52 results about "Sinusoidal excitation" patented technology

The invention belongs to the technical field of sewage treatment and membrane separation, and provides an in-situ nondestructive membrane pollution detection system and method based on an ultrasonic transmission signal, and the system comprises an ultrasonic excitation module which is used for generating a sine wave excitation signal which penetrates through a membrane body to excite the ultrasonic transmission signal for pollution detection; the signal processing module is used for continuously collecting and preprocessing ultrasonic transmission signals of the clean membrane body and the membrane bodies with different pollution degrees, extracting ultrasonic transmission signal characteristics under different pollution degrees, and establishing a pollution thickness-signal characteristic mapping model; wherein the ultrasonic transmission signal features comprise a time-frequency domain energy gravity center feature and a frequency attenuation spectrum slope feature; and the pollution detection module is used for judging the pollution stage of the membrane body to be detected based on the pollution thickness-signal feature mapping model, and completing in-situ nondestructive membrane pollution detection. According to the technical scheme, the sludge pollution state in the ceramic membrane and flat membrane filtering process can be monitored in real time, and early warning and pollution dynamic tracking are achieved.

The utility model relates to a sine wave excitation circuit for a magnetic flux type current sensor. The device comprises a square wave generator used for generating a square wave signal; the resonant oscillator is connected with the square wave generator, at least generates sine wave signals of fundamental frequency based on the square wave signals generated by the square wave generator and loads the generated sine wave signals to the magnetic core, and the frequency of the fundamental frequency is consistent with the frequency of the square wave signals; the excitation signal sampling feedback circuit is connected with the square-wave generator and is adaptively connected with the magnetic core, so that a magnetic core excitation signal adaptively connected with the magnetic core is sampled and then transmitted to the square-wave generator, and the excitation signal sampling feedback circuit comprises a signal conditioning circuit and a peak detection circuit. According to the utility model, the magnetic core can be effectively modulated, and the noise is lower.

The application relates to the technical field of servo motor driving, and particularly discloses an inertia identification method based on double-frequency sinusoidal speed instructions, two different frequency sinusoidal speed instructions are sent to a motor by a servo driver, according to Newton's second law, a motion equation of a rotating system, a speed signal or an acceleration signal is multiplied by both sides of the motion equation of the rotating system, and integral operation is carried out in a complete period; for the test of the frequency omega1, the collected torque T e1 (t) is integrated with the acceleration, and thus the rotational inertia J can be directly solved. In the method, the speed instruction is a sinusoidal wave, compared with the trapezoidal acceleration and deceleration method and the step response method, the instruction is smoother, mechanical impact is small, and in addition, technical difficulties existing in the single-frequency sinusoidal excitation method can be avoided.

The invention belongs to the field of aerospace electronic measurement, and provides an inductance type proximity sensor resolving method and system based on an improved DFT algorithm, and the method comprises the steps: applying a sine excitation signal of an excitation frequency; synchronously acquiring a sine excitation signal and a sensor response signal of the output end of the proximity sensor; an improved DFT algorithm is adopted, the amplitude and the phase under the excitation frequency are extracted, and the voltage vector relation among the excitation voltage, the output voltage of the sensor and the complex impedance of the sensor is constructed; the inductance value and the parasitic resistance value of the proximity sensor are calculated through triangular transformation and calibrated, and the calibrated inductance value is obtained. According to the method, the reliability is high, complex electronic hardware is not needed, the development cost is low, the inductance value of the sensor is obtained on a DSP28335 platform based on the improved DFT algorithm, the precision reaches 0.15 mH, and the consumed time of single-path calculation does not exceed 2 ms. The expansion is easy, and the newly increased time is not more than 1ms when one path of sensor is newly increased.

The invention belongs to the field of aerospace electronic measurement, and provides an inductance type proximity sensor resolving method and system based on a time domain integration algorithm, and the method comprises the steps: applying a generated sine excitation voltage to a measurement loop; synchronously acquiring sine excitation voltage and response voltage of an inductive proximity sensor in a measurement loop; based on a time domain integration algorithm, respectively carrying out orthogonal integration on the sine excitation voltage and the response voltage, and calculating respective amplitudes and phases; according to the amplitude, the phase and the resistance value of the reference resistor, an inductance value and a parasitic resistance value of the inductive proximity sensor are calculated through a trigonometric function relationship; and establishing a piecewise linear fitting model through a least square method, and calibrating the inductance value to obtain a calibrated inductance value. The method has the advantages of high reliability, strong anti-noise capability, no need of complex electronic hardware, and reduction of the development cost at a lower development guarantee level.

