KR101201530B1 - Hybrid electrical sensor with probation and correction functions for structure measuring instrument and method for generating a control voltage using the sensor - Google Patents

Abstract

The present invention can perform the calibration and calibration of the wavelength of the light source output from the internal variable light source using the external variable light source, and further comprises an electric sensor measuring device for the same measurement target for the electric sensor and the optical fiber Introduces a hybrid instrument that can apply sensors simultaneously and compare the results from sensors from two different sensing metrology techniques. The hybrid meter includes an optical sensor measurement and probe calibration / calibration, an electrical sensor measurement unit, an external variable light source unit, an calibration and calibration connection unit, a processor, an external equipment connection unit, a time information synchronization connection unit, and a processor unit.

Fiber Optic Grid, Black, Calibration, Linearity, Temperature

Description

Hybrid electrical sensor with probation and correction functions for structure measuring instrument and method for generating a control voltage using the sensor}

The present invention relates to a composite measuring instrument having a calibration and calibration function for a structure measuring instrument and a method for generating a control voltage used in the measuring instrument. In particular, the present invention includes an external variable light source (ETLS) and an optical port. It has an interlocking function with external electric measuring equipment, and generates a control voltage for linearly changing the wavelength of the light source and the complex measuring instrument that can accurately determine the result of the sensor by using the measurement results of the optical fiber grating sensor and the electric sensor. It is about a method.

delete

In general, the measuring principle of an optical fiber grating sensor is as follows.

Unlike a general optical fiber, the optical fiber grating reflects light of a specific wavelength by giving a change in refractive index at regular intervals in the longitudinal direction to the core. This reflected wavelength is determined by the distance between the temperature and the grating. The optical fiber grating can be used as a sensor if it is packaged so that the wavelength value changes due to a change in a specific physical quantity.

The optical fiber grating sensor measures the center wavelength of the reflected light. There are two methods for measuring the reflected wavelength of the optical fiber grating sensor. The first method is to connect a broad band light source with a wide wavelength range to an optical fiber grating and analyze the returned light in an optical spectrum analyzer (OSA). In this method, a 2 x 1 optical coupler is connected between the light source and the optical fiber grating and the reflected light enters the optical spectrum analyzer to connect the reflected light to the optical spectrum analyzer. The second method uses a tunable light source (TLS) as a light source and connects a photo diode module (PDM) that can measure only the amount of light instead of an optical spectrum analyzer. By analyzing the reflected light amount, the center wavelength of the reflected light of the optical fiber grating can be measured.

Compared to the method using an optical spectrum analyzer, the method of using a variable light source has an advantage in that a plurality of optical fiber cables can be connected and measured simultaneously by dividing the light source into an optical coupler. Because of the multi-channel optical sensor cabling advantages, most interrogators in fiber optic gratings use variable light sources. Therefore, it can be seen that the performance of the interrogator is determined by the performance of the variable light source.

The fiber grating sensor measuring method using the variable light source will be described in detail as follows.

The variable light source is a light source that can select a wavelength, the wavelength of the output light source changes according to the control signal, there is no output at a wavelength other than the selected wavelength, the selectable wavelength range is limited by the characteristics of each model and part.

To measure the reflected wavelength of the fiber grating sensor, a control signal is given to the variable light source to sweep from the lowest selectable wavelength to the highest wavelength. At this time, the amount of light reflected back to the photoelectric converter is acquired together with the selective wavelength of the variable light source and accumulated in the signal processing device. The accumulated data for one sweep becomes a waveform representing the intensity of the reflected light amount for each wavelength within the wavelength sweep range. In this waveform, find the center wavelength of the peak (called peak detection) that satisfies certain conditions (critical level (e.g.> -20 dBm), bandwidth (e.g.> 50 pm)) that can be recognized as an optical fiber grating (called peak detection). It is recognized as the central wavelength of. The measured wavelength value is expressed as a physical quantity value of the sensor through a conversion formula made by the fiber grating sensor manufacturer.

Referring to Figure 1 attached to the conventional optical fiber grating sensor measurement instrument of this type is as follows.

1 is a configuration diagram of a conventional optical fiber grating sensor measurement instrument, and FIG. 2 is a configuration diagram of the optical fiber grating interrogator of FIG. 1, and FIG. 3 is a variable used in the interrogator of FIG. 2. Nonlinear sweep signal wavelength diagram by an optical filter.

1 to 3, a conventional optical fiber grating sensor measuring instrument includes a processor 10, an optical sensor measuring unit 20, and a processor unit 80.

Here, the processor 10 is connected to the processor unit 80 by, for example, a built-in interface 11 made of a communication protocol such as RS-232, RS-485, CAN, TCP / IP, and the like.

