CN114659611A - Track fastener state monitoring system based on fiber grating array - Google Patents
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- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
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Abstract
The application discloses a track fastener state monitoring system based on a fiber bragg grating array, which comprises a detection device and a data processing module; the detection device comprises a vibration sensing optical cable which is arranged on a detected track along the running direction of the train; the detection device is used for sending a modulated optical signal and acquiring a reflected optical signal of the modulated optical signal after being reflected by the vibration sensing optical cable; obtaining a vibration signal to be detected according to the reflected light signal, and transmitting the vibration signal to be detected to the data processing module; the data processing module is used for processing the vibration signal to be detected to obtain a characteristic value of the vibration signal to be detected; and judging the health state of the rail fastener to be tested according to the characteristic value of the vibration signal to be tested. The rail fastener state monitoring device has the advantages of simple structure, convenience in installation, low detection cost, high detection sensitivity, strong anti-electromagnetic interference capability and higher detection precision, and can realize large-scale and long-distance state monitoring on the rail fastener.
Description
Technical Field
The invention relates to the technical field of train track detection, in particular to a track fastener state monitoring system based on a fiber bragg grating array.
Background
In recent years, China has a large number of high-speed railways to complete construction and put into operation and use. With the increase of operation time and the increase of service life of the rail, more and more vehicles and rail systems are damaged. Railway track fasteners are important parts of railway infrastructure and are necessary connecting parts between the track and the track bed. The fastener is used for connecting the steel rail and the sleeper to form a rail panel, bearing the load of a train, preventing the longitudinal and transverse displacement of the steel rail and preventing the steel rail from tipping. In ballastless tracks, fasteners are essentially the only providers of track elasticity and gauge, leveling capability, the performance of which directly affects the stability and elasticity of the track. Along with the increase of the service time, the phenomena of loosening, breaking and even loss of the fastener occur at all times, so that the state of the railway track fastener needs to be monitored in real time.
In the prior art, the automatic detection technology of the rail fastener mainly comprises a computer vision detection technology, a sensor arrangement real-time monitoring technology and the like. The computer vision detection technology uses an image sensor to obtain the image information of a detected object, and a computer processes the image to complete the detection function, so that the computer vision detection technology has the advantages of high speed and high precision; however, this method is costly, complicated to handle, and less prone to detect slightly damaged fasteners. The real-time monitoring technology of sensor arrangement generally comprises the steps of mounting strain, acceleration and displacement sensors on a fastener, and the method can find slightly damaged fasteners; however, a plurality of sensors are required to be mounted on each fastener, and the process of arranging the sensors is complex, so that long-distance distributed monitoring is difficult to realize; because the sensors are mostly electronic sensors, batteries need to be replaced for the sensors regularly, and the workload of routing inspection is undoubtedly increased.
Therefore, the existing rail fastener detection has the problems of high detection cost, low detection efficiency and incapability of carrying out long-distance distributed accurate monitoring on the rail fastener, and cannot meet the use requirements of modern railways.
Disclosure of Invention
In view of this, it is necessary to provide a system for monitoring the state of a track fastener based on a weak fiber grating array, so as to solve the problems in the prior art that the detection cost of track fastener detection is high, the detection efficiency is low, and long-distance distributed accurate monitoring cannot be performed.
In order to solve the above problems, the present invention provides a rail fastener state monitoring system based on fiber grating array, which includes a detection device and a data processing module;
the detection device comprises a vibration sensing optical cable which is arranged on a detected track along the running direction of the train; the detection device is used for sending a modulated optical signal and acquiring a reflected optical signal of the modulated optical signal after the modulated optical signal is reflected by the vibration sensing optical cable; obtaining a vibration signal to be detected according to the reflected light signal, and transmitting the vibration signal to be detected to the data processing module;
the data processing module is used for processing the vibration signal to be detected to obtain a characteristic value of the vibration signal to be detected; and judging the health state of the track fastener to be tested according to the characteristic value of the vibration signal to be tested.
