JPH06160033A - Measuring method of diameter - Google Patents

Abstract

PURPOSE: To measure stably accurately the diameter of a hose and a wire rod on-line without performing manual measurement. CONSTITUTION: A scanned laser light is branched, and one laser light is made incident on a sample object 8 side, and the other laser light is made incident on a grating 10 comprising multiple slits with a specified interval, and, based on the laser light, among the ones irradiated on the sample object 8 side, passing on both sides of the sample object 8, a gate signal corresponding to the diameter of sample object 8 is detected. Then, based on the laser light, among the ones irradiated on the grating 10, passing the slit with a specified interval, multiple count pulse signals corresponding to a specified interval are detected, and during a period of gate signal detection, each count pulse signal is counted. With the counting result, size conversion is performed with a specified interval or corresponding grating constant, and the diameter of sample object 8, which is the conversion result, is outputted.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to hose and wire rod diameter measurement technology, and more particularly to on-line measurement using laser beam scanning.

[0002]

2. Description of the Related Art Nowadays, in China, a hand measuring method is commonly used as a technique for measuring the diameter of a hose and a wire rod, for example. However, this manual measurement method has low accuracy and slow return of information, so it takes time,
In addition, there is a problem that the measured result meets the high rejection rate. Moreover, this manual measurement method is a heavy labor and a heavy burden on the measurement operator. On the other hand, in the United States, this kind of diameter measurement is performed by using a laser.

In the diameter measuring technique disclosed in US Pat. No. 4,007,158, the object to be measured is scanned by a parallel beam formed by a scanning mirror. When this parallel beam encounters the object to be measured, it is blocked and the shadow area ratio to the diameter of the object to be measured (shadow area pr
and is converted into an electrical signal after being received by the optoelectronic device. The diameter of the measured object can be obtained by multiplying the time for which the measured object shields the laser light and the scanning speed. The half peak is the half intensity part of the total peak that is attenuated. The intersection of the overall peak and the half peak is considered to be the tip of the half peak. It has the advantage that the heights of the overall peaks during the scanning period are essentially equal, and that the exact value of the diameter is obtained if the scanning speed is permanently constant.

[0004]

However, in the diameter measuring technique as described above, an accurate value of the diameter cannot be obtained unless the dedicated scanning mirror operates accurately in a wide range of scanning speeds. Guarantee of operation is required.

Further, since the obstacle of measurement is caused by dispersed light, the laser device is required to have high stability in order to obtain a stable peak value. As a result, the manufacturing cost of the laser device is rising. An object of the present invention is to provide a diameter measuring method capable of stably and accurately measuring the diameters of a hose and a wire rod online without relying on manual measurement.

[0006]

According to a first aspect of the present invention, in a diameter measuring method for measuring a diameter of an object to be measured by scanning the laser beam, the scanned laser beam is branched, and one of them is divided. Of the laser light of the laser beam irradiating the measured object side, the other laser beam is irradiated to the grating having a plurality of slits at predetermined intervals, and the measured laser beam is irradiated to the measured object side. Based on the laser light passing through both sides of the object, to detect the gate signal corresponding to the diameter of the object to be measured, of the laser light irradiated to the grating, the laser light passing through the slits of the predetermined interval A plurality of counting pulse signals corresponding to the predetermined interval based on the above, counting each counting pulse signal during the detection period of the gate signal, and the predetermined interval or a grid corresponding to the counting result. Subjected to size conversion by number, the diameter measuring method for outputting the diameter of the measured object is the result of conversion.

Here, in particular, as the gate signal, the laser beams passing through both sides of the object to be measured are converted into pulse signals, and the values at the tops of these pulse signals are smoothed and held, and the respective pulses are Detect a plurality of half peaks corresponding to half the held value from the signal, find each half peak that is detected from different pulse signals and faces each other among these half peaks, and the interval between the corresponding half peaks May be the effective interval of the gate.

As the above-mentioned scanning, the scanning is performed by disposing a common-focus lens on the central optical axis of the scanned laser beam by the focal length thereof from the scanning unit, and scanning by the scanning unit. Light may be transmitted through the common focus lens.