In addition, the optical sensor measuring unit 20 includes an internal tunable light source (ITLS) 22 connected to the processor 10, an optical fiber grating sensor 23 connected to the internal variable light source 22, and An optical coupler A 25-1 positioned between the internal variable light source 22 and the optical fiber grating sensor 23 to couple the internal variable light source 22 and a reference optical filter 24; An optical coupler B 25-2 positioned between an internal variable light source 22 and the optical fiber grating sensor 23 to couple the internal variable light source 22 to a photo diode 26-2 and the reference; The photodiode 26-1 connected to the optical filter 24 is provided.

In addition, the processor unit 80 may be connected to the processor 10 through an interface 81 including, for example, a communication protocol such as RS-232, RS-485, CAN, TCP / IP, and the like. A motor operated by the control algorithm control processor 82, the motor drive / hydraulic drive unit 83 operated by the measurement, structural analysis and control algorithm control processor 82, and the motor drive / hydraulic drive unit 83. / Hydraulic device 84 is provided.

This conventional fiber optic grating sensor measuring instrument also requires regular calibration and calibration to provide the high accuracy measurement data desired by the user, as in other general measuring devices. There is a problem that it is difficult to secure data reliability because there is no correction and correction function for the wavelength measurement error.

In addition, there is a problem that the accuracy of the wavelength measurement of the conventional optical fiber grating sensor measurement instrument can not be measured by a separate calibration and calibration equipment connected to the outside (that is, the interrogator of the conventional optical fiber grating sensor measurement instrument is calibrated and For calibration, the reference optical filter, a component mounted in the product, must be disassembled to measure the wavelength characteristic (reflected wavelength).

In addition, the conventional optical fiber grating sensor measurement instrument has a problem that can not be interlocked with the electric sensor measurement device widely used at present.

In addition, the conventional optical fiber grating sensor measurement instrument has a problem that can not measure the signal of the electric sensor and the signal of the optical fiber sensor together.

In addition, in the interrogator of the conventional optical fiber grating sensor measuring instrument, a reference optical filter that selects the wavelength at the light source side or the photodiode side is used to separate the reflected light of the optical fiber grating sensor in the wavelength region, which is used in the interrogator. The reference optical filter adjusts the wavelength of light passing through the filter in proportion to the applied control voltage. Here, the control voltage and the selected wavelength of the filter are in some proportional relation but are not perfectly linear. These characteristics vary depending on the type, sweep speed, and wavelength range of the reference optical filter, and there is a problem in that the linear wavelength sweep cannot be formed even if the controller provides the linear sweep signal. Here, the non-linear wavelength sweep causes a difference in the output light amount of the variable light source for each wavelength band and the number of sampling points of the photodiode signal, thereby causing a difference in the measurement data quality of the sensor for each wavelength band (see FIG. 3).

Existing interrogators have minimized this problem by using filters in the non-linear wavelength range, limiting the sweep range, and scanning speed to reduce this problem. However, market demands are increasing. Because of the need for faster scan speeds, more competitive prices, and more accurate measurement results, more linear wavelength sweeps are required to achieve these functions, which requires the use of expensive variable optical filters.

In addition, the conventional technology is in the form of transmitting data using a control device and a communication port for measurement, structural analysis and control using the measurement results obtained using the optical fiber interrogator. In other words, the signal measured by the sensor is transmitted to a processor in the control device, and generates a control signal based on a predetermined algorithm, and thus is configured to deliver a motor or hydraulic device signal.

Technical problem to be solved by the present invention, by using the external variable light source can be calibrated and calibrated for the wavelength of the light source output from the internal variable light source, and further comprises an electric sensor measuring device to the same measurement target The present invention provides a hybrid measuring instrument that can simultaneously apply the electrical sensor and the optical fiber sensor and compare the results measured by the sensors of two different sensing techniques.
Another technical problem to be solved by the present invention is to provide a method for generating a non-linear control signal for linear wavelength sweep so that the selected wavelength of the filter constituting the complex measuring instrument has a linearity.

Hybrid measuring device according to the present invention for achieving the above technical problem, light sensor measurement and probe calibration / calibration, electrical sensor measurement, external variable light source, calibration and calibration connection, processor, external equipment connection, time information synchronization It has a connection portion and a processor portion.
The optical sensor measurement and calibration / calibration of the probe irradiates an internal optical signal having a constant wavelength output from the internal variable light source to the measurement object and receives and processes the reflected signal reflected from the measurement object. The electrical sensor measuring unit measures the same information as the information to be measured for the measurement object in the optical sensor measurement and probe / calibration of the probe. The external variable light source unit transmits an external optical signal having a predetermined wavelength to the optical sensor measurement and the probe / calibrator. The calibration and calibration connection unit receives an optical signal output from the internal variable light source or the external variable light source unit and extracts information included in the optical signal. The processor verifies / calibrates the wavelength of the optical signal output from the internal variable light source, and compares the information measured by the optical sensor measurement and the calibration / calibration of the probe with the information measured by the electric sensor measurement unit. The external device connection is an interface between the processor and the external device. The time information synchronization connector is an interface of a module providing time information with the processor. The processor unit drives a motor and controls measurement and structural analysis of the processor.