The present invention belongs to the field of AC servo systems and discloses a method and system for online identification of the rotor time constant of a sensorless induction motor based on a complex coefficient flux observer. The method comprises: estimating the rotor flux using a complex coefficient rotor flux estimator; injecting a biased sinusoidal excitation into the d-axis to obtain the rotor flux and filtered stator current along the dq axes through park transformation; online identification of the rotor time constant using a designed rotor time constant estimator based on a sliding mode observer; and estimating the stator frequency and rotor position using a phase-locked loop. The present invention decouples rotor time constant identification from rotor speed estimation, enabling parallel estimation of the two. The designed rotor flux estimator effectively suppresses DC bias and higher harmonics in back electromotive force. Compared to the traditional least squares method, the designed rotor time constant estimator based on a sliding mode observer improves the robustness of the estimation algorithm while ensuring convergence speed.

The invention discloses an evaluation method for vibration impedance performance of a range extender rotor hub, and the method comprises the steps: setting a plurality of response points on the surface of the rotor hub, and enabling the response points to be distributed at two axial sides and to be circumferentially symmetrical; broadband sine excitation is applied to the radial direction of each response point, and excitation force and multidirectional vibration response of each point are recorded; calculating a global vibration impedance response function based on the exciting force and the vibration response data, and drawing a vibration impedance curve; based on the vibration impedance curve, a radial secondary mode, a radial tertiary mode, a shafting primary core mode and a shafting secondary core mode of the vibration impedance curve are identified respectively, and related numerical values are recorded; and then calculating a radial vibration impedance coefficient RK according to the radial modal parameters, calculating a shafting vibration impedance coefficient SK according to the shafting modal parameters, calculating a total vibration impedance coefficient by combining the RK and the SK, and performing grading evaluation.

This invention discloses a method for extracting and compensating eddy current hardness features to suppress valve geometry interference, relating to the fields of nondestructive testing and signal processing. The method includes: acquiring the original impedance voltage signal and key geometric parameters of the valve under a preset multi-frequency sinusoidal excitation signal; constructing a geometry-electromagnetic coupling interference compensation model based on the key geometric parameters, excitation frequency, and electromagnetic parameters; calculating the multivariable coupled geometric interference coefficient; removing geometric interference from the original signal to obtain a pure impedance voltage signal; extracting three-dimensional features from the pure signal to obtain amplitude features, phase features, and hardness-sensitive features; introducing a dynamic temperature compensation model to nonlinearly compensate the three-dimensional feature vector according to the ambient temperature; and outputting the compensated three-dimensional hardness feature vector. This invention, by constructing a geometry-electromagnetic coupling interference compensation model, suppresses the influence of valve geometry differences on the eddy current signal, improving the accuracy and robustness of eddy current hardness detection.

The invention provides a lithium niobate film MEMS traveling-wave motor design structure and a preparation method, and relates to the technical field of traveling-wave motors, and the lithium niobate film MEMS traveling-wave motor design structure comprises an upper electrode, a lower electrode, a piezoelectric driving layer and a traveling-wave micro-actuator with displacement amplification tooth structure; the upper electrode is arranged on the piezoelectric driving layer, the lower electrode is arranged under the piezoelectric driving layer, and the traveling wave micro-actuator with the displacement amplification tooth structure is arranged under the lower electrode; the piezoelectric driving layer is made of lithium niobate, the piezoelectric driving layer is divided into a plurality of driving electrode subareas, driving is achieved by applying multi-phase sine excitation signals to the piezoelectric driving layer, and one sine excitation signal is applied to each driving electrode subarea. The lithium niobate film MEMS traveling wave motor is prepared based on an LN-SOI wafer or an LN-SI wafer. The micro-motor has the advantage of improving the reliability and the output performance of the micro-motor.

