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32 results about "Waterfall plot" patented technology

A waterfall plot is a three-dimensional plot in which multiple curves of data, typically spectra, are displayed simultaneously. Typically the curves are staggered both across the screen and vertically, with 'nearer' curves masking the ones behind. The result is a series of "mountain" shapes that appear to be side by side. The waterfall plot is often used to show how two-dimensional information changes over time or some other variable such as rpm. The term waterfall plot is sometimes used as a synonym of spectrogram or cumulative spectral decay (CSD) plot.

Fracture monitoring using pressure-frequency analysis

Changes occurring downhole during a fracturing process can create or reflect pressure signals. Capturing and evaluating such pressure waves during fracturing enables personnel to monitor, in real time or later, what happens downhole. When a fracture extends, a burst of acoustic noise is embodied in a pressure wave or signal, as is noise coming from other sources. By transforming time-based pressure signals to a frequency base, one can monitor this acoustic noise. In a particular implementation, a waterfall plot of frequency spectra at successive time slices of the original signal is used to determine frequency ridges, such as a ridge of decreasing frequencies indicates fracture extension and a ridge of increasing frequencies indicates either closure or proppant backing up in the fracture. Filtering, such as wavelet filtering, can be used. A fracturing process can be controlled in response to determining whether the fracture is extending.
Owner:HALLIBURTON ENERGY SERVICES INC

Blade vibration blade tip timing online monitoring method and device during inconstant rotation speed

The invention discloses a blade vibration blade tip timing online monitoring method and device during inconstant rotation speed, wherein the method comprises the following steps: 1) obtaining a bladetip timing signal sequence and a rotation speed signal sequence during blade vibration; 2) constructing a blade tip timing angular domain uniformly sampled blade vibration displacement model; 3) establishing a reconstruction formula for the blade vibration blade tip timing angular domain undersampled reconstruction signal; 4) calculating the order spectrum of the blade vibration blade tip timing angular domain undersampled reconstruction signal and extracting synchronous vibration order; 5) calculating the spectrum waterfall plot of the blade vibration blade tip timing angular domain undersampled reconstruction signal to extract the asynchronous vibration frequency. The method can reconstruct the blade tip timing vibration signal with inconstant rotation speed, and the reconstructed signalhas no order aliasing. The method can simultaneously recognize the synchronous and asynchronous vibration characteristics of the blades, and the calculation process is simple and easy to implement. The high-order vibrations can be identified with very few blade tip timing sensors so as to save installation costs and space.
Owner:HUNAN UNIV OF TECH

Railway health monitoring method based on distributed optical fiber vibration sensing system

The invention discloses a railway health monitoring method based on a distributed optical fiber vibration sensing system. The railway health monitoring method comprises steps of using an existing communication optical fiber which is paved along a railway to perform sensing, capturing vibration information along the railway after a train passes, using data to constitute a waterfall plot which uses a gray scale to express intensity along a timeline, adopting a rim extraction algorithm based on dynamic planning to extract a track generated by a moving train after wavelet decomposition filtering is performed, marking off two areas, wherein one area is before the track and the other area is after the track, performing time frequency analysis on the track area and areas before and after the track, extracting a wheeltrack vibration characteristic frequency spectrum and a steel rail resonance characteristic frequency spectrum, obtaining wheeltrack vibration characteristic frequency and steel rail resonance characteristic frequency through a characteristic spectrum extraction algorithm, constantly repeating a monitoring process to obtain a change of a steel rail vibration characteristic along the time, and establishing a corresponding database. Newly collected data is compared with data inside the database and the database is updated, and health monitoring on the train and the steel rail is realized.
Owner:NANJING FAAIBO OPTOELECTRONICS TECH

Radio signal identification method based on end-to-end convolutional neural network

