JPH0979838A - Straightness measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the straightness even in case of a long material having a large warp quantity by correcting the warp quantity of the long measured material measured by a displacement measuring instrument, based on the following moving quantity of displacement measuring instrument relative to the measurement reference position. SOLUTION: A running measuring device 2 is self-propelled in parallel with a long material 1 to be measured, the distance to the material 1 is measured with a displacement measuring instrument 7, a displaced (dislocated) quantity from the reference position of the measuring instrument is output to a computing device 30, a stepping motor 31-1 is driven through an analogue/pulse converter 33-1 so as to followingly move the measuring instrument 7 by the displaced quantity, and the moved quantity is measured 32-1 so as to output to the device 30. The device 30 computes a relative displaced quantity relative to the device 2, based on the displaced quantity and the moved quantity. Meanwhile, reference patterns 20 on respective measuring positions are image picked up 21 so as to input to an image processing device 22, the dislocated quantity of a traveling carriage 2a based on the gravity center positions of the patterns 20 is obtained, so as to output to the device 30. The device 30 corrects the previously obtained relative displace quantity, based on the dislocated quantity, and computes the warp quantity at respective measuring points.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring bending or warping (hereinafter, collectively referred to as "strain") of a long material such as a bar or a strip that is long in one direction. In particular, it relates to a straightness measuring device for moving a displacement measuring device along a long material.

[0002]

2. Description of the Related Art A long member is sometimes used as a member of a mechanical device. However, depending on the application, a high straightness is required for the long member, and a long member having a strain cannot be used. Therefore, the long material must be straightened to remove the distortion so as to meet the usage conditions.

In order to effectively perform the straightening process on a long material, it is indispensable to quantitatively measure and grasp the strain amount and distribution of the long material in advance. For this reason, a technique for measuring the straightness of a long material with high accuracy is important.

Conventionally, the straightness of a long material is measured by measuring the strain of the long material by running a displacement measuring device such as a magnetic sensor or a laser displacement gauge in parallel along the long material. are doing. Simultaneously with the displacement measurement by the displacement measuring device, the reference pattern provided on the carriage of the displacement measuring device is photographed by the camera on the fixed side to measure the deviation amount of the reference pattern, and this deviation amount and the above distortion amount measurement result are mutually measured. The straightness of the long material is measured by comparing and analyzing.

FIG. 3 shows an example of the configuration of the straightness measuring device described above. In the figure, reference numeral 1 is a long material which is an object to be measured, and specifically, an example of a rail is shown. In order to run the measuring device 2 in parallel with the long material 1, a traveling platform 3
A set of guide rails 4a, 4 parallel to the long member 1 on the upper surface of the
b is laid. The measuring device 2 is self-propelled by engaging a pinion (not shown) rotatably driven by a servomotor 5 fixed to the traveling carriage 2a with a rack 6 laid between the guide rails 4a and 4b. Further, the measuring device 2 is equipped with a non-contact type displacement measuring device 7 so that the displacement measuring device 7 can be brought close to a side surface of the long material 1 to a predetermined measuring position by a cylinder 8 fixed to the traveling carriage 2a. . FIG.
Shows a state in which the displacement measuring device 7 is brought close to the side surface of the long material 1 to a predetermined measuring position. The displacement measuring device 7 measures the displacement in the x-axis (horizontal) direction, but another displacement measuring device having the same configuration and measuring the displacement in the y-axis (vertical) direction is provided on the traveling carriage 2a of the measuring device. (Not shown).

On the other hand, the traveling carriage 2a of the measuring device 2 is provided with a reference pattern 20 for seeing the measurement reference, and the traveling carriage 3
A television camera 21 for continuously receiving the reference pattern 20 is fixed to one end of the. The image signal output from the television camera 21 is input to the image processing device 22 to drive the traveling vehicle 2a.
The amount of deviation from the reference position in each of the x-axis (horizontal) direction and the y-axis (vertical) direction is calculated. FIG. 4 shows displacement amounts x1 and y1 of the center of gravity position of the reference pattern 20 received by the television camera 21 with respect to the center of gravity position (measurement reference). The deviation amount calculated by the image processing device 22 is calculated by the calculation device 23.
Is input to and the displacement detection data measured by the displacement measuring device 7 is corrected.

By the way, in the non-contact type displacement measuring instrument 7, the displacement resolution changes according to the measurement position as shown in FIG. The displacement resolution is highest when the measurement position, which is the relative distance between the displacement measuring instrument 7 and the object to be measured, is the proper position, and the displacement resolution decreases as the amount of deviation of the measurement position from the proper position increases. Further, if the measurement range is made large, the linearity of the output characteristic of the displacement measuring device becomes poor even at the proper position.