The invention discloses a large-span current-carrying acceleration test device for evaluating the durability of a connection point, belongs to the technical field of mechanical detection, and is suitable for evaluating the durability of the connection point of a power transmission and distribution line under a wind-induced vibration and current-carrying heating coupling working condition. The device integrates a main body structure, a wire clamp test module, a driving module and a wire tensioning module, constructs a main wire longitudinal pre-tightening-auxiliary wire dragging force adjustment-sine reciprocating excitation three-field coupling integrated platform, realizes stepless adjustment of main wire tensioning force through a spring tightener, and outputs high-frequency sine excitation by adopting a cam and crank slide block combined mechanism. The auxiliary line dragging force and posture are accurately regulated and controlled in cooperation with an air cylinder, current carrying is synchronously connected, and multi-dimensional test data are collected. The defects that an existing device is insufficient in loading dimension, poor in parameter adjustability and low in working condition reduction degree are overcome, the repeatability of test results and the test efficiency are remarkably improved, and a reliable experiment basis is provided for connection point fatigue life evaluation, failure mechanism research and structure optimization.

The present application relates to motor manufacturing process technical field, more specifically, it relates to a kind of high torsion multi-stage series motor and structural stability detection process, including the modal response of the axial and radial of the frame of high torsion multi-stage series motor is collected, axial main frequency, axial damping ratio and the phase difference of radial two test points are calculated, and compared with preset threshold value;Continuous sweep frequency sinusoidal excitation is applied to motor frame, the nonlinear index of each frequency point is calculated and compared with preset threshold value, while detecting whether resonance peak is split;Then short-time half-sine pulse impact is applied to motor frame, free decay vibration signal is collected, and attenuation main frequency, logarithmic attenuation rate and cross-correlation peak delay are extracted from the time domain of free decay vibration signal, the pretightening force and connection stiffness index of two connecting points are back calculated, finally ensure that high torsion multi-stage series motor can meet the requirement of structural stability when leaving factory, and can be closed-loop corrected by detection Parameter of assembly process.

The application provides a lithium niobate thin film MEMS traveling wave motor design structure and a preparation method, relates to the technical field of traveling wave motors, and comprises an upper electrode, a lower electrode, a piezoelectric driving layer and a traveling wave micro-actuator belt displacement amplification tooth structure; the upper electrode is arranged on the upper surface of the piezoelectric driving layer, the lower electrode is arranged on the lower surface of the piezoelectric driving layer, and the traveling wave micro-actuator belt displacement amplification tooth structure is arranged on the lower surface of the lower electrode; the material of the piezoelectric driving layer is lithium niobate; the piezoelectric driving layer is divided into a plurality of driving electrode partitions; driving is realized by applying a multi-phase sinusoidal excitation signal to the piezoelectric driving layer, and each driving electrode partition is respectively applied with a sinusoidal excitation signal; the lithium niobate thin film MEMS traveling wave motor is prepared based on an LN-SOI wafer or based on an LN-SI wafer. The application has the advantages of improving the reliability and output performance of the micro motor.

The application discloses a method, device and processor for determining magnetic property information of nanocrystalline strip. The method comprises the following steps: obtaining non-sinusoidal excitation data of the nanocrystalline strip; decomposing the non-sinusoidal excitation data into a plurality of sinusoidal harmonic data; determining a plurality of equivalent magnetic path lengths based on the plurality of sinusoidal harmonic data; and determining the magnetic property information of the nanocrystalline strip based on the plurality of equivalent magnetic path lengths, wherein the magnetic property information at least comprises magnetic property information and / or magnetostriction property information. The application solves the technical problem that the magnetic property of the nanocrystalline strip cannot be determined.

This application provides a phase synchronization method, system, device, and medium for a rotary transformer. It involves periodically acquiring sine and cosine signals output by the rotary transformer in response to a loop trigger counter outputting a loop trigger signal. Both the loop trigger signal and the sinusoidal excitation signal used to drive the rotary transformer are generated by converting a synchronization pulse signal output by an RPWM counter. Within each acquisition cycle, the sine and cosine signals are positively zero-crossing detected to obtain a zero-crossing detection result. Based on the zero-crossing detection result, the phase difference between the sine and cosine signals and the sinusoidal excitation signal in the current cycle is determined, and phase synchronization compensation is performed on the sinusoidal excitation signal based on the phase difference. This enhances the signal fidelity and control accuracy of the encoder under strong interference without increasing hardware costs.