Further, the detection device further comprises: the device comprises a pulse light source, an optical circulator and a demodulation module;
the optical circulator has three ports; the pulse light source is connected with the first port of the optical circulator; the second port of the optical circulator is connected with the vibration sensing optical cable; a third port of the optical circulator is connected with the demodulation module;
the pulse light source is used for sending a modulated light signal; the optical circulator is used for transmitting the modulated optical signal to the vibration sensing optical fiber and transmitting the reflected optical signal to the demodulation module; the demodulation module is used for obtaining a vibration signal to be detected according to the reflected light signal and transmitting the vibration signal to be detected to the data processing module.
Furthermore, a coaxial vibration sensing optical fiber is arranged in the vibration sensing optical cable, and a plurality of weak fiber gratings are arranged on the vibration sensing optical fiber at equal intervals.
Further, the section of vibration sensing optical cable is circular, from inside to outside includes in proper order: the vibration sensor comprises a vibration sensing optical fiber, an inner protection component, a reinforcing component and an outer protection component.
Furthermore, the signal processing module comprises a data acquisition card, a data processor and a database;
the data acquisition card is used for receiving the vibration signal to be detected sent by the detection device;
the data processor is used for analyzing the vibration signal to be detected to obtain the characteristic information of the vibration signal to be detected and judging the health state of the track fastener according to the characteristic information of the vibration signal to be detected;
and the database is used for storing the vibration signals and the health states of the track fasteners corresponding to the vibration signals.
Further, data processor according to the vibration signal characteristic information that awaits measuring, judges track fastener's health status, includes:
the data processor acquires reference vibration signals received by the data acquisition card when a plurality of groups of pre-measured rail fasteners stored in the database are in a non-loosening state;
the data processor obtains reference characteristic information according to the reference vibration signal; and comparing the characteristic information of the signal to be detected with the reference characteristic information, and judging whether the track fastener is loosened.
Further, the data processing module obtains the reference characteristic information according to the reference vibration signal, and includes:
averaging the multiple groups of reference vibration signals to obtain multiple groups of average vibration signals;
calculating an average characteristic value of each group of the average vibration signals;
judging whether the difference value of each group of average characteristic values is larger than a preset difference range or not; if the difference value is larger than the difference range, reselecting the reference vibration signal; and if the difference value is not larger than the difference range, taking the average vibration characteristic value as the reference characteristic information when the track fastener state is normal.
Further, the characteristic information of the signal to be detected comprises a maximum peak-to-peak value and a Hilbert marginal spectrum of the signal to be detected; the reference characteristic information comprises a maximum peak-to-peak value and a Hilbert marginal spectrum of a reference signal when the track fastener is in a normal state.
Furtherly, according to the signal characteristic information that awaits measuring, judge orbital fastener health status awaits measuring includes:
calculating the ratio of the maximum peak value of the signal to be detected to the maximum peak value of the reference signal to obtain the maximum peak value ratio;
judging whether the maximum peak value ratio is larger than a first preset ratio or not; when the maximum peak ratio is larger than a first preset ratio, calculating the ratio of the peak frequency in the Hilbert marginal spectrum of the signal to be detected to the peak frequency in the Hilbert marginal spectrum of the reference signal to obtain the maximum frequency ratio;
judging whether the maximum frequency ratio is larger than a second preset ratio or not; and when the maximum frequency ratio is larger than a second preset ratio, determining that the track fastener is loosened.
Furthermore, the data processor is also used for positioning the track fastener with abnormal state according to the time-course curve of the vibration signal to be detected.
