JPH06137852A - Measuring device for motion error of linear moving body - Google Patents

Abstract

(57) [Summary] [Purpose] Perform 6-axis motion error measurement of a slide table at high speed and with high accuracy without attaching any other measuring device. [Structure] One of the three 3-axis measurement units 13 and 14
The linear scale 2 of the axis measuring unit 13 is attached so that the scale surfaces of the linear scale 2 are in the same direction with respect to the slide surfaces 4 and 6 on the base 1, and the linear scale 9 of the other three-axis measuring unit 14 is Since the scale surface of the linear scale 9 is attached to the slide surfaces 4 and 6 on the base 1 so as to be inclined at a predetermined angle, the slides can be obtained by combining the measurement results of the two three-axis measurement units 13 and 14 to calculate. It is possible to measure the displacement of 6 axes of the table 10 accurately and at high speed at the same time without separately installing another measuring device as in the conventional case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion error measuring device for a linear motion body used in a linear motion mechanism section for highly accurate measurement in machine tools and measuring machines.

[0002]

2. Description of the Related Art Conventionally, a motion error measuring device for a linear motion body used in a linear motion mechanism part of a machine tool or a measuring machine has two components of error components of 5 components excluding positioning error in the feed direction, that is, two angles of pitching and rolling. Is measured using a digital electronic level, and the three-point method that combines one angle of yawing and three electronic micrometers for straightness two components and a straight edge master composed of a bar that serves as a measurement standard. And the displacement of 5 axes was measured.

[0003]

However, in the above-mentioned conventional configuration, since the digital electronic level is used, it is difficult to increase the measurement speed while maintaining the measurement accuracy, and the coordinate of the slide table is used. There is a problem that another measuring device such as an encoder needs to be separately attached in order to measure the position.

The present invention solves the above-mentioned conventional problems, and a motion error measuring device for a linear motion body capable of accurately measuring a 6-axis motion error of a slide table at high speed without separately attaching another measuring device. The purpose is to provide.

[0005]

In order to solve the above problems, a motion error measuring device for a linear moving body according to the present invention is a measuring instrument provided on a slide table on a scale surface of a linear scale provided on a base. Facing each other and reading the scale of the scale surface with the measuring instrument, the three-axis measurement of the slide table which moves linearly on the base, the displacement of the slide table as a motion error and the inclination angle can be measured. Two measuring units are installed in parallel,
The linear scale of one of the three-axis measurement units of the three-axis measurement unit is attached so that the scale surface is in the same direction or a vertical direction with respect to the slide surface on which the slide table slides on the base. The linear scale of the other three-axis measurement unit is attached so that the scale surface is inclined at a predetermined angle with respect to the slide surface, and the measurement result of the two three-axis measurement units is 1
The configuration is such that the movement position of the axis and the movement error of the five axes can be measured.

[0006]

With the above structure, the linear scale of one of the two 3-axis measuring units is adjusted so that the scale surface of the linear scale is in the same direction or in the vertical direction with respect to the slide surface on the base. Installation, the other 3
Since the linear scale of the axis measuring unit is attached so that the scale surface of the linear scale is tilted by a predetermined angle with respect to the slide surface on the base, it is possible to calculate by combining the measurement results of the two three-axis measuring units. The 6-axis displacement of the table can be accurately measured at a high speed at the same time without separately attaching another measuring device as in the conventional case.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of a motion error measuring device for a linear moving body according to an embodiment of the present invention. Figure 1
In the above, a groove 3 into which a glass scale 2 as a linear scale is fitted is provided in the longitudinal direction on the upper surface of the base 1 extending in the front-back direction in a straight line direction. A linear guide portion 4 for guiding the surface is provided, and a linear guide portion 6 is provided in parallel with the linear guide portion 4 via a groove 5. Further, between the straight line guide portion 6 and the side surface 7 of the base 1, there is formed an inclined surface 8 which is inclined outward at a predetermined angle .theta.
It is provided in parallel with.