[0009]

Therefore, according to the invention corresponding to claim 1, by taking the above-mentioned means, the laser beam to be scanned is branched, and one of the laser beams is irradiated to the object to be measured to emit the laser beam. Detects a gate signal corresponding to the diameter of the measured object to be shielded, and irradiates the other laser beam to the grating and counts a plurality of counts corresponding to the predetermined intervals of the slit from the laser beam that has passed through the slit of the grating. Pulse signal is detected,
The diameter of the object to be measured is measured by counting each counting pulse during the detection period of the gate signal and converting the counted counting pulses into dimensions, so that the hose and wire can be measured online without using manual measurement. The diameter of the rod can be measured stably and accurately.

According to the second aspect of the invention, the pulse signal, which is detected from both sides of the object to be measured and whose intensity changes when shielded by the object to be measured, holds the value at the top of the pulse signal. As a result, the half peak when the intensity changes can be accurately obtained, and the gate signal is created with the interval of the half peak as the effective interval, so that the measurement accuracy of the diameter measurement can be improved.

In the invention according to claim 3, since the common focus lens can replace the scanning lens that makes the scanned laser light parallel, the versatility of diameter measurement can be improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are block diagrams showing the structure of a diameter measuring apparatus according to an embodiment of the present invention. This diameter measuring device is provided with a laser 2 which emits a laser beam by electric power supplied from a laser power source 1, and a laser beam expanded 5 times by a beam expander 3 arranged on the optical axis of the laser 2. Is reflected by a total reflector 4 having a width of 20 mm and a height of 60 mm, and is incident on a scanning rotary mirror 5 rotatably supported by a motor 5a. The scanning rotary mirror 5 is formed in a cylindrical shape and has 18 reflecting surfaces on the outer peripheral portion thereof, and the motor 5a has a cylindrical central axis as a rotation center.
It has a function of sequentially reflecting the laser light incident from the total reflector 4 and scanning the laser light by being rotationally driven by.

The scanning lens 6 has a focal length of 40.
It is arranged on the reflection optical axis of the scanning rotary mirror 5 apart from the reflecting surface of the scanning rotary mirror 5 by 0 mm, and emits a laser beam scanned by the scanning rotary mirror 5 as a parallel beam. The effective diameter of the scanning lens 6 is 60 mm.

The half mirror 7 has, for example, a width of 20 mm and a height of 60 mm, is arranged on the emission optical axis of the scanning lens 6, splits a parallel beam emitted by the scanning lens 6 into both, and outputs one parallel laser beam. Is sent to the first light receiving lens 9 via the measured object 8 arranged on the emission optical axis of the scanning lens 6, and the other parallel beam is sent to the second light receiving lens 11 via the grating 10. I have In addition, here, the measured object 8 has an effective diameter of the scanning lens 6 of 6
Since it is 0 mm, it has a diameter of 0.1 mm to 50 mm.

Here, when the first light receiving lens 9 receives the laser light that has passed through both sides of the object 8 to be measured among the parallel laser light sent from the half mirror 7, it refracts the received laser light. And has a function of condensing the object defining light signal on a first photoelectric conversion light receiver 12 provided on the central optical axis at a focal distance from the first light receiving lens 9 main body. There is.

The first photoelectric conversion receiver 12 is, for example, a silicon PIN capable of detecting light having a wavelength up to 900 nm.
When it is a photoelectric conversion diode and has a light receiving surface with a diameter of 4 mm, and receives the object defining optical signal condensed by the first light receiving lens 9, the received object defining optical signal is converted into an electrical object defining electrical signal. It has a function of converting and applying to the first signal processing unit 13.

The first signal processing section 13 creates a gate signal corresponding to the diameter of the object 8 to be measured on the basis of the object-determining electric signal received from the first photoelectric conversion photodetector 12, and makes it to the counter 14. It has a function to output. The specific configuration will be described later.