Compared with the prior art, the invention has the beneficial effects that: the invention comprises a detection device and a data processing module; the detection device comprises a vibration sensing optical cable arranged along the running direction of the train, has the advantages of simple structure and convenient installation, can realize the detection of vibration signals and complete the transmission of data, belongs to a passive sensor, and greatly reduces the detection and maintenance cost; in addition, the vibration sensing optical cable is high in sensitivity, strong in anti-electromagnetic interference capability and high in detection precision, and can realize large-scale and long-distance monitoring. The detection device sends a modulated optical signal to obtain a reflected optical signal of the modulated optical signal after being reflected by the vibration sensing optical cable, a vibration signal to be detected is obtained according to the reflected optical signal, and the health state of the track fastener to be detected is judged according to the vibration signal to be detected; can survey vibration signal's different characteristics, distinguish the health status of track fastener fast, have higher monitoring accuracy.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a track fastener state monitoring system based on a fiber grating array according to the present invention;
fig. 2 is a schematic structural diagram of another embodiment of a track fastener status monitoring system based on a fiber grating array according to the present invention;
FIG. 3 is a schematic view of a laying interface of an embodiment of a vibration sensing optical cable provided by the present invention;
FIG. 4 is a cross-sectional view of an embodiment of a weak grating array vibration sensing optical cable according to the present invention;
FIG. 5 is a schematic structural diagram of a data processing module according to an embodiment of the present invention;
fig. 6 is a schematic flow chart of an embodiment of a medium fastener state determination algorithm provided in the present invention.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
The invention provides a rail fastener state monitoring system based on a fiber bragg grating array, which takes a vibration sensing optical fiber as a sensor and is used for solving long-distance distributed monitoring; when the train passes through the vibration sensing optical fiber, the vibration signal to be detected can be obtained according to the signal change of the reflected light, the vibration signal to be detected is analyzed, and the health state of the track fastener can be monitored. The present invention will be described in detail below.
The embodiment of the invention provides a track fastener state monitoring system based on a fiber bragg grating array, and as shown in fig. 1, the system comprises a detection device 100 and a data processing module 200;
the detection device 100 comprises a vibration sensing optical cable 104 arranged on a detected track along the running direction of the train; the detection device 100 is configured to send a modulated optical signal and obtain a reflected optical signal of the modulated optical signal after being reflected by the vibration sensing optical cable; obtaining a vibration signal to be detected according to the reflected light signal, and transmitting the vibration signal to be detected to the data processing module;
the data processing module 200 is configured to process the vibration signal to be detected to obtain a characteristic value of the vibration signal to be detected; and judging the health state of the track fastener to be tested according to the characteristic value of the vibration signal to be tested.
Compared with the prior art, the track fastener state monitoring system based on the fiber bragg grating array comprises a detection device and a data processing module; the detection device comprises a vibration sensing optical cable arranged along the running direction of the train, has the advantages of simple structure and convenience in installation, can detect vibration signals and complete data transmission, and meanwhile, the vibration sensing optical cable is a passive sensor and does not need to be additionally provided with a power supply or a battery is not required to be replaced periodically, so that the detection cost is reduced; in addition, the vibration sensing optical cable has high sensitivity and strong anti-electromagnetic interference capability, so that the vibration sensing optical cable has higher detection precision and can realize large-scale and long-distance monitoring. The system of the embodiment sends the modulated optical signal through the detection device, obtains a reflected optical signal of the modulated optical signal after being reflected by the vibration sensing optical cable, obtains a vibration signal to be detected according to the reflected optical signal, and judges the health state of the track fastener to be detected according to the vibration signal to be detected; can survey vibration signal's different characteristics, distinguish the health status of track fastener fast, have higher monitoring accuracy.
As a preferred embodiment, the detection device further comprises: the device comprises a pulse light source, an optical circulator and a demodulation module;
the optical circulator has three ports; the pulse light source is connected with the first port of the optical circulator; the second port of the optical circulator is connected with the vibration sensing optical cable; the third port of the optical circulator is connected with the demodulation module;
the pulse light source is used for transmitting a modulated light signal; the optical circulator is used for transmitting the modulated optical signal to the vibration sensing optical fiber and transmitting the reflected optical signal to the demodulation module; the demodulation module is used for obtaining a vibration signal to be detected according to the reflected light signal and transmitting the vibration signal to be detected to the data processing module.
As a specific embodiment, the status monitoring system for the rail clip based on the fiber grating array is described with reference to fig. 2 and 3. As shown in fig. 2, the system includes a detection apparatus 100 and a data processing module 200; the detection device 100 comprises a pulse light source 101, an optical amplifier 102, an optical circulator 103, a weak grating array vibration sensing optical cable 104, an end face reflection eliminating device 105 and a demodulation module 106. The optical circulator 103 includes 3 ports: 103-1, 103-2 and 103-3. The pulse light source 101 is connected with the optical amplifier 102, the optical amplifier 102 is connected with the first port 103-1 of the optical circulator 103, the second port 103-2 of the optical circulator 103 is connected with the starting end of the weak grating array vibration sensing optical cable 104, and the tail end of the weak grating array vibration sensing optical cable 104 is connected with the end face reflection eliminating device 105. As shown in fig. 3, the weak grating array vibration sensing optical cable 104 is adhered to the waist of the measured rail along the train running direction.
