324results about "Resonant frequency" patented technology

A system for material detection and identification includes an interface configured to access a. material database associating each of a plurality of materials with one or more corresponding resonance frequencies: an RF transmitter configured to, for each material of at least a subset of the plurality of materials in the material database, transmit into an environment an RF signal at a first resonance frequency for the material; an RF receiver configured, to receive a response signal from the environment for each RF signal; and a processor configured to analyze each response signal for resonance characteristics that indicate a presence of the material and identifying the material to a user if the presence of the material is indicated by the resonance characteristics.

The invention discloses a loss tuning method of a power transformer, which is applied to a transformer body sleeved with a winding and comprises the following steps: applying scanning current excitation containing fundamental waves and harmonic waves to the winding, synchronously acquiring a body vibration signal and converting the body vibration signal into a frequency spectrum; extracting a formant from the frequency spectrum, matching the formant with a theoretical electromagnetic force wave and a structure inherent frequency library, and identifying a coupling formant to be optimized; aiming at each formant, installing a vibration exciter in a corresponding area, sending out an anti-phase periodic pulse force, and dynamically and finely adjusting a pulse force parameter by monitoring a vibration response in real time and taking equivalent mechanical impedance minimization as a target; when the optimal damping state is achieved, the vibration exciter output rod is locked, and static pre-tightening force is formed; and after all formants are adjusted and optimized in sequence and the prestress is locked, final pressing and fixing of the transformer body are completed in the state that the pretightening force is kept. According to the invention, the dynamic loss source of the individual transformer can be actively inhibited and cured before assembly and curing, the operation loss and noise are effectively reduced, and the structural stability is improved.

The invention relates to a cable joint resonance real-time diagnosis method and device and a medium, and belongs to the technical field of power equipment state monitoring, and the method comprises the following steps: obtaining a high-frequency current signal collected by a high-frequency current sensor and an ultrasonic vibration signal collected by an ultrasonic sensor array; performing signal synchronization on the high-frequency current signal and the ultrasonic vibration signal, and extracting a high-frequency current feature and an ultrasonic array feature; calculating a dominant frequency synchronization index, a normalized phase stability index and a nonlinear coupling index based on the high-frequency current characteristics and the ultrasonic array characteristics, and performing weighted summation to determine a fusion confidence coefficient function; and judging whether resonance exists or not based on the fusion confidence coefficient function, and if so, carrying out resonance source positioning. Compared with the prior art, the method has the advantages of high precision, low false alarm and high adaptability, and is suitable for key power system scenes such as new energy grid connection, urban smart power grids and wind power.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure phase information and amplitude associated with the resistive-inductive-capacitive sensor, and a noise detection circuit communicatively coupled to the measurement circuit and configured to determine a presence of external interference in the system based on at least one of the phase information and the amplitude information.

A system may include an array of sensor elements, the array of sensor elements each comprising a first type of passive reactive element, a second type of passive reactive element electrically coupled to the array of sensor elements, a driver configured to drive the array of sensor elements and the second type of passive reactive element, and control circuitry configured to control enabling and disabling of individual sensor elements of the array of sensor elements to ensure no more than one of the array of sensor elements is enabled at a time such that when one of the array of sensor elements is enabled, the one of the array of sensor elements and the second type of passive reactive element together operate as a resonant sensor.

The invention discloses a rotor system with a resonance point self-test function, a measurement method, equipment and a medium. The system comprises a controller, an active electromagnetic bearing, a radial vibration displacement sensor and a spectrum analyzer, the controller is used for generating a control signal according to the user configuration parameters and sending the control signal to the active electromagnetic bearing; the active electromagnetic bearing is used for outputting electromagnetic excitation force to the rotor system according to the control signal, so that the rotor system generates radial vibration displacement under the action of the electromagnetic excitation force; the radial vibration displacement sensor is used for collecting a radial vibration displacement signal of the rotor system and sending the radial vibration displacement signal to the spectrum analyzer; and the spectrum analyzer is used for generating a spectrum signal according to the radial vibration displacement signal and determining a rotor resonance point according to the spectrum signal. According to the technical scheme, self-testing of the resonance point of the rotor system can be realized without a speed increasing and decreasing test and an additional excitation device, the safety of the rotor is guaranteed, and uncontrollable accidents are avoided.