On the other hand, in the grating 10, a plurality of slits are formed at predetermined intervals, and the scanned parallel laser light received from the half mirror 7 is intermittently passed by the slits and applied to the second light receiving lens 11. It has a function to do. It should be noted that the slits of the lattice 10 are formed in a width of 1 mm so that the lattice constant is, for example, 5 slits / mm.

When the second light-receiving lens 11 receives the parallel laser light that has passed through the grating 10, it refracts the received parallel laser light into a grating light signal, and this grating light signal is used at the focal length of the light-receiving lens 11. The light is condensed and incident on the second photoelectric conversion photodetector 15 arranged on the central optical axis thereof with a distance of 30 mm.

The second photoelectric conversion photodetector 15 receives the lattice light signal condensed by the second light receiving lens 11 and converts it into a lattice electric signal of an electric digital pulse corresponding to the lattice constant, and second It is applied to the signal processing unit 16 of.

The second signal processing unit 16 has a function of multiplying the frequency of the grid electric signal applied from the second photoelectric conversion photodetector 15 and sending the multiplied counting pulse signal to the counter 14. There is. Here, the signal frequency is set to 2
It is set to make it 0 times.

When the gate signal received from the first signal processing unit 13 is applied to the counter 14, the second signal processing unit 1
The number of pulses of the counting pulse signal applied from 6 is counted,
It has a function of dividing the counting result (x lines) by the lattice constant (5 lines / mm) and the frequency multiplication factor (20 times). The result of this division is sent to the display unit 17 as the diameter of the measured object 8. The display unit 17 outputs the diameter of the measured object 8 obtained by the counter 14.

Next, a specific configuration of the first signal processing section 13 for producing a gate signal will be described with reference to FIG. The first signal processing unit 13 is an operation including an amplifier L1 for amplifying a target confirmation signal received from the first photoelectric conversion light receiver 12 and an operational amplifier 21 and a resistor R1 connected between its input terminal and output terminal. The amplifier circuit is connected, and the RC circuit and the follower 22 are connected to the output section of the operational amplifier circuit via the double phase door circuit L2. The output of the follower 22 and the output of the amplifier L1 are connected to the gate signal output L3. Here, the amplifier L1 is, for example, an "LM318" operational amplifier. Further, the double phase door circuit L2 is a switch controlled to be turned on / off by the amplifier L1, and for example, a 2-way analog switch of "4066" is used.

The RC circuit holds and smoothes the output of the amplifier L1 via the double phase door circuit L2, and then the follower 2
2, R is set to 1 kΩ and C is set to 1 μF. Further, load resistors R2 and R3 are connected to the output part of the follower 22. The resistor R2 and the resistor R3 are connected to the negative side input terminal of the operational amplifier 21.

On the other hand, the gate signal output section L3 has a comparator 23 connected to the resistor R4 for dividing the output signal voltage of the follower 22 into 1/2 and the output section of the amplifier L1. The output section is connected to the AND circuit 24. The gate signal output section L3 has a pulse shaping circuit 25 connected to the output of the amplifier L1. The output section of the pulse shaping circuit and the output section of the comparator 23 are connected to the counter 14 via the AND circuit 24. Connected to.

Here, the comparator 23 is set to 1 by the resistor R4.
A half-peak intensity of the amplifier L1 obtained by dividing the voltage by 1/2 is compared with the output of the amplifier L1, and a half-peak detection signal is sent to the AND circuit 24 when the output of the amplifier L1 is smaller than the half-peak intensity. Is. In addition,
This half-peak detection signal indicates a case where the output of the amplifier L1 is small because the laser light is blocked by the measurement target 8.

Further, the pulse shaping circuit 25 has a function of producing a measurement effective signal indicating an effective scanning range based on the output of the amplifier L1 and sending the measurement effective signal to the AND circuit 24.

The AND circuit 24 allows the half-peak detection signal received from the comparator 23 to pass during the period in which the pulse shaping circuit 25 sends the measurement valid signal, and the passed half-peak detection signal to the counter 14 as a gate signal. To give. Next, a diameter measuring method by the diameter measuring device configured as described above will be described with reference to FIGS. 3 to 5.

