JPH08233784A - Optical vibration detector - Google Patents

Abstract

PURPOSE: To obtain an optical vibration detector in which the positional relationship can be adjusted easily between an object and an optical head. CONSTITUTION: The optical vibration detector comprises an optical head 10 supported by a pan tilting mechanism 35 which is supported on a tripod 37 through a slide mechanism 36. Positional relationship between the optical head 10 and an insulator can be adjusted in the direction intersecting the line connecting them by means of the slide mechanism 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an optical vibration detection device used to determine the quality of an insulator from the vibration characteristics.

[0002]

2. Description of the Related Art For example, there is an optical vibration detection device (hereinafter referred to as a vibration detection device) as a device for determining the quality of an insulator suspended from a steel tower. The vibration detecting device includes an optical head having an irradiation optical system for irradiating the insulator with a laser beam and an optical receiving system for receiving a reflected laser beam from the insulator.

The optical head is supported on a tripod or the like via a pan (horizontal rotation) / tilt (vertical rotation) mechanism, and is arranged at an appropriate measurement position facing the insulator. Before the vibration measurement is started, the beam diameter of the laser light is expanded, and the insulator is irradiated with laser light for confirmation of reflection (hereinafter, confirmation laser light). Then, for example, the reflection state of the confirmation laser light captured by a television camera or the like provided in the optical head is confirmed by a display or the like. Accordingly, the optical head is operated by the pan / tilt mechanism to change the direction of the irradiation optical axis, and the optical head is fixed at the point where the insulator strongly reflects the confirmation laser light (hereinafter referred to as the strong reflection point).

In this state, the vibration detecting operation is started, and the confirmation laser light is applied to the insulator as vibration detecting laser light (hereinafter, irradiation laser light) whose beam diameter is narrowed. The irradiation laser light is reflected by an insulator that is vibrated by a sound wave applying device or the like, and is incident on the optical receiving system of the optical head as reflected laser light whose frequency has been shifted by the insulator. Then, the reflected laser light and the reference laser light serving as a standard of the frequency of the irradiation laser light are superposed in the same space, and optical interference occurs. The optical interference signal is converted into an electric signal by an optical / electrical converter, and FM demodulation is performed to measure the vibration of the insulator. In order to measure vibration, the intensity of the reflected laser light incident on the optical receiving system of the optical head must be sufficiently high and the interference beat level of the optical interference signal must be high.

[0005]

However, in particular, when the distance between the insulator and the optical head is large,
As described above, even when vibration detection is performed with the irradiation optical axis fixed to the strong reflection point, the level of the interference beat may not increase, and vibration measurement may become unstable or impossible.

As one of the causes of this, it is conceivable that the reflected laser light incident on the optical receiving system of the optical head has a bright and dark pattern. This bright and dark pattern is caused because the surface of the insulator has an uneven shape on the micro order. As shown in FIG. 5, the reflection angle of the irradiation laser light is slightly changed by the unevenness of the surface of the insulator 1, and the reflection is reflected. A bright portion (bright portion: portion where reflected laser light is strong) L2α and a dark portion (dark portion: portion where reflected laser light is dark) L2β are formed in the laser light L2. The distance between the light portion L2α and the dark portion L2β is equal to that of the insulator 1.
And the distance from the optical head increases.

Therefore, when the dark portion L2β is incident on the optical head, the interference beat level between the reflected laser light L2 and the reference light is not sufficiently increased, and accurate vibration measurement cannot be performed. In FIG. 5, the bright portions L2α and the dark portions L2β are depicted as being alternately arranged in the horizontal direction as an image, but in reality, the bright portions L2α and the dark portions L2β are actually arranged.
Are randomly present in the reflected laser light L2.

As described above, the dark portion L2 of the reflected laser light L2
When β is incident on the optical head, the optical head is moved together with the tripod that supports the optical head to shift the installation position, and the positional relationship between the optical head and the insulator 1 is set in a direction intersecting a straight line connecting them. It must be adjusted (this adjustment can be done manually).

However, if the installation position of the apparatus is shifted, the bright portion L2α of the reflected laser light L2 is not always incident on the optical head, and the above operation is repeated in some cases. Therefore, it is hard work to move the optical head, which is a heavy object, together with the tripod, and the positional relationship with the insulator 1 cannot be delicately adjusted.

Further, when the steel tower is installed in a mountainous area, etc., the places where the apparatus can be installed stably are limited,
It was not possible to move the entire device described above. The present invention has been made by paying attention to the problems existing in the above-mentioned prior art, and an object thereof is an optical vibration detection device capable of easily adjusting a positional relationship between an object to be measured and an optical head. To provide.

