CN103076082A - Single mode-multimode-single mode fiber intermode interference-based vibration and stress sensing device - Google Patents
Single mode-multimode-single mode fiber intermode interference-based vibration and stress sensing device Download PDFInfo
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- CN103076082A CN103076082A CN201310002002XA CN201310002002A CN103076082A CN 103076082 A CN103076082 A CN 103076082A CN 201310002002X A CN201310002002X A CN 201310002002XA CN 201310002002 A CN201310002002 A CN 201310002002A CN 103076082 A CN103076082 A CN 103076082A
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Abstract
The invention discloses a single mode-multimode-single mode (SMS) fiber intermode interference-based vibration and stress sensing device, which comprises a laser, an SMS fiber, a positive-intrinsic negative (PIN) diode, a data acquisition card and a signal processor, wherein the SMS fiber consists of a first single mode fiber, a multimode fiber and a second single mode fiber, which are cascaded; the output of the laser is connected with the first single mode fiber at one end of the SMS fiber; the second single fiber is connected with the input of the PIN diode; the output of the PIN diode is connected with the input of the data acquisition card; the output of the data acquisition card is connected with the signal processor; and the signal processor obtains measured vibration and stress values by utilizing intermode relative phase change information carried by the output optical power of the SMS fiber.
Description
Technical field
The present invention relates to sensor technical field, relate in particular to a kind of based on single mode-multi-mode-single mode modal interference vibration, stress sensing device.
Background technology
Widely used vibration transducer mainly is based on electrical measuring method on market at present, and piezoelectric effect type, piezoresistive effect type, electromagnetic induction type etc. are arranged.Vibration transducer based on electrical measuring method, have that volume is little, lightweight, wide frequency range, advantage that dynamic range is large, but have simultaneously that low, the steady in a long-term performance of sensitivity is poor, the frequency range of poor anti jamming capability, sensor is narrow, can not realize the shortcomings such as intelligent.
Widely used strain gauge is traditional resistor foil gauge strain gauge on the market, it is higher that it has precision, moderate advantage, but exist zero drift phenomenon serious, be subject to electromagnetic interference (EMI), permanance, humidity, anti-fouling performance are poor, serviceable life is short, and is unstable, the shortcomings such as bad dynamic performance.
Compare with standard machinery and electrical type sensor, Fibre Optical Sensor has the integrated level height, volume is little, lightweight, antijamming capability is strong, with low cost, sensitivity and precision height, bandwidth, good insulating, can realize the advantages such as distribution measuring, so Fibre Optical Sensor has become the research field of a hot topic.Use Fibre Optical Sensor can well solve the problem that in vibration, stress measurement, runs into.
Vibration, strain gauge based on Fibre Optical Sensor has Michelson (Michelson) interferometric optical fiber sensor, Mach-Zehnder (Mach-Zehnder) interferometric optical fiber sensor, Fabry-Perot (Fabry-Perot) interferometric optical fiber sensor, Bragg grating type (FBG) Fibre Optical Sensor at present.These sensing system structures are comparatively complicated, to having relatively high expectations of optical fiber and detector, are unfavorable for the reduction of cost.
Summary of the invention
The purpose of this invention is to provide a kind of simple in structure, cheap vibration, stress sensing device.
In order to solve the prior art problem, the embodiment of the invention discloses a kind of based on single mode-multi-mode-single mode modal interference vibration, stress sensing device, comprise laser instrument, SMS optical fiber, the PIN pipe, data collecting card and signal processor, described SMS optical fiber is by the first single-mode fiber, multimode optical fiber and the second single-mode fiber cascade form, described laser instrument output connects the first single-mode fiber of an end of SMS optical fiber, the second single-mode fiber is connected with the input of PIN pipe, the output of PIN pipe is connected with the data collecting card input, data collecting card output connects signal processor, described signal processor utilizes SMS optical fiber Output optical power to carry intermode relative phase change information, obtains vibration, strain measurements.
