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263 results about "Parametric identification" patented technology

High-speed platform motion parameter self-tuning method based on model identification and equivalent simplification

A high-speed platform motion parameter self-tuning method based on model identification and equivalent simplification is provided, comprising: establishing a test of a motion state of a high-speed platform, identifying model parameters, and optimizing motion parameters of an equivalent simplified model; selecting any motion function from a pre-set parameterized curve, setting initial parameters, and driving the high-speed platform to move under the action of a controller and an actuator; collecting dynamic response information of the platform, calculating dynamic characteristic information of the platform such as stiffness, frequency, damping and the like; establishing a dynamic response equivalent simplified model by using the acquired dynamic characteristic information, and performing the optimization constrained by meeting motion precision and targeting at shorter execution time for the motion parameters in the selected parameterized motion function to obtain the optimum parameters. The method of the present invention gives consideration to the dynamic characteristic requirement of the platform and the comprehensive requirement of the parameter identification and optimization on the industrial site, facilitates the implementation of an algorithm in a motion control card, and is suitable for rapidly acquiring the optimum motion parameters of the actual high-speed platform on site.
Owner:GUANGDONG UNIV OF TECH

Electromotor dynamic/stable stage parameter identification method based on stator resistance observer

The invention discloses an electromotor dynamic / stable stage parameter identification method based on a stator resistance observer. For the parameter identification at a dynamic stage of an electromotor, a stator resistance T-S (Takagi-Sugeno) fuzzy observer is introduced to obtain an actually-measured value of stator resistance on the basis that the existing MRAS (Model Reference Adaptive System) method is still adopted, and dynamic correction is carried out on a rotating speed reference model and a resistance reference model according to the actually-measured value of the stator resistance; and for the parameter identification at a stable stage, the identification method for the rotating speed of a rotor is achieved by adopting the MRAS method and the stator resistance T-S fuzzy observer which are the same as those adopted in the parameter identification at the dynamic stage, and the identification method for the resistance of the rotor is achieved by adopting simple conversion. The electromotor dynamic / stable stage parameter identification method based on the stator resistance observer has the beneficial technical effects that the problem of inaccurate reference models is solved, the low-speed operating performance of the electromotor can be improved, the adoption of a current injection method is avoided, the current injection equipment is saved, the complexity of a system is lowered, the introduction of torque ripple is avoided, and the like.
Owner:CHONGQING JIAOTONG UNIVERSITY

Structural modal parameter identification system based on binocular stereo vision

The invention discloses a structural modal parameter identification system based on binocular stereo vision. The method of the system comprises the following steps of building a binocular stereo vision system, calibrating two camera units, and acquiring internal and external parameters of the two camera units to carry out three-dimensional correction; establishing easily identifiable key points of a detected structure surface; loading impact force to enable the detected structure to move freely, obtaining a synchronic image sequence file, identifying the three-dimensional coordinates of all key points to each frame of image orderly, and obtaining the three-dimensional movement data of all key points in the whole test time finally; through the three-dimensional movement data of all key points, carrying out modal identification by using a characteristic system realization algorithm, obtaining the modal parameters of the detected structure, and outputting a result. Compared with the traditional technology, the structural modal parameter identification system can measure the modal parameters of the detected structure in a non-contact way or in a way that less impact is applied to the detected structure, and the system has the advantages of low cost, fast speed and high precision and is especially suitable for the modal parameter measurement of large lightweight structure with inconvenient layout of sensors.
Owner:TSINGHUA UNIV

Acquiring system eigenfunction and signal feature value method

A method of catching systematic eigenfunctions and signal eigenvalues under the condition of only response output available belongs to the parametric recognition technique in dynamic test field. The technique is a method of adopting cross spectral density functions of each response point instead of frequency response functions to perform time-frequency filtering and the parametric recognition of frequency domain, and includes the following steps: (1) carrying out analytic calculation of the cross spectral density functions of different metering signal of output points; (2) analyzing and calculating the nonorthogonal wavelets in the time-frequency domain according to the cross spectral calculating result; (3) inversing the fourier transformation to gain the time-frequency analyse coefficient; (4) adding a rectangular window to perform the time-frequency filtering; (5) calculating the cross spectrum of the output signal after filtering as the systematic function for recognition; (6) performing curvefitting to obtain the systematic parameter; the technique improves the recognition precision of the systematic parameters, precisely recognizes modal parameters, is simple and convenient, and is suitable for the dynamic analyses, the performance verification and the failure diagnosis of large civil engineering establishments such as large and complex mechanical equipments under operation status, high-rise buildings, bridges, etc.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Bridge structure modal parameter authenticity and falsity discrimination method and terminal device

