JP2017044540A - Attitude correction method for measurement instrument and device for measuring distance between planes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measurement accuracy by correcting an attitude of a device for measuring distance between planes in a state of being set in a calibrator so as to reduce slight inclination generated by a manufacturing error.SOLUTION: A device 1 for measuring distance between planes comprises a support medium 2 which can be inserted into facing two planes, three contact type displacement sensors 3a provided in one end part of the support medium 2 and three contact type displacement sensors 3b provided in the other end part of the support medium 2 and finds inclination to the facing two planes and measures distance therebetween. When the device 1 for measuring distance between planes is calibrated, inclination is changed from the state in which the device 1 for measuring distance between planes is set to a calibrator 7 with already-known distance between parallel two planes, to perform distance measurement and acquire a measurement error. Next, on the basis of the measurement error, an initial angle generated by a manufacturing error of the device 1 for measuring distance between planes is determined. Next, the initial angle is corrected by, for example, inserting a shim so as to reduce the initial angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a posture correction method suitable for application to a measuring instrument that can measure the distance to an object and determine the posture with respect to the object, for example, an inter-surface distance measuring device.

In a measuring instrument that can measure the distance to an object and determine the posture with respect to the object, the initial posture may affect the measurement accuracy.
In the following, the inter-surface distance measuring device that measures the distance between two surfaces proposed by the present applicant will be described as an example, and then the initial posture will affect the measurement accuracy. .
As one of the management of the rolling mill, measuring and managing the distance between two opposing surfaces (referred to as housing window width) in the housing window of the rolling mill housing (see, for example, Patent Document 1). During rolling by a rolling mill, wear and deformation occur in the rolling mill housing and liner due to the rolling load generated on the roll, so it is necessary to measure and manage the housing window width periodically.
Conventionally, the measurement of the housing window width is often performed using an inside micro gauge or the like. However, the measurement work using the inside micro gauge or the like is a burdensome work because two or more people are required and the work for cleaning the grease to be measured is required. Also, skill is required for measurement work using the inside micro gauge (since it is difficult to visually determine the direction in which the measurement surface and the gauge are perpendicular, it is difficult to move the gauge in the vertical vicinity. There is also a problem that measurement error due to human error is likely to occur.

Japanese Patent No. 5332606 Japanese Patent No. 5610443 JP 2005-37353 A

In the Japanese Patent Application No. 2015-72118, the applicant of the present invention has disclosed a support body that can be inserted between two opposing surfaces as a measurement instrument suitable for use in measuring the housing window width, and one end portion of the support body. Provided at the other end of the support, and three or more distance measuring sensors for measuring a distance from a predetermined position of the inter-surface distance measuring device to one of the two surfaces. The inter-surface distance measuring device includes three or more other distance measuring sensors that measure the distance from a predetermined position of the inter-surface distance measuring device to the other of the two surfaces. .
This inter-surface distance measuring device calculates the inter-point distance between two surfaces and calculates the inter-surface distance from the angle formed by the line segment and the surface. Thereby, at the time of distance measurement, it is not necessary to maintain the orthogonal relationship with the surface of the housing window, and measurement independent of the measurer is possible.

  As a measuring instrument for measuring the distance to an object, for example, Patent Document 2 discloses a non-contact three-dimensional measuring device. The non-contact type three-dimensional measuring instrument is composed of two rotary motors with encoders and a laser ranging system. The encoder measures two angles φ and θ, and measures the distance to the measurement object with the laser ranging system. Thus, the coordinate information of the measurement point is obtained, and the three-dimensional shape data of the entire shape to be measured is generated. Further, for example, Patent Document 3 discloses a surface texture measuring machine including a detector capable of taking a plurality of measurement postures with respect to a workpiece.

