JPH11153409A - Long body length measuring method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a length measuring method and device in which length measuring error does not occur based on irregularity condition (including holes, grooves, etc., in a subject body, or partial humps by corrugated board or paper. SOLUTION: Three Doppler sensors A, B, C are provided, each Doppler sensor radiates a laser beam in a length direction of a long body which is continuously running, and modulated light of difusion light from the long body by Doppler effect is detected as a Doppler signal. A device is also provided with a signal synthesizing circuit 12 to synthesize plural Doppler signals detected by the respective Doppler sensors A, B, C, and a circuit 13 to operate moving speed and moving quantity of the long body based on a synthesized Doppler signal outputted from the signal synthesizing circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical material (for example, a pipe, an electric wire, a round bar, etc.), a triplex electric wire (a thick stranded wire), a wire rope (a thick material), a steel material, and a paper, a corrugated cardboard, etc. In the field of measuring the amount of movement of a long object, the present invention relates to a method and apparatus for measuring the amount of movement of a moving long object in a non-contact manner.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the length of a continuously running long object, a pulse is generated for each unit rotation amount using a pulse encoder, and the movement amount is measured. For example,
As shown in FIG. 7, a thick stranded electric power cable (hereinafter, referred to as a triplex electric wire) 51 that continuously runs is sandwiched and conveyed by a caterpillar 52. A pulse is generated for each unit rotation amount by a pulse encoder 54 attached to the caterpillar 52, the moving amount (speed) of the continuously running long object 51 is measured, and the long object is cut by the cutter 53.
In addition, 55 is a motor for driving the cabilla, 56 is a motor driving device, 57 is a control device, and 58 is a setter for various data.

The triplex type electric wire 51 uses a caterpillar method because the material itself is twisted (stranded), but the caterpillar method cannot be conveyed at a high speed due to the structure of the machine. The productivity is low and the measurement error is several centimeters.

[0004] Further, in a continuous cutting device for a continuously running cylindrical material or the like (for example, a pipe or a round bar) shown in FIG. 8, a long object 61 is nipped (contacted) by a measuring roll 62,
The measuring roll 62 rotates as the long object 61 travels, and a pulse is generated for each unit rotation amount by the pulse encoder 64, and while the moving amount (speed) of the continuously traveling long object 61 is measured, the cutter 63 is used. Cut long objects.
In addition, 65 is a motor for driving the cutter, 66 is a motor driving device, 67 is a control device, and 68 is a setter for various data.

[0005] Of these cylindrical materials, for example, oil, water and the like may adhere to long surfaces such as pipes and round bars, so that the measuring roll 62 slips during running. . A measuring roll 62 is provided on the surface of a long object.
There is an error in the measurement due to abrasion caused by the nip pressure, or wear of the measuring roll 62 over time.

Similarly, in a rotary cutter (not shown) for cutting long objects such as paper and corrugated cardboard, long objects such as continuously running paper and corrugated cardboard are nipped (contacted) by measuring rolls to form long objects. The measuring roll rotates as the vehicle travels, and a pulse is generated for each unit rotation amount by a pulse encoder to measure the moving amount (speed) of the continuously running long object. If a partial hump (bulge) occurs in the running paper or cardboard, the measuring roll rises and an error occurs in the measurement.

In order to solve some of the problems described above,
Laser measurement by optical detection means has been attempted as a method for measuring the amount of movement of a long object such as paper, cardboard, or the like that travels continuously without contact. In the laser measuring device using the optical detecting means, a continuously traveling long object is irradiated with laser light from a Doppler sensor, and modulated light due to the Doppler effect of the scattered light is detected by the optical means. A method of measuring the speed of an object has been used.

[0008] An example of such a laser length measuring device is disclosed in Japanese Patent Publication No. 3-55797. According to this laser length measuring device, a continuously traveling steel material or the like is irradiated with laser light from a Doppler sensor, and modulated light due to the Doppler effect of the scattered light is detected by optical means. A correction circuit is provided to measure the speed and reduce the speed measurement error when the irradiation distance between the moving object and the optical detection means fluctuates.

Japanese Patent Application Laid-Open No. 2-145290 discloses an application example of an apparatus for measuring the speed of a continuously running cardboard by optical contact with an optical detecting means. This measuring device irradiates a laser in the longitudinal direction of a long corrugated cardboard, detects modulated light due to the Doppler effect of the scattered light by optical means, and generates a pulse from the Doppler signal due to the modulated light every unit movement of the corrugated cardboard sheet. Is generated, a predetermined moving amount of the sheet is detected from the number of pulses, and the speed of the moving object is measured.