The invention belongs to the bridge monitoring technical field and provides a bridge structure modal parameter authenticity and falsity discrimination method and a terminal device. The method includesthe following steps that: the monitoring data of the structure of a bridge under an environmental excitation condition are obtained through data acquisition devices disposed in a plurality of measuring points of the bridge; the NExT (natural excitation technique) is adopted, at first, the cross power spectrum density function of the monitoring data is calculated, and Fourier inverse transformation is performed on the cross power spectrum density function, so that the cross-correlation function of the monitoring data is obtained, the cross-correlation function is adopted as the input data of amodal parameter identification algorithm, so that modal parameter identification can be carried out, and a stability diagram can be drawn; the auto-power spectrum density function and cross-power spectrum density function of the monitoring data of the measuring points are calculated, the auto-power spectra and cross-power spectra of all the measuring points are summated, and the auto-spectra andthe cross spectra are summated in the same order of magnitude, so that the sum function of the power spectra can be obtained; and a diagram of the sum function, and true and false modal parameters canbe discriminated according to the stability diagram of the sum function. According to the method, the stability diagram method and a power spectrum summation peak method are combined to perform bridge structure modal parameter authenticity and falsity discrimination, so that discrimination accuracy can be improved.
Owner:SHIJIAZHUANG TIEDAO UNIV

Universal electromagnetic signal automatic searching method

The invention relates to a universal electromagnetic signal automatic searching method. The method mainly comprises the following steps of: (1) performing frequency-domain scanning and threshold value detection to form a list of signals to be searched; (2) performing frequency-domain feature extraction on the signals in the list of the signals to be searched, and matching the extracted frequency-domain features with the set frequency-domain features of the signals to be searched; (3) identifying modulation parameters of the signals of which the frequency-domain features are matched with the set frequency-domain features of the signals to be searched, and matching the modulation parameters with the set modulation parameters of the signals to be searched; and (4) performing demodulation processing and time-domain feature parameter extraction on the signals of which the modulation parameters are matched with the set modulation parameters of the signals to be searched, and then matching the time-domain features with the set time-domain features of the signals to be searched; and if the similarity is greater than a set similarity coefficient, then determining that the current processed signal is a target signal to be searched. According to the method provided by the invention, electromagnetic signals with certain specific features can be searched automatically without human intervention; the intercept probability of the signals can be improved remarkably; and the work efficiency of detection personnel can be improved greatly.
Owner:CHINA ELECTRONIS TECH INSTR CO LTD

Method for identifying unfrozen meat and fresh meat based on impedance spectrum

The invention discloses a method for identifying unfrozen meat and fresh meat based on an impedance spectrum. The method comprises the following steps of: 1, generating a plurality of continuous sine wave signals with different frequencies and mean amplitude of zero and loading the sine wave signals on a raw meat sample; 2, including the raw meat sample and a resistor R1 with fixed nominal value on a branch circuit through which the sine wave signals flow, and detecting voltage division values of impedance and the resistor R1; 3, converting the ratio of the voltage division values into a voltage form and then into a digital signal, calculating the impedance of each frequency fi according to the resistor R1 and the digital signal, and representing the change of the impedance along with thefrequency fi as a curve to obtain the impedance spectrum; 4, detecting phase difference between a plurality of sine wave signals generated in the step 1 and the signal passing through the raw meat sample to be measured, converting the phase difference into voltage output and then into a digital signal, and representing the change of the phase difference along with the frequency fi as a curve to obtain phase spectrum; and 5, identifying the unfrozen meat according to the impedance spectrum and a phase spectrum export parameter. By the method, the unfrozen meat and the fresh meat can be completely and objectively identified.
Owner:CHINA AGRI UNIV

Method for identifying parameters of resonant fatigue crack propagation test vibration system based on soft sensing technology