  The angle resolution of the inter-plane distance measuring apparatus proposed by the applicant described above is 0.0004 ° (sin 0.0004 = 7/1000000), and therefore high-precision measurement can be expected. In the case of the present invention, it has an expected accuracy of 0.04 ° (calculated from an expected accuracy of 0.05 mm) and sufficient unit accuracy. However, the actual measurement accuracy (error) before application of the present invention is 0.025 °, and assuming that all of these errors are calibration errors, it can be seen that the double precision of the expected accuracy cannot be secured. Thus, there is a problem that the current calibration method cannot sufficiently exhibit the measurement performance.

  When using a measuring instrument that can measure the distance to an object and determine the attitude to the object, the present invention uses the function to correct the attitude and reduce the measurement accuracy (error). The objective is to ensure the double precision of the expected accuracy, improve the measurement accuracy, and fully demonstrate the measurement performance.

The measuring instrument posture correction method of the present invention is a method for measuring the distance to an object and correcting the posture of the measuring instrument that can determine the posture with respect to the object. The distance of the plane is measured, the initial posture of the measuring instrument with respect to the reference plane is obtained, and the initial posture is corrected.
The method for correcting the posture of the inter-surface distance measuring apparatus according to the present invention includes a support body that can be inserted between two opposing surfaces, and one end portion of the support body, from a predetermined position of the inter-surface distance measurement apparatus. Three or more distance measurement sensors for measuring the distance to one of the two surfaces, and the other end of the support, and the second distance sensor from a predetermined position of the inter-surface distance measurement device. An inter-surface distance measurement that includes three or more other distance measurement sensors that measure a distance to the other of the surfaces, and calculates a tilt between the two opposing surfaces and measures a distance between the two surfaces. It is for correcting the posture of the apparatus, and the distance measurement is performed by changing the inclination from the state in which the inter-surface distance measurement apparatus is set in a calibrator in which the distance between two parallel surfaces is known, and the measurement error is measured. Based on the acquisition procedure and the measurement error, the inter-surface distance measurement device A step of determination of the initial angle, and having a procedure for correcting the initial angle.
Another aspect of the posture correction method of the inter-surface distance measurement apparatus according to the present invention is that, in the procedure for obtaining the measurement error, the inter-surface distance measurement apparatus is set in the calibrator, and the surface is measured. The distance is measured by changing the inclination at one end of the inter-distance measuring device to obtain a measurement error at a predetermined inclination, and then the distance is measured by changing the inclination at the other end of the inter-surface distance measuring device. The measurement error at the predetermined inclination is obtained. In this case, in the procedure of obtaining the measurement error, the neutral value of the measurement error at the predetermined inclination obtained on the one end side and the measurement error at the predetermined inclination obtained on the other end side In the procedure of calculating the measurement error with respect to the neutral value and calculating the initial angle, it is preferable to determine the initial angle based on the measurement error with respect to the neutral value.
Further, another feature of the posture correction method of the inter-surface distance measurement apparatus according to the present invention is that, in the procedure for obtaining the initial angle, as a measurement error Δ, a distance L between the two surfaces of the calibrator, and an inclination θ, The initial angle θ ′ is expressed by the following equation: θ ′ = tan ⁻¹ (Δ · 180 / L · π · θ)
It is in the point to ask

  According to the present invention, when using a measuring instrument that can measure the distance to an object and obtain the posture with respect to the object, the posture is corrected using the function to reduce the measurement accuracy (error). Thus, it is possible to ensure the double precision of the expected accuracy, improve the measurement accuracy, and sufficiently exhibit the measurement performance.