The present invention discloses a method for restoring sinusoidal motion blurred images based on a priori models. The point spread function of the sinusoidal motion sequence images is calculated by using the gradient optical flow method and the Gaussian fitting method. Based on the prior information of the sinusoidal excitation signal, the motion image at the maximum displacement position is used as a reference frame with a zero point spread function blur kernel. The Lucy-Richardson restoration method and the solved point spread function are used to enhance the characteristic edges of the corresponding sinusoidal motion blurred images to obtain restored images with clear characteristic edges. The noise of the restored images is eliminated by the NL-Means method to suppress the boundary ringing effect of the restored images and improve the signal-to-noise ratio. Finally, objective image quality evaluation indicators and sub-pixel edge detection methods based on Zernike moments are used to evaluate the effect of the restored images and extract the characteristic edges respectively. This method can meet the growing development needs of high-precision linear and angular vibration measurement, pose estimation, target detection, etc. in machine vision.

This invention belongs to the field of precision drive and positioning technology, specifically relating to a bidirectional drive linear piezoelectric motor. It includes a motor base, a preload mechanism, a linear guide rail, a linear slider, and a pair of piezoelectric mechanisms. Each piezoelectric mechanism includes a motor stator, a piezoelectric plate, and motor drive feet. The piezoelectric plate is fixed to the inner side of the side frame of the motor stator, and one end of the motor drive foot is fixed to the outer side of the corresponding side frame of the motor stator. This results in a pair of motor drive feet on the piezoelectric mechanisms being horizontally arranged and symmetrical about the y-axis of the motor base. The pair of motor drive feet and the linear slider are in inclined contact. When a sinusoidal excitation voltage of 90–360V is applied to the piezoelectric plate, it causes the corresponding side of the motor stator to vibrate periodically. Therefore, the linear piezoelectric motor of this invention uses single harmonic drive and can operate in a resonant state. It not only achieves bidirectional linear movement, but also the driving action of the linear piezoelectric motor is "push-disengage," thus eliminating sliding friction and improving the working efficiency of the piezoelectric motor.

The application discloses a kind of line angular vibration sensor sensitivity dynamic calibration method based on multi-frequency sine excitation.It includes constructing line angular vibration sensor sensitivity dynamic calibration device based on multi-frequency sine excitation;Providing multi-frequency sine line angular excitation;Collecting motion sequence image and output signal;Solving the line angular excitation displacement of the line angular vibration sensor to be calibrated;Calculating the sensitivity of the line angular vibration sensor to be calibrated and the like steps.The method is efficient, accurate and simplifies the calibration process;Using monocular vision-based method to measure the vibration displacement of line angular vibration sensor under different frequencies, only a simple monocular vision measurement system is needed;The multi-frequency sine line angular excitation output by line and angular vibration generating device can be controlled, and the influence of other additional excitation on the sensor can also be effectively avoided;It is suitable for different types of sensors, and the multi-frequency sine excitation method has a wide range of applications, which can be used to calibrate different types of line angular vibration sensors, such as gyroscopes and accelerometers.

An inductive sensor, in particular a length sensor or an angle sensor, including an oscillator for generating a sinusoidal excitation signal having a first excitation frequency. A resonant circuit is connected to the oscillator and may be excited by the excitation signal to generate an electromagnetic field. A coupling element is movable relative to the resonant circuit, for changing the field as a function of a length or a rotation angle. A sensor generates an electrical sensor signal as a function of the field, A measuring transducer generates a measuring transducer output signal as a function of the electrical sensor signal, which represents the length or the rotation angle, and a checking filter checks the sinusoidal form of the excitation signal.

This invention discloses a method and system for controlling the pressure of stacked iron cores to reduce transformer no-load losses. The method includes acquiring the excitation current signal of the stacked iron cores under constant-voltage sinusoidal excitation conditions; extracting the harmonic characteristic components of the signal and decoupling them into stress characterization indicators and air gap characterization indicators, calculating the corresponding hysteresis loss components and air gap additional loss components; gradually increasing the clamping force under a monotonically increasing pressure application path, determining the total loss gradient based on the components at each pressure step, and locating the first optimal pressure point; acquiring pre-configured compensation parameters, performing offset compensation calculations on the first optimal pressure point, obtaining the target curing pressure, and locking it. This invention, through electrical harmonic analysis, can solve the deviations caused by magnetic coupling hysteresis and process relaxation, achieving optimized control of no-load losses.