The present invention relates to a radio signal identification method based on an end-to-end convolutional neural network. The method is characterized in that: an original I / Q sampling data of an observation window is subjected to execution of preprocessing and identification through a convolutional neural network in order. The preprocessing step is that: the original I / Q sampling data of the observation window is taken as input, and a frequency spectrum waterfall plot is output after discrete Fourier transform and data format alignment processing; the step of identification through the convolutional neural network is that: the frequency spectrum waterfall plot obtained by preprocessing is taken as input, and a one-dimensional boolean vector configured to show whether all the signals to beidentified are existed or not is output after the input passes through a CNN feature extraction layer, an MLP feature mapping layer and a BR multi-tag classification layer. Compared with the mode offeature extraction and classification identification, the radio signal identification method employs the end-to-end technical solution thinking to avoid complex and low-efficient feature engineering,improve the signal identification accuracy, robustness and intelligence level, and has important meaning of radio monitoring of important areas and important activity scenes.
Owner:INST OF SOFTWARE - CHINESE ACAD OF SCI

Interference identification model based on deep convolutional neural network and intelligent identification algorithm

The invention discloses an interference identification model based on a deep convolutional neural network and an intelligent identification algorithm. Describing the interference identification modelbased on the deep convolutional neural network as follows: describing the interference identification model based on the deep convolutional neural network; the receiver used for interference identification collects data of interference signals sent by one or more jammers. And taking the frequency spectrum waterfall plot of the receiver as a receiving end as a network input layer to carry out a plurality of trainings, and taking the frequency spectrum waterfall plot of the receiver as network input to carry out online identification according to a trained storage model and the frequency spectrum waterfall of the receiving end after an enough fitting degree training model is reached. And in combination with other structures or methods, the model is complete, the physical significance is clear, the design algorithm is reasonable and effective, and the interference identification scene based on the deep convolutional neural network algorithm can be better described.
Owner:ARMY ENG UNIV OF PLA

Frequency spectrograph waterfall plot display system and method

The invention relates to a frequency spectrograph waterfall plot display system and a frequency spectrograph waterfall plot display method. The frequency spectrograph waterfall plot display system comprises a frequency spectrum data reading module, a color data generating module, a color data caching module and a graphics drawing module, wherein the frequency spectrum data reading module reads the frequency sweep frequency spectrum data in real time; the color data generating module converts amplitude data into color data according to a predefined amplitude-color conversion ratio table; the color data caching module caches the color data according to a time sequence; and the graphics drawing module draws the data in the color data caching module to a display screen in a waterfall plot form. According to the waterfall plot method, the defect that the relationship among the signal frequency, the amplitude and the time cannot be simultaneously displayed under the same interface in a common spectral analysis interface can be overcome.
Owner:NANJING GUORUI ANTAIXIN TECH

Direction-finding method and installation for detection and tracking of successive bearing angles

A direction-finding method and apparatus for detection and tracking of successive bearing angles of sound-emitting targets, wherein intensity plots of successive clock cycles in a waterfall plot show bearing traces of successive bearing angles, and preferred bearing traces are marked by a tracker. In order to automate the setting and deletion of trackers, starting from trace state vectors, which are determined at the time t=k−1, are each associated with one bearing trace and each have a bearing angle as well as its time derivative, which is referred to as the bearing rate, and possibly an intensity and its time derivative, which is referred to as the intensity rate, and trace errors associated with the trace state vectors for the time t=k, predicted state vectors are predicted together with predicted estimation errors. Bearing traces are displayed as a function of a trace quality
Owner:ATLAS ELEKTRONIC GMBH

Rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform

The invention discloses a rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform, comprising the following steps: (10) echo signal windowing: discretizing echo data of a rocket bomb measured by radar, and using a Blackman window to carry out time-domain windowing on the discretized data; (20) power spectrum waterfall plot acquiring: constantly sliding time-domain windows, carrying out time-domain signal reconstruction, low-frequency coefficient extraction and instantaneous velocity calculation on the echo data in each time-domain window, and drawing a power spectrum waterfall plot according to the power spectrums in all the time-domain windows; and (30) muzzle velocity determining: finding out the position of the signal according to the power spectrum waterfall plot, fitting out the muzzle velocity of the rocket bomb according to the Doppler frequency-velocity relationship corresponding to the peak, and drawing a velocity fitted curve of the rocket bomb. The invention aims to provide a rocket bomb muzzle velocity measurement method based on short-time Fourier transform, which has the advantages of small amount of calculation and high measurement accuracy.
Owner:NANJING UNIV OF SCI & TECH

Amplitude spectrum array waterfall plot for shaft vibration analysis of starting-stopping process