It is a figure showing a schematic structure of an inter-surface distance measuring device concerning an embodiment. It is a figure which shows typically the use condition of the inter-surface distance measuring apparatus which concerns on embodiment. It is a figure for demonstrating the usage example of a surface distance measuring apparatus. It is a figure for demonstrating the calculation method of the distance between surfaces. It is a figure which shows an example of a calibrator. It is a flowchart which shows the procedure which calculates | requires the initial angle of the inter-surface distance measuring apparatus set to the calibrator. It is a figure which shows the example of the relationship between the inclination and distance which were obtained by the left-right operation of the inter-plane distance measuring apparatus. It is a figure which shows the relationship between the inter-surface distance measuring apparatus when one side is lifted, and a calibrator. It is a characteristic view which shows the relationship between a measurement error and an initial angle. It is a figure which shows the example of the relationship between the inclination after reducing an initial angle, and distance. It is a figure for demonstrating the case where a laser tracker is made into object as other embodiment.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
First, with reference to FIGS. 1-4, the inter-surface distance measuring apparatus which is a measuring instrument made into object by this embodiment is demonstrated.
FIG. 1 shows a schematic configuration of an inter-plane distance measuring apparatus 1 according to the embodiment. FIG. 2 schematically shows a usage state of the inter-plane distance measuring apparatus 1 according to the embodiment. The inter-surface distance measuring device 1 is used to measure a distance between two opposing surfaces 101a and 101b, for example, a housing window width of the rolling mill housing 100 as shown in FIG.

  As shown in FIG. 2, the inter-surface distance measuring device 1 includes a support 2 that can be inserted between two opposing surfaces 101 a and 101 b in a housing window, and one of the three provided at one end of the support 2. Distance measuring sensor 3 a and three other distance measuring sensors 3 b provided at the other end of the support 2. Each one of the distance measuring sensors 3a measures the distance from the predetermined position 4 of the inter-surface distance measuring device 1 to the one surface 101a. The other distance measuring sensor 3b measures the distance from the predetermined position 5 of the inter-surface distance measuring device 1 to the other surface 101b.

  As shown in FIG. 1, the support body 2 includes a rod body 201 and a pair of support plates 202 a and 202 b provided at both ends of the rod body 201.

  The rod 201 is composed of a pipe material 201a and a pair of sub-pipe materials 201b inserted at both ends of the pipe material 201a. If the sub-pipe material 201b having a plurality of lengths is prepared, the total length of the rod body 201 can be freely changed by selecting the sub-pipe material 201 according to the inter-surface distance to be measured.

Further, the support plates 202a and 202b are formed in a disc shape, and an insertion portion 203 provided at the center thereof is inserted into an end portion of the rod body 201, and is arranged perpendicular to the rod body 201.
A contact displacement sensor is disposed on the support plate 202a as the distance measuring sensor 3a. Similarly, a contact-type displacement sensor is disposed on the support plate 202b as the distance measuring sensor 3b. The contact-type displacement sensors 3a and 3b have a stroke type probe 301, and the probe 301 can be extended in the axial direction by air (see arrow X in FIG. 1). By using a driving structure using air as the probe driving structure, it is possible to reduce the size and to control the contact pressure to the surfaces 101a and 101b of the probe 301 with high accuracy. In the present embodiment, in the support plate 202a, three contact displacement sensors 3a are arranged at the vertices of an equilateral triangle. Similarly, on the support plate 202b, three contact displacement sensors 3b are arranged at the apexes of the equilateral triangle.

  Here, as shown in FIG. 2, the predetermined position 4 of the inter-surface distance measuring device 1 is a non-movable part of the inter-surface distance measuring device 1 and the closest position to the surface 101a, that is, the contact-type displacement sensor 3a. Among these, the position closest to the surface 101a in the casing part 302 excluding the probe 301 which is a movable part is said. Similarly, the predetermined position 5 of the inter-surface distance measuring apparatus 1 is a non-movable part of the inter-surface distance measuring apparatus 1 and the position closest to the surface 101b, that is, the movable part of the contact displacement sensor 3b. The position closest to the surface 101b in the casing part 302 excluding the probe 301 is said.

As shown in FIG. 1, a cylindrical protector 204 is attached to the peripheral portions of the support plates 202a and 202b so as to protect the contact displacement sensors 3a and 3b.
Further, the support plates 202a and 202b may be supported by a string (not shown) or the like in order to prevent the support plates 202a and 202b from tilting.
The rod body 201 and the support plates 202a and 202b are preferably made of, for example, an aluminum alloy and have a weight that allows the inter-surface distance measuring device 1 to be lifted by one person in order to reduce weight while ensuring rigidity. .