[0008]

As described above, in the straightness measuring device described above, the displacement resolution is lowered in response to the deviation of the measurement position from the proper position, so that the range in which strain can be measured with high accuracy is displacement measurement. It is limited to the measurable range X _S of the instrument, and the measurement accuracy of a long material having a large strain that deviates from the measurable range X _S deteriorates.
In addition, if the measurement range is made large, the linearity of the output characteristic of the displacement measuring device deteriorates, and as a result, the measurement accuracy deteriorates.

The present invention has been made in view of the above circumstances, and it is possible to correct the positional deviation with respect to the measurement reference and at the same time measure the straightness of a long material having a large amount of strain with high accuracy. It is an object of the present invention to provide a long material straightness measuring device.

[0010]

In order to achieve the above object, the present invention takes the following measures. The present invention corresponding to claim 1 is a straightness measuring device for measuring a strain of a long material by translating a displacement measuring device for detecting relative displacement between the long material and the longitudinal direction of the long material. Traveling means for moving the displacement measuring device in parallel in the longitudinal direction of the long material, driving means for moving the displacement measuring device in a relative direction facing the long material based on a drive signal, and the displacement measuring device. Conversion means for converting the measured displacement amount into a driving signal for moving the displacement measuring device to follow the strain of the long material and sending the driving signal to the driving means, and the converting amount for the strain amount measured by the displacement measuring device. And a calculation means for making a correction based on the movement amount instructed by the drive signal to the drive means.

According to the straightness measuring device of the present invention, when the displacement measuring device is translated by the traveling means in the longitudinal direction of the long material, the displacement measuring signal output from the displacement measuring device is input to the calculating means. It is input together with the conversion means. The conversion means converts the displacement detection signal output from the displacement measuring device into a drive signal for moving the displacement measuring device to follow the strain of the long material and sends the drive signal to the driving means. It will follow the distortion of. Therefore, by setting the displacement measuring instrument to the proper measurement position for the long material before traveling, it is possible to deviate from the measurable range of the displacement measuring instrument even for long materials with large distortion. It is possible to carry out the measurement without the need. On the other hand, the computing means corrects the amount of strain measured by the displacement measuring device based on the amount of movement indicated by the drive signal.

According to a second aspect of the present invention, a straightness for measuring a strain of a long material by translating a displacement measuring device for detecting relative displacement between the long material and the longitudinal direction of the long material. In the measuring device, a traveling means for moving the displacement measuring device in parallel with the longitudinal direction of the long material, a driving means for moving the displacement measuring device in a relative direction facing the long material based on a drive signal, and the displacement. Conversion means for converting the displacement amount measured by the measuring device into a driving signal for moving the displacement measuring device to follow the strain of the long material and sending the driving signal to the driving means, and the moving amount of the displacement measuring device by the driving means. And a calculation unit that corrects the strain amount measured by the displacement measuring device based on the movement amount of the displacement measuring device measured by the measuring device.

According to the straightness measuring apparatus of the present invention, when the displacement measuring device is translated by the traveling means in the longitudinal direction of the long material, the displacement measuring signal output from the displacement measuring device is sent to the computing means and the converting means. Inputted, the conversion means converts the displacement detection signal into a drive signal and sends it to the drive means. The movement amount of the displacement measuring device by the driving means is indirectly or directly measured by the measuring device and sent to the calculating means. The calculation means corrects the amount of strain input from the displacement measuring device as a displacement measurement signal based on the amount of movement of the displacement measuring device input from the measuring device.

Here, a feed screw rotation angle sensor can be used as a measuring device for indirectly measuring the movement amount of the displacement measuring device. If a feed screw rotation angle sensor is used, it becomes semi-closed loop control, and it can measure more accurately than open loop control.

A sensor such as a linear scale can be used as a measuring device for directly measuring the movement amount of the displacement measuring device. If a linear scale sensor is used, complete closed loop control will be achieved, and more accurate measurement will be possible compared to semi-closed loop control.

According to a third aspect of the present invention, in any one of the straightness measuring devices described above, when the displacement measuring device is moved in parallel, the displacement detecting device detects the amount of displacement of the displacement measuring device at each measurement position. And a correction unit that corrects the displacement amount measured by the displacement measuring device by the displacement amount detected by the displacement detection unit.

According to the straightness measuring apparatus of the present invention, when the displacement measuring device is moved by the traveling means, the displacement of the displacement measuring device itself is detected by the displacement detecting device, and the displacement is measured from the displacement amount measured by the displacement measuring device. The deviation of the container itself is removed by the correction means.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of a long material straightness measuring device according to the present invention. The same components as those of the long material straightness measuring device shown in FIG. 4 are designated by the same reference numerals.