First, the beam from the laser 2 reaches a scanning rotary mirror 5 driven by a motor via a beam expander 3 and a total reflector 4. Since the reflective side surface of the scanning rotation mirror 5 is provided at the focal point of the scanning lens 6, the laser light scanned by the scanning rotation mirror 5 is refracted when passing through the scanning lens 6 to form parallel laser light. .

This parallel laser beam is split into two optical paths via the half mirror 7, one of which is irradiated on the measured object 8 side and the other of which is irradiated on the grating 10 side. The laser beam applied to the measured object 8 side is shielded by the measured object 8 and passes on both sides thereof, and a shaded area and a light receiving area corresponding to the diameter of the measured object 8 are formed. The light receiving lens 9 of No. 1 is irradiated. The parallel laser light with which the first light receiving lens 9 is irradiated has a focus formed by the first light receiving lens 9 and is received by the first photoelectric conversion light receiver 12 as a target confirmation light signal. On the other hand, the parallel laser light applied to the grating 10 intermittently passes through the slits of the grating and is applied to the second light receiving lens 11, and the second light receiving lens 11
Thus, a focal point is formed and is received by the second photoelectric conversion photodetector 15 as a grating light signal.

Here, the spot of the laser light incident on the object 8 to be measured has a geometric dimension as shown in FIG. Therefore, when the laser light scans the object 8 to be measured, the light receiving area and the shadow area do not instantaneously transition at the boundary, but the light receiving area and the shadow area continuously transition within a predetermined time. To be done. Geometrically, when half of the spot of the laser light is shielded by the measured object 8, the diameter of the measured object 8 can be accurately obtained. Further, this diameter is obtained by obtaining the effective shadow area time by the difference between the time Tb of one half peak and the time Te of the other half peak, and converting the effective shadow time into the length. . In the figure, Vs
And Vw respectively indicate the target confirmed electric signal when the light is strong and when the light is weak.

The first photoelectric conversion photodetector 12 receives an object defining optical signal having a shaded area and a light receiving area corresponding to the diameter of the object 8 to be measured, and outputs the object defining optical signal as an electrical object defining electrical signal. It is converted into a signal and applied to the first signal processing unit 13. When the target confirmation electric signal is applied, the first signal processing unit 13 amplifies the target confirmation electric signal by the amplifier L1 to create an L1 output signal as shown in FIG. The output signal is the resistance R1 and the operational amplifier 2
1 to the double phase door circuit L2. The double-phase door circuit L2 is in an open state when the L1 output signal is at a high level to allow the L1 output signal to pass therethrough to be supplied to the RC circuit, and is in a closed state when the L1 output signal is at a low level to output the L1 output. Block the signal.

Here, as shown in FIG. 4 (b), the RC circuit is L level when the double phase door circuit L2 is in the open state.
1 output signal is charged (time Tg, Ti), and when the double-phase door circuit L2 is in the closed state, the charged L1 output signal is discharged (time Th, Tj) to hold and smooth the L1 output signal to RC. Create a voltage signal. Also, R
The C circuit applies the RC voltage signal to the voltage dividing resistor R4 in the gate signal output section L3 via the follower 22. The value V2 of the RC voltage signal almost exactly matches the high level value V1 of the L1 output signal. Therefore, the RC voltage signal is divided by 1/2 by this voltage dividing resistor R4, and V1
It is applied to the comparator 23 as a / 2 signal. On the other hand, the L1 output signal is also sent from the amplifier L1 to the comparator 23 and the pulse shaping circuit 25.

The comparator 23 compares the first and second pulses included in the L1 output signal with the V1 / 2 signal as shown in FIG. 5C, and the L1 output signal is smaller than the V1 / 2 signal. Only at this time, a half peak detection signal is generated as shown in FIG. 5D, and the half peak detection signal is sent to the AND circuit 24.

Further, the pulse shaping circuit 25 is shown in FIG.
As shown in FIG. 2, of the first and second pulses that are the L1 output signal, the first pulse rises from the completion time T2 to the second pulse.
The measurement effective signal having the pulse width up to the falling start time T5 of the pulse is generated, and the pulse output signal is output to the AND circuit 24.