Next, an outline of the inter-surface distance measurement by the inter-surface distance measurement device 1 will be described.
As shown in FIG. 2, the inter-surface distance measuring device 1 is inserted between the two surfaces 101a and 101b facing each other in the housing window. At this time, the inter-surface distance measuring device 1 may be inclined with respect to the two surfaces 101a and 101b.
In this case, the operator may lift the inter-surface distance measuring device 1 and insert it between the two surfaces 101a and 101b. Alternatively, as shown in FIG. 3, the surface is supported by a support member 6 (for example, a tripod and an arm). The inter-distance measuring device 1 may be supported and inserted between the two surfaces 101a and 101b. By using the support member 6, it is possible to measure the housing window width at a high position.

  With the inter-surface distance measuring device 1 inserted between the two surfaces 101a and 101b, the probes 301 of the contact displacement sensors 3a and 3b are extended to contact the surfaces 101a and 101b. That is, the probes 301 of the three contact displacement sensors 3a supported by the support plate 202a are extended to contact one surface 101a, and the probes 301 of the three contact displacement sensors 3b supported by the support plate 202b are extended. To be brought into contact with the other surface 101b. When grease is applied to the part to be measured, the probe 301 is driven to penetrate the grease and contact the surfaces 101a and 101b.

Hereinafter, a method for calculating the inter-surface distance will be described with reference to FIG. The inter-surface distance is calculated on the assumption that the two opposing surfaces 101a and 101b are parallel.
As shown in FIG. 2, the inter-surface distance L _HW is the inter-surface distance in the state where the inclination of the inter-surface distance measuring device 1 is θ and the probes 301 of the contact displacement sensors 3a and 3b are in contact with the surfaces 101a and 101b. The length of the distance measuring device 1 is represented by L _m as follows.

As shown in FIG. 4, three contact displacement sensors 3a are arranged at the vertices a, b, c of the equilateral triangle, and three contact displacement sensors 3b are arranged at the vertices d, e, f of the equilateral triangle. The The vertex a and the vertex d are arranged in the same phase around the axis of the inter-plane distance measuring device 1. The same applies to vertex b and vertex e, vertex c and vertex f. In addition, the length between the predetermined position 4 on the one end side of the inter-surface distance measuring device 1 and the predetermined position 5 on the other end side is k. In addition, the pitch between the contact type displacement sensors 3a and 3b is assumed to be w. Further, the distance measured by each contact displacement sensor 3a on one surface 101a is l, m, n, and the distance measured by each contact displacement sensor 3b on the other surface 101b is l ', m', n '. And
When the coordinates of each of the contact points P _{1 to} P ₆ are measured, an average surface is formed by three points on one surface 101a and the other surface 101b, and a normal distance from each point on the target surface is calculated, the distance L _m is represented by the following formula (2). If the target surface is strictly parallel, averaging is not necessary, but in practice it is preferable to average.

Further, cos θ is, for example, a normal vector n ₁ → of an equilateral triangle composed of vertices a, b, and c (→ is assumed to be attached on n ₁ ) and a normal vector n ₂ → of the surface 101a. (→ is assumed to be attached on n ₂ ).
Here, the normal vectors n ₁ → and n ₂ → are obtained from the equation of the point in the measuring machine and the plane expressed by the following equation (4) and the equation of the point on the measuring surface and the plane expressed by the following equation (5), respectively. It is represented by the following formula (6) and the following formula (7).

By substituting the distance L _m calculated by Expression (2) and cos θ calculated by Expression (3) into Expression (1), the inter-surface distance L _HW can be calculated.