A method for identifying parameters of a resonant fatigue crack propagation test vibration system based on a soft sensing technology comprises the following steps: 1, establishing a system three-degree-of-freedom vibration mechanical model to obtain a kinetic equation, and deriving to obtain a system frequency equation about a relationship among the system inherent frequency, the spring rigidity and the particle mass; 2, calculating according to a finite element technology to obtain the rigidity of a test piece under different crack lengths, and testing the system resonant frequency when a crack is propagated to different lengths; 3, substituting the system resonant frequency value and the corresponding test piece rigidity under different crack lengths into the system frequency equation in order to obtain overdetermined equations about the mass to be identified and unknown rigidity; 4, solving the overdetermined equations through a least squares technique to obtain nonlinear equations about the mass and rigidity; and 5, solving the nonlinear equations by using a Newton-Raphson formula, and identifying the vibration system parameters comprising the mass and the rigidity. The method has the advantages of good maneuverability, low cost and good accuracy.
Owner:ZHEJIANG UNIV OF TECH

Bridge impact coefficient optimization method based on parameter identification technology

The invention provides a bridge impact coefficient optimization method based on the parameter identification technology, solving the problems in the calculation of impact coefficient and the optimization of impact coefficient sensitivity in stochastic dynamics, which can reduce the damage of bridge. The method is carried out in this manner: (1) defining a vehicle model, (2) deriving the equation of motion MU<..>+CU<.>+KU=F<g>+F<w>, according to the D'Alembert's principle; using the PIM method to solve deterministic response and using the PEM to calculate random response, U(t)=integral H(t-[tau], t)(F<g>([tau])+F<w>([tau])) differential [tau], t belongs to (0, t). The invention provides an effective optimization method for non-stationary random vibration of a vehicle-bridge coupling system, and improves comfort and safety of the vehicle and the bridge. The method of the invention has both accuracy and efficiency, and can provide better technical support for vehicle-bridge coupling vibration sensitivity analysis and optimization. The computational time required by the PEM-PIM numerical method is more than ten times that of the Newmark method when the computational accuracy is the same, and the method of optimizing the sensitivity of the self-identification design variables is proposed.
Owner:ZHENGZHOU UNIV

Air conditioner control method and device

The invention discloses an air conditioner control method and device and belongs to the technical field of automobile electronic control. The air conditioner control method comprises judging whether an automobile satisfies boundary conditions or not and obtaining throttle valve parameters of an acceleration pedal of the automobile when the automobile satisfies the boundary conditions; identifying whether emergency acceleration power supply is needed or not according to the throttle valve parameters; performing control to close the air conditioner if the emergency acceleration power supply is needed and the air conditioner is in an opening state; and performing control to open the air conditioner if the emergency acceleration power supply is not needed and the air conditioner is in a closed state. The air conditioner control method enables the accuracy of air conditioner control to be improved due to the fact that when an air conditioner switch is at an opening position, whether the automobile satisfies the boundary conditions or not is firstly judged, then whether the emergency acceleration power supply is needed or not according to the acceleration pedal throttle valve parameters is judged to confirm whether the air conditioner is controlled or not; the flexibility of air conditioner control is increased due to the fact that judging whether the automobile satisfies the boundary conditions or not is added before judging the acceleration pedal throttle valve parameters.
Owner:CHERY AUTOMOBILE CO LTD

Recognition device and method for parameters of execution mechanism in electro-hydraulic linear velocity servo system

The invention discloses a recognition device and method for parameters of an execution mechanism in an electro-hydraulic linear velocity servo system. The recognition device comprises a step current signal generator, an electro-hydraulic servo valve, a hydraulic cylinder, a mechanical load, a liner-velocity detection sensor, a recorder and a hydraulic source; and the recognition method comprises the steps of: inputting step current signals into the electro-hydraulic servo valve, and detecting the motion liner velocity of the mechanical load; recording the varying process of the step current signals and linear velocity signals with the time till the steady-state value of the linear velocity signal is achieved; dividing the amplitude of the step current signals by the steady-state value of the linear velocity signals to obtain an equivalent viscous damping coefficient of the execution mechanism; and multiplying the equivalent viscous damping coefficient by a time value corresponding to a state that the 0.632 times of the steady-state value of the linear velocity signals is reached to obtain an equivalent mass of the execution mechanism. By means of the recognition device and method disclosed by the invention, the regulation of the parameters of a controller of the electro-hydraulic linear velocity servo system is timesaving and laborsaving, and the electro-hydraulic servo system can achieve better static and dynamic properties.
Owner:JIANGSU UNIV OF SCI & TECH

Measuring system for dynamic contact state of wheels and rail of high-speed railway