[0011]

In order to achieve the above-mentioned object, in the invention of claim 1, the optical head is supported by a support body through a slide mechanism, and the optical head and the optical head are supported by the slide mechanism. It is an optical vibration detection device configured so that the positional relationship with an object to be measured can be adjusted in a direction intersecting with a straight line connecting the two.

According to a second aspect of the present invention, the support is provided with a pan / tilt mechanism for horizontally and vertically rotating the optical head. In the invention of claim 3, the optical head is supported by a pan / tilt mechanism,
The tilt mechanism is supported by the support through a slide mechanism.

[0013]

According to the first aspect of the present invention having the above-mentioned structure, the positional relationship between the optical head and the object to be measured is changed by operating the slide mechanism while the dark portion of the reflected laser light is incident on the optical head. You can easily adjust to the straight line connecting the two and the crossing direction. As a result, the strong reflection point position of the irradiation laser light, that is, the uneven state of the object to be measured is subtly changed. Therefore, the pattern of the bright portion and the dark portion of the reflected laser light changes, and the bright portion is introduced into the optical head.

According to the second aspect of the invention, the strong reflection point search can be easily performed by the pan / tilt mechanism. In the invention of claim 3, the optical head is supported by a pan / tilt mechanism, and the pan / tilt mechanism is supported by a support through a slide mechanism. Therefore, the weight of the slide mechanism does not become a burden during the pan / tilt operation of the optical head, which requires higher accuracy than the slide operation.

[0015]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 6, an insulator 1 as an object to be measured.
Is suspended from a support arm 3 of a steel tower 2 that is erected on the ground, and insulates and supports a power transmission line 4. The optical vibration detecting device (hereinafter referred to as vibration detecting device) 5 is the tower 2
It is transported and installed in the vicinity, and it is designed to judge whether the insulator 1 is good or bad.

First, the optical head 10 constituting the present vibration detecting device 5 will be described. As shown in FIG. 1, the laser light generator 11 is arranged in the housing 12 and generates the laser light L. The first polarization beam splitter 13 is arranged on the front optical axis of the laser light generator 11, and the generated laser light L is partly moved straight by the same beam splitter 13 to become irradiation laser light L1 for vibration detection, and the rest. Is reflected in the right-angled direction to become the reference laser light L3 that serves as a frequency standard.

The second polarization beam splitter 14 is the first polarization beam splitter.
It is arranged on the straight optical axis of the polarization beam splitter 13 and linearly travels the irradiation laser beam L1. The concave lens 15 is arranged on the straight optical axis of the second polarization beam splitter 14, and expands the beam diameter of the irradiation laser light L1. The concave lens 15 is provided on a loading platform 16 that is slidable in the optical axis direction, and a linear moving mechanism 17 is connected to the loading platform 16. Therefore, the irradiation laser beam L1 can be switched to the reflection confirmation laser beam (hereinafter referred to as confirmation laser beam) L4 having a large beam diameter by the linear motion mechanism 17. The quarter-wave plate 18 is arranged in front of the concave lens 15 and changes the plane of polarization of the irradiation laser beam L1 from linearly polarized light to circularly polarized light. Through hole 12
α is formed through the wall surface of the housing 12 corresponding to the front of the quarter-wave plate 18, and a cylindrical body 19 is attached to the housing 12 so as to surround the through hole 12α. The objective lens 20 is arranged in the same cylindrical body 19, and the laser light L1 emitted through the objective lens 20 is applied to the insulator 1 as parallel light. The change in the beam diameter of the laser light L is not shown in the drawing.

Next, the optical receiving system will be described. In this embodiment, the irradiation optical system and the receiving optical system are the objective lens 20,
The quarter wavelength plate 18 and the second polarization beam splitter 14 are shared. Therefore, the optical axis of the irradiation optical system and the optical axis of the receiving optical system are aligned between them. And
The reflected laser light L2 from the insulator 1 is reflected by the objective lens 2
The light is incident on the second polarization beam splitter 14 through the 0, 1/4 wavelength plate 18 and reflected at a right angle. The third beam splitter 21 is arranged on the right-angled reflection optical axis of the second polarization beam splitter 14, and makes the reflected laser light L2 travel straight.

