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1182 results about "Vibration sensing" patented technology

Fully distributed optical fiber strain and vibration sensing method and sensor

The invention discloses a fully distributed optical fiber strain and vibration sensor comprising a laser (1), a first coupler (2), a pulse modulation module (3), an optical amplifier (4), a circulator (5), a sensing optical fiber (6), a fiber bragg grating (7), a polarization scrambler, a second coupler, a balance photoelectric detector, an analyzer, a photoelectric detector (12) and a signal processing unit. Continuous light output by the laser (1) is split into two paths through the first coupler (2), wherein one path is used as reference light and is accessed to a first input end of the second coupler (9) through the polarization scrambler (8); and the second path is processed by the pulse modulation module (3) and the optical amplifier (4) and then used as detection pulse light to be injected into a first port of the circulator (5). In the invention, Brillouin optical time domain reflectometry (BOTDR) and polarization optical time domain reflectometry (POTDR) are simultaneously utilized for respectively and correspondingly carrying out fully distributed measurement on strain and vibration on a signal optical fiber, the defects of a system with single BOTDR or POTDR are overcome, and the false alarm rate or missed report rate of the system is decreased.
Owner:NANJING UNIV

Long-distance distributed optical fiber vibration sensing system and method thereof

The invention discloses a long-distance distributed optical fiber vibration sensing system and a method thereof. The system comprises an induction system for inducting outside vibration events and a detecting and controlling system for detecting and controlling vibration signals; the induction system is connected with the detecting and controlling system. The induction system comprises a light source, a pulse modulator, an optical fiber circulator, a first optical fiber amplifier, and a light switch of a first optical fiber filter. The detecting and controlling system comprises a plurality of optical-electrical converters and a system control unit; the system control unit collects output light of the converters, analyzing the collected signals and judges whether the alarm is needed according to the analysis result. The invention adopts the optical switch technology to adopt time-division processing on backward Rayleigh scattering light which is reflected back, the dynamic range of the system is large, and the sensible distance can be tens of kilometers as high as possible, even hundreds of kilometers; and the invention adopts phase detecting technology and optical time domain reflection technology and can greatly improve detecting sensibility of the system and positioning precision.
Owner:SHANGHAI BOOM FIBER SENSING TECH +1

Interference type optical fiber perimeter vibration intrusion recognition algorithm

The invention relates to the technical field of optical fiber vibration sensing and in particular relates to an interference type optical fiber perimeter vibration intrusion recognition algorithm suitable for security perimeter. The interference type optical fiber perimeter vibration intrusion recognition algorithm is characterized by comprising the following operations: reading data acquired by an optical fiber vibration sensor from a data acquisition end, and normalizing the acquired data; performing empirical mode decomposition; calculating a characteristic value of an empirical mode decomposition result; detecting multiple characteristic values, judging whether intrusion exists, if so, alarming, otherwise repeating the steps 1-5 for performing recognition in the next round. Compared with the prior art, the interference type optical fiber perimeter vibration intrusion recognition algorithm has the advantages that an original signal is subjected to empirical mode decomposition, the judgment accuracy is improved, the possibility that false alarm is caused due to a certain occasional specific characteristic can be eliminated by adopting a multi-characteristic value threshold detection mode, and intrusion alarm can be accurately realized under the condition that interferences of wind, rain, vehicles and the like exist.
Owner:WEIHAI BEIYANG ELECTRIC GRP CO LTD BEIJING BRANCH

Deep learning based distributed optical fiber vibration sensing type intelligent safety monitoring method