The detection principle of the detection device is as follows: modulated optical signals sent by a pulse light source 101 pass through an optical amplifier 102 and an optical circulator 103 and reach a weak grating array vibration sensing optical cable 104; the modulated optical signal is reflected by the grating array on the weak grating array vibration sensing optical cable 104 to obtain a reflected optical signal, the reflected optical signal reaches the demodulation module 106, and the demodulation module 106 demodulates the vibration signal to be measured in a wavelength division/time division hybrid multiplexing mode. The end surface reflection eliminating device 105 is used for eliminating the reflected light noise at the end of the optical fiber, and the demodulation accuracy is improved. Utilize weak grating array vibration sensing optical cable as the sensor, have the advantage that anti electromagnetic interference ability is strong, in addition, weak grating array vibration sensing optical cable is passive sensor, need not additionally provide power supply, has reduced detection cost and later maintenance cost, can realize extensive, long distance state monitoring to the track fastener, has higher sensitivity, detects the precision height.
As a specific embodiment, the demodulation module demodulates the interference signal; the demodulation principle is that a modulated optical signal is transmitted on a vibration sensing optical cable, reflected light of an nth grating on the vibration sensing optical cable interferes with reflected light of an n +1 th grating, and when a light path between the nth grating and the n +1 th grating is disturbed, the wavelength and the phase of the reflected light can be correspondingly changed, so that the intensity of the interference signal is changed. When a train passes through a road section of a measured rail, an excitation signal generated by the train acts on the rail, and a weak grating array vibration sensing optical cable laid at the waist of the rail is influenced by the vibration of the train to generate strain, so that the wavelength and the phase of a reflected light signal are changed, and the intensity and the frequency of interference signals of two adjacent weak gratings are changed. The demodulation module demodulates the vibration signal through analyzing the interference signal change.
In a preferred embodiment, a coaxial vibration sensing optical fiber is arranged in the vibration sensing optical cable, and a plurality of weak fiber gratings are arranged on the vibration sensing optical fiber at equal intervals. The weak fiber bragg grating is used as a sensing point, so that the monitoring sensitivity of the train vibration is improved, and the detection precision is high.
As a preferred embodiment, the section of the vibration sensing optical cable is circular, and comprises, from inside to outside: the vibration sensor comprises a vibration sensing optical fiber, an inner protection component, a reinforcing component and an outer protection component. The internal protection component effectively prevents the invasion of moisture and plays a role of mechanical buffering for the vibration sensing optical fiber; the mechanical strength of the optical cable is increased through the reinforcing component; the outer protection component can enhance the insulating property and flexibility of the optical cable, protect the optical fiber and avoid the optical fiber from being damaged mechanically.
As a specific embodiment, as shown in fig. 4, the vibration sensing optical cable sequentially includes, from inside to outside, a vibration sensing optical fiber 401, a fiber paste 402, a PBT loose tube 403, a water blocking tape 404, a first double-coated steel strip 405, an HDPE inner sheath 406, a steel wire reinforcement 407, a water blocking cable paste 408, a second double-coated steel strip 409, and an HDPE outer sheath 410. Through the arrangement, the vibration sensing optical fiber has good mechanical flexibility and strength and has the performances of environmental interference resistance and electromagnetic interference resistance. The average value of the wall thickness of the HDPE outer sheath 410 is 1.8mm, and the outer diameter is 13.5 +/-0.3 mm; the thickness of the first double-coated steel strip 405 and the second double-coated steel strip 409 are both 0.21mm +/-0.02 mm; the outer diameter of the steel wire reinforcement 407 is 1.2mm +/-0.05 mm, and the steel wire reinforcement is made of a phosphatized steel wire; the minimum wall thickness (distance between the outer edge of the steel wire and the outer edge of the inner sheath) of the HDPE inner sheath 406 is 0.6 mm; the external diameter of the PBT loose tube 403 is 2.5mm +/-0.05 mm, and the internal diameter is 1.9mm +/-0.05 mm. The epoxy structural adhesive for the weak grating array vibration sensing optical cable is adhered to the waist of the steel rail, so that the steel rail has certain tension, low optical loss and high sensitivity, can accurately monitor vibration signals, cannot damage the measured steel rail, and is convenient to install.