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

In accordance with another aspect of the present invention, there is provided a method for generating a nonlinear control signal for sweeping a linear wavelength, the wavelength of the optical signal output from the internal variable light source constituting the complex measuring instrument of claim 1,
Applying a linear sweep control voltage to the internal variable light source and measuring a wavelength of the internal variable light source according to the voltage level of the control voltage being swept, the measured wavelength varying nonlinearly with the voltage level of the linearly varying control voltage Accumulating the data in the form of a data table, correcting the linearly varying control voltage so that the wavelength having the linear tendency is nonlinear with reference to the table and the corrected nonlinearity. And applying a control voltage to the internal variable light source.

As described above, the hybrid meter according to the present invention is designed to act as a backup of the internal variable light source by connecting an external variable light source, and is equipped with an external device connection part, so that the calibration and calibration of the wavelength measurement error can be performed. This can be done in the field, and the accuracy of the wavelength measurement can be measured with externally connected separate calibration and calibration equipment.
In addition, it can be interlocked with the electric sensor measuring device, and the electric sensor signal and the optical fiber sensor signal can be measured together, and the control voltage and the selected wavelength of the filter have perfect linearity. The advantage is that the wavelength range of the variable optical filter can be utilized to the maximum, and the precise measurement results can be calculated.

Hereinafter, an electric sensor and a fiber grating sensor measuring hybrid instrument having a calibration and calibration function for a structure measuring instrument according to the present invention and a method of generating a nonlinear control signal for linear wavelength sweep using the same will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to a client's or operator's intention or custom. Therefore, the definition should be based on the contents throughout this specification.

Like numbers refer to like elements throughout the drawings.

FIG. 4 is a schematic diagram of an electric sensor and a fiber grating sensor measurement hybrid instrument having a calibration and calibration function for a structural instrument according to the present invention, and FIG. 5 is a digital-analog configuration of the variable light source and the variable optical filter of FIG. 4. 6 is a schematic diagram of the optical fiber grating interrogator of FIG. 4, and FIG. 7 is a diagram illustrating linear sweep signal wavelengths by the variable optical filter used in the interrogator of FIG. 4. Reference peak search graph of the reference optical filter of the electric and optical fiber grating sensor measurement hybrid instrument with calibration and calibration function for the structure instrument according to the present invention.

4 to 8, the electric and optical fiber grating sensor measurement hybrid instrument having the calibration and calibration function for the structure measuring instrument according to the present invention, the processor 10, optical sensor measurement and probe calibration / calibration (20) -1), electrical sensor measurement unit 30, calibration and calibration connection 40, external equipment connection 50, time information synchronization connection 60, calibration / calibration and internal TLS to serve as a backup of the internal variable light source An external variable light source unit 70 and a processor unit 80 for backup are provided.

Optical sensor measurement and probe calibration / calibration (20-1) consists of a digital analog converter (21), an internal variable light source (22), an optical fiber grating sensor (23), a reference optical filter (24), an optical coupler A (25-). 1), optical coupler B 25-2, two photodiodes 26-1, 26-2 and two analog-digital converters 27-1, 27-2.
The digital-to-analog converter 21 converts the control voltage of the digital form output from the processor 10 into an analog voltage and transmits it to the internal variable light source 22. The internal variable light source 22 outputs a light source having a wavelength (selection wavelength) corresponding to the control voltage converted into the analog form. Optical coupler A (25-1) is a light source that is output from the internal variable light source 22 to the light sensor measurement and probe calibration / calibration (20-1) inside, calibration / calibration connection 40 and calibration / calibration and inside It distributes to the external variable light source part 70 for TLS backup. The optical fiber grating sensor 23 transmits the light source output from the internal variable light source 22 to the measurement target, and measures the reflected signal reflected from the measurement target object. The optical coupler B 25-2 transmits the light source output from the internal variable light source 22 to the optical fiber grating sensor 23 or selects and outputs one of a plurality of reflection signals measured from the optical fiber grating sensor 23.
The reference optical filter 24 selects a light source having a selective wavelength output from the internal variable light source 22 applied via the optical coupler A 25-1. The first photodiode 26-1 detects a light source that has passed through the reference optical filter 24. The second photodiode 26-2 detects the reflection signal selected by the optical coupler B 25-2. The first analog digital converter 27-1 converts an analog light source detected by the first photodiode 26-1 into a digital signal corresponding thereto and transmits the converted analog signal to the processor 10. The first analog digital converter 27-2 converts the reflected signal of the analog type detected by the second photodiode 26-2 into a digital signal corresponding thereto and transmits the converted signal to the processor 10.