The invention relates to an amplitude spectrum array waterfall plot for shaft vibration analysis of starting-stopping process of equipment. A making method of the waterfall plot comprises three steps: (1) reading a pair of vibration displacement signal arrays, i.e. an x signal array and a y signal array of a rotating shaft in the process of starting or stopping; (2) evaluating a synthesized amplitude spectrum of the x signal array and the y signal array at each rotation speed; and (3) arranging the synthesized amplitude spectrum in rising speed or reducing speed sequence into an array plot which is the made amplitude spectrum array waterfall plot. Any amplitude on the waterfall plot made by the method can represent the true amplitude of the corresponding shaft vibration component in a bearing cross section; the shape of the waterfall plot is only involved with the starting and stopping process and has no relation with the installation position of a sensor; and the invention is convenient for understanding the characteristics of machine states.
Owner:NANJING UNIV

Frequency spectrum analysis real-time waterfall plot implementing method

The invention discloses a real-time waterfall plot implementing method, and relates to a method used for implementing real-time waterfall plot in the frequency spectrum monitoring field. The method comprises the steps: a frequency spectrum data generation unit reads frequency spectrum data through a DMA mode, and circularly stores the frequency spectrum data in a data region by means of a ping-pong operation; the frequency spectrum data processing unit uses a weighting factor method to perform weight calculation on data at the same location of the frequency spectrum data in each frame; according to a time order, the amplitude of the frequency spectrum data after being subjected to weighting factor weighing is converted into color data and display on a display screen according to a self-defined color-amplitude ratio. The method disclosed by the invention has characteristics of real-time collection, real-time analysis, and real-time display; important information features of the frequency spectrum cannot be lost; the problem of frame loss caused by differences between processing speeds among hardware can be effectively avoided; and the method is particularly adapted to manufacturing a real-time frequency spectrum machine that can rapidly detect a momentary signal such as a hop signal in the frequency spectrum monitoring field.
Owner:NO 54 INST OF CHINA ELECTRONICS SCI & TECH GRP

High-speed rail track health online monitoring method based on phi-OTDR

The invention discloses a phi-OTDR-based high-speed rail track health online monitoring method, which uses existing communication optical fibers laid along a railway for sensing to capture vibration information of the railway after a train passes by. The method comprises the following steps: organizing data into a waterfall plot with gray scale representing intensity according to a time axis, performing wavelet decomposition filtering, extracting a track generated by train running by adopting an edge extraction algorithm based on dynamic programming, and dividing two regions before and after the track; making time-frequency analysis on the track area and the areas before and after the track, extracting a wheeltrack vibration characteristic frequency spectrum and a steel rail resonance characteristic frequency spectrum, and obtaining a wheeltrack vibration characteristic frequency and a steel rail resonance characteristic frequency through a characteristic frequency spectrum extractionalgorithm; continuously repeating the monitoring process to obtain the change of the steel rail vibration characteristics along with time, and establishing a corresponding database; comparing the newly acquired data with the data in the database and updating the database to realize real-time health monitoring of the train and the steel rail.
Owner:NANJING UNIV

Method for reconstructing, displaying and analyzing engine test data three-dimensional waterfall plot

The invention belongs to the technical field of aerospace experiments, and particularly relates to a method for reconstructing, displaying and analyzing an engine test data three-dimensional waterfall plot. The method comprises the main steps of: 1, exporting a text-format file from an original three-dimensional waterfall plot of Desktop-Advanced software of LMS Test.Lab Rev; 2, reading amplitude column data in spectrum data from the text-format file; 3, storing the spectrum data as a two-dimensional array; and 4, reconstructing a three-dimensional waterfall plot and carrying out display and analysis, wherein an analysis method comprises analysis steps of extracting data by spectral slices, carrying out dynamic perspective viewing, carrying out data comparison and the like. By the method disclosed by the invention, the defects of display aliasing, fuzzy display effect and poor discrimination of spectrum data of a single-color three-dimensional waterfall plot automatically generated by Desktop-Advanced software of a current LMS Test.Lab Rev are overcome, and the problem of inconvenience for an operator to carry out analysis processing is solved.
Owner:XIAN AEROSPACE PROPULSION TESTING TECHN INST

Frequency hopping signal detection and parameter estimation method based on deep neural network