The AND circuit 24 allows the half-peak detection signal output from the comparator 23 during the output period of the measurement valid signal by the pulse shaping circuit 25 to pass as a gate signal as shown in FIG. Output to the counter 14.

On the other hand, the second photoelectric conversion photodetector 15 has the grating 1
Receiving the intermittent grating light signal corresponding to the slit of the grating of 5 lines / mm through the 0 and the second light receiving lens 11,
This grating optical signal is converted to a digital electrical grating electrical signal as shown in FIG. 5 (g) and applied to the second signal processing section 16. The second signal processing unit 16 multiplies the frequency of this grid electric signal by 20 and, as shown in FIG. 5 (h), the counter 14 as a counting pulse signal corresponding to 100 pulses / mm.
Send to.

The counter 14 obtains the counting pulse signal received from the second signal processing unit 16 during the output period of the gate signal by the first signal processing unit 13 as shown in FIG. Count pulse signals. Also, the counter 1
4 obtains the diameter of the measured object 8 by dividing the counting result by the lattice constant and the frequency multiplication factor, and sends the diameter value to the display unit 17. The display unit 17 outputs the diameter of the measured object 8 obtained by the counter 14.

As described above, in this embodiment, the gate signal corresponding to the diameter of the object 8 to be measured which splits the laser beam to be scanned and irradiates one of the objects to be measured 8 to shield the laser beam. Is detected, and a plurality of counting pulse signals corresponding to the predetermined intervals of the slits of the grating are detected from the laser light that has passed through the grating 10 by irradiating the other with the gate signal and each counting pulse signal. Since the diameter of the measured object is measured by counting how many times the diameter of the measured object is the predetermined interval of the slit, the diameter of the hose and wire rod can be stabilized online without relying on manual measurement. Can be measured accurately.

Further, in this embodiment, an RC circuit is provided, and by holding and smoothing the laser light whose intensity changes due to the shielding by the object to be measured detected from the object side to be measured by the RC circuit. Since the half peak when the intensity changes can be easily detected and the gate signal is generated from the interval of the half peak, the measurement accuracy of the diameter measurement can be improved.

Further, in the present embodiment, since the dedicated scanning lens for collimating the scanned laser beam can be replaced with a general common focus lens, the versatility of diameter measurement can be improved and at the same time, It is possible to drastically reduce the manufacturing cost of the device body.

Further, in this embodiment, since a bundle of parallel laser beams simultaneously scans the object to be measured and the grating, fluctuations in the motor rotation, system malfunctions and instability of tolerances caused by many external factors. Can be eliminated and the reliability of measurement can be improved.

In this embodiment, the half peak detection is performed after smoothing the electric signal (L1 output signal), and the instability due to the dispersed light and the instability of the laser power are completely eliminated due to the adverse effect caused by the measurement. Since it is solved, accuracy and stability can be improved. Further, in this embodiment, the non-contact diameter measurement of the hose and the wire rod can be realized with high reproducibility by an easy operation.

Further, in the present embodiment, for example, when applied to the product inspection at the time of manufacturing, the diameter measurement is performed with high accuracy and accuracy, so that the manufacturing work is efficiently improved, and the waste of raw materials is reduced. , Can save huge amount of raw material and get great profit.

In the above embodiment, the case where only the diameter measurement is performed has been described, but the present invention is not limited to this. For example, a RAM that stores a set value, a CPU that compares the measured value with the set value, and the comparison result. Even if the upper and lower limit alarm function including an alarm device that outputs an alarm when an abnormality is shown is added and the diameter of the object to be measured is inspected, the same effect can be obtained by implementing the present invention. be able to.

In the above embodiment, the case where only the measured value is output has been described. However, the present invention is not limited to this, and the standard value and the deviation value of each measured value are also output based on a large number of measured values. Even in the configuration, the present invention can be implemented in the same manner and the same effect can be obtained.

In the above embodiment, the case where the hose and the wire rod are used as the object to be measured has been described, but the present invention is not limited to this, and the diameter can be measured like a measurement cable, a rubber hose, a plastic hose and the like. The same effect can be obtained by carrying out the present invention in the same manner, regardless of what is measured.