[0010]

As described above, the speed of continuously running steel or corrugated cardboard has been measured in a non-contact manner by optical detection means. Surface irregularities (holes, grooves, etc.)
There is a problem that a length measurement error occurs due to the measurement, and a problem that a length measurement error occurs due to a partial hump (bulge) due to corrugated cardboard or paper.

When the speed of a continuously running cylindrical member or the like is measured in a non-contact manner by optical detection means, the cylindrical member or the like has a small area where the Doppler sensor can irradiate a laser beam and is affected by mechanical vibrations and the like. And the like itself oscillates up and down and left and right, so that the irradiation position of the laser beam may shift and the Doppler signal may be lost. Therefore, accurate measurement cannot be performed.
This is because the measurement range is limited by the curvature condition of the cylindrical member or the like even when the surface of the cylindrical member or the like is within the focal range of the Doppler sensor.

Similarly, for long objects such as triplex-type electric wires and wire ropes, since the material itself is twisted, furthermore, as described above, the condition of the focal range (distance) of the Doppler sensor and the length of the object are not limited. Since the measurement range is limited by the curvature condition of the measurement object, the irradiation position of the laser light of the Doppler sensor shifts, the Doppler signal is lost, and the length cannot be measured accurately.

Further, the processed steel material has holes, grooves, irregularities, and the like, and the irradiation position of the laser beam of the Doppler sensor shifts, and the Doppler signal is lost, so that accurate measurement cannot be performed.

As described above, these problems are caused by the conditions of the irradiation distance (focal range) of the laser beam of the Doppler sensor,
Since the measurement range is limited by the surface condition of the measured object and the curvature condition of the measured object, a remarkable advantage of measuring the length of the moving object in a non-contact manner is lost.

An object of the present invention is to provide a method and an apparatus for measuring a long object which have solved the above-mentioned problems.

[0016]

According to the method for measuring the length of a long object according to the present invention, a plurality of Doppler sensors are set at positions corresponding to the movement of a continuously running long object. Laser light is irradiated in the longitudinal direction of the long object to be detected, the modulated light due to the Doppler effect of the scattered light from the long object is detected as a Doppler signal, and a plurality of Doppler signals detected by each Doppler sensor are combined, and combined. The moving speed and moving amount of the long object are calculated from the obtained synthesized Doppler signal.

Further, the length measuring apparatus for a long object according to the present invention includes a plurality of Doppler sensors. Each Doppler sensor irradiates a laser beam in the longitudinal direction of the continuously running long object, and outputs the laser light from the long object. A signal combiner that detects modulated light due to the Doppler effect of the scattered light as a Doppler signal, and combines a plurality of Doppler signals detected by each Doppler sensor, and a combined Doppler signal output from the signal combiner to obtain a long object. Means for calculating a moving speed and a moving amount.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a length measuring device for a long object of the present invention. This length measuring device includes three Doppler sensors A, B, and C, a signal synthesis processing unit 2, and an arithmetic control unit 3.

The Doppler sensors A, B, and C irradiate a laser beam to a long object to be measured. That is,
Doppler sensor A is attached to surface A of a long object and Doppler sensor B
Irradiates a laser beam to the B surface of the long object, and the Doppler sensor C irradiates the C surface of the long object to the laser beam.

The signal synthesizing unit 2 includes a signal synthesizing circuit 11 for synthesizing a plurality of Doppler signals and a signal processing circuit 12. The arithmetic control unit 3 includes an arithmetic circuit 13, a control circuit 14, and an output circuit. 15, an F / V converter 16, a display 17, a setting device 18, and an interpolation circuit 19. The arithmetic circuit 13 and the control circuit 14 can be actually configured by a microcomputer.

FIG. 2 shows the principle of the Doppler sensor. As shown in FIG. 2, after the laser beam emitted from the laser light source 31 is converted into a parallel beam via a collimating lens 32, the laser beam is split into two by a beam splitter 33, one of which is made to go straight, and the other is made to be reflected by a mirror 34. Then, the moving moving object 35 is irradiated at the intersection angle. The scattered light from the moving object 35 is detected by a photodetector (APD) 37 via a light receiving lens 36. Doppler signal f _D obtained from the time the photodetector (APD) 37 is expressed by the following equation.