The electric sensor measuring unit 30 includes four electric sensors 30 to 34, four signal controllers 31-1 to 34-4, and four analog to digital converters 35-1 to 35-4.
The four electrical sensors 30-34 are electrical strain sensors 31, electrical LVDT sensors 32, electrical temperature sensors 33, and electrical accelerometer sensors 34. The functional features of these sensors are generally known and are not described in detail here.
The information detected by the electric strain sensor 31 is transmitted to the processor 10 via a signal regulator 31-1 and an analog-to-digital converter 35-1 for the electric strain sensor. The information detected by the electric LVDT sensor 32 is transmitted to the processor 10 via the signal regulator 32-1 for the electric LVDT sensor and the analog-to-digital converter 35-2. The information detected by the electric temperature sensor 33 is transmitted to the processor 10 via the electric temperature sensor signal controller 33-1 and the analog-digital converter 35-3. The information detected by the electrical accelerometer sensor 34 is transmitted to the processor 10 via a signal controller 34-1 and an analog-to-digital converter 35-4 for the electrical accelerometer sensor. Here, LVDT (Linear Variable Differential Transformer) means a linear variable differential transformer.
Here, the optical sensor measurement and probe calibration / calibration (20-1) and the electric sensor measurement unit 30 operates independently. The hybrid meter according to the present invention simultaneously applies four electrical sensors 30 to 34 using electrical energy to the same object as the optical fiber grating sensor 23 using the reflected signal reflected from one measurement object, and these By allowing the result of the processor 10 to be compared, there is an advantage in that the state of the measurement target can be accurately determined.

The calibration and calibration connection 40 is an optical power meter (OPM) 41, an optical spectrum analyzer 42, which measures the amount, spectrum, and wavelength of light output through the optical coupler A 25-1, respectively. And a wavelength meter 43.

The external device connector 50 has a trigger input / output device 51 connected to the processor 10. The time information synchronization connector includes a GPS, GSM and CDMA module 61 connected to the processor 10.

delete

The external variable light source unit 70 for the calibration / calibration and internal TLS backup that performs the backup role of the internal variable light source 22 and the calibration and calibration of the light source output from the internal variable light source 22 has an external variable light source 71 and a wavelength. Meter 72 is provided. The external variable light source 71 generates an external optical signal having a wavelength determined according to the instruction of the processor 10, and the wavelength meter 72 measures the wavelength of the external optical signal.
When the internal variable light source 22 is verified as a result of verifying the internal variable light source 22, or when a variable light source having a different setting range from the internal variable light source 22 is desired, the internal variable light source 22 is used. The external variable light source 71 can be used as a backup role.
First, the black and calibration connection unit 40 detects the characteristics of the light source output from the external variable light source 71 and the characteristics of the light source output from the internal variable light source 22. Since the external variable light source 71 generally has a complete electrical characteristic, when the characteristics of the light source output from the external variable light source 71 and the characteristics of the light source output from the variable variable light source 22 are the same, the internal variable is variable. It is determined that the calibration is not necessary because the light source 22 is operating normally and optimally. When there is a difference in the characteristics of the test result, the processor 10 corrects the characteristics of the light source output from the internal variable light source 22 to be the same as the characteristics of the light source output from the external variable light source 71.

The processor unit 80 may include a motor driving / hydraulic driving unit 83 operated by a processor 82 for measurement, structural analysis, and control algorithm control connected to the processor 10, a processor 82 for measurement, structural analysis, and control algorithm control; A motor / hydraulic device 84 operated by the motor drive / hydraulic drive 83 is provided. The motor / hydraulic device 84 is used to control the state of the measurement object when the hybrid meter according to the present invention is fixed to the measurement object. For example, the hybrid meter according to the present invention may be operated to perform a function of mitigating an abnormal displacement of a shaft on which a rotary blade of a wind generator is fixed. In general, a wind turbine is installed in a place where strong winds blow, and when the shaft of the wind turbine is bent in a direction opposite to the wind due to the strong wind, a motor / motor providing the energy required for the device applying the opposite force to the shaft of the wind turbine is provided. The hydraulic device 84 can be controlled.

delete

In the present invention, the GPS, GSM, CDMA module 61, which can provide information on the exact time of the measured data, can access the processor 10 so as to utilize an international standardized communication protocol including time information. It has a time information synchronization connection.
When analyzing the data in the processor 10, the time information is used to synchronize the stored data, and can be used as an important element technology when sharing data with various types of sensor measuring equipment. Equipment interworking function that can work with GPS, GSM, CDMA module 61 is one of the key ideas of the present invention.

