to the five actuators 16a, 16b, 16c, 16d, 16e by the above-mentioned algorithm, and then the actuator 16a is transmitted via the actuator driver 14. , 16b, 16c, 16d, 16e are driven. In this way, the 5-axis motion error correction is performed.

Therefore, by mounting two CCD cameras, which are measuring units capable of measuring the three-axis components of the linear motion over a relatively long distance, on both sides of the slide table, it is possible to measure the position of the slide table in the traveling direction. A 5-axis motion error measurement system that simultaneously measures 5-axis motion errors is constructed, and a 5-axis attitude control table that operates according to a simple algorithm is mounted on a slide table. By combining with a 5-axis attitude control table, it is possible to correct and control the submicron 5-axis motion error that accompanies the motion of the slide table as a whole, improving the accuracy of linear motion over a long stroke of 50 cm. Can be planned. In this way, the posture can be maintained while moving the posture control table itself over a long distance of 50 cm, so that, for example, even in a work flow work line, precise realignment is not required. Not only can it be processed, but it can also be used for precise measurement and processing over long distances.

[0028]

As described above, according to the present invention, two 3
By measuring the position of the slide table in the traveling direction and the motion error of the 5-axis by combining and calculating the 3-axis measurement results by the axis measuring unit, the 5-axis attitude control table is mounted on the slide table, By combining this 5-axis attitude control table and 5-axis motion error measuring unit, the 5-axis attitude control table itself can perform sub-micron 5-axis error correction over a long distance of several tens of centimeters. Accurate linear movement can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a posture error control device for a linear moving body according to an embodiment of the present invention.

FIG. 2 is a perspective view of the 6-axis measurement unit 10 in FIG.

FIG. 3 is a perspective view showing the assembly of the attitude control table 15 in FIG. 1 to the slide table 3.

4 is a perspective view of an attitude control table 15 in FIG. 1, A
And B are mirrors for viewing the back side of the attitude control table 15.

5A is a support in the attitude control table 15 of FIG.
16 is a perspective view of the support body 16, b is a perspective view of the support body 16 which is displaced from the state of the support body 16 of a in the XY direction, and c is the support body of a.
16 is a transverse perspective view of the support 16 showing a state in which the support 16 is displaced from the state 16 in the Z direction.

FIG. 6 is an explanatory diagram of an error of a triaxial element in the triaxial measuring unit 8.

[Figure 7] 3 with a bar code slanted on a linear scale
Schematic perspective view of axis measuring unit

[Explanation of symbols] 1 base 3 slide table 4,5 glass scale 6,7 CCD camera 8,9 3-axis measuring unit 10 6-axis measuring unit 11,12 3-axis measuring controller 13 arithmetic unit 14 actuator driver 15 attitude control table 16 Support 17, 17a-17e Actuator

Claims (1)

[Claims] 1. A moving position of a slide table that linearly moves on the base by reading a scale of a linear scale provided on the base with a measuring device provided on the slide table, and displacement as a motion error of the slide table. And two three-axis measurement units capable of performing three-axis measurement of the tilt angle are provided in parallel, and the movement position of the slide table and the progress are calculated by performing calculation based on the measurement results of the two three-axis measurement units. 2 perpendicular to the direction
A motion error measuring unit for measuring a 5-axis motion error of displacement, pitching, rolling, and yawing inclination angles; a 5-axis attitude control table mounted on the slide table and configured to enable 5-axis attitude control; Based on the 5-axis motion error measured by the motion-error measuring unit, the 5-axis attitude control table is moved with the movement of the slide table.
A posture error control device for a linear moving body, comprising: a control unit for correcting and controlling an axial movement error.