The invention discloses a frequency hopping signal detection and parameter estimation method based on a deep neural network, belongs to the field of image recognition, and can be used for frequency hopping signal detection and parameter estimation. The method comprises the following steps: 1) generating and acquiring frequency hopping signal data; 2) classifying and sorting the frequency hopping signal data according to parameters such as a modulation mode, a signal-to-noise ratio and a frequency modulation frequency; 3) generating a time-frequency distribution waterfall plot from the classified frequency hopping signals, and generating an image data set; 4) constructing an SSD model; 5) labeling the generated time-frequency waterfall plot as input of an SSD target detection framework model for training; 6) applying the trained model to a test set to complete frequency hopping signal detection and parameter estimation, wherein k _ means clustering-based time-frequency waterfall plot correction is continued aiming at the noise problem of the time-frequency waterfall plot, and 8) performing comparative analysis on the performance before and after the time-frequency waterfall plot correction. The method is high in frequency hopping signal detection rate and accurate in parameter estimation, and has important significance for frequency hopping signal processing.
Owner:SICHUAN UNIV

Vehicle calibration method and system

PendingCN107608230AOptimize acceleration performanceReduce development costsSimulator controlParallel computingWaterfall plot
The invention discloses a vehicle calibration method and system. The method comprises the steps: inputting a shifting strategy mapping table and an accelerator pedal curve mapping table into a vehiclesimulation model; selecting a plurality of accelerator fixed values from the accelerator pedal curve mapping table, and carrying out the fixed acceleration simulation according to the plurality of accelerator fixed values through a simulation model; selecting a vehicle speed and a corresponding acceleration from a simulation result, and drawing a fixed acceleration waterfall plot according to theselected vehicle speed and the corresponding acceleration; and optimizing a torque in an accelerator pedal curve under the corresponding accelerator value and a shifting point in the shifting strategy mapping table according to the acceleration waterfall plot. According to the invention, the method can achieve the fixed acceleration simulation through the model, can achieve the quick and efficient searching of the most ideal shifting point, improves the efficiency, reduces the independence on a real-vehicle test, saves the development cost of a vehicle, and reduces the test risks.
Owner:BORGWARD AUTOMOTIVE CHINA CO LTD

Method for rapidly evaluating electromagnetic disturbance under dynamic working conditions of electric vehicle

The invention relates to a method for rapidly evaluating electromagnetic disturbance under dynamic working conditions of an electric vehicle. The method includes the steps of A, enabling the vehicle to be driven on a dynamometer and undergo a series of working conditions, and at a sampling frequency of not lower than 5 Hz, synchronously collecting a drum linear speed of the dynamometer and time-domain data of drum force as well as time-domain signals in a vertical direction of an electric field and three orthogonal directions of a magnetic field and conducted emission time-domain signals, wherein the drum speed of the dynamometer is equal to a vehicle speed under the condition that wheels don't slip; B, transforming the time-domain signals in the vertical direction of the electric field and the three orthogonal directions of the magnetic field and the conducted emission time-domain signals into frequency-domain signals of corresponding time points in real time through a fast Fourier transform algorithm and displaying the frequency-domain signals as a waterfall plot; C, displaying the drum linear speed of the dynamometer and the time-domain data of the drum force correspondingly to the frequency-domain signals of the time points corresponding to the vertical direction of the electric field, the three orthogonal directions of the magnetic field and conducted emission through a data fusion algorithm. The method is capable of evaluating the real conditions of the electromagnetic disturbance of the electric vehicle more reliably.
Owner:CHINA NAT ELECTRIC APP RES INST

Rotating machinery frequency-doubled fault diagnosis method based on three-dimensional holographic difference spectrum