The weak grating array vibration sensing optical cable 104 comprises a weak grating array with the same reflectivity continuously inscribed on a wire drawing tower on line, the 3dB reflection bandwidth of the weak array grating is 2-3 nm, and the reflectivity is-30 dB to-50 dB. The weak optical fiber grating array is engraved on the weak optical grating array vibration sensing optical cable 104 at equal intervals, and the interval is 3 times of the interval between two adjacent track fasteners. Through above setting, can survey to the actual characteristics of track fastener, improve the accuracy that detects.
As a specific example, the installation of the weak grating array vibration sensing optical cable has a great influence on the detection of the vibration signal. When deployed, the weak grating array vibration sensing cable 104 must be paid out from above the coil, remaining in a loose arc. Torsion is avoided in the laying process, and phenomena such as small circles, surge and back buckling are strictly prohibited; the laying optical cable is not required to be drawn too tightly, the laying tension is not more than 500N, a good contact means is required in the laying process, and once the phenomena of torsion, looping and the like occur, the laying is stopped immediately; after the optical cable is laid, the two ends of the optical cable are required to be respectively coiled for 30m for convenient fusion, and the end heads are required to be subjected to sealing and moisture-proof treatment; the bending radius of the optical cable should be larger than 200mm, and the bending radius should not be smaller than 250mm in the construction process. By the mode, noise generated in the process of transmitting optical signals by the weak grating array vibration sensing optical cable is reduced, and the detection accuracy can be improved; meanwhile, the failure rate in the using process is reduced, the service life is prolonged, and the using reliability is enhanced through the laying modes of sealing, moisture prevention, strict torsion, looping and the like.
As a preferred embodiment, as shown in fig. 5, the data processing module 200 includes a data acquisition card 201, a data processor 202 and a database 203;
the data acquisition card 201 is configured to receive a vibration signal to be detected sent by the detection device;
the data processor 202 is configured to analyze the vibration signal to be detected to obtain characteristic information of the vibration signal to be detected, and determine a health status of the track fastener according to the characteristic information of the vibration signal to be detected;
the database 203 is used for storing the vibration signals and the health states of the track fasteners corresponding to the vibration signals.
As a preferred embodiment, the data processor determines the health status of the rail fastener according to the characteristic information of the vibration signal to be detected, including:
the data processor acquires reference vibration signals received by the data acquisition card when a plurality of groups of pre-measured rail fasteners stored in the database are in a non-loosening state;
the data processor obtains reference characteristic information according to the reference vibration signal; and comparing the characteristic information of the signal to be detected with the reference characteristic information, and judging whether the track fastener is loosened.
As a specific embodiment, the data acquisition card 201 receives the vibration signal to be detected demodulated by the demodulation module 106, the data processor 202 first preprocesses the vibration signal to be detected, where the preprocessing includes performing noise reduction processing on the vibration signal to improve the signal-to-noise ratio; after the preprocessing, the vibration signal to be detected is analyzed, the characteristic information of the vibration signal to be detected, such as amplitude, maximum peak-to-peak value, frequency spectrum information, Hilbert marginal spectrum information and the like, is extracted, the extracted characteristic information is compared with the characteristic information of the rail fastener stored in the database 203 in the non-loosening state, and the loosening state of the fastener is finally judged.
As a preferred embodiment, the characteristic information of the signal to be measured includes a maximum peak-to-peak value and a hilbert marginal spectrum of the signal to be measured; the reference characteristic information comprises a maximum peak-to-peak value and a Hilbert marginal spectrum of a reference signal when the track fastener is in a normal state.