A sensorless method for machine tool chatter detection. A motor torque signal is analyzed in the time domain to determine whether a bit is currently cutting workpiece material. When not cutting material, an air-cut reference signal is stored for later use. When cutting material, the motor torque signal is converted to the frequency domain and filtered in a two-step process. The first filtering step includes removal of the air-cut reference signal via spectral subtraction, which removes noise and harmonics not directly related to chatter. The second filtering step includes further removal of spindle harmonic components at frequencies known from the spindle speed provided by the machine controller, where this step removes harmonic contents without distorting nearby contents. After filtering, two indicator criteria are evaluated to detect chatter, including a magnitude of the filtered torque signal and a magnitude ratio of the filtered torque signal to the air-cut reference signal.

To provide a sensorless method for machine tool chatter detection.SOLUTION: A motor torque signal is analyzed in the time domain to determine whether a bit is currently cutting workpiece material. When not cutting material, an air-cut reference signal is stored for later use. When cutting material, the motor torque signal is converted to the frequency domain and filtered in a two-step process. The first filtering step includes removal of the air-cut reference signal via spectral subtraction, which removes noise and harmonics not directly related to chatter. The second filtering step includes further removal of spindle harmonic components at frequencies known from the spindle speed provided by the machine controller, where this step removes harmonic contents without distorting nearby contents. After filtering, two indicator criteria are evaluated to detect chatter, including a magnitude of the filtered torque signal and a magnitude ratio of the filtered torque signal to the air-cut reference signal.SELECTED DRAWING: Figure 3

Methods to perform through tubing cement evaluation using converted multipole resonance modes. A first acoustic transmission is emitted outward toward the cement such that a portion of the first acoustic transmission penetrates the cement. The receiver array detects the first acoustic response derived from the first acoustic transmission. The system then determines the multimode wellbore resonance based on the first acoustic response. In response to the first acoustic transmission penetrating the cement, a first mode of the multimode wellbore resonance is converted into a second mode different from the first mode. The receiver array detects a second acoustic response derived from the converted mode of the multimode wellbore resonance. The system determines the converted mode using the second acoustic response. A property of the cement is evaluated based on the multimode wellbore resonance and the converted mode.

The invention provides an inhaul cable self-vibration fundamental frequency automatic identification method and system based on a harmonic product spectrum, and relates to the technical field of structure monitoring, and the method comprises the steps: receiving vibration acceleration data of an inhaul cable, carrying out the windowing processing of the vibration acceleration data through employing a Hanning window, and generating a windowed signal; carrying out fast Fourier transform on the windowed signal, and improving the frequency resolution by implementing zero filling to obtain an initial frequency spectrum; smoothing the initial frequency spectrum to form a smooth frequency spectrum; performing passband clipping on the smooth frequency spectrum to zero the passband outer amplitude to form a clipped frequency spectrum; calculating the signal-to-noise ratio of the frequency spectrum after cutting, and comparing the signal-to-noise ratio with a preset threshold value; if the signal-to-noise ratio is lower than a preset threshold value, judging that the signal quality is unqualified and terminating the processing flow; and if the signal-to-noise ratio is equal to or higher than the preset threshold value, continuing the normal processing flow. According to the invention, automatic and high-precision identification of the self-vibration fundamental frequency of the inhaul cable can be realized.

The invention discloses a method for detecting and inhibiting resonance of a two-axis photoelectric pod. Belongs to the technical field of photoelectric pod control systems, and particularly relates to the technical field of two-axis photoelectric pod resonance detection and suppression. According to the invention, a stable precision index is taken as a discrimination standard of a resonance condition, a self sensor is utilized, a resonance frequency automatic detection and identification method is adopted, filter parameters are adaptively adjusted according to resonance frequency point distribution characteristics, and the resonance frequency is suppressed through a signal processing algorithm, so that interference of the resonance frequency on a test is effectively avoided. According to the method, the self-adaptive capability of the photoelectric pod is enhanced, so that the photoelectric pod can cope with different external interference factors, and especially in a special vibration environment, the pod can keep relatively high stability and precision. According to the method, the problem of vibration interference in a traditional method can be effectively solved, and the adaptability of the photoelectric pod in a vibration environment can be remarkably improved.

Cookware identification includes exciting a cooking vessel using an excitation component. It further includes sensing an acoustic response of the cooking vessel to the excitation using a sensor. It further includes determining a type of the cooking vessel based at least in part on the acoustic response of the cooking vessel to the excitation that is sensed via the sensor.Ingredient state detection includes sensing, using an acoustic sensor, vibrations pertaining to cooking of an ingredient in a cooking vessel. It further includes monitoring, over time, a signal that is based on the vibrations sensed by the acoustic sensor. It further includes, based on detecting a change in the signal that is based on the vibrations sensed by the acoustic sensor, determining a state of the ingredient.