Further, as preferably, described SMS optical fiber is by G.652 standard single-mode fiber and 50/125 multimode stepped-index optical fiber consist of.
Further, as preferably, described signal processor utilization is done Fast Fourier Transform (FFT) to light signal and is obtained signal spectrum information, finally obtains the frequency information that vibrates.
Further, as preferably, described signal processor utilization is carried out data to light signal and is processed the amplitude change information that obtains light signal, finally obtains the change information of stress.
Beneficial effect of the present invention: use Fibre Optical Sensor, make vibration, strain gauge possess the characteristics of general Fibre Optical Sensor,, good insulating strong, with low cost such as antijamming capability etc. have had very high reliability and stability; Only use multimode optical fiber in the SMS optical fiber as transducing part, make sensor had simple in structure, cost is low, easy for installation, the characteristics that can detect at a distance; Because used the SMS optical fiber structure, and multimode optical fiber has the attribute that can conduct various modes light, the light of various modes interferes in multimode optical fiber, thereby has greatly improved accuracy of detection; Because this sensor is based on measuring light power, system detector adopts common PIN pipe, greatly reduces cost; In system integration box, make the whole system structure more compact laser instrument and signals collecting part, volume is little; The signal processing of this system is used LabVIEW software, greatly reduces the cost of system.
Description of drawings
When considered in conjunction with the accompanying drawings, by the following detailed description of reference, can more completely understand better the present invention and learn easily wherein many advantages of following, but accompanying drawing described herein is used to provide a further understanding of the present invention, consist of a part of the present invention, illustrative examples of the present invention and explanation thereof are used for explaining the present invention, do not consist of to improper restriction of the present invention, wherein:
Fig. 1 is SMS optical fiber structure synoptic diagram.
Fig. 2 is this fiber-optic vibration, stress sensing device synoptic diagram.
Fig. 3 measures the system schematic of vibrator vibration for this vibration, stress sensing device.
Fig. 4 is the excitation frequency using the system shown in Figure 3 outside and apply and the graph of relation of practical frequency.
Fig. 5 measures the system schematic of sound vibration for this vibration, stress sensing device.
Fig. 6 is for using the graph of relation of system shown in Figure 5 sound equipment audio plays frequency and practical frequency.
Fig. 7 is the system schematic that this vibration, stress and temperature sensing device are measured the semi-girder vibration.Fig. 8 is for using system shown in Figure 7, and semi-girder length is 36cm, and the magnitude of voltage of the optical power signals that counterweight weight records when being 50g is curve over time.
Fig. 9 is the spectrogram that the magnitude of voltage of the corresponding optical power signals of Fig. 8 obtains after Fast Fourier Transform (FFT) (FFT).
Figure 10 when counterbalance mass is 50g, records the relation curve of semi-girder natural frequency and semi-girder brachium for using system shown in Figure 7.
Figure 11 is the use system shown in Figure 7, when semi-girder length is 36cm, and the relation curve of the voltage amplitude that applies weight and optical power signals that records.
Figure 12 is that this vibration, stress sensing device are measured the stress system synoptic diagram.
The magnitude of voltage of Figure 13 optical power signals during for the stress application that uses system shown in Figure 12 and record is curve over time.
Embodiment
Describe with reference to Fig. 1-13 pair embodiments of the invention.
For above-mentioned purpose, feature and advantage can be become apparent more, the present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.
The present invention is realized by following technical proposals, this fiber-optic vibration, strain gauge comprise, 1550nm Distributed Feedback Laser light source, output power is about 10mw, the laser instrument tail optical fiber connects one section SMS optical fiber, the SMS optical fiber structure is by G.652 standard single-mode fiber and 50/125 multimode stepped-index optical fiber consist of, optical fiber places test environment, signal process part is comprised of PIN pipe, data collecting card and signal processor (LabVIEW software), and laser instrument and signals collecting part are in system integration box.