This long material straightness measuring device is a measuring device 2
X displacement measuring device 7-1 for detecting relative displacement in the x-axis direction between the long material 1 and another Y displacement measuring device 7-for detecting relative displacement in the y-axis direction. 2 (not shown in FIG. 1). The X displacement measuring device 7-1 is made movable in the x-axis direction by the stepping motor 31-1, and the amount of movement of the stepping motor 31-1 in the x-axis direction is read by the rotary encoder 32-1. The Y displacement measuring device 7-2 is also provided with a stepping motor 31-2 and a rotary encoder 32-2. The movement amount of the stepping motor 31-1 is controlled by the pulse signal supplied from the analog / pulse converter 33-1 to the stepping motor 31-1. The same is applied to the y-axis direction. The measuring device 2 including these components is provided on the traveling carriage 2a, and the traveling carriage 2a travels on the guide rails 4a and 4b.

Further, a reference pattern 20 is provided on the traveling carriage 2a of the measuring device 2, and a TV camera 21 is provided on one end side of the traveling stand 3 so as to face the reference pattern 20 so as to capture the reference pattern as an image. ing.
The television camera 21 is composed of image pickup devices arranged two-dimensionally.

FIG. 2 shows functional blocks of an electric system of the long material straightness measuring device according to this embodiment. The output signal of the X displacement measuring device is output as a displacement amount to the arithmetic unit 30 and also to the analog / pulse converter 33-1. A pulse signal corresponding to the detected displacement is generated from the analog / pulse converter 33-1 to generate the stepping motor 31-
1 is driven. The output signal of the rotary encoder 32-1 reading the amount of movement of the stepping motor 31-1 is output to the arithmetic unit 30. The same is applied to the y-axis direction. The computing device 30 calculates the relative displacement amount of the long material with respect to the measuring device 2 based on the displacement amount and the movement amount.

The image signal output from the television camera 21 is input to the image processing device 22. The image processing device 22 processes the input image signal and stores the positional deviation amount of the traveling carriage 2a of the measuring device in the arithmetic device 30 with the center of gravity of the reference pattern as a reference. Arithmetic unit 30
Then, the above-mentioned displacement amount is corrected to the displacement amount described above to calculate the actual strain amount of the long material 1.

Next, the operation of the straightness measuring device for straightness of the long material constructed as described above will be explained. Note that the description will be made without distinguishing the x-axis direction and the Y-axis direction. First, the long material 1 as the object to be measured is carried in via the roller device 13, and then is positioned at a predetermined measurement position by using the clamp device 14. After that, if this is left as it is, distortion occurs in the long material 1 and an error occurs in the measurement. Therefore, in order to prevent this, the clamp device is released before starting the measurement.

The measuring device 2 is self-propelled along the long material 1 in parallel. At this time, the displacement measuring device 7-1 (7-2) measures the distance from the long material 1 and outputs the amount of deviation from the measuring device reference position to the arithmetic unit 30. At the same time, the displacement measuring device 7-1
Analog / pulse converter 33-using the output signal of (7-2)
1 (33-2) via the stepping motor 31-1
Displacement measuring device 7-
Follow-up control is performed so that 1 (7-2) comes to the measurement reference position. The following movement amount at that time is determined by the rotary encoder 32.
-1 (32-2).

The computing device 30 calculates the relative position amount of the long material 1 with respect to the measuring device based on the displacement amount and the movement amount. This will be described with reference to FIG. A ₀ is the displacement measuring device 7-
1 (7-2) is a measurement reference distance, A ₁ is a displacement amount at a certain position, B ₁ is a movement amount of a stepping motor, δ is a tracking delay amount due to a time delay, and C is a relative displacement with respect to the measurement reference position. These relationships are shown by the following equation.

A ₁ = A ₀ + δ≈A ₀ (1) δ = A ₁ -B ₁ (2) C = B ₁ + δ = A ₁ + B ₁ -A ₀ (3) According to the above formula (3) The relative displacement between the long material 1 and the measuring device 2 is continuously detected and stored in the computing device 30 as strain amount data. The tracking delay amount due to the time delay is set to fall within a certain range by setting the speed of the traveling carriage 2a of the measuring device 2.

On the other hand, when the traveling vehicle 2a is traveling, the television camera 21 continuously receives the reference pattern 20 at each measurement position, and the image signal is sent from the television camera 21 to the image processing device 22.

As shown in FIG. 5, the image processing device 22 has an x of the barycentric position O of the photographed reference pattern and the prestored barycentric position origin O _{0 at} each measurement position.
Misalignment amount x ₁ in each of the axial direction and the y-axis direction,
The y ₁ is calculated and output to the arithmetic unit 30.

The arithmetic unit 30 calculates the positional deviation amount data x ₁ ,
The amount of strain at each measurement point is calculated by correcting the relative displacement data previously obtained based on y ₁ . As described above, according to the present embodiment, it is possible to measure a large strain amount of the long material 1 by combining the displacement measuring device 7-1 (7-2) and the rotary encoder 32-1 (32-2). At the same time, the error caused by the self-propelled measuring device 2 can be accurately corrected, so that the accurate strain amount of the long material 1 can be measured.