The invention discloses a single-port detection resonator resonant frequency on-line real-time measurement system for an MEMS gyroscope, and the system comprises a closed-loop drive circuit which is used for driving a resonator to resonate and outputting a drive detection signal; the first C / V conversion circuit converts the current into a detection voltage signal, and the on-off of the first C / V conversion circuit and the negative resistance circuit is controlled by a voltage control switch; the negative resistance circuit enables the equivalent input resistance of the first C / V conversion circuit to be a negative value so as to generate positive damping feedback force on the detection resonator; the multiplier is used for carrying out multiplication demodulation on the detection voltage signal and the driving detection signal, and the angular velocity of the MEMS gyroscope is output after the signals are filtered by the low-pass filter; the upper computer controls the on-off of the voltage control switch, the frequency fd and the frequency fs are calculated through fast Fourier transform by driving the detection signal and the detection voltage signal respectively, the frequency difference is obtained by solving the difference, and the resonant frequency of the single-port detection resonator is measured on the premise that the work of the MEMS gyroscope is not affected.

A method for determining a vortex-induced resonance region of a wind turbine blade and an anti-vortex device are provided, and relates to the technical field of wind power equipment. The method includes: obtaining the natural frequency of the wind turbine blade; segmenting the wind turbine blade to obtain a plurality of blade sections; calculating a vortex shedding frequency of a cross section of each of the plurality of blade sections at different wind speeds or under different operating conditions; and determining at least one vortex-induced resonance region of the wind turbine blade by comparing the vortex shedding frequency of the cross section of each of the plurality of blade sections at different wind speeds or under different operating conditions with the natural frequency.

A method for detecting interference between a transducer of acoustic signals and a sensor having a mechanical resonance frequency with a frequency band that includes transmitting an acoustic signal within a known range of frequencies, in a sequence during a predetermined time window, monitoring the output signal from the sensor within said time window, comparing the transmitted signal with the sensor output signal and detecting deviations in the sensor output signal corresponding to frequencies in the acoustic signal, and determining the acoustic frequencies interfering with the sensor signal. A system for detecting interference including a transducer, configured to emit a sequence of acoustic signals, and a sensor configured to produce an output signal, an analysis unit adapted to monitor said output signal with the acoustic signal.

The invention provides a quartz crystal microbalance resonant frequency detection system, a control method and a terminal, a direct digital frequency synthesis excitation unit is adopted to generate a frequency sweep excitation signal with a preset frequency range and stepping, and the frequency sweep excitation signal is conditioned by a signal injection and conditioning unit and then injected into a QCM sensor. And then the pure amplitude response detection unit measures and quantifies voltage response amplitudes of the QCM sensor under different excitation frequencies, and the resonant frequency intelligent determination unit determines the resonant frequency of the QCM sensor according to the voltage response amplitudes. According to the invention, a QCM self-oscillation circuit does not need to be designed and debugged, a precise phase detection assembly does not need to be configured, the circuit board layout is simpler, and components are greatly reduced. The QCM resonant frequency can be accurately measured only through efficient amplitude detection, a complex algorithm is avoided, the operational capability requirement and the software development difficulty are reduced, the QCM resonant frequency measuring device has the advantages of being simple in structure, low in cost, easy to integrate and the like, miniaturization and low-power-consumption design can be easily achieved, and the QCM resonant frequency measuring device is suitable for portable and wearable application.

A method for machine tool chatter detection which combines sensorless and sensor-based measurement methods and makes a determination based on analysis of both sensorless and sensor-based signals. The sensorless branch uses data known to the machine tool controller, such as spindle torque data or servo motor position / velocity data, where a time-series sample is recorded, the data is converted to the frequency domain and filtered, and criteria are evaluated to detect chatter. The sensor-based branch uses sound data recorded by a microphone, where data is again recorded, converted to the frequency domain, filtered, and evaluated. When both sensorless and sensor-based evaluation branches detect chatter at a common frequency, it is determined that chatter is occurring in the machine tool and appropriate steps are taken. The integrated chatter detection technique avoids false indicators of chatter which may arise due to noise present at different frequencies in the sensorless and / or sensor-based signals.