The present invention discloses a measuring system for the dynamic contact state of wheels and rails of a high-speed railway. The measuring system comprises a data acquisition system mounted on a vibration-damping frame, as well as a data processing system and a data display system mounted in an on-board control platform. The data acquisition system comprises encoding structural optical image acquisition units and an inertial measurement device; the vibration-damping frame is connected with the compartment bottom through a fixing device at the top of the vibration-damping frame and suspended between the center suspension and the axle box suspension of the frame of a bogie; the encoding structural optical image acquisition units directly face the left and right wheel-rail contact areas and form a surrounding structure; the data processing system is used for obtaining geometrical parameters of the wheel-rail contact through three-dimensional geometric reconstruction, characterization parameter identification and data interaction according to high-definition images captured by the encoding structural optical image acquisition units and data of the acceleration and the like measured by the inertial measurement device, to obtain a wheel-rail relationship spectrum; and the data display system is used for displaying the images, the data and the wheel-rail relationship spectrum through a human-computer interaction interface in real time. The measuring system for the dynamic contact state of the wheels and the rail of the high-speed railway can achieve real-time capture of the wheel-rail dynamic contact state.
Owner:BEIJING JIAOTONG UNIV

Dynamic calibration method for high-frequency force balance

The invention discloses a dynamic calibration method for a high-frequency force balance, which comprises the steps of performing whitening on a measurement signal x(t) to acquire a whitened signal z(t); seeking an orthogonal matrix V, enabling the whitened signal z(t) to equal to Vq(t), and thus acquiring a separated signal q(t); performing natural frequency and modal damping ratio recognition on the separated signal in modal coordinates; correcting the separated signal according to recognized parameters; and inversely deducing according to the separated signal to acquire a corrected pneumatic load. According to the invention, separation is performed on a coupling signal, and for independent components acquired by separation, natural frequency and modal damping ratio recognition is performed on the separated signals one by one by adopting a curve fitting method through combining aerodynamic characteristics, so that a dynamic amplification effect of a modal coupling system is corrected and eliminated, a real aerodynamic load spectrum density matrix is acquired finally, the reliability of parameter recognition and corresponding HFFB (High-Frequency Force Balance) dynamic signal calibration can be improved to the maximum extent, and an important basis is laid for subsequent accurate estimation for high-rise building prototype wind-induced responses.
Owner:SOUTH CHINA UNIV OF TECH

Power transmission line parameter identification method and system

InactiveCN108226710AReduce out-of-sync timeImprove accuracyFault locationMaster stationPower grid
The invention provides a power transmission line parameter identification method and system. The method comprises the following steps: reading a double-ended wave recording file of a faulty line, andobtaining double-ended electrical quantity information of the faulty line; carrying out time synchronization on the double-ended electrical quantity information of the faulty line; and carrying out line parameter identification according to the synchronized double-ended electrical quantity information of the faulty line, so that a reactance identification value is obtained. By virtue of the technical scheme provided by the invention, power transmission line steady state parameter identification based on fault wave recording data is realized, and synchronization alignment treatment is carried out on the fault wave recording data, so that non-synchronous time of the double-ended wave recording file is shortened, a new means and a good data foundation are provided for accurately identifying power grid branch circuit parameters of a dispatching master station, power grid branch circuit steady state impedance parameter identification accuracy is practically improved, and further the accuracy and availability of a power grid online dispatching analysis software result are improved.
Owner:CHINA ELECTRIC POWER RES INST +4

Measurement and control method in suspension pouring construction process of continuous rigid frame bridge

The invention discloses a measurement and control method in a suspension pouring construction process of a continuous rigid frame bridge, and belongs to the technical field of measurement and control of highway engineering. According to the method, a parameter identification step is added based on the prior art. The measurement and control method comprises the steps of obtaining overall rigidities EI1 and EI2 of to-be-identified rigidity beam segments; obtaining weights mL1 and mL2 of to-be-identified weight beam segments; performing identification in a high-order mode under the condition that the identification effect is greatly influenced by test environment conditions or is interfered by other influence factors; and adjusting an elevation of the front end of a hanging basket on site to realize suspended poured line shape control. According to the method, the overall rigidity and the quality are identified, the down-warping amount generated by a to-be-poured beam segment is predicted, and the construction camber is reserved, so that a reasonable completed bridge line shape of the bridge is realized. The method has the main advantages that the temperature influence is avoided and the measurement does not need to be carried out at night, so that the potential safety risk of operation is lowered; software and hardware are mature, data processing is concise, and sensors can be connected for wireless communication, so that unmanned monitoring is realized; and the precision is improved and passive control methods and means are added.
Owner:云南省公路科学技术研究院
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