Further, in the above embodiment, the case where the diameter is measured has been described. However, the present invention is not limited to this. For example, a rectangular parallelepiped is used as an object to be measured to measure the length of a side or the length of a diagonal line. Even if the length is measured, the same effect can be obtained by implementing the present invention in the same manner.

Further, in the above embodiment, the case where the counting result of the counting pulse signal is divided by the lattice constant and the frequency multiplication factor has been described, but the present invention is not limited to this, and the counting result is a predetermined slit interval (0.2 mm / piece). ), And a configuration in which the frequency multiplication factor is used for division, the same effects can be obtained by implementing the present invention in the same manner. In addition, the present invention can be modified in various ways without departing from the scope of the invention.

[0051]

As described above, according to the present invention, a laser beam to be scanned is branched and one of the laser beams is irradiated onto the object to be measured to detect a gate signal corresponding to the diameter of the object to be measured. , Irradiating the other side of the grating with a plurality of pulse signals corresponding to the predetermined intervals of the slits of the grating, counting each counting pulse during the detection period of the gate signal, and slitting each counting pulse counted. Since the diameter of the object to be measured is measured by converting the dimensions based on the specified interval of, the diameter of the hose and wire rod can be measured stably and accurately online without relying on manual measurement. A measurement method can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a diameter measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a first signal processing unit in the embodiment.

FIG. 3 is a diagram for explaining a target confirmation electric signal in the embodiment.

FIG. 4 is a time chart showing holding and smoothing of a signal related to half peak detection in the example.

FIG. 5 is a time chart showing from the L1 output signal to the counting of counting pulse signals in the embodiment.

[Explanation of symbols]

1 ... Laser power supply, 2 ... Laser, 3 ... Beam expander, 4 ...
Total reflector, 5 ... Scanning rotation mirror, 5a ... Motor, 6 ... First scanning lens, 7 ... Half mirror, 8 ... Object to be measured, 9 ... First light receiving lens, 10 ... Lattice, 11 ... Second Light receiving lens, 12 ... First photoelectric conversion light receiver, 13 ... First
Signal processing unit, 14 ... Counter, 15 ... Second photoelectric conversion light receiving device, 16 ... Second signal processing unit, 17 ... Display unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Li Feng Shan China Beijing, Heidianchu, Chinhwayuan (No house number) in Cinfa Dashue (72) Inventor Ryu Dashao People's Republic of China Beijing, Heidianchu, Chinhhuayuan (No house number) Inside Chinfa Darshwe

Claims (3)

[Claims] 1. A diameter measuring method for measuring a diameter of an object to be measured by scanning laser light, wherein the scanned laser light is branched, and one of the laser lights is irradiated to the object to be measured side. , Irradiating the other laser light to the grating having a plurality of slits at predetermined intervals, among the laser light radiated to the measured object side, based on the laser light passing through both sides of the measured object, A gate signal corresponding to the diameter of the object to be measured is detected, and based on the laser light passing through the slits at the predetermined intervals among the laser lights applied to the grating, a plurality of counts corresponding to the predetermined intervals. A pulse signal is detected, each of the counting pulse signals is counted during the detection period of the gate signal, and the count result is subjected to size conversion by the predetermined interval or a lattice constant corresponding thereto, and the conversion result Diameter measuring method and outputting the diameter of a said measured object. 2. The gate signal converts laser light passing through both sides of the object to be measured into pulse signals, holds the values of the tops of these pulse signals in a smoothed state, and holds the values from each of the pulse signals. Detect a plurality of half peaks corresponding to half of the held value, find each half peak that is detected from different pulse signals and face each other among these half peaks, and determine the interval between the corresponding half peaks of the gate. The diameter measuring method according to claim 1, wherein the effective interval is set. 3. In the scanning, a common focus lens is arranged on the central optical axis of the scanned laser light at a focal distance thereof from the scanning unit, and the laser light scanned by the scanning unit is moved to the common focus. The diameter measuring method according to claim 1, which is performed by transmitting the light through a lens.