The invention discloses a structure and method for decoupling pipeline system bypass pipeline flow acoustic resonance, a branch pipe is connected to the pipe wall of a main pipeline to form a three-way pipe structure, one ends of a plurality of bypass pipelines are communicated to the branch pipe, the other ends of the bypass pipelines extend respectively, and the tail ends of the bypass pipelines are closed. The vortex at the joint of the main pipeline and the branch pipeline falls off to generate the pressure pulsation frequency, if the acoustic cavity modal frequency of the branch pipelines is coupled with the pressure pulsation frequency to cause flow acoustic resonance, the communicating pipeline is additionally arranged to communicate the two branch pipelines, so that the acoustic cavity modal frequency of the branch pipelines is changed, and the acoustic cavity modal frequency of the branch pipelines is changed. And the acoustic cavity modal frequency is far away from the pressure pulsation frequency, and decoupling is carried out. And therefore, noise elimination and vibration reduction of a pipeline system can be realized.

The invention relates to a method for rapidly measuring the resonant frequency of a resonant cavity based on frequency spectrum polynomial fitting, and belongs to the technical field of acoustic / optical measurement. The objective of the invention is to solve the problems of tedious steps, low efficiency, long time, poor stability and the like of a resonant cavity or resonant photoacoustic cavity resonant frequency measurement method. According to the method, the frequency spectrum of the resonant cavity is obtained through frequency mixing excitation, the frequency is obtained after curve fitting is conducted on frequency spectrum data points through a frequency spectrum polynomial fitting algorithm, and then resonant frequency measurement of the resonant cavity is achieved. According to the method, the measurement time of the resonant frequency of the resonant cavity is remarkably shortened, the measurement steps are simplified, and the measurement precision is improved; meanwhile, the resonance frequency is solved through frequency spectrum polynomial fitting, data noise interference can be effectively reduced, and the method has higher robustness. All frequency signals within the resonant frequency drift range are transmitted at a time through frequency mixing excitation, one-by-one scanning is not needed, and therefore the method has the advantages of being good in real-time performance, high in response speed, high in precision and the like, and is suitable for rapid frequency calibration and real-time monitoring in the fields of acoustic resonators, resonant photoacoustic spectra and the like. And a novel method for measuring the resonant frequency is provided for the fields of high-sensitivity resonance photoacoustic spectroscopy, acoustic trace gas detection and the like.

The invention belongs to the field of surface acoustic wave nondestructive testing equipment, and particularly relates to a method for nondestructive measurement of the thickness of a non-transparent film in a film / substrate layered structure based on a surface acoustic wave resonator, and the method comprises the steps: building an experimental platform for nondestructive testing of the thickness of the non-transparent film through the surface acoustic wave resonator; obtaining an S11 parameter frequency domain curve of the surface acoustic wave resonator under different film thicknesses by using a vector network analyzer, obtaining a corresponding resonant frequency, and fitting a relation curve of the film thickness and the resonant frequency; and the film thickness of the to-be-measured sample is experimentally measured, and the accuracy of measuring the thickness of the non-transparent film by the surface acoustic wave resonator is verified. According to the method, the limitation of an SEM method and an ellipsometry method in the field of lossless characterization of the thickness of the non-transparent film is effectively made up.

Disclosed herein is a system and method for optimizing RF power delivery to a plasma process chamber. This invention utilizes a data-driven approach to determine resonant frequencies for various plasma states, eliminating the need for conventional PID controls. By collecting performance data from an RF power generator as a function of operating frequency during the process recipe execution and analyzing portions of the waveform, the system continuously identifies resonating frequencies for each plasma state. Consequently, the RF power generator adapts in real-time to deliver optimal stability and performance.

The invention relates to the technical field of micro-nano-scale dynamic testing, and discloses a high-rigidity cantilever beam oscillation starting device, which comprises a cantilever beam placing frame, an oscillation starting device and a vibration starting device, the displacement module is provided with an experiment probe used for being in contact with the high-rigidity cantilever beam; the downward pressing control module is connected with the displacement module and used for controlling the experiment probe to execute downward pressing loading action so as to enable the high-rigidity cantilever beam to deform and then execute rapid separation action; and the data acquisition module is used for acquiring a free vibration signal generated by the high-rigidity cantilever beam after the experimental probe is separated from the high-rigidity cantilever beam. A set of experimental device combining a displacement table, piezoelectric ceramics and an experimental probe is designed. The displacement table has multi-degree-of-freedom and high-resolution displacement output capacity, the experimental probe can be quickly moved to a target area, piezoelectric ceramics are high in response frequency and high in stretching speed, and remarkable deformation can be generated in a short time.