The invention relates to a rotating machinery frequency-doubled fault diagnosis method based on a three-dimensional holographic difference spectrum. The method comprises the following steps of: firstly, determining a measuring point with the most sensitive fault response on a unit shaft system, analyzing the main excitation frequency and amplitude variation trend of the measuring point by utilizing a frequency spectrum waterfall chart or a characteristic trend chart, and judging whether the fault type is a frequency-doubled fault or not by combining a rule; then calculating a double-frequencythree-dimensional holographic spectrum matrix of the shaft system in a normal state and a plurality of fault states, and constructing a double-frequency three-dimensional holographic differential spectrum matrix corresponding to the fault states on the basis; and finally, drawing a frequency-doubled three-dimensional holographic differential spectrogram of the shaft system in a plurality of faultstates to obtain a pure fault frequency-doubled ellipse of the whole shaft system in a fault development process and change characteristics of characteristics of the pure fault frequency-doubled ellipse, determining a fault source position by combining the characteristics, and carrying out qualitative diagnosis on the frequency-doubled fault. According to the method, the difference of the fault response signs is represented from time and space dimensions, and key diagnosis information is provided for accurately distinguishing rotor cracks and misalignment faults.
Owner:XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY

Method for calculating radiation noise of silencer of exhaust system

The invention discloses a method for calculating radiation noise of a silencer of an exhaust system. The method comprises the following steps: S1, extracting a static pressure curve of each cavity inthe silencer to be analyzed from simulation software; S2, performing pretreatment through a conversion tool completed during analysis process development, and converting static pressure into frequencyspectrum excitation; S3, conducting finite element modeling on the silencer, and making frequency response calculation; S4, extracting a calculation result, and synthesizing the calculation result into a waterfall plot and a total sound pressure curve; S5, evaluating the total sound pressure curve and the waterfall plot, if the total sound pressure curve and the waterfall plot do not pass the evaluation, returning to the adjustment structure, and starting evaluation again from the step S1; and if so, completing the step of analyzing the radiation noise of the silencer, and then entering a sample piece manufacturing stage. Compared with the prior art, the invention has the advantages that the recognition capability of the earlier-stage risk of silencer development is improved, the originaldevelopment process depending on tests and repeated iteration is simplified, and the development cost and time are saved.
Owner:SHANGHAI TENNECO EXHAUST SYST

Enhanced phase waterfall plot-based rotor crack weak fraction harmonic feature identification method

The invention provides an enhanced phase waterfall plot-based rotor crack weak fraction harmonic feature identification method. Identification of weak frequency components is realized by using signal frequency domain phase spectrum features based on the characteristic that the phase value of the frequency components is independent of energy. The method comprises the following steps: 1, carrying out short time mobile sampling on signals to be analyzed to obtain serial short time signals, and adopting fast Fourier transform (FFT) to obtain frequency domain phase spectra respectively corresponding to the serial short time signals; 2, processing the obtained frequency domain phase spectra through adopting a line unit form filtering technology to obtain filtered feature enhanced frequency domain phase spectra in order to complete feature enhancement of the phase spectra; and 3, sequentially arranging the enhanced frequency domain phase spectra in a sampling time sequence to form an enhanced phase waterfall plot to realize separation of the regular phase band in the real frequency components and the random phase value caused by FFT calculating error and noises in order to complete identification of the rotor crack weak fraction frequency components.
Owner:XI AN JIAOTONG UNIV

A method and device for on-line monitoring of blade vibration tip timing when the rotational speed is not constant

The invention discloses a blade vibration blade tip timing online monitoring method and device during inconstant rotation speed, wherein the method comprises the following steps: 1) obtaining a bladetip timing signal sequence and a rotation speed signal sequence during blade vibration; 2) constructing a blade tip timing angular domain uniformly sampled blade vibration displacement model; 3) establishing a reconstruction formula for the blade vibration blade tip timing angular domain undersampled reconstruction signal; 4) calculating the order spectrum of the blade vibration blade tip timing angular domain undersampled reconstruction signal and extracting synchronous vibration order; 5) calculating the spectrum waterfall plot of the blade vibration blade tip timing angular domain undersampled reconstruction signal to extract the asynchronous vibration frequency. The method can reconstruct the blade tip timing vibration signal with inconstant rotation speed, and the reconstructed signalhas no order aliasing. The method can simultaneously recognize the synchronous and asynchronous vibration characteristics of the blades, and the calculation process is simple and easy to implement. The high-order vibrations can be identified with very few blade tip timing sensors so as to save installation costs and space.
Owner:HUNAN UNIV OF TECH

A Railway Health Monitoring Method Based on Distributed Fiber Optic Vibration Sensing System