The present invention realizes vibrating, the principle of stress measurement is as follows:
The SMS optical fiber structure is made of at one section multimode optical fiber in the middle of them two section single-mould fibers and welding.Laser instrument output light enters multimode optical fiber through Single-Mode Fiber Coupling, a large amount of mode transfer in the excitation multimode optical fiber, these patterns are interfered mutually, form different interference patterns at cross section of optic fibre, be speckle, the light intensity output of the Single-Mode Fiber Coupling regional area of output terminal.The space distribution form of speckle is determined by the phase differential incentive condition (single-mode fiber is to the coupling of multimode optical fiber) and the numerous pattern, therefore, in the constant situation of coupling condition, the variation that detects luminous power gets final product the variation of the phase differential between the acquisition model, and then demodulation obtains causing the external factor of phase differential variation, such as vibration, stress, thus the detection of realization vibration, stress.
As shown in Figure 2, a kind of based on single mode-multi-mode-single mode modal interference vibration, stress measurement device, comprise laser instrument 202, SMS optical fiber, PIN pipe 206, data collecting card 207 and signal processor 208, described SMS optical fiber is by the first single-mode fiber 103, multimode optical fiber 104 and the second single-mode fiber level 105 form, described laser instrument 202 outputs connect the first single-mode fiber 103 of an end of SMS optical fiber, the second single-mode fiber 105 is connected with 206 inputs of PIN pipe, 206 outputs of PIN pipe are connected with data collecting card 207 inputs, data collecting card 207 outputs connect signal processor 208, described signal processor 208 utilizes SMS optical fiber Output optical power to carry intermode relative phase change information, obtains vibration, strain measurements.
As shown in Figure 1, laser instrument output light 101 is coupled into multimode optical fiber fibre core 107 through the first single-mode fiber fibre core 106, a large amount of mode transfer in the excitation multimode optical fiber, these patterns are interfered mutually, form different interference patterns 110 at cross section of optic fibre 109, be speckle, the light intensity output of the second single-mode fiber 105 coupled fiber xsects 109 certain regional area of output terminal.Known that by above analysis output intensity 102 and the residing ambient vibration of multimode optical fiber, stress are relevant.
SMS optical fiber make step: at first use the optical fiber wire-stripping pliers to divest covering and the coat of single-mode fiber and multimode optical fiber, obtain the fibre core of a segment length, use optical fiber splicer that single mode and multimode optical fiber fibre core are carried out without acceptance of persons welding, wherein multimode optical fiber fibre core one end is connected with incident the first single-mode fiber, the other end is connected with outgoing the second single-mode fiber, incident the first single-mode fiber is connected with light source, and outgoing the second single-mode fiber is connected with the PIN pipe.
Fig. 3 measures the system schematic of vibrator vibration for this vibration, stress sensing device.The groundwork process is: Laser output light is coupled to multimode optical fiber 104 through the first single-mode fiber 103, is coupled into the second single-mode fiber 105 again; By applying external drive, so that vibrator 306 is with certain frequency vibration, thereby make the multimode optical fiber 104 that is pasted on the vibrator be subjected to the impact of vibrator vibration, cause input optical power to change.The PIN pipe is converted to electric signal with the output optical signal of the second single-mode fiber 105, data collecting card is converted to digital electric signal with analog electrical signal, be transferred to signal processor 208(computing machine), by LabVIEW software digital signal is carried out digital filtering and process and Fast Fourier Transform (FFT) (FFT), finally obtain the vibration frequency of vibrator.
Fig. 4 is the excitation frequency using the system shown in Figure 3 outside and apply and the graph of relation of practical frequency.Experimental result shows, in the 200Hz interval, accurate to the response of frequency, error is within ± 0.4Hz at 30Hz for this sensor.