Hereinafter, a detailed operation of the electric sensor and the optical fiber grating sensor measurement hybrid measuring instrument having a calibration and calibration function for the structure measuring instrument according to the present invention will be described.
Optical sensor measurement and probe calibration / calibration 20-1 is outputted from the processor 10 and the wavelength of the light output from the internal variable light source 22 according to the control voltage converted by the digital-analog converter 21. This change and change in the wavelength of the output light are transmitted to the optical fiber grating sensor 23 via the optical couplers 25-1 and 25-2. The optical fiber grating sensor 23 transmits a specific wavelength backward, which is transmitted to the photodiode 26-2 for the sensor and measured.

Light generated from the internal variable light source 22 is transmitted to one photodiode 26-1 through the reference optical filter 24, and the reflected signals measured from the optical fiber grating sensor 23 are transmitted to the two photodiodes 26-. 1 and 26-2, respectively, are converted into electric signals in an analog form, and are converted into digital signals by the analog-to-digital converters 27-1 and 27-2, and are transmitted to the processor 10.

The external device connection unit 50 includes a trigger input / output device 51 that can synchronize with an external electric measurement device or a device connected for control with the measurement device. The trigger input / output device 51 is provided with a trigger terminal (not shown) for synchronizing between an electric sensor and an optical fiber grating sensor measurement composite instrument and external equipment having a calibration and calibration function for structure adjustment according to the present invention.

delete

The trigger input / output device 51 is provided with respective input / output terminals (not shown) capable of transmitting and receiving a trigger signal and a sampling signal, so that the electrical measuring equipment 30 and the optical sensor measuring instrument 23 are at the same time. By sampling at, and matching the measured data at the same time point when analyzing the data measured by each measuring instrument, no time error occurs even if measured for a long time.

Hereinafter, the structure of the variable light source and the digital-to-analog converter of the variable optical filter of the electric sensor and the optical fiber grating sensor measurement hybrid instrument having the calibration and calibration function for the structure measuring instrument according to the present invention will be described.

Referring to FIG. 5, an internal variable light source includes a semiconductor optical amplifier 52, a Fabry-perot tunable filter 53, an optical coupler 54-1, and an optical isolator 55. A ring laser for an optical fiber sensor composed of -1) can be used.

Light in the tens to hundreds of nm bands generated by the semiconductor optical amplifier 52 passes through the Fabry-Perot variable optical filter 53 to generate light in a band as narrow as the line width of the Fabry-Perot variable optical filter 53. Will pass. At this time, the wavelength is variable by the applied voltage of the Fabry-Perot variable optical filter 53. Any digitized wavelength value transmitted from the processor 10 is converted into an analog voltage value by the digital-to-analog converter 54 and transmitted to the driver 55. The MEMS 56-1 drives the Fabry-Perot variable optical filter 53 with a driving voltage generated using the voltage value transmitted from the driver 55. Light output from the Fabry-Perot variable optical filter 53 is reused as an input of the semiconductor optical amplifier 52 through the optical isolator 55-1.
The semiconductor optical amplifier 52 amplifies light having a narrow wavelength made by the Fabry-Perot variable optical filter 53, thereby generating light having a narrow line width of high output. The output of the semiconductor optical amplifier 52 is selectively output from the optical coupler 54-1 to the Fabry-Perot variable optical filter 53 or the optical output terminal (not shown). The thermistor 57 and TEC (Thermal Electric Cooler) 58 added to the semiconductor optical amplifier 52 prevent the change of the temperature of the semiconductor optical amplifier 52, thereby stabilizing the output of the semiconductor optical amplifier 52.
Likewise, the temperature is controlled by the controller 56 using the thermistor 57 and the TEC 58 to prevent the temperature change of the Fabry-Perot variable optical filter 53. The analog temperature measurement value output from the thermistor 57 converts the analog-to-digital converter 59 into a digital value by converting the analog temperature value into a digital value by using the digital-to-analog converter 54. To provide.

A variable light source used in a typical interrogator has a relatively precise proportional relationship between the wavelength selection voltage and the wavelength of the output light source, but due to technical and cost limitations, it does not have a perfect proportional relationship that satisfies the precision required by users. Can't.