Next, the reference optical system will be described. An acousto-optic modulator 22 is arranged on the reflection optical axis of the first polarization beam splitter 13, and the acousto-optic modulator 22 is connected to it and is not shown in the drawing. High frequency application is driven by the circuit, and the frequency of the reference laser beam L3 is shifted. The reflection mirror 23 is arranged in front of the acousto-optic modulator 22 and reflects the reference laser beam L3 at a right angle. Then, the reference laser beam L reflected at a right angle by the reflection mirror 23.
The light beam 3 enters the third beam splitter 21 and is reflected by the beam splitter 21 at a right angle. Therefore, the reflected laser light L2 and the reference laser light L3
Are superposed by the third beam splitter 21 and interfere with each other. An optical / electrical converter 24 is arranged on the optical axis of the interference laser light L5, and the interference laser light L5 incident on the optical / electrical converter 24 is converted from an optical signal to an electric signal.

As shown in FIGS. 1 and 6, the optical head 10 having the above construction is provided with a measuring device 25 in parallel. That is, the demodulator 26 constituting the measuring device 25 is connected to the photoelectric converter 24 of the optical head 10. An interference beat level meter 27 and a frequency (vibration) analyzer (FFT analyzer) 28 are connected to the demodulator 26. Then, the electric signal input to the demodulator 26 is subjected to AM detection, and its value is displayed on the interference beat level meter 27 as the reception level of the interference laser light L5. Further, the electric signal is FM-detected and input to the frequency analysis device 28 as vibration data. The frequency analysis device 28 performs FFT transformation (Fourier transformation) on the vibration data to analyze the frequency and response level of the insulator 1.

In FIG. 6, reference numeral 29 denotes a speaker which constitutes a sound wave applying device as a vibrating device for vibrating the insulator 1. The speaker 29 is arranged near the vibration detecting device 5 and is directed to the insulator 1. ing.

Next, the support structure of the optical head 10 will be described. In FIG. 3, reference numeral 31 denotes a pan / tilt carrier, and a support shaft 32 extending in the left-right direction in the figure is rotatably held on the pan / tilt carrier 31. The optical head 10 configured as described above is fixed to the left end of the support shaft 32. The counterweight 33 is attached to the right end portion of the support shaft 32, and holds the support balance of the pan / tilt carrier 31. A motor (not shown) is connected to the support shaft 32, and the optical head 10 can be vertically rotated (tilt operation) about the axis T of the support shaft 32 by driving the motor.

Further, the pan / tilt carrier 31 is pivotally supported by a column 34 arranged below the pan / tilt carrier 31.
The tilt platform 31 is rotated in the left-right direction about the axis P of the column 34 by driving a motor (not shown) (pan operation).
It is possible.

The above structure constitutes the pan / tilt mechanism 35 for pan / tilt the optical head 10. In this embodiment, the pan / tilt mechanism 35 that supports the above-described optical head 10 is supported by the tripod 37 as a support body via the slide mechanism 36. That is, as shown in FIGS. 3 and 4, the guide frame 38 having a concave front shape is attached and fixed to the upper portion of the foldable tripod 37. The pair of guide rods 39 are supported on the front and rear sides of the guide frame 38 (on the front side and the back side in FIG. 3) between the side walls 38α facing each other. The screw rods 40 are arranged in the same direction between the guide rods 39, and one end of the screw rods 40 is connected to a drive motor 41 arranged outside the guide frame 38.

The slide carrier 42 has support legs 4 on the back side thereof.
2α, and the guide rod 3 is provided by the support leg 42α.
9 is gripped, and the slide carrier 42 is held on the guide frame 38 so as to be movable in the direction of the guide rod 39. Further, a screw receiving portion 43 having a screw hole 43α is provided at a substantially central portion on the back surface of the slide carrier 42, and the screw rod 40 is screwed into the screw hole 43α. Therefore, the screw rod 40 is rotated by the drive rotation of the drive motor 41, and the slide carrier 42 is slidable in the left-right direction as shown by the chain double-dashed line in FIG.

Then, the pan / tilt mechanism 35 having the above-mentioned structure
Are fixed on the slide loading platform 42 of the slide mechanism 36 by the columns 34, and the slide loading platform 42 described above is fixed.
The optical head 10 can be moved together with the pan / tilt mechanism 35 in the direction intersecting with the axis P of the support column 34 by the sliding movement of.

As shown in FIG. 2, an operating device 45 is connected via a controller 44 to the drive motor 41 for driving the slide mechanism 36 and the motor for driving the pan / tilt mechanism 35. The slide mechanism 36 and the pan / tilt mechanism 35 are operated via the operation device 45.