When the train passes through the track that the fastener became invalid, the wheel rail interact increases, and each dynamics index value increases at double, and increases along with the fastener number of losing efficacy, and the power response amplification is obvious, so the amplitude change of the vibration signal that can await measuring judges track fastener pine off-take state.
According to related researches, the vibration frequency of the fastener elastic strip is similar to that of a steel rail, the response of the fastener elastic strip has strong randomness, namely the phase and the amplitude of the vibration response of the fastener elastic strip have randomness, but the vibration response necessarily contains certain invariant characteristics due to the certainty of a track structure, and therefore, the frequency domain characteristics of the response are analyzed. Relevant research shows that the dominant frequency of the vibration of the fastener elastic strip is fixed and unchangeable under different driving conditions.
Compared with a Fourier spectrum commonly used for frequency domain analysis, for a signal of which the frequency components do not exist in the whole duration of the signal, although the Fourier spectrum can analyze the frequency components of each order of the signal, the energy leakage is serious, and the spectral line becomes wider; while the hilbert marginal spectrum still maintains a narrow linewidth and the energy leakage is relatively mitigated. Therefore, the Hilbert marginal spectrum can obtain a more real spectral line of an original signal, and particularly, the advantage of the Hilbert marginal spectrum is more obvious for a frequency time-varying signal.
The marginal spectrum is a description of the distribution of amplitudes (or energies) along the frequency axis, unlike the fourier spectrum: the fourier transform assumes that if a signal has a value at a certain frequency, a sine (or cosine) wave of that frequency exists throughout the sampling time, and the magnitude of the value represents the amplitude of that frequency component. In practice, the instantaneous frequency does not necessarily exist over the entire sampling time. Therefore, processing non-stationary signals using fourier spectra may corrupt the true frequency of the signal and introduce spurious frequencies.
Under the action of a moving load, along with the increase of the loosening degree of the fastener, the energy concentration area of the low-frequency part in the marginal spectrum has the tendency of generating frequency shift' towards a high-frequency area, and the frequency shift degree is gradually reduced along with the increase of the loosening degree of the fastener; under the impact load effect, the difference between the marginal spectrums of the steel rail vibration signals under different fastener loosening degrees is difficult to see out obvious change rules intuitively, and a more determined identification basis cannot be provided for fastener loosening. However, the amplitude values of the marginal spectrum of the steel rail vibration signal under different fastener loosening degrees in different frequency bands are changed to a certain extent, and the amplitude value of the marginal spectrum in a certain frequency band range is obviously lower than that of the marginal spectrum in the same frequency band when the fastener is not loosened.
On a road section with a good track fastener state, Hilbert marginal spectrum energy of vibration signals is concentrated in a low-frequency area, when the track fastener is loosened, interaction between wheels and rails is increased, amplitude of the vibration signals is obviously increased, and the low-frequency part with concentrated energy in the Hilbert marginal spectrum has a tendency of frequency shift. Therefore, the Hilbert marginal spectrum can identify vibration signals of the steel rail under the condition that different fasteners are loosened.
From the analysis, the health state of the track fastener can be judged by detecting the amplitude change of the vibration signal time domain and the frequency shift in the frequency spectrum.
As a preferred embodiment, the obtaining, by the data processing module, the reference characteristic information according to the reference vibration signal includes:
averaging the multiple groups of reference vibration signals to obtain multiple groups of average vibration signals;
calculating an average characteristic value of each group of the average vibration signals;
judging whether the difference value of each group of average characteristic values is larger than a preset difference range or not; if the difference value is larger than the difference range, reselecting the reference vibration signal; and if the difference value is not larger than the difference range, taking the average vibration characteristic value as the reference characteristic information when the track fastener state is normal.
As a specific embodiment, the determining process of the data processor is:
taking the average value of the reference vibration signals of the fasteners of the sensing points of the five groups of fiber bragg gratings on the vibration sensing optical cables in the non-loose state from the database to obtain the average vibration signals; calculating the maximum peak value and the Hilbert marginal spectrum of the average vibration signal; comparing the difference between the maximum peak value of each group of average value data and the frequency of the peak value of the Hilbert marginal spectrum, and if the difference is more than 10%, reselecting the vibration data of the fastener without looseness in the database; and if the difference is less than 10%, storing the average value data into a database as the reference data of the normal state of the fastener.