Therefore, in order to secure additional precision, a reference channel having a transmission wavelength value selected for wavelength calibration separately from the sensor channel is made and measured simultaneously with the sensor channel. As a reference optical filter used to form such a reference channel, an etalon filter, a gas cell, or the like can be used. Among them, the etaron filter used as an example of the reference optical filter has a plurality of reflected wavelengths having an equal interval (0.4 or 0.8 nm) or less of 1 nm or less in a range beyond the sweep possible range of the variable light source. By making a sweep light source with a variable light source and measuring the amount of reflected light reflected from the sensor, the reference optical filter is also measured. Based on the reflected wavelength of the reference optical filter, the reflected wavelength value of the sensor is converted by interpolation. Ensure precision.

Therefore, if the proportional relationship of the voltage of the variable optical filter to the selected wavelength does not change so much as to incorrectly find the starting peak position of the reference optical filter, and the reflected wavelength of the reference optical filter has the same value as in the previous calibration / calibration, It can be said that no error occurred in the wavelength of the interrogator.

As a result, the interrogator calibration / calibration process must simultaneously correct the proportional relationship between the reflected wavelength value of the reference optical filter, the sweep voltage of the variable light source, and the output wavelength value.

Since the calibration / calibration process of the interrogator has already been described, a method of matching the control voltage to the output wavelength value of the interrogator internal variable optical filter 22 and a reference optical filter will be described below.

delete

As described above, after calibrating / calibrating the reflection wavelength of the reference optical filter inside the interrogator, the optical fiber grating 23 having the selected reflection wavelength is connected to the sensor channel and output from the internal variable light source 22. While sweeping the wavelength of the light source, the reference peak can be found in the wavelength sweep waveform by referring to the wavelength value measured by the optical fiber grating sensor and the reflected wavelength data of the reference optical filter. Once the reference peak is found, the wavelengths of the peaks of all remaining reference optical filters can be matched.

delete

delete

Referring to FIG. 8, it is possible to obtain a proportional relation between the control voltage and the output wavelength value swept using the measured wavelength value and the reflected wavelength data, and then the peak of the reference optical filter is obtained without the optical fiber grating sensor having the selected reflected wavelength. You can find it.

In the present invention, the reference optical filter 24 can filter the light source output from the internal variable light source 22 by adjusting the change in the control voltage applied from the processor 10 to the internal variable light source 22. In the conventional case illustrated in FIG. 3, it can be seen that as the control voltage increases linearly with time, the wavelength of the light source output from the internal variable light source changes nonlinearly with time. If the wavelength of the light source changes non-linearly with time, the characteristics of the reference optical filter 24 for detecting it also need to change accordingly, which is disadvantageous in that it becomes expensive. In the present invention, in order for the wavelength of the light source to be linear, the processor 10 changes the control voltage nonlinearly with time, so that the wavelength of the light source output from the internal variable light source 22 increases linearly. Suggest that.
In addition, the present invention proposes to use an etalon filter as the reference optical filter 24 in order to filter light sources having a constant interval. Since the characteristics of the etalon filter are generally known, the operation characteristics are not described here. Referring to FIG. 3, it can be seen that when the control voltage is linearly increased, the interval between peaks detected by the etalon filter is narrowed toward the longer wavelength even if the etalon filter is used. If this interval is narrower than the reference interval, a problem occurs that the function of the etalon filter is degraded. The reference interval here is generally 0.8 nm. In the nonlinear control signal generation method of non-linearly increasing the control voltage according to the present invention, referring to FIG. 7, it can be seen that the interval of peaks detected by the etalon filter is constant.

Electrical and optical fiber grating sensor measurement with the calibration and calibration function for the structure measuring instrument according to the present invention by measuring a variable light source 71 that can generate a specific wavelength to the outside, measured in the optical fiber sensor measuring instrument 23 Compared with the measured values, the instrument has the functions of measuring, verifying, and calibrating stability, reliability, and errors in wavelength measurement.

Nonlinear control signal generation method for linear wavelength sweep using a hybrid instrument according to the present invention to compensate for the nonlinear sweep signal to form a linearized wavelength sweep, nonlinear to compensate the nonlinear wavelength selection control characteristics of the variable optical filter A sweep signal is applied to the variable optical filter as a control voltage.
The reference optical filter is used to measure the selective wavelength of the variable optical filter. The reference optical filter is mostly used to correct an error occurring when converting the peak position of the sensor to a wavelength value in an existing interrogator. In addition, the reference optical filter has a reflected wavelength at a predetermined wavelength interval and is used as a reference because there is little change in temperature. When a linear sweep signal is applied to the variable optical filter, the selected wavelength of the variable optical filter for each control voltage level can be measured through the position of the reflected peak of the reference optical filter. The measured value can be applied to generate a nonlinear compensation sweep control signal pattern. Can be. Applying this nonlinear compensation sweep control signal to the variable optical filter enables linear wavelength sweep.