Fig. 5 measures the system schematic of sound vibration for this vibration, stress sensing device.The groundwork process is: Laser output light is coupled to multimode optical fiber 104 through the first single-mode fiber 103, is coupled into the second single-mode fiber 105 again; Sound equipment is connected to computing machine, plays the certain frequency audio frequency by computing machine, so that sound equipment 506 is with certain frequency vibration, thereby make the multimode optical fiber 104 that is pasted on the sound vibration film be subjected to the impact of sound vibration film vibration, cause input optical power to change.The PIN pipe is converted to electric signal with the output optical signal of the second single-mode fiber 105, data collecting card is converted to digital electric signal with analog electrical signal, be transferred to signal processor 208(computing machine), by LabVIEW software digital signal is carried out digital filtering and process and Fast Fourier Transform (FFT) (FFT), finally obtain the vibration frequency of sound equipment.
Fig. 6 is for using the graph of relation of system shown in Figure 5 sound equipment audio plays frequency and practical frequency.Experimental result shows, in the 1000Hz interval, very accurate to the response of frequency, error is within ± 0.7Hz at 30Hz for this sensor.
Fig. 7 is the system schematic that this vibration, stress and temperature sensing device are measured the semi-girder vibration.The groundwork process is: Laser output light is coupled to multimode optical fiber 104 through the first single-mode fiber 103, is coupled into the second single-mode fiber 105 again; Semi-girder 706 is fixed on the workbench 707, by hang counterweight at the semi-girder edge, the mode that the line that connects counterweight is cut off, so that semi-girder begins vibration with certain amplitude, thereby make the multimode optical fiber 104 that is pasted on the semi-girder be subjected to the impact of semi-girder vibration, cause input optical power to change.The PIN pipe is converted to electric signal with the output optical signal of the second single-mode fiber 105, data collecting card is converted to digital electric signal with analog electrical signal, be transferred to signal processor 208(computing machine), by LabVIEW software digital signal is carried out digital filtering and process and Fast Fourier Transform (FFT) (FFT), finally obtain the vibration frequency of semi-girder.
Fig. 8 is for using system shown in Figure 7, and the length of semi-girder 706 is 36cm, the magnitude of voltage of optical power signals curve over time when counterweight weight is 50g.
Fig. 9 is the spectrogram that the magnitude of voltage of the corresponding optical power signals of Fig. 8 obtains after Fast Fourier Transform (FFT) (FFT).Record when the length of semi-girder is 36cm, its natural frequency is 5.8Hz herein.
Figure 10 is for using system shown in Figure 7 to record the relation curve of semi-girder natural frequency and semi-girder brachium.The fit equation that the data that recorded by experiment can get this curve is
Satisfy the theoretical relationship of semi-girder natural frequency and semi-girder brachium:
Figure 11 is for using system shown in Figure 7 to record the relation curve of the voltage amplitude that applies weight and optical power signals.Experimental result shows that the quality of the voltage amplitude of optical power signals and institute's suspension counterweight is linear.
Figure 12 is that this vibration, stress sensing device are measured the stress system synoptic diagram.The groundwork process is: Laser output light is coupled to multimode optical fiber 104 through the first single-mode fiber 103, is coupled into the second single-mode fiber 105 again; Multimode optical fiber 104 is fixed on the workbench 707, by 1206 pairs of multimode optical fiber 104 stress applications of stress bringing device, thereby causes the input optical power of the second single-mode fiber 105 to change.The PIN pipe is converted to electric signal with the output optical signal of the second single-mode fiber 105, data collecting card is converted to digital electric signal with analog electrical signal, be transferred to signal processor 208(computing machine), the voltage amplitude variation of optical power signals is analyzed the final stress applied information that obtains by LabVIEW software.
Figure 13 is optical power signals magnitude of voltage curve over time during for the stress application that uses system shown in Figure 12 and record.This experimental result is, to 2.7s in the time, the stress bringing device has applied stress to multimode optical fiber 104 at 1.5s.
Although more than described the specific embodiment of the present invention, but those skilled in the art is to be understood that, these embodiments only illustrate, those skilled in the art can carry out various omissions, replacement and change to the details of said method and system in the situation that does not break away from principle of the present invention and essence.For example, merge the said method step, then belong to scope of the present invention thereby carry out the identical function of essence according to the identical method of essence to realize the identical result of essence.Therefore, scope of the present invention is only limited by appended claims.