  The above-described calculation of the inter-surface distance is executed by a calculation device including, for example, a CPU, a ROM, a RAM, and the like. In this case, the calculation device and the display device that displays the calculation result by the calculation device may be installed anywhere. For example, if a small calculation device and a small display device are installed at appropriate positions of the inter-surface distance measuring device 1 and the support member 6, the inter-surface distance can be confirmed while an operator works. Further, the distance measured by each of the contact-type displacement sensors 3a and 3b may be transmitted by, for example, wireless communication, and the inter-surface distance may be calculated and displayed by a separately installed calculation device and display device.

In the inter-surface distance measuring apparatus 1 as described above, the distance between each point between two surfaces is calculated, and the inter-surface distance is calculated from the angle formed by the line segment and the surface. Thereby, at the time of distance measurement, it is not necessary to maintain the orthogonal relationship with the surface of the housing window, and measurement independent of the measurer is possible.
The measuring operation using the inter-surface distance measuring apparatus 1 requires only one person and eliminates the need for the grease cleaning operation for the part to be measured, thereby reducing the work burden. Further, since the inter-surface distance measuring device 1 is only inserted between the two surfaces and the probe 301 is extended, a measurement error due to a human error is unlikely to occur. Thus, the distance between two opposing surfaces in a large structure or the like can be quickly measured without skill.

Next, calibration of the inter-surface distance measuring device 1 will be described.
As a pre-use preparation, the inter-surface distance measuring device 1 is calibrated using a calibrator. FIG. 5 shows an example of the calibrator 7. The calibrator 7 has a bottom surface 7a and left and right side surfaces 7b, and is formed by, for example, machining. The parallelism of the left and right side surfaces 7b is ensured, and the distance L between the left and right side surfaces 7b is strictly controlled to a certain length. As the distance L, 1470 mm close to the housing window width is set as an example. The bottom surface 7a is provided with left and right set stands 7c on which the inter-surface distance measuring device 1 is placed. The left and right set bases 7 are ensured to be level so that the inter-surface distance measuring device 1 can be placed horizontally.

The condition necessary for calibration is orthogonality between the main axis of the inter-surface distance measuring apparatus 1 (a line segment connecting the centers of the contact displacement sensors at three points on one side) and the side surface 7b of the calibrator 7.
However, due to manufacturing errors such as the processing accuracy of the aluminum alloy and the mounting accuracy of the contact-type displacement sensors 3a and 3b, the surface distance measuring device 1 is set in the calibrator 7 and actually has a very small inclination (initial angle). Is called). Therefore, a reduction in the initial angle is required for calibration. In this case, it is conceivable to reduce the initial angle using a level or the like, but it is difficult to measure and adjust a minute angle (for example, 0.05 ° or less).

Therefore, as described below, the distance measurement is performed by changing the inclination from the state in which the inter-surface distance measuring device 1 is set in the calibrator 7, the measurement error is obtained, and the inter-surface distance measuring device 1 is obtained based on the measurement error. Find the initial angle of.
FIG. 6 shows a procedure for obtaining the initial angle of the inter-plane distance measuring device 1 set in the calibrator 7.
In step S1, distance measurement is performed by changing the inclination from the state in which the inter-surface distance measuring device 1 is set in the calibrator 7, and a measurement error, that is, an error with respect to the known distance L of the calibrator 7 is obtained.
Specifically, with the inter-surface distance measuring device 1 set in the calibrator 7, the distance is measured by operating the right side of the inter-surface distance measuring device 1 in the vertical direction, and the inclination θ is also obtained. Similarly, the distance is measured by operating the left side of the inter-surface distance measuring device 1 so as to be lifted in the vertical direction, and the inclination θ is also obtained. As a result, for example, as shown in FIGS. 7A and 7B, measurement results are obtained at each inclination θ until the left and right sides are lifted by 3 °. The inclination of 3 ° was determined in order to obtain an initial angle resolution of 0.0004 ° (1/10 order of 0.005 °). It should be noted that the degree of tilting operation may be determined according to the required tilt resolution or the like.