A glass scale 2 is provided in the groove 3 of the base 1.
Are fitted vertically over each other in the longitudinal direction, and the side surface of the glass scale 9 is placed and fixed on the inclined surface 8 in parallel with the glass scale 2. In addition, the slide table 10 is provided on the linear guide portions 4 and 6 of the base 1.
Is slidably mounted. A CCD camera 11 is attached to one side surface of the slide table 10 so that the measuring section faces the upper surface of the glass scale 2, and the other side surface is an inclined surface which is inclined at right angles to the inclined surface 8. A CCD camera 12 is attached to the upper surface of the glass scale 9 so that the measuring unit faces the inclined surface. Coded scales are engraved on the upper surfaces of the glass scales 2 and 9, respectively.

These glass scale 2 and CCD camera 11
The first three-axis measuring unit 13 is constituted by, and the second three-axis measuring unit 14 is constituted by the glass scale 9 and the CCD camera 12.
Make up. These three-axis measuring units 13 and 14 are provided with three units by reading the coded scales on the upper surfaces of the glass scales 2 and 9 with the CCD cameras 11 and 12, respectively.
The measurement values of the axis measuring units 13 and 14 are combined and calculated by a calculation unit (not shown) to measure one axis at the movement coordinate position X of the slide table 10, and as a movement error, C
A vertical displacement amount Z between the measurement surface of the CD camera 11 and the upper surface of the glass scale 2, a lateral displacement amount Y calculated from the displacement amount between the measurement surface of the CCD camera 12 and the upper surface of the glass scale 9, and a vertical direction along the front-rear direction. In-plane swing, Pitchi
ng angle (hereinafter referred to as rocking angle P), Yawing angle (hereinafter referred to as rocking angle Y) that is a rocking in a horizontal plane, Rolling angle (hereinafter rocking R that is a rocking in a vertical plane along the left-right direction)
5) displacement measurement is performed.

With the above configuration, the triaxial measuring units 13 and 14
A total of 6-axis displacement measurement including 1-axis coordinate position measurement and 5-axis motion error measurement by the slide table 10 will be described. First, the measurement of biaxial motion error in addition to coordinate positioning will be described. The motion error to be measured can be selected by the mounting method of the triaxial measurement unit, and the case of the motion error measurement similar to that of the triaxial measurement unit 13 is shown in FIG. In FIG. 2, a glass scale 22 having a coded scale on its upper surface is provided along the longitudinal direction on the side surface of the base 21, and the CCD is arranged so that the measuring surface faces the upper surface of this glass scale 22. The camera 23 is arranged and fixed on the side surface of the slide table 24. When the slide table 24 moves linearly on the base 21, C
The CD camera 23 also moves in the same manner, but the CCD camera 23 does not always move vertically with respect to the glass scale 22, but moves according to the accuracy of the object to be measured as shown in FIG. In this case, the measurement value from the CCD camera 23 is calculated by a calculation unit (not shown) to measure one axis of the coordinate position X of the slide table 24 as a linear moving body, The biaxial measurement of the swing angle P in the vertical plane along the front-rear direction, which is the displacement amount Z from the upper surface of the glass scale 22 and the inclination angle α ₁ , is performed. That is, the three elements of the slide table 24 that moves linearly on the base 21 (the movement coordinate position X, the vertical displacement amount Z, and the swing angle P are three.
Axis) can be measured simultaneously.

Next, FIG. 4 shows another simultaneous motion error measurement in which the mounting method of the triaxial measuring unit is different from that in FIG. In FIG. 4, on the upper surface of the base 31, a glass scale 32 having a coded scale on its side is placed and fixed along the longitudinal direction of the base 31, and the measuring unit faces the side of this glass scale 32. The CCD camera 33 is attached to the side surface of the slide table 34 so as to do so. In this case, the measurement value from the CCD camera 33 is calculated by a calculation unit (not shown) to measure one axis of the coordinate position X of the slide table 34 as a linear moving body, The biaxial measurement of the displacement amount Y with respect to the side surface of the glass scale 32 and the swing angle Y in the horizontal plane, which is the inclination angle α ₂ , is performed. That is, it is possible to simultaneously measure three elements of the slide table 34 that linearly moves on the base 31 (three axes of the movement coordinate position X, the lateral displacement Y, and the swing angle Y).