[0022]

(Equation 1)

Thus, the frequency of the Doppler signal f _D is
The frequency is proportional to the surface speed V of the moving object 35. Assuming that the distance that the object has moved at the speed V is S, S is expressed by the following equation.

[0024]

(Equation 2)

From the above formula of f _D , the speed V is:

[0026]

(Equation 3)

## EQU1 ## Therefore, the moving distance S is

[0028]

(Equation 4)

## EQU1 ## Based on the above principle, the speed V and the moving distance S of the moving object are obtained.

Returning to FIG. 1, each of the Doppler sensors A, B, C
The Doppler signals f _D 1, f _D 2, f _D 3 output from are sent to the signal synthesis circuit 11 of the signal synthesis processing unit 2.

FIG. 3 shows an example of the signal synthesis circuit. This signal combining circuit is a resistor combining circuit including resistors R1, R2, R3 connected to Doppler sensors A, B, C, respectively, and R4 connected to the ground. According to the resistance synthesis circuit, at a node D of the resistors R1, R2, R3, three Doppler signal f _D 1, f _D 2, f _D 3 are superimposed. The superimposed signal f _D is sent to the signal processing circuit 12.

[0032] In the signal combining circuit 11, the three Doppler sensors A, B, the Doppler signal f _D 1 from C, f _D 2, f
Of _D 3, even if any two of the Doppler signal is missing, at least one Doppler signal if it is detected, and outputs a Doppler signal f _D.

FIG. 4 is a block diagram showing the configuration of the signal processing circuit 12. This signal processing circuit generates the Doppler signal f
_This circuit removes noise superimposed on _D.

The frequency converter 21a outputs the Doppler signal f _D
Is converted to a frequency that can pass through the bandpass filter 22a. The frequency converter 21b further converts the output of the bandpass filter 22a to a frequency that can pass through the bandpass filter 22b. The converted frequency signal is reproduced by the PLL control oscillator 23a as a signal having a constant amplitude and the same frequency. The reproduced signal is converted to a voltage by the F / V converter 26. The frequency shift in the frequency converter 21a is taken out in the form of a voltage, and corrected by negative feedback to the PLL control oscillator 23b. In the frequency converter 21c, the frequency converter 21b
Is inversely transformed. Further by the frequency converter 21d, performs inverse transformation of the frequency converter 21a, back into the frequency of the Doppler signal f _D. In the above process, the bandpass filters 22a, 22
Noise is removed by 2b and 22c. In addition, 25 is a level detector.

The Doppler signal f _D from which noise has been removed is sent to the arithmetic circuit 13 of the arithmetic control unit 3. The arithmetic circuit 13 calculates the speed V and the moving distance S by the formulas 3 and 4. The laser wavelength λ, the beam crossing angle φ, and the deviation angle Δθ from the perpendicular of the beam normal and the moving object required for this calculation are set in advance by the setting unit 18. These set values are sent from the control circuit 14 to the arithmetic circuit 13.

The speed V calculated by the arithmetic circuit 13 is F /
It is converted into a voltage by the V converter 16 and output as a speed signal. The calculated moving distance is output from the output circuit 15 as a length measurement signal.

Hereinafter, the present invention will be further described with respect to a specific object to be measured (a long object). First, an embodiment of the length measuring device when the long object is a triplex type electric wire (thick stranded wire) will be described. As shown in FIG. 5, the triplex-type electric wire is an electric wire in which three thick electric wires 4-1, 4-2, and 4-3 are twisted (hereinafter, referred to as "twist"). When this triplex type electric wire is viewed from the side, the wire is gently twisted at intervals of, for example, several tens of centimeters or more. For this reason,
When the triplex wire is running, the triplex wire appears to rotate slowly in the cross section at the measurement position.

In order to correspond to these three electric wires, the Doppler sensor A is set vertically at a position where the longest measurement is possible from the upper part of the triplex electric wire. Doppler sensor B
Is set horizontally at the position where the longest length can be measured from the side of the triplex type electric wire. Further, the Doppler sensor C is set obliquely at a position where the longest length can be measured from obliquely above the triplex electric wire.

As described above, when the triplex type electric wire is viewed from the length measurement position of the Doppler sensor, the electric wires 4-1, 4
-2, 4-3 appear to run while rotating.
Therefore, the laser light of each Doppler sensor is transmitted by electric wires 4-1 and
Irradiation is performed while sequentially changing the surfaces of 4-2 and 4-3 and the groove between these electric wires.