In step S2, the neutral value of the measurement error caused by the left / right operation is obtained. As shown in FIGS. 7A and 7B, when the inclination θ = 3 °, the measurement error on the left side is −0.05 mm, the measurement error on the right side is 0.02 mm, and the neutral value is (−0.05 + 0). .02) /2=−0.015 mm.
In step S3, a value obtained by subtracting the neutral value obtained in step S2 from the measurement error caused by the left and right operation is obtained as a measurement error. The measurement error on the left side is −0.05 − (− 0.015) = − 0.035 mm, the measurement error on the right side is 0.02 − (− 0.015) = 0.035 mm, and the inclination θ The measurement error at 3 ° is ± 0.035 mm.
The measurement error caused by the inclination of the inter-surface distance measuring device 1 includes factors other than the initial angle (for example, thermal expansion and contraction due to temperature fluctuation). In order to eliminate factors other than the initial angle as much as possible, that is, in order to narrow down to the initial angle, the data from the operation on both the left and right sides as well as one side is used, and the measurement error with respect to the neutral value is taken as the calculation error of the initial angle. Can be improved.

In step S4, the initial angle of the inter-surface distance measuring device 1 is obtained based on the measurement error obtained in step S3.
FIG. 8 shows the relationship between the inter-surface distance measuring device 1 and the calibrator 7 when one side is lifted. As is clear from FIG. 8, the measurement error Δ (mm), the inter-surface distance L (mm), the inclination θ (°), and the initial angle θ ′ (°) are expressed by the following equation (8). θ ′ is obtained by the following equation (9).
Δ = (L · π · θ / 180) · tan θ ′ (8)
θ ′ = tan ⁻¹ (Δ · 180 / L · π · θ) (9)
FIG. 9 shows the relationship between the measurement error Δ represented by the equation (9) and the initial angle θ ′. As can be seen from FIG. 9, in this example, an initial angle of 0.25 ° is obtained based on a measurement error of 0.035 mm.

  Although the calibration rule for the vertical direction has been described here, the calibration rule for the horizontal direction is the same.

  After obtaining the initial angle as described above, the initial angle is corrected. For example, the posture of the inter-plane distance measuring device 1 is physically corrected by inserting a shim between the set base 7c and the inter-surface distance measuring device 1 so as to reduce the initial angle. Alternatively, in order to reduce the initial angle, a correction term may be incorporated into the calculation formulas shown in the formulas (1) to (7), or a countermeasure may be taken from the viewpoint of software.

  FIG. 10 shows the effect of reducing the initial angle. Even when the inter-surface distance measuring apparatus 1 was inclined with respect to the two surfaces at an inclination angle θ = 3 °, the measurement error was −0.02 mm on the left and right. That is, the error range before the initial angle reduction was 0.02 to -0.05 mm, but the error range after the initial angle reduction was 0.00 to -0.02 mm, which improves the distance measurement accuracy. I was able to.

(Other embodiments)
In the above-described embodiment, the initial angle with respect to the side surface 7b when the inter-surface distance measuring device 1 is set in the calibrator 7 has been described. However, any measuring instrument that can acquire the distance and angle to the object is used. The scope of application is not limited to this.
For example, there is a laser tracker as a measuring instrument that can measure a distance to an object and obtain an angle with respect to the object. As shown in FIG. 11, in the laser tracker, the laser tracker body 8 irradiates the target 9 brought into contact with the object with laser light, and measures the distance by receiving the laser light reflected from the target 9. The three-dimensional position of the target 9 is determined.

  In the present embodiment, the initial posture of the laser tracker body 8 with respect to a reference plane (hereinafter referred to as a reference surface) is obtained, and the initial posture is corrected. That is, the X, Y, and Z axes of the laser tracker body 8 are aligned with the reference plane. The reference surface may be, for example, a measurement surface of an object or a surface on which the laser tracker body 8 is placed.