The invention discloses a railway health monitoring method based on a distributed optical fiber vibration sensing system. The railway health monitoring method comprises steps of using an existing communication optical fiber which is paved along a railway to perform sensing, capturing vibration information along the railway after a train passes, using data to constitute a waterfall plot which uses a gray scale to express intensity along a timeline, adopting a rim extraction algorithm based on dynamic planning to extract a track generated by a moving train after wavelet decomposition filtering is performed, marking off two areas, wherein one area is before the track and the other area is after the track, performing time frequency analysis on the track area and areas before and after the track, extracting a wheeltrack vibration characteristic frequency spectrum and a steel rail resonance characteristic frequency spectrum, obtaining wheeltrack vibration characteristic frequency and steel rail resonance characteristic frequency through a characteristic spectrum extraction algorithm, constantly repeating a monitoring process to obtain a change of a steel rail vibration characteristic along the time, and establishing a corresponding database. Newly collected data is compared with data inside the database and the database is updated, and health monitoring on the train and the steel rail is realized.
Owner:NANJING FAAIBO OPTOELECTRONICS TECH

Intrusion alarm method and system based on vibration optical fiber detection and complete action extraction

The invention provides an intrusion alarm method and system based on vibration optical fiber detection and complete action extraction, and the method comprises the steps: S1, solving and storing a signal, and setting a threshold value to judge an intrusion action signal and give an alarm; s2, obtaining an original vibration signal curve and carrying out normalized leveling processing on the original vibration signal curve; s3, performing high-frequency high-pass filtering processing on the leveled signal, performing binarization processing on the image, and performing external contour extraction to obtain a minimum enclosing rectangle; s4, low-frequency high-pass filtering processing is carried out on the signals after leveling processing, a time-frequency image data set of a classification network is constructed, and an EfficientNet classification network model is trained; and S5, according to the information of the minimum enclosing rectangle, in combination with a matrix obtained through an OfficientNet classification network, realizing classified alarm. According to the method, the energy waterfall plot with a relatively good effect can be quickly obtained, so that the position point of the suspicious intrusion signal can be quickly obtained in the spatial dimension, and the coverage time of the suspicious intrusion signal can be accurately obtained in the time dimension.
Owner:上海微波技术研究所(中国电子科技集团公司第五十研究所)

Sonar image recognition method and device

The invention discloses a sonar image recognition method and device, and the method comprises the steps: intercepting a target sonar image from a sonar waterfall plot according to a preset frame number interval, and recording a frame identifier of a specified echo data frame; recognizing the target sonar image based on a preset target recognition model, acquiring the preset information of a target object in the target sonar image, and acquiring the preset target recognition model by training a one-stage type target detection algorithm based on a first training set formed by synthesizing the sonar image, wherein the preset information comprises position information and category information; based on the frame identifier, determining position information of a target sonar image in a sonar waterfall plot; and marking the target object in the sonar waterfall plot based on the position information of the target sonar image in the sonar waterfall plot and the preset information of the target object in the target sonar image. The method and the device are high in recognition speed, can improve the recognition efficiency of the sonar image, and can be applied to actual production.
Owner:北京星天科技有限公司

Qualitative diagnosis method for power frequency fault of rotary machinery

The invention discloses a qualitative diagnosis method for a power frequency fault of rotary machinery. The method comprises the following steps: firstly, synchronously acquiring multiple groups of shaft vibration displacement signals and corresponding key phase signals at two measuring points which are vertically arranged at a rotor fault response sensitive section; then extracting a pure fault power frequency component in the vibration signal by using a two-dimensional holographic difference spectrum, and finally constructing a two-dimensional holographic difference spectrum waterfall plot corresponding to the power frequency and a characteristic trend plot thereof to completely describe the change characteristics of pure fault procession trajectory characteristics. According to the method, the change rule of pure fault power frequency track characteristics can be visually reflected, differentiated information is effectively mined from the fault development process, and accurate qualitative diagnosis of the rotor power frequency fault is realized.
Owner:XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY

A Transformation and Update Method of Sonar Fan Diagram

The invention provides a conversion updating method for a sonar sector diagram. The method comprises the steps: a, carrying out the module solving and transposition of a complex matrix after a wave beam is formed, and building a pixel index; b, calculating a wide w period and a high h period of a sector diagram of expected imaging; c, assigning values to x and y coordinates of the sector diagram; d, calculating the corresponding (r, theta) in a polar coordinates space; e, solving a pixel value of a point (x0, y0) in a Cartesian coordinate system mapped to a point (r0, theta 0) in a polar coordinate system in an original waterfall plot at step a through the built index; f, repeatedly carrying out the step d, carrying out the interpolation calculation of pixel values of all points, and obtaining a sonar image in the Cartesian coordinate system; g, updating the assigned values of y coordinates with the changing of depth, then repeatedly carrying out the steps d-f, and achieving the updating of the sector diagram. According to the invention, an upper computer is used for building the index and the interpolation, and the method avoids the tedious trigonometric or inverse trigonometric function conversion of an FPGA, improves the calculation efficiency and accuracy, and saves the time.
Owner:江苏中海达海洋信息技术有限公司

Weak Fractional Harmonic Feature Identification Method for Rotor Cracks Based on Enhanced Phase Waterfall Diagram

The invention provides an enhanced phase waterfall plot-based rotor crack weak fraction harmonic feature identification method. Identification of weak frequency components is realized by using signal frequency domain phase spectrum features based on the characteristic that the phase value of the frequency components is independent of energy. The method comprises the following steps: 1, carrying out short time mobile sampling on signals to be analyzed to obtain serial short time signals, and adopting fast Fourier transform (FFT) to obtain frequency domain phase spectra respectively corresponding to the serial short time signals; 2, processing the obtained frequency domain phase spectra through adopting a line unit form filtering technology to obtain filtered feature enhanced frequency domain phase spectra in order to complete feature enhancement of the phase spectra; and 3, sequentially arranging the enhanced frequency domain phase spectra in a sampling time sequence to form an enhanced phase waterfall plot to realize separation of the regular phase band in the real frequency components and the random phase value caused by FFT calculating error and noises in order to complete identification of the rotor crack weak fraction frequency components.
Owner:XI AN JIAOTONG UNIV

A Flywheel Stiffness Parameter Extraction Method Based on Microvibration Waterfall Diagram

ActiveCN108534996BReflect radial dynamic characteristicsStructural parameters are comprehensive and more accurateMachine part testingPeak valueFlywheel
The invention provides a flywheel rigidity parameter extraction method based on a micro-vibration waterfall plot. The method comprises the steps of: (1) building a radial kinetic model and a radial micro-vibration transmission model of a flywheel rotor; (2) testing micro-vibration during speed rise of the flywheel and generating a waterfall plot; (3) obtaining local peak value coordinates on the micro-vibration waterfall plot of the flywheel; (4) based on classification and robust regression of the coordinate data, obtaining function expressions of a mode and vortex motion curve in a full rotating speed range through fitting and performing transposition multiplying on the four expressions to obtain a structure feature polynomial; (5) obtaining an optimized target function; (6) solving thetarget function through an optimal method to obtain rigidity parameters in the radial kinetic model and the vibration transmission model of the flywheel. The method can be applied to optimal configuration of rotor structural rigidity, vortex motion and modes during flywheel design and can serve as proof for judging the consistence and the qualification of product structures in a mass production process of flywheels.
Owner:BEIJING INST OF CONTROL ENG

Time-varying modal parameter identification method

InactiveCN111174996ASolve the problem of modal parameter identificationDesign optimisation/simulationVibration testingTime domainAlgorithm
The invention belongs to the technical field of modal tests and particularly relates to a time-varying modal parameter identification method which comprises the following steps: constructing a spectrum analysis module; performing time domain acquisition on acceleration sensor data and force sensor signals through the spectrum analysis module; constructing a time-varying analysis module; analyzingthe data acquired in the step 2 through the time-varying analysis module to obtain a waterfall plot of a frequency response function; selecting different frequency response functions from the frequency response function waterfall plot for analysis, and obtaining modal parameters. According to the time-varying modal parameter identification method provided by the invention, the time-varying analysis module is constructed to analyze the time-domain acquisition data, and finally, the modal parameters are obtained, so that the modal parameter identification problem of the time-varying system can be solved.
Owner:SHENYANG AIRCRAFT DESIGN INST AVIATION IND CORP OF CHINA
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