In the following, step-by-step how to generate a non-linear control signal for linear wavelength sweep using an electric sensor and a fiber grating sensor measurement hybrid instrument having a calibration and calibration function for the measurement instrument, by applying a linear sweep control signal to the internal variable optical filter Measuring the selected wavelength of the internal variable optical filter according to the voltage level of each of the control voltages, accumulating the voltage level of the control voltage of the internal variable optical filter and nonlinearity of the selected wavelength in the form of a data table; Forming a nonlinear compensation sweep control signal with accumulated nonlinearity and applying the formed nonlinear compensation sweep control signal to a variable optical filter to generate a linear wavelength sweep signal.

In this way, a linear wavelength sweep is possible using a nonlinear compensated sweep control signal. When the linear wavelength sweep is possible, the amount of light and measurement accuracy for each wavelength band are uniform, which can widen the wavelength sweep range and reduce the cost by using a variable optical filter having nonlinear characteristics. In addition, the use of the reference optical filter inside the interrogator can compensate for the nonlinearity of each scan speed, enabling faster scan speeds and fine changes of nonlinear characteristics that change in real time due to variable environments such as temperature, air pressure, and humidity. Can also compensate.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various changes, modifications or adjustments to the example will be possible. Therefore, the protection scope of the present invention should be construed as including all changes, modifications or adjustments belonging to the gist of the technical idea of the present invention.

1 is a block diagram of a conventional optical fiber grating sensor measurement instrument.

2 is a block diagram of the optical fiber grating interrogator of FIG.

3 is a diagram illustrating nonlinear sweep signal wavelengths due to a linear sweep signal applied to a variable optical term filter used in the interrogator of FIG. 2;

4 is a block diagram of the electric sensor and the optical fiber grating sensor measurement hybrid instrument having a calibration and calibration function for the structure instrument according to the present invention.

FIG. 5 is a detailed view of the structure of the variable light source of FIG. 4 and the digital-analog converter of the variable optical filter. FIG.

6 is a block diagram of the optical fiber grating interrogator of FIG.

7 is a diagram illustrating a linear sweep signal wavelength due to a nonlinear sweep signal applied to a variable optical filter used in the interrogator of FIG. 4.

8 is a reference optical reference peak search graph of an electric sensor and a fiber grating sensor measurement hybrid instrument having a calibration and calibration function for a structure instrument according to the present invention.

Explanation of symbols on main parts of drawing

10: processor 20; Optical sensor measurement unit

20-1: Optical sensor measurement and probe calibration / calibration

21: internal variable light source 28: reference optical filter

30: electric sensor measuring unit 31: electric strain sensor

32: electric LVDT sensor 33: electric temperature sensor

34: Electrical accelerometer sensor 40: Black and calibration connection

41: external variable light source 50: external equipment connection

51: trigger input / output device

Claims (13)