The invention relates to a flexible connection-based method for autonomously identifying additional rigidity of a cable between two stages of platforms, which relates to the field of spacecraft attitude control, and comprises the following steps of: in a cable-free connection state, sequentially outputting sine excitation by voice coil motors in all actuators, and measuring by an eddy current sensor to obtain motion displacement; calculating the stiffness of the actuators based on the two groups of data, and then calculating the equivalent stiffness of each actuator in the state of cable connection according to the previous step; the method has the advantages that the additional rigidity of the cable in the on-orbit state can be obtained, the influence of the cable is reduced by adopting control measures, the control capacity of a three-super platform is guaranteed, the stability of the three-super platform is improved, and the reliability of the three-super platform is improved. And a technical basis is provided for high-precision pointing, high-stability control and rapid and stable control of the load of a new-generation spacecraft.

An on-site reciprocity calibration method for a piezoelectric accelerometer, including a vibration test and a reciprocity test. In the vibration test, a sine excitation with a corresponding frequency and amplitude is provided by a vibration exciting device to the piezoelectric accelerometer fixed on a motion plane, and output signals of a drive port and a signal port of the reciprocal piezoelectric accelerometer are collected by a data acquisition device. In the reciprocity test, a sine voltage excitation is provided by a signal generator to the drive port, and then an excitation signal and an output signal of the signal port are collected by the data acquisition device. An amplitude ratio of the two signals is obtained based on signal sine-fitting. Finally, the on-site calibration is enabled according the sensitivity amplitude ratio obtained in the vibration test and the sensitivity amplitude product obtained in the reciprocity test.

The invention belongs to the technical field of steel strand prestress monitoring, and particularly relates to a temperature compensation high-frequency resonance type in-service steel strand prestress loss real-time monitoring method which comprises the following steps: S1, two coils are arranged on a corrugated pipe in a steel strand, one coil serves as an excitation coil, and the other coil serves as an induction coil; s2, a temperature compensation inductor is arranged at the unstressed end of the steel strand, and the temperature compensation inductor is electrically connected with the induction coil; the temperature compensation inductor is used for performing temperature compensation when the resonant transformer works; s3, inputting a sine excitation signal to the excitation coil; s4, output voltage is obtained, and the output voltage is obtained by the fact that current flows through the temperature compensation inductor after the induction voltage forms the current in the induction coil; s5, calculating the change of the output voltage obtained in the step S4 to obtain the change of the magnetic conductivity of the steel strand; and obtaining the stress condition of the steel strand through the change of the magnetic conductivity of the steel strand based on the magnetostriction theory. According to the invention, the real-time accurate monitoring of the in-service structure can be realized.

A method is disclosed for determining an electrical signal characteristic indicative of the magnitude of and / or change in an impedance that varies in response to a magnetic, electric, or electromagnetic field affected by an approaching object. The method includes performing measurements over at least one group of measurement intervals, each group preceded by at least one compensation interval. A sinusoidal excitation voltage is applied to the impedance during each interval, inducing a measuring current. A compensation current is determined during the compensation interval and subtracted from the measuring current of at least one subsequent measurement interval to generate an analog evaluation current. The evaluation current serves as a signal representative of the impedance's magnitude and / or change in the impedance.

Provided is a method for managing a transformer core may include preliminarily obtaining a Steinmetz equation considering temperature correction factor through fitting; converting a non-sinusoidal excitation current waveform into an equivalent sinusoidal excitation current waveform for calculation, and continuing to correct the Steinmetz equation considering temperature correction factor to obtain a corrected empirical formula; and utilizing a pre-trained neural network model to process the empirical predicted value of the loss of the core and corresponding temperature, excitation current, magnetic flux density, and frequency of the excitation current to obtain a final predicted value of loss of a core to be detected. When the final predicted value of the loss exceeds a first threshold, maintenance is performed on the core to be detected; and when it exceeds a second threshold, the core to be detected is replaced.