The Doppler signals f _D 1, f _D 2, f _D 3 from the Doppler sensors A, B, C are superimposed in the signal synthesizing circuit 11. The triplex type electric wire has an uneven surface due to a stranded wire. However, by providing three Doppler sensors as described above, a Doppler signal is generated from at least one Doppler sensor. continuously Doppler signal f _D is output from the circuit 11. Therefore, although Doppler signals from at most two of the Doppler sensors A, B, and C may be lost, Doppler signals from the signal combining circuit 11 will not be lost.

As described above, even for a long object having irregularities on the surface such as a triplex-type electric wire, accurate speed and moving distance can be measured by using a plurality of Doppler sensors.

Next, a case where the object to be measured is a pipe will be described. In the case of a cylinder such as a pipe, the position (area) where the laser beam of the Doppler sensor can be irradiated on the surface of the cylinder is limited. Missing signal. The cause of the dropout is that the measurement range is limited by the curvature condition of the cylinder even in the focal range of the Doppler sensor.

FIG. 6 shows, according to the direction of the swing of the pipe,
An example in which a plurality of Doppler sensors are used to compensate for the limitation of the measurement range due to the curvature condition of the pipe will be described. FIG. 6 (a),
In FIG. 6B, two Doppler sensors A and B are connected as shown in FIG.
Uses three Doppler sensors A, B, and C.

The Doppler sensor A is mounted vertically on the top of the pipe 5 with respect to the center of the pipe 5, and the Doppler sensor B is mounted horizontally on the side of the pipe 5 with respect to the center of the pipe 5. C is attached obliquely above the pipe 5 at an angle to the center of the pipe 5.

The case of FIGS. 5A and 5B will be described. The moving pipe 5 is affected by mechanical vibration and the like.
In the case of swinging up and down as in (a), the irradiation position of the Doppler sensor B provided on the side is shifted with respect to the surface of the pipe, so that the Doppler signal f _D2 is missing. However, the Doppler sensor A provided on the upper side has a Doppler signal f _D 1
Is output normally, the signal combining circuit 11 outputs the Doppler signal f _D. Alternatively, when the running pipe 5 sways left and right under the influence of mechanical vibration or the like, the irradiation position of the Doppler sensor A provided at the upper part is shifted with respect to the pipe surface, so that the Doppler signal f _D 1 is missing. I do. However, the Doppler sensor B provided on the side
Output the Doppler signal f _D 2 normally, so that the signal combining circuit 11 outputs the Doppler signal f _D.
As described above, even if the pipe swings up and down and left and right during traveling, the Doppler sensor at the top or the side can output a Doppler signal, so that accurate speed and moving distance can be measured.

It is desirable to determine the swing direction of the pipe in addition to the vertical and horizontal directions and measure the swing direction, and to additionally set a Doppler sensor at an effective position. In the example of FIG. 6C, when the pipe sways in an oblique direction, the Doppler sensor C always outputs a Doppler signal. Thus, when three Doppler sensors are used, the pipe 5
At least 1
Since the Doppler sensors can output Doppler signals, it is possible to accurately measure the speed and the moving distance.

In each of the above embodiments, at least one Doppler sensor generates a Doppler signal, and the signal synthesizing circuit 1
It is assumed that one output exists. However, if all the Doppler sensors do not generate a Doppler signal for a short time due to the unevenness of the surface of the long object or unexpected shaking of the long object, the measurement is interrupted. If the workpiece is a work piece,
All of the plurality of Doppler sensors do not generate a Doppler signal, and the Doppler signal may be lost, and the measurement may be interrupted. In order to avoid such a situation, FIG.
The arithmetic circuit 3 includes an interpolation circuit 19 as shown in FIG.

The interpolation circuit 19 constantly monitors the Doppler signal f _D output from the signal synthesizing circuit 11, and immediately enters the hold operation when the Doppler signal is interrupted.
Holds the previous Doppler signal. Interpolation circuit 19
Supplies the held f _D to the signal processing circuit 12.
This allows the measurement to continue without interruption. When the output of the Doppler signal f _D from the signal synthesizing circuit 11 is resumed, the interpolation circuit 19 stops the supply of the hold value.

As described above, while the Doppler signal from the signal synthesis circuit is interrupted, the held Doppler signal is supplied from the interpolation circuit 19, so that the measurement is not interrupted.