As shown in FIG. 11, it is assumed that the X axis or Y axis of the laser tracker body 8 has an inclination of angle α and the Z axis has an inclination of angle β as an initial posture with respect to the reference plane.
On the reference plane, the distance is measured at a plurality of points (preferably three or more points) while shifting the target 9 in one direction. Thereby, a vector can be generated on the reference plane. Similarly, on the reference plane, the distance is measured at a plurality of points (preferably three or more points) while shifting the target in a direction orthogonal to the one direction. Thereby, a vector can be generated on the reference plane.
Then, the initial posture of the laser tracker body 8 is set so that the X axis or Y axis of the laser tracker body 8 and the Z axis match the vector generated on the reference plane, that is, the angles α and β are set to 0. to correct. For example, the posture of the laser tracker body 8 is physically corrected by inserting a shim between the surface on which the laser tracker body 8 is placed and the laser tracker body 8.
If measurement is performed while the X, Y, and Z axes of the laser tracker body 8 are deviated from the measurement surface of the object, calculations such as coordinate conversion are required later, resulting in an increase in work man-hours and calculation work. There is a risk of dropping digits. By correcting the initial posture of the laser tracker body 8 with respect to the reference surface, it is possible to eliminate the need for arithmetic operations such as coordinate conversion and to improve measurement accuracy without causing any digit loss or the like.

  Although the present invention has been described together with the embodiments, the above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention is interpreted in a limited manner by these. It must not be. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

1: Inter-surface distance measuring device 2: Support 3a, 3b: Distance measuring sensor (contact displacement sensor)
7: Calibrator 7b: Side 8: Laser tracker body 9: Target

Claims (5)

An attitude correction method for correcting the attitude of a measuring instrument that can measure the distance to an object and determine the attitude to the object,
A measuring instrument posture correction method comprising: measuring a distance of a reference plane using the measuring instrument; obtaining an initial attitude of the measuring instrument with respect to the reference plane; and correcting the initial attitude. . A support body that can be inserted between two opposing surfaces, and provided at one end of the support body, and measures the distance from a predetermined position of the inter-surface distance measuring device to one of the two surfaces Three or more distance measuring sensors that are provided, and a distance measuring sensor provided at the other end of the support, and measuring a distance from a predetermined position of the inter-surface distance measuring device to the other of the two surfaces 3 An attitude correction method for correcting the attitude of an inter-surface distance measuring device that measures the distance between the two surfaces by obtaining an inclination with respect to the two opposing surfaces, and comprising two or more other distance measuring sensors. ,
A procedure for measuring the distance from the state in which the distance between two parallel surfaces is set in a calibrator whose distance between two parallel surfaces is already known, and obtaining a measurement error;
A procedure for obtaining an initial angle of the inter-surface distance measuring device based on the measurement error;
A method for correcting the initial angle, and a method for correcting a posture of the inter-surface distance measuring apparatus.   In the procedure for obtaining the measurement error, in the state where the inter-surface distance measuring device is set in the calibrator, the distance is measured by changing the inclination at one end of the inter-surface distance measuring device, and at a predetermined inclination. The measurement error is obtained, and then the distance is measured by changing the inclination on the other end side of the inter-surface distance measuring device, and the measurement error at the predetermined inclination is obtained. Posture correction method for inter-surface distance measurement device. In the procedure for obtaining the measurement error, the neutral value of the measurement error at the predetermined inclination obtained on the one end side and the measurement error at the predetermined inclination obtained on the other end side is obtained, Calculate the measurement error for the neutral value,
4. The method of correcting a posture of an inter-plane distance measuring device according to claim 3, wherein in the step of obtaining the initial angle, the initial angle is obtained based on a measurement error with respect to the neutral value. In the procedure for obtaining the initial angle, the initial angle θ ′ is expressed by the following equation θ ′ = tan ⁻¹ (Δ · 180 / L · π · θ), with the measurement error Δ, the distance L between the two surfaces of the calibrator, and the inclination θ. )
5. The attitude correction method for an inter-surface distance measuring apparatus according to claim 2, wherein the attitude correction method is obtained by:

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