A deep learning based distributed optical fiber vibration sensing type intelligent safety monitoring method includes: signal demodulation and disturbance positioning of a distributed optical fiber vibration sensing technique; demodulation pattern acquisition; sample library construction and network training for network model generation; online real-time disturbance type recognition with a networkmodel; network model online training optimization and the like. Safety monitoring is realized by adoption of detection lines or zone boundary communication cables, and the method has advantages of high extensibility, convenience in networking, low cost, lightning interference prevention and the like. In addition, the method takes full distributed advantages of distributed optical fiber vibration sensing to realize classification and recognition of disturbance information by the aid of a deep learning network, high intelligent recognition accuracy and online optimization performances are achieved, long-distance and large-range circuit safety alarm information management cost and onsite confirmation cost can be reduced, and engineering application process and development of the field of distributed optical fiber safety monitoring systems are greatly promoted.
Owner:SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI

Distributed optical fiber vibration sensing system disturbance event identifying and positioning method

The invention discloses a distributed optical fiber vibration sensing system disturbance event identifying and positioning method. The method includes the steps that according to the position and the number of peaks with signals exceeding a certain threshold value, the number of the peaks occurring within the scope ranging from deltal/2 in front of each point to deltal/2 behind each point in an optical fiber is obtained, whether disturbance events exist or not is judged, and backgrounds are extracted with an amplitude limiting one-order inertia filtering method when the disturbance events do not exist; space-time terminals of the disturbance events are obtained according to the backgrounds when the disturbance events exist, fitting is carried out within the area range to obtain a background event probability density function, Gaussian mixture distribution parameters including the specific gravity, the expectations and the covariance matrix of Gaussian contents of the event peaks including the backgrounds in the area are solved through iteration of the EM algorithm, the parameters, the parameters of the background event probability density function and the total number of the event peaks in the area are fed into a classifier, the disturbance types are judged, and the expectations of the Gaussian contents represent the space positions of the events.
Owner:SOUTHEAST UNIV

Optical fiber vibration sensing head and manufacturing method thereof

The invention discloses an optical fiber vibration sensing head, which consists of a vibration sensitive chip, a dual fiber collimator and an encapsulation shell, wherein the inside of the encapsulation shell under the dual fiber collimator is provided with a cavity, the vibration sensitive chip is arranged in the cavity and consists of micro light reflector, a silicon supporting frame and a substrate glass sheet; the silicon supporting frame is bonded with the substrate glass sheet; the micro light reflector is arranged in the silicon supporting frame; a damping air cavity is reserved between the micro light reflector and the substrate glass sheet; two sides of the micro light reflector is symmetrically provided with torsion shafts; and one end of each of the torsion shaft is connected with the silicon supporting frame. An MEMS process is used to integrate a MEMS vibration sensitive chip. Based on an asymmetric torsion micro light reflector structure, the MEMS vibration sensitive chip can be manufactured in batch. The torsion shafts are used as elastic elements, and the micro light reflector is used as a sensitive mass block to reflect vibration acceleration. The damping air cavity is used for controlling the damping characteristic of torsion. The invention has the advantages of batch production, low cost and high consistency.
Owner:上海前所光电科技有限公司

Terrain semantic perception method based on vision and vibration tactile fusion

The invention provides a terrain semantic perception method based on vision and vibration touch fusion. The terrain semantic perception method comprises the steps: firstly, giving an implementation method of vision three-dimensional semantic mapping based on ORB_SLAM2 and semantic segmentation; secondly, in combination with a terrain semantic classification and recognition method based on CNN-LSTM, giving a realization thought and a fusion strategy of vision/touch fusion; and finally, based on the blue whale XQ unmanned vehicle platform, the Kinect V1.0 visual sensing unit and the vibration sensing unit, carrying out algorithm testing in a real object environment. Therefore, the semantic marking precision of the method obtained by comparing a test result with a real environment can meet the application requirements; and meanwhile, whether the terrain semantic cognition is good or not can be obviously compared according to the fusion result of whether the vibration touch exists or not,so that more reliable sensing capacity can be provided for the patroller through fusion of the vibration touch and the terrain semantic cognition, and the vibration touch can still provide terrain cognition precision within a limited range even under the condition of visual failure.
Owner:HARBIN INST OF TECH