As a preferred embodiment, according to the characteristic information of the signal to be detected, determining the fastener health status of the track to be detected includes:
calculating the ratio of the maximum peak value of the signal to be detected to the maximum peak value of the reference signal to obtain the maximum peak value ratio;
judging whether the maximum peak value ratio is larger than a first preset ratio or not; when the maximum peak ratio is larger than a first preset ratio, calculating the ratio of the peak frequency in the Hilbert marginal spectrum of the signal to be detected to the peak frequency in the Hilbert marginal spectrum of the reference signal to obtain the maximum frequency ratio;
judging whether the maximum frequency ratio is larger than a second preset ratio or not; and when the maximum frequency ratio is larger than a second preset ratio, determining that the track fastener is loosened.
As a specific embodiment, as shown in fig. 6, the process of determining the health status of the fastener of the track to be tested includes:
step S601, calculating the maximum peak value and the peak frequency of the Hilbert marginal spectrum of the vibration signal to be detected;
step S602, judging whether the ratio of the maximum peak-to-peak value of the vibration signal to be detected to the maximum peak-to-peak value of the reference signal is greater than 1.5; if the ratio is greater than 1.5, go to step S603; if the ratio is less than or equal to 1.5, go to step S604;
step S603, judging whether the ratio of the Hilbert marginal spectrum peak frequency of the vibration signal to be detected to the Hilbert marginal spectrum peak frequency of the reference signal is greater than 1.2; if the ratio is greater than 1.2, go to step S605; if the ratio is less than or equal to 1.2, go to step S604;
step S604, determining that the fastener of the track to be detected is not loosened;
step S605, it is determined that the fastener of the rail to be tested is loosened.
As a specific embodiment, the data processor is further configured to position the track fastener in an abnormal state according to a time-course curve of the vibration signal to be detected.
As a specific embodiment, a time division multiplexing demodulation mode is utilized, and according to a time course curve of a vibration signal to be detected, the position of a sensing point where a delayed interference signal is located is determined, so that the position of a fastener which falls off is located.
As a specific embodiment, the data processing module is connected with a computer, and monitoring software is installed on the computer, so that vibration information of the steel rail can be checked in real time, and an alarm is given to an abnormal vibration signal.
The invention discloses a track fastener state monitoring system based on a fiber bragg grating array, which comprises a detection device and a data processing module, wherein the detection device comprises a detection unit and a data processing module; the detection device comprises a vibration sensing optical cable arranged along the running direction of the train, has the advantages of simple structure and convenience in installation, can detect vibration signals, can complete data transmission, and reduces the detection cost; in addition, the vibration sensing optical cable has high sensitivity and strong anti-electromagnetic interference capability, so that the vibration sensing optical cable has higher detection precision and can realize large-scale and long-distance monitoring. The detection device sends a modulated optical signal to obtain a reflected optical signal of the modulated optical signal after being reflected by the vibration sensing optical cable, a vibration signal to be detected is obtained according to the reflected optical signal, and the health state of the track fastener to be detected is judged according to the vibration signal to be detected; can survey vibration signal's different characteristics, distinguish the health status of track fastener fast, have higher monitoring accuracy.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (10)
1. The rail fastener state monitoring system based on the fiber bragg grating array is characterized by comprising a detection device and a data processing module;
the detection device comprises a vibration sensing optical cable arranged on a detected track along the running direction of the train; the detection device is used for sending a modulated optical signal and acquiring a reflected optical signal of the modulated optical signal after the modulated optical signal is reflected by the vibration sensing optical cable; obtaining a vibration signal to be detected according to the reflected light signal, and transmitting the vibration signal to be detected to the data processing module;
the data processing module is used for processing the vibration signal to be detected to obtain a characteristic value of the vibration signal to be detected; and judging the health state of the track fastener to be tested according to the characteristic value of the vibration signal to be tested.