The present disclosure discloses a two-point sampling optimized method and system for sinusoidal excitation-based frequency response measurement. A plurality of points are sampled at equal intervals within the starting frequency and ending frequency range as initial information, the interpolation error of each sub-frequency band is estimated according to existing sampling information, the sub-frequency band with the largest interpolation error is selected, two new sampling points are added within the sub-frequency band, and the above steps are repeated until the quantity of sampling points reaches the total quantity set by a user; and the user is asked whether new sampling points need to be added, if so, after the user specifies a new quantity of sampling points, the interpolation error of each sub-frequency band is estimated again and sampling continues, otherwise, the sampling ends. The present improves the practicality of a sinusoidal excitation-based frequency response measurement method.

The application discloses a kind of three float instrument magnetic suspension control circuits, and digital signal processor circuit generates PWM square wave;Excitation generation circuit modulates PWM square wave into sinusoidal excitation signal, and sinusoidal excitation signal is output to position detection bridge;Position detection bridge is driven under the action of sinusoidal excitation signal and magnetic suspension coil works;Position detection bridge obtains AC voltage signal for representing the position of magnetic suspension coil, and AC voltage signal is output to signal processing circuit through multiplexed gating switch;Signal processing circuit converts the AC voltage signal input by position detection bridge into DC signal for representing the position of magnetic suspension coil;Digital signal processor circuit obtains force control signal according to DC signal;Force control circuit responds to force control signal, and provides suspension force for magnetic suspension coil.The application realizes the localization, miniaturization of three float instrument magnetic suspension circuit and the rapid, precise control to controlled object.

The application discloses a kind of linear feeding device and method based on piezoelectric transducer inertia drive, feeding device includes base, first to fourth spring piece, first to second connecting block, piezoelectric transducer, top disc, piezoelectric bimorph, first to third stop piece, and M+N+P adjusting bolts;When working, sine excitation signal is applied to piezoelectric transducer, the second order longitudinal vibration mode of piezoelectric transducer can be excited, to induce the reciprocating bending vibration of spring piece, drive top disc to generate horizontal and vertical direction movement.Material placed in top disc moves forward and upward with top disc in material groove.When spring piece moves to limit position, elastic potential energy stored in spring piece drives top disc to move back, at this time, material continues to move forward and falls under the action of inertia in parabolic curve.Under this periodic motion, the transportation of material in top disc is realized.The application has simple structure, and is easy to process and assemble.

The invention discloses a method for positioning and detecting in-plane crack defects of a CFRP composite material based on a rectangular differential probe, and relates to the technical field of engineering nondestructive testing. Comprising the steps that a to-be-detected damage-free CFRP laminated board workpiece is flatly placed on a table top and fixed, and a rectangular differential probe is placed at a preset position; a sine excitation current signal is applied to enable the eddy current probe to rotate around a central rotating shaft for one time until the probe rotates for one circle, a differential signal and a voltage signal of each rotating position are recorded, and the part with the numerical value smaller than 0.1 in the normalized differential signal is combined with the voltage change at the corresponding moment to obtain the fiber orientation and the up-and-down position relation of the CFRP laminated board. And arranging a CFRP laminated board containing longitudinal surface cracks, determining fiber orientation, performing C scanning, and accurately positioning crack defects. According to the method, the technical limitation that the unidirectional / orthogonal CFRP in-plane cracks are difficult to detect at high precision in an existing eddy current method is broken through, and rapid and accurate positioning of the defects is realized.

The present invention discloses an online scattering parameter measurement device and a distortion compensation method using a single inductive coupler, and relates to the field of inductive coupling measurement of scattering parameters of a device under test. The device comprises: a signal processing system, a vector network analyzer (VNA), an inductive coupler, a limiting insulating column, a device under test (DUT), and a power supply. The signal processing system establishes a communication connection with the vector network analyzer (VNA) via a miniUSB cable, controls the vector network analyzer (VNA) to perform measurement, and transmits and processes measured data. The vector network analyzer (VNA) is connected to the inductive coupler via an N-type connector, and a swept-frequency sinusoidal excitation signal is injected into the inductive coupler to measure the scattering parameters of the device under test (DUT). The limiting insulating column is sheathed on a power line to limit the position of the inductive coupler so that the power line passes through the center of a coupling window of the inductive coupler. The power supply is used to power the device under test (DUT).