In FIG. 3, reference numeral 30 denotes a TV camera, and an image showing the irradiation state of the irradiation laser beam L1 captured by the TV camera 30 is displayed on a display (not shown).

Next, the operation of this embodiment will be described.
Laser light L output from the laser light generator 11
Enters the concave lens 15 through the irradiation optical system described above. At this time, the concave lens 15 is arranged at a position where the beam diameter is expanded by the linear movement mechanism 17. Therefore, the laser light L is applied to the insulator 1 as the laser light L4 for confirming the expansion of the beam diameter. This irradiation state is captured by the television camera 30, and its image is displayed on a display (not shown).

Then, the operator operates the pan / tilt mechanism 35 via the operation device 45 while confirming the irradiation state of the confirmation laser light L4 on the display, and the strongest reflected light of the confirmation laser light L4 is obtained. Optical head 10
Rotate up and down, left and right.

The optical head 10 has a confirmation laser beam L4.
It is fixed at a position (strong reflection point K) where the strongest reflected light of is obtained. In this state, the concave lens 15 is moved on the optical axis of the confirmation laser beam L4 by the linear movement mechanism 17, whereby the beam diameter of the confirmation laser beam L4 is narrowed and the irradiation laser beam L4.
Insulator 1 is irradiated as 1. Therefore, the reflected light intensity of the irradiation laser beam L1 is increased, and the vibration detection operation of the insulator 1 is performed.

That is, the irradiation laser beam L1 is reflected by the insulator 1 which is excited and vibrated by the sound wave of the speaker 29, and the objective lens 20 is reflected laser beam L2 frequency-shifted (Doppler-shifted) by the insulator 1. Is incident on. The reflected laser light L2 incident on the objective lens 20 reaches the second polarization beam splitter 14 via the quarter-wave plate 18, is reflected at a right angle there, and reaches the third beam splitter 21.

Then, the reflected laser light L2 incident on the third beam splitter 21 is superposed on the reference laser light L3 there and undergoes optical interference. The interference laser beam L5 is guided to the optical / electrical converter 24 and converted from an optical signal to an electric signal. The electric signal is AM-detected by the demodulator 26,
The reception level of the interference laser beam L5 is displayed on the interference beat level meter 27. Simultaneously with this AM detection, the same electric signal is also FM detected by the demodulator 26 and sent to the frequency analysis device 28 as vibration data. Vibration data is FFT-transformed (Fourier transform) by the frequency analysis device 28.
Then, the frequency and level of the insulator 1 are analyzed. Based on this result, it is judged whether the insulator 1 is good or bad.

However, the irradiation laser beam L1 is reflected at the strong reflection point K.
However, there is a case where the reception level of the interference laser beam L5 does not sufficiently rise even if it is possible to irradiate the light. This is because the dark portion L2β of the reflected laser light L2 is incident on the optical head 10 due to the unevenness of the surface of the insulator 1 as shown in the related art (shown in FIG. 5).

In such a case, in this embodiment, the slide mechanism 36 is operated via the operating device 45 to slide the optical head 10. As a result, the positional relationship between the optical head 10 and the insulator 1 is in a direction intersecting with a straight line that connects the optical head 10 and the insulator 1 (the same straight line as the laser beam L1 when the irradiated laser beam L1 is applied to the insulator 1). Adjusted. If this positional relationship is changed, the strong reflection point K is naturally changed, so that the pan / tilt mechanism 35 is again operated to fix the irradiation laser beam L1 to the strong reflection point K, and the interference beat level meter is measured. If it can be confirmed at 27 that the reception level of the interference laser light L5 is sufficiently increased, the vibration detection operation is performed at that position. However, if the reception level of the interference laser beam L5 does not rise, the sliding movement and pan / tilt operation of the optical head 10 are repeated.

That is, the slide mechanism 36 is operated to adjust the positional relationship between the optical head 10 and the insulator 1 in the intersecting direction with respect to the straight line connecting the both 1 and 10, so that the insulator 1 of the irradiation laser beam L1 is irradiated. The strong reflection point K is changed, and accordingly, the uneven shape of the surface of the insulator 1 at the strong reflection point K is changed. Along with this, the patterns of the bright portion L2α and the dark portion L2β of the reflected laser light L2 are changed, and the bright portion L2α is introduced into the optical head 10.