In the above description, the displacement measuring device 7-1
(7-2) to stepping motor 31-1 (31-2)
However, it may be moved by another drive mechanism such as a servo cylinder. Further, the movement amount of the displacement measuring device 7-1 (7-2) at this time is measured by the rotary encoder 32-1 (32-2) on the carriage of the measuring device 2, but it is measured by the feed monitor or the camera 21. The amount of movement may be detected by photographing and performing image processing.

In the above embodiment, the movement of the displacement detector is indirectly measured by the rotary encoder 32 and fed back to the arithmetic unit 30. In the semi-closed loop, the linear scale is used. Closed loop, or open loop control in which a part of the signal sent from the analog / pulse converter 33 to the stepping motor 31 is input to the arithmetic unit 30 and the movement amount is judged without providing a measuring device. May be. The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the spirit of the present invention.

[0032]

As described above in detail, according to the present invention, the position control is performed so that the relative displacement of the long material with respect to the displacement measuring device is kept constant. The measurement range can be narrowed, and the measurement accuracy can be improved if the displacement measuring devices have the same resolution. Further, since the measuring device itself can be made small, it becomes possible to select a sensor having an appropriate size for a long material, and more accurate measurement can be performed. Further, the method of detecting the movement amount of the displacement measuring device can be selected according to the application. Furthermore, since the output signal of the displacement measuring instrument is used as the drive source of the actuator that moves the displacement measuring instrument itself, the followability is good and the system configuration is simple.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a long material straightness measuring device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of an electric system in the long material straightness measuring device shown in FIG.

3 is a diagram showing a relationship between a displacement amount detected by a displacement measuring device and a moving amount of the displacement measuring device itself in the long material straightness measuring device of FIG.

FIG. 4 is a perspective view showing a conventional long material straightness measuring device.

FIG. 5 is a diagram showing a relationship between a long material and a displacement measuring device.

FIG. 6 is an explanatory diagram showing the relationship between the origin of the center of gravity of the reference pattern and the center of gravity of the reference pattern at a certain measurement point.

FIG. 7 is a diagram showing a relationship between a measurement reference position of a displacement measuring device, a measurement range, and output characteristics.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Long material, 2 ... Running measuring device, 2a ... Measuring device truck, 3 ... Running platform, 4a, 4b ... Guide rail, 5 ... Servo motor, 6 ... Rack, 7-1 ... X displacement measuring device, 7 -2
... Y displacement measuring device, 13 ... Roller device, 14 ... Clamping device, 20 ... Reference pattern, 21 ... Television camera, 22 ...
Image processing device, 30 ... Arithmetic device, 31-1, 31-28
... Stepping motors 32-1, 32-2 ... Rotary encoders, 33-1, 33-2 ... Analog / pulse converter.

Claims (3)

[Claims] 1. A straightness measuring device for measuring a strain of a long material by translating a displacement measuring device for detecting a relative displacement between the long material and the longitudinal direction of the long material, the displacement measuring device Traveling means for moving in parallel to the longitudinal direction of the long material, driving means for moving the displacement measuring device in a relative direction facing the long material based on a drive signal, and a displacement amount measured by the displacement measuring device. A conversion means for converting the displacement measuring device into a driving signal for moving the displacement measuring device to follow the strain of the long material and sending the driving signal to the driving means, and the converting amount of the strain amount measured by the displacement measuring device to the driving means. On the other hand, a straightness measuring apparatus comprising: a calculating unit that corrects the movement amount based on a movement amount instructed by a drive signal. 2. A straightness measuring device for measuring a strain of a long material by translating a displacement measuring device for detecting a relative displacement between the long material and the longitudinal direction of the long material. Traveling means for moving in parallel to the longitudinal direction of the long material, driving means for moving the displacement measuring device in a relative direction facing the long material based on a drive signal, and a displacement amount measured by the displacement measuring device. And a conversion means for converting the displacement measuring device into a driving signal for moving the displacement measuring device to follow the strain of the long material and sending the driving signal to the driving means, and indirectly or directly measuring the movement amount of the displacement measuring device by the driving means. A straightness measuring device, comprising: a measuring device for adjusting the strain amount; and a computing unit that corrects the strain amount measured by the displacement measuring device based on the movement amount of the displacement measuring device measured by the measuring device. 3. The straightness measuring device according to claim 1, wherein when the displacement measuring device is translated, a deviation amount of the displacement measuring device at each measurement position is detected. A straightness measuring device comprising: a deviation detecting means; and a correcting means for correcting the displacement amount measured by the displacement measuring device with the deviation amount detected by the deviation detecting means.