When the measuring elements shown in FIGS. 2 and 4 are combined, it is possible to measure one axis of the coordinate position X of the linear moving body and the glass scale 22 with the CCD camera 23.
The CCD camera 33 and the two axes of the swing angle P in the vertical plane along the front-back direction, which is the displacement amount Z in the vertical direction with respect to the upper surface and the inclination angle α _1.
And the lateral displacement Y with respect to the side surface of the glass scale 32,
It is possible to measure the tilt angle α ₂ and the 4-axis of the swing angle Y in the horizontal plane.

Here, there are two types 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 obliquely 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).

[0014]

[Table 1] One of the three-axis measurement units shown in FIGS. 2 and 4 is tilted by a predetermined angle θ with respect to the vertical direction. In the case of FIG. 1, 3 in FIG.
This is the case where the axis measuring unit is tilted by a predetermined angle θ with respect to the vertical direction. The 6-axis displacement calculation method will be described below. Make the bar code diagonal to the linear scale (βra
d) The carved 3-axis measuring unit 13 is set as SPACER1,
SPA is a 3-axis measuring unit 14 with a bar code engraved at right angles.
When CER2 is set, the coordinates of each X axis are ξ ₁ , ξ ₂ ,
The displacement of the Z axis is η ₁ and η ₂ , and the tilt angles are α ₁ and α ₂ .
The interval between SPACER1 and SPACER2 is L, S
The mounting angle of PACER2 is θ.

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

[0016]

[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).

[0017]

[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.

[0018]

As described above, according to the present invention, two three-axis measuring units capable of measuring the displacement of two axes and the angle of one axis are provided in parallel, one of which has a scale surface of a linear scale horizontal or vertical. On the other hand, the other side is installed by inclining the scale surface of the linear scale by a predetermined angle, and the measurement values of the two 3-axis measurement units are combined and calculated to measure the 6-axis motion error of the slide table. It is possible to perform high-speed and high-accuracy at the same time without separately installing another measuring device as in the past.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of a motion error measuring device for a linear moving body according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a motion error measuring device for a linear moving body showing a first mounting example of a triaxial measuring unit.

FIG. 3 is an explanatory diagram of a triaxial element in a triaxial measuring unit.

FIG. 4 is a perspective view showing a configuration of a motion error measuring device for a linear moving body showing a second mounting example of the triaxial measuring unit.

[Figure 5] 3 with a linearly engraved barcode on a linear scale
Schematic perspective view of axis measuring unit

[Explanation of symbols]

 1,21,31 Base 2,9,22,32 Glass scale 4,6 Sliding surface 10,24,34 Slide table 11,12,23,33 CCD camera 13,14 3-axis measuring unit

Claims (1)

[Claims] 1. A slide which linearly moves on a base by causing a measuring instrument provided on a slide table to face a graduation surface of a linear scale provided on the base and reading the graduation on the graduation surface with the measuring instrument. Two parallel 3-axis measurement units capable of measuring the movement position of the table, the displacement as the movement error of the slide table, and the inclination angle are provided in parallel, and one of the two 3-axis measurement units is used for 3-axis measurement. The linear scale of the unit is attached so that the scale surface is in the same direction or the vertical direction with respect to the slide surface on which the slide table slides on the base, and the linear scale of the other three-axis measurement unit is slid on the slide surface. The measurement result of the two 3-axis measurement units is attached so that the scale surface is inclined at a predetermined angle with respect to the surface. 1 axial movement position measurement and five axis of motion error measurable structure as the linear motion of the motion error measuring device.