As described above, in this embodiment, by providing the slide mechanism 36, the positional relationship between the optical head 10 and the insulator 1 can be adjusted in the direction intersecting with the straight line connecting the both 1 and 10. . Therefore, even if the dark portion L2β of the reflected laser light L2 is incident on the optical head 10, it is not necessary to move the entire device 5 as in the conventional case, and the positional relationship can be adjusted by a simple and easy operation, Subtle adjustments are possible. Moreover, since it is not necessary to change the installation position of the device 5, it is effective even when the place where the device 5 can be stably installed is limited, such as in a mountain area.

Further, by providing the pan / tilt mechanism 35, the strong reflection point K can be searched easily and easily. Furthermore, for example, when the slide mechanism 36 is provided on the pan / tilt mechanism 35, the weight of the slide mechanism 36 makes it difficult to perform the pan / tilt operation with high accuracy of the optical head 10. However, in the present embodiment, this is not a concern because the pan / tilt mechanism 35 is provided on the slide mechanism 36 (the accuracy of the pan / tilt operation is not required for the sliding movement of the optical head 10).

The following embodiments can be carried out without departing from the spirit of the present invention. (1) To be used for vibration detection other than the insulator 1, for example, for detecting deterioration of a bridge or the like, which is difficult for an operator to approach. (2) The slide mechanism 36 includes a screw rod 40 and a screw hole 4.
Although it is configured by 3α, it may be changed to another linear reciprocating mechanism such as a rack and a pinion gear or a worm gear and a rack. Further, the slide loading platform 42 may be moved by a hydraulic cylinder. (3) The optical head 10 is supported by the slide mechanism 36, and the slide mechanism 36 is supported by the support body 37 via the pan / tilt mechanism 35.

The technical idea which can be understood from the above-mentioned embodiment will be described below. The optical head 10 of the receiving optical system and the optical head 10 of the irradiation optical system are independently provided, and only the receiving optical system is slid while the irradiation optical system is fixed at the strong reflection point K. To do.

In this way, the pan / tilt operation for searching for the strong reflection point K again becomes unnecessary, and moreover,
The bright portion L2α of the reflected laser light L2 can be made incident on the optical receiving system by one movement. That is, the bright portion L2α of the reflected laser light L2 is positively introduced into the optical head.

[0042]

As described in detail above, the positional relationship between the optical vibration detection device and the object to be measured (eg, insulator) is adjusted in the direction intersecting the straight line (the irradiation laser optical axis) connecting the two. According to the invention of claim 1, even if the reflected laser light has a bright and dark pattern, it is possible to raise the level of the interference beat, so that the vibration measurement can be satisfactorily performed.
Then, this adjustment can be performed by a simple and easy operation.

According to the invention of claim 2, the strong reflection point search can be easily performed. According to the invention of claim 3, the optical head can perform the pan / tilt operation with high accuracy.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an optical head and a block diagram of an optical vibration detection device.

FIG. 2 is a block diagram of a slide mechanism and a pan / tilt mechanism.

FIG. 3 is a front view showing a support structure of an optical head.

FIG. 4 is a cross-sectional view of a slide mechanism.

FIG. 5 is an image diagram showing a reflection state of reflected laser light.

FIG. 6 is a schematic diagram showing an installation state of an optical vibration detection device.

[Explanation of symbols]

1 ... Insulator as an object to be measured, 10 ... Optical head, 36 ...
Slide mechanism, 37 ... Tripod as support, L1 ... Irradiated laser light, L2 ... Reflected laser light, L3 ... Reference laser light.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuuhiro Akizuki 2 56 Sudamachi, Mizuho-ku, Nagoya City Nippon Insulators Co., Ltd. (72) Taiki Usami 2 56 56 Sudamachi, Mizuho-ku, Nagoya City Japan Insulator Within the corporation

Claims (3)

[Claims] 1. An optical head having an irradiation optical system for irradiating an object to be measured with laser light, an optical receiving system for receiving reflected laser light from the object to be measured, and supporting the optical head at a measurement position. A support body for controlling the frequency of the reflected laser light and the reference light serving as a reference of the frequency of the irradiation laser light in the same space to cause optical interference, and FM demodulates the optical interference signal to obtain the object to be measured. In an optical vibration detection device for measuring vibration, the optical head is supported on a support body through a slide mechanism, and the slide mechanism connects the optical head and the object to be measured to each other. An optical vibration detection device that can be adjusted in a direction that intersects a straight line. 2. The optical vibration detection device according to claim 1, wherein the support is provided with a pan / tilt mechanism capable of horizontally rotating and vertically rotating the optical head. 3. The optical vibration detection device according to claim 2, wherein the optical head is supported by a pan / tilt mechanism, and the pan / tilt mechanism is supported by a support through a slide mechanism.