Distributed optical fiber vibration sensor based on relay amplifying and sensing technology and method thereof

The invention discloses a distributed optical fiber vibration sensor based on the relay amplifying and sensing technology and a method thereof, belonging to the technical field of optical fiber vibration sensing. The system comprises a light source, an electro-optical modulator, a pulse driver, a light amplifier, a circulator, a polarizing beam splitter, a collector and a signal analysis processing system. The sensor is characterized in that the system also comprises a pumping laser light source and an optical remote sensing relay amplifying and sensing optical module. The pumping laser light source is arranged in the distributed optical fiber vibration sensing demodulation device and the optical remote sensing relay amplifying and sensing optical module is embedded between multistage sensing fibers. The passive optical modules of the pumping laser light source and optical remote sensing relay amplifying and sensing optical module perform long-distance connection through transmission fiber to form the light amplifier, the gain of the optical remote sensing relay amplifying and sensing optical module is utilized to overcome fibre loss, increase the intensity of the spontaneous Rayleigh scattering light of the optical fibre, enhance the signal-to-noise ratio of the distributed optical fiber vibration sensing system, enlarge the transmission distance of the system and increase the measurement accuracy of vibration events in the target area. The system is mainly used in the fields requiring long-distance measurement vibration signals such as perimeter safety precaution, border precaution, seismic detection and tsunami early warning.
Owner:SHANGHAI BOOM FIBER SENSING TECH

Railway rockfall early warning system and method

The invention discloses a railway rockfall early warning system and method. The railway rockfall early warning system comprise a fiber bragg grating vibration sensing part, a fiber bragg grating demodulating instrument and an analyzing and alarming device, wherein the fiber bragg grating vibration sensing part is provided with a fiber bragg grating suitable for generating strains along with the vibration of a track; the fiber bragg grating demodulating instrument is used for guiding light emitted by a light source to the fiber bragg grating, receiving light reflected back from the fiber bragg grating and outputting an electric signal reflecting wavelength variation, caused by the strains, of the reflected light; and the analyzing and alarming device is used for acquiring the wavelength variation information of the light reflected back from the fiber bragg grating so as to determine whether to give out an alarm on the fault of the track. The invention also relates to a railway rockfall early warning method, comprising the following steps of: providing the fiber bragg grating generating strains along with the vibration of the track; acquiring the electric signal reflecting the wavelength variation of the light reflected back from the fiber bragg grating through the fiber bragg grating demodulating instrument; acquiring the wavelength variation information of the light reflected back from the fiber bragg grating on the basis of the electric signal; and determining whether to give out an alarm on the basis of the wavelength variation information.
Owner:NUCTECH CO LTD

Optical fiber grating acceleration sensor and test method thereof

The invention discloses an optical fiber grating acceleration sensor and a test method thereof, relating to the technical field of optical fiber grating vibration sensing. The optical fiber grating acceleration sensor comprises a U-shaped shell, a steel beam, a first optical fiber grating, a second optical fiber grating, a mass block, a spring, damping fluid, a clamping groove, a concave lever, a folding arch beam and a seal cover, wherein the opening end of the U-shaped shell is provided with the seal cover; the inner wall of the U-shaped shell is connected with one end of the steel beam, and the other end of the steel beam is fixedly connected with the folding arch beam; the folding arch beam is fixedly connected with the concave lever; the concave lever fixed to the clamping groove is connected with the mass block; the mass block is connected with the inner wall of the shell by the spring; the first optical fiber grating and the second optical fiber grating are respectively arranged on the folding arch beam; and the damping fluid is filled in the U-shaped shell. The invention realizes the repeated design and use according to the engineering practical demand and changes the system rigidity by conveniently disassembling and replacing folding arch beams with different sizes, thereby realizing the adjustability of sensitivity and natural vibration frequency and achieving the aim of temperature self compensation.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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