2. The system for monitoring the status of a rail fastener based on a fiber grating array according to claim 1, wherein the detection device further comprises: the device comprises a pulse light source, an optical circulator and a demodulation module;
the optical circulator has three ports; the pulse light source is connected with the first port of the optical circulator; the second port of the optical circulator is connected with the vibration sensing optical cable; the third port of the optical circulator is connected with the demodulation module;
the pulse light source is used for sending a modulated light signal; the optical circulator is used for transmitting the modulated optical signal to the vibration sensing optical fiber and transmitting the reflected optical signal to the demodulation module; the demodulation module is used for obtaining a vibration signal to be detected according to the reflected light signal and transmitting the vibration signal to be detected to the data processing module.
3. The system for monitoring the state of a track fastener based on a fiber grating array is characterized in that a vibration sensing optical fiber is coaxially arranged inside the vibration sensing optical cable, and a plurality of weak fiber gratings are arranged on the vibration sensing optical fiber at equal intervals.
4. The system for monitoring the state of the track fastener based on the fiber bragg grating array according to claim 1, wherein the cross section of the vibration sensing optical cable is circular and sequentially comprises from inside to outside: the vibration sensor comprises a vibration sensing optical fiber, an inner protection component, a reinforcing component and an outer protection component.
5. The system for monitoring the state of the rail fastener based on the fiber bragg grating array as claimed in claim 1, wherein the signal processing module comprises a data acquisition card, a data processor and a database;
the data acquisition card is used for receiving the vibration signal to be detected sent by the detection device;
the data processor is used for analyzing the vibration signal to be detected to obtain the characteristic information of the vibration signal to be detected and judging the health state of the track fastener according to the characteristic information of the vibration signal to be detected;
and the database is used for storing the vibration signals and the health states of the track fasteners corresponding to the vibration signals.
6. The system for monitoring the state of the track fastener based on the fiber grating array according to claim 5, wherein the data processor determines the health state of the track fastener according to the characteristic information of the vibration signal to be detected, and the system comprises:
the data processor acquires reference vibration signals received by the data acquisition card when a plurality of groups of pre-measured rail fasteners stored in the database are in a non-loosening state;
the data processor obtains reference characteristic information according to the reference vibration signal; and comparing the characteristic information of the signal to be detected with the reference characteristic information, and judging whether the track fastener is loosened.
7. The system for monitoring the state of the rail fastener based on the fiber grating array according to claim 6, wherein the data processing module obtains the reference characteristic information according to the reference vibration signal, and the system comprises:
averaging the multiple groups of reference vibration signals to obtain multiple groups of average vibration signals;
calculating an average characteristic value of each group of the average vibration signals;
judging whether the difference value of each group of average characteristic values is larger than a preset difference range or not; if the difference value is larger than the difference range, reselecting the reference vibration signal; and if the difference value is not larger than the difference range, taking the average vibration characteristic value as the reference characteristic information when the track fastener state is normal.
8. The system for monitoring the state of the rail fastener based on the fiber grating array as claimed in claim 6, wherein the characteristic information of the signal to be tested includes a maximum peak-to-peak value and a Hilbert marginal spectrum of the signal to be tested; the reference characteristic information comprises a maximum peak-to-peak value and a Hilbert marginal spectrum of a reference signal when the track fastener is in a normal state.
9. The system for monitoring the state of the rail fastener based on the fiber bragg grating array according to claim 8, wherein the determining the health state of the rail fastener to be tested according to the characteristic information of the signal to be tested comprises:
calculating the ratio of the maximum peak value of the signal to be detected to the maximum peak value of the reference signal to obtain the maximum peak value ratio;
judging whether the maximum peak value ratio is larger than a first preset ratio or not; when the maximum peak ratio is larger than a first preset ratio, calculating the ratio of the peak frequency in the Hilbert marginal spectrum of the signal to be detected to the peak frequency in the Hilbert marginal spectrum of the reference signal to obtain the maximum frequency ratio;
judging whether the maximum frequency ratio is larger than a second preset ratio or not; and when the maximum frequency ratio is larger than a second preset ratio, determining that the track fastener is loosened.
10. The system for monitoring the state of the track fastener based on the fiber bragg grating array according to claim 5, wherein the data processor is further configured to locate the track fastener with an abnormal state according to a time-course curve of the vibration signal to be detected.
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