Claims (4)
1. one kind based on the vibration of single mode-multi-mode-single mode modal interference, stress sensing device, it is characterized in that, comprise laser instrument, SMS optical fiber, the PIN pipe, data collecting card and signal processor, described SMS optical fiber is by the first single-mode fiber, multimode optical fiber and the second single-mode fiber cascade form, described laser instrument output connects the first single-mode fiber of an end of SMS optical fiber, the second single-mode fiber is connected with the input of PIN pipe, the output of PIN pipe is connected with the data collecting card input, data collecting card output connects signal processor, described signal processor utilizes SMS optical fiber Output optical power to carry intermode relative phase change information, obtains vibration, strain measurements.
2. described based on single mode-multi-mode-single mode modal interference vibration, stress sensing device according to claim 1, it is characterized in that described SMS optical fiber is by G.652 standard single-mode fiber and 50/125 multimode stepped-index optical fiber consist of.
3. described based on single mode-multi-mode-single mode modal interference vibration, stress sensing according to claim 1, it is characterized in that described signal processor utilization is done Fast Fourier Transform (FFT) to light signal and obtained signal spectrum information, finally obtains the frequency information that vibrates.
4. described based on single mode-multi-mode-single mode modal interference vibration, stress sensing according to claim 1, it is characterized in that, described signal processor utilization is carried out data to light signal and is processed the amplitude change information that obtains light signal, finally obtains the change information of stress.
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Cited By (6)
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| CN104061996A (en) * | 2014-01-17 | 2014-09-24 | 东北大学 | Novel vibration measurement experimental device based on intermodal interference principle |
| CN104266668A (en) * | 2014-10-20 | 2015-01-07 | 天津理工大学 | Optical fiber sensor for temperature and curvature double-parameter measurement |
| CN105136056A (en) * | 2015-09-15 | 2015-12-09 | 华中科技大学 | Multimode fiber strain sensor with high sensitivity and measuring system |
| CN106289600A (en) * | 2016-09-21 | 2017-01-04 | 江苏大学 | A kind of optical fiber stress sensor part |
| CN110388949A (en) * | 2019-08-19 | 2019-10-29 | 深圳市矽赫科技有限公司 | A kind of fibre optical sensor |
| CN113390500A (en) * | 2021-05-19 | 2021-09-14 | 中国三峡新能源(集团)股份有限公司 | Vibration displacement measurement system, method, equipment and storage medium |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104061996A (en) * | 2014-01-17 | 2014-09-24 | 东北大学 | Novel vibration measurement experimental device based on intermodal interference principle |
| CN104061996B (en) * | 2014-01-17 | 2016-08-17 | 东北大学 | A kind of novel vibrating experiments of measuring device based on intermode interference principle |
| CN104266668A (en) * | 2014-10-20 | 2015-01-07 | 天津理工大学 | Optical fiber sensor for temperature and curvature double-parameter measurement |
| CN105136056A (en) * | 2015-09-15 | 2015-12-09 | 华中科技大学 | Multimode fiber strain sensor with high sensitivity and measuring system |
| CN106289600A (en) * | 2016-09-21 | 2017-01-04 | 江苏大学 | A kind of optical fiber stress sensor part |
| CN110388949A (en) * | 2019-08-19 | 2019-10-29 | 深圳市矽赫科技有限公司 | A kind of fibre optical sensor |
| CN113390500A (en) * | 2021-05-19 | 2021-09-14 | 中国三峡新能源(集团)股份有限公司 | Vibration displacement measurement system, method, equipment and storage medium |
| CN113390500B (en) * | 2021-05-19 | 2022-12-06 | 中国三峡新能源(集团)股份有限公司 | Vibration displacement measurement system, method, equipment and storage medium |
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Application publication date: 20130501 |