[0050]

As described above, according to the present invention, according to the method and apparatus for measuring a long object using a Doppler sensor, a plurality of Doppler sensors are used, and a Doppler signal from these Doppler sensors is used. As long as at least one Doppler sensor normally generates a Doppler signal, the combined Doppler signal is always output, so that irregularities (holes, grooves, etc.) on the surface of the object to be measured can be eliminated. The present invention has solved the problem that a length measurement error occurs due to a partial hump caused by a cardboard card, paper, or the like. In addition, when the object to be measured is a cylinder, the limitation of the measurement range due to the curvature condition of the cylinder is solved.

Further, when an interpolating circuit is provided, interruption of the measurement can be prevented even if the output of the signal synthesizing circuit is interrupted.

As described above, according to the present invention, it is possible to realize a method and an apparatus for measuring a long object without losing the remarkable advantage of measuring a moving object in a non-contact manner.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a length measuring device for a long object of the present invention.

FIG. 2 is a diagram for explaining the principle of a Doppler sensor.

FIG. 3 is a diagram illustrating an example of a signal synthesis circuit.

FIG. 4 is a block diagram illustrating a configuration of a signal processing circuit.

FIG. 5 is a diagram showing an embodiment of a length measuring device when a long object is a triplex type electric wire (thick stranded wire).

FIG. 6 is a diagram showing an embodiment of a length measuring device when a long object is a pipe.

FIG. 7 is a diagram showing a caterpillar-type thick stranded cable transport device for electric power.

FIG. 8 is a view showing an inter-running cutting device for a continuously running cylindrical member or the like.

[Explanation of symbols]

 Reference Signs List 2 signal synthesis processing unit 3 operation control unit 11 signal synthesis circuit 12 signal processing circuit 13 operation circuit 14 control circuit 15 output circuit 16 F / V converter 17 display 18 setting unit 19 interpolation circuit 21a, 21b, 21c, 21d frequency conversion Devices 22a, 22b, 22c Bandpass filters 23a, 23b PLL controlled oscillator 24 Oscillator 25 Level detector 26 F / V converter 31 Laser light source 32 Collimating lens 33 Beam splitter 34 Mirror 35 Moving object 36 Light receiving lens 37 Light detector

Claims (8)

[Claims] 1. A plurality of Doppler sensors are set at positions corresponding to the movement of a continuously running long object, and each of the Doppler sensors irradiates a laser beam in a longitudinal direction of the continuously running long object, The modulated light due to the Doppler effect of the scattered light from the long object is detected as a Doppler signal, a plurality of Doppler signals detected by the respective Doppler sensors are combined, and the long object is obtained from a combined Doppler signal obtained by combining. And calculating a moving speed and a moving amount of the long object. 2. The method according to claim 1, wherein the combining of the plurality of Doppler signals is performed by superimposing the plurality of Doppler signals. 3. When all of the plurality of Doppler sensors do not detect a Doppler signal and the combined Doppler signal is missing, the combined Doppler signal immediately before the missing is held, and the combined Doppler signal is lost at the held value. 3. The method according to claim 1, wherein the synthesized Doppler signal is interpolated. 4. The length measurement of a long object according to claim 1, wherein the long object is any one of an electric wire or a stranded wire of a wire, a cylindrical material, and a processed material. Method. 5. A Doppler sensor comprising a plurality of Doppler sensors, each of which irradiates a laser beam in a longitudinal direction of the continuously running elongated object, and modulates light scattered from the elongated object by Doppler effect. A signal combiner that detects a Doppler signal and combines a plurality of Doppler signals detected by the Doppler sensors; and a combined Doppler signal output from the signal combiner.
Means for calculating a moving speed and a moving amount of the long object, a length measuring device for the long object. 6. The length measuring apparatus for a long object according to claim 5, wherein the synthesis of the plurality of Doppler signals is performed by superimposing the plurality of Doppler signals. 7. When all of the plurality of Doppler sensors do not detect a Doppler signal and the combined Doppler signal is missing, the combined Doppler signal immediately before the missing is held, and the combined Doppler signal is lost at the held value. 7. The apparatus according to claim 5, further comprising an interpolation circuit for interpolating the synthesized Doppler signal. 8. The length measurement of a long object according to claim 5, wherein the long object is any one of an electric wire or a stranded wire of a wire, a cylindrical material, and a processed material. apparatus.