Calibration / calibration of an optical sensor measurement and probe for irradiating an internal optical signal having a constant wavelength output from an internal variable light source to a measurement object and receiving and processing a reflection signal reflected from the measurement object; An electric sensor measuring unit measuring the same information as the information to be measured with respect to the measurement object in the optical sensor measurement and the calibration / calibration of the probe; An external variable light source for transmitting an external optical signal having a predetermined wavelength to the optical sensor measurement and probe / calibration; A calibration and calibration connection unit for receiving an optical signal output from the internal variable light source or the external variable light source unit and extracting information included in the optical signal; A processor for calibrating / calibrating the wavelength of the optical signal output from the internal variable light source, and comparing the information measured by the optical sensor measurement and the calibration / calibration of the probe with the information measured by the electric sensor measurement unit; An external device connection unit that interfaces with the processor and external devices; A time information synchronous connection unit that is an interface between the processor and a module providing time information; And And a processor unit for driving a motor and controlling measurement and structural analysis of the processor. The method of claim 1, wherein the optical sensor measurement and calibration / calibration of the transducer, A digital analog converter for converting a digital control voltage output from the processor into an analog control voltage; An internal variable light source for generating the internal optical signal whose wavelength is determined according to the analog control voltage; An optical coupler A for distributing the internal optical signal; An optical fiber grating sensor that irradiates the internal optical signal received to the measurement object and receives a reflected signal reflected from the measurement object; An optical coupler B for transmitting the internal optical signal distributed from the optical coupler A to the optical fiber grating sensor or selectively outputting the reflected signal detected by the optical fiber grating sensor; A reference optical filter for selectively receiving an optical signal output from the internal variable light source distributed by the optical coupler A; A first photodiode for converting an optical signal output from the reference optical filter into an electrical signal; A second photodiode for converting the reflected signal output from the optical coupler B into an electrical signal; A first analog digital converter which converts an electrical signal output from the first photodiode into a digital signal corresponding thereto and transmits the converted digital signal to the processor; And And a second analog digital converter which converts an electrical signal output from the second photodiode into a digital signal corresponding thereto and transmits the converted digital signal to the processor. The method of claim 2, wherein the reference optical filter, A hybrid instrument characterized in that it is an etalon filter. The method of claim 2, wherein the internal variable light source, Semiconductor optical amplifiers; A Fabry-Perot variable optical filter coupled to the semiconductor optical amplifier; An optical isolator coupled to the semiconductor optical amplifier; And An optical coupler connected between the Fabry-Perot variable optical filter and the optical isolator, Light generated by the semiconductor optical amplifier is generated as a specific light through a filter and circulated through the optical coupler; The temperature control is controlled by using a thermistor and TEC (Thermal Electric Cooler), thereby preventing a change due to the temperature of the Fabry-Perot variable optical filter and the semiconductor optical amplifier. The method of claim 1, wherein the electric sensor measuring unit, An electrical strain sensor measuring strain of the measurement object; An electric LVDT sensor measuring a voltage of the measurement object; An electric temperature sensor measuring a temperature of the measurement object; An electrical accelerometer sensor measuring acceleration of the measurement object; A signal regulator for an electric strain sensor for generating a control signal corresponding to the information detected from the electric strain sensor; A signal regulator for an electric LVDT sensor generating a control signal corresponding to the information detected from the electric LVDT sensor; A signal controller for an electric temperature sensor for generating a control signal corresponding to the information detected from the electric temperature sensor; A signal regulator for an electrical accelerometer sensor generating a control signal corresponding to the information detected from the electrical accelerometer sensor; A first analog digital converter for converting a control signal output from the signal controller for electric strain sensor into a digital signal; A second analog digital converter for converting a control signal output from the signal controller for the electric LVDT sensor into a digital signal and transmitting the digital signal to the processor; A third analog digital converter which converts a control signal output from the electric temperature sensor signal controller into a digital signal and transmits the digital signal to the processor; And And a fourth analog digital converter for converting a control signal output from the signal controller for the electrical accelerometer sensor into a digital signal and transmitting the digital signal to the processor. The method of claim 2, wherein the calibration and calibration connection, An optical power meter (OPM) for measuring power of the internal optical signal or the external optical signal respectively output from the optical coupler A; An optical spectrum analyzer for analyzing the spectra of the internal optical signal and the external optical signal respectively output from the optical coupler A; And And a wavelength meter for detecting wavelengths of the internal optical signal and the external optical signal output from the optical coupler A, respectively. The method of claim 1, wherein the external equipment, Hybrid instrument, characterized in that the trigger input / output device. The method of claim 7, wherein the trigger input / output device, Each input / output terminal for transmitting and receiving a trigger signal and a sampling signal is installed, so that the electrical measurement equipment and the optical sensor instrument are sampled at the same time, and the data measured at the same time are analyzed at the same time. And by matching the data, thereby synchronizing the measurements in each instrument. The method of claim 1, wherein the time information synchronization connection unit, The module for providing the time information is a hybrid instrument, characterized in that one of GPS, GSM, CDMA. The method of claim 1, wherein the external variable light source unit, An external variable light source for generating the external optical signal having a wavelength determined according to the instruction of the processor; And A wavelength meter for measuring a wavelength of the external optical signal, And a back-up of the internal variable light source in case of abnormality or failure of the internal variable light source. The method of claim 1, wherein the processor unit, A control algorithm processor coupled to the processor, the control algorithm processor including a control algorithm for performing measurement and structural analysis and controlling an algorithm for operating the entire instrument; A motor drive / hydraulic drive controlled by the processor; And And a motor / hydraulic device operated by the motor drive / hydraulic drive unit. According to claim 1, The optical sensor measuring unit and the electrical sensor measuring unit, A hybrid instrument characterized by independent operation. A control voltage generation method for determining a wavelength of an optical signal output from the internal variable light source constituting the complex meter of claim 1, Applying a linear sweep control voltage to the internal variable light source and measuring a wavelength of the internal variable light source according to a voltage level of the control voltage being swept; Accumulating, in the form of a data table, a voltage level of the control voltage that changes linearly and a measured wavelength that changes nonlinearly; A correction step of nonlinearly correcting the linearly varying control voltage such that the wavelength having a tendency of nonlinearity is referred to as a linear tendency with reference to the table; And And applying the corrected nonlinear control voltage to the internal variable light source.

Images