The present application relates to the technical field of compression spring resonance frequency detection, and specifically relates to a compression spring resonance frequency detection method and system, the method comprising the following steps: collecting a mixed vibration signal of a compression spring to be measured; collecting a background noise signal of a test device as a reference noise signal; collecting a synchronous signal of a specific noise source of the test device; performing adaptive noise cancellation processing on the mixed vibration signal, the adaptive noise cancellation processing performing initial parameter training using the reference noise signal and using the noise source synchronous signal as a real-time reference input to separate a pure vibration response signal of the compression spring to be measured; performing frequency spectrum analysis on the pure vibration response signal; identifying a wideband vibration response region of the compression spring to be measured, the wideband vibration response region having a continuous amplitude higher than a preset energy threshold and having a specific width; calculating a characteristic parameter of the wideband vibration response region; and judging a degradation state of the compression spring to be measured according to the characteristic parameter. The above improves the accuracy of degradation judgment.

An embodiment hammer device includes a driver, an upper body configured to move in a direction set by power generated from the driver, an elastic body provided on the upper body, a hammer provided in the elastic body, a force sensor provided in the hammer, and a support configured to support the elastic body and the hammer.

Some electric hair cutting devices have a stationary blade, a reciprocating blade, and an oscillating motor. Oscillating motors include pivot motors and linear motors. Both motors have a stator, an armature and at least one spring. The armature drives a load such as the reciprocating blade. The armature, the spring and the load have a mechanical resonant frequency. An H- bridge is supplied with pulse width modulated (PWM) signals from a controller and converts direct current from a battery to alternating current having the frequency of the PWM signals. The controller measures the mechanical resonant frequency when power to the motor is turned off and the armature continues to oscillate due to stored energy. The controller adjusts the frequency of the PWM signals to the measured mechanical resonant frequency and stores it in a memory for use the next time the motor is turned on.

A method for identifying the dynamic behavior of a non-rigid object (10), the object being fixedly attached to a platform (12) that can be set in motion by an actuation device (14) is proposed. The method comprises actuation of the drive device (14) so ​​as to impart to the object a predefined periodic movement at a frequency, called the "cycle frequency". The periodic movement is a combination of at least two geometrically independent periodic elementary movements. The method comprises recording during actuation the variation of at least one quantity representative of a dynamic behavior, called the "dynamic quantity", and calculating for each of the cycle frequencies of the components called "elementary components", a Fourier transform of the variation of said at least one dynamic quantity for each elementary frequency.A dynamic behavior of the object is determined based on the variation of the elementary components. Abstract figure: Figure 2.

The application discloses a method, device and equipment for determining a resonant frequency. The resonant frequency of a first vibration component under the driving of a first excitation signal is detected to obtain a first resonant frequency. A first frequency offset is obtained based on the first resonant frequency and a first driving frequency of the first excitation signal. The first frequency offset is mapped to a second frequency offset based on a target mapping relationship, which is a mapping relationship between an actual frequency offset and a detected frequency offset. The first driving frequency is compensated by the second frequency offset to obtain a target resonant frequency, which is an actual resonant frequency of the first vibration component, so that the resonant frequency of the vibration component can be determined quickly and accurately.

Provided are an apparatus and method for blood pressure measurement using an electroacoustic transducer in combination with a piezoelectric ultrasonic transducer. The apparatus and method can provide continuous, noninvasive blood pressure monitoring.

The present invention relates to a vibration detection device (12) for a battery pack (10) for a vehicle. The vibration detection device according to the invention has at least one sensor (14), for example a knock sensor, arranged on the battery pack (10) of the vehicle, and at least one resonator (20a, 20b, 20c), for example a tuning fork, arranged on the battery pack (10). The at least one resonator (20a, 20b, 20c) generates a signal (24A, 24B, 24C) when the battery pack (10) experiences an impact. The signal (24A, 24B, 24C) is then transmitted to the at least one sensor (14). When the battery pack (10) experiences a shock or impact during operation, each resonator (20a, 20b, 20c) oscillates at a specific frequency and the at least one sensor (14) detects these frequencies in addition to the original impact.The at least one sensor (14) then sends the frequency spectra to an electronic control unit (ECU) of the vehicle, which determines the amplitude of the different frequencies and calculates the intensity and position of the impact using triangulation.