WO2023113641A1

WO2023113641A1 - Method for measuring vibration velocity and vibration velocity sensor

Info

Publication number: WO2023113641A1
Application number: PCT/RU2022/000351
Authority: WO
Inventors: Александр Александрович ГОЛОВЛЕВ; Александр Витольдович КАЛИНИН; Василий Сергеевич ЕЖОВ; Юстина Олеговна ЦИГА
Original assignee: Публичное акционерное общество "СИБУР Холдинг"
Priority date: 2021-12-16
Filing date: 2022-11-30
Publication date: 2023-06-22

Abstract

The claimed invention relates to a MEMS-type vibration velocity sensor for monitoring the level of infra-low-frequency and low-frequency vibrations, comprising an explosion-proof housing having mounted therein a printed circuit board on which are arranged at least two micro-electromechanical triaxial accelerometers capable of cyclically measuring an instantaneous acceleration value along three mutually orthogonal axes, and a microcontroller containing: at least two integrators capable of forming at least two sets of instantaneous vibration velocity value arrays; at least two spectral analysis modules capable of forming at least two sets of vibration velocity spectral distribution arrays; a spectrum cross-correlation module capable of forming a result set of vibration velocity spectra; and a module for calculating vibration velocity result values, which is capable of calculating a vibration velocity result vector and a set of vibration velocity values. Also claimed is a method for measuring vibration velocity using the above vibration velocity sensor. The technical result is more accurate measurement of the level of infra-low-frequency and low-frequency, low-amplitude vibrations in space.

Description

VIBRATION VELOCITY MEASUREMENT METHOD AND VIBRATION VELOCITY SENSOR

FIELD OF TECHNOLOGY

[1] The present technical solution, in general, refers to measuring technology, and more specifically, to a MEMS-type vibration velocity sensor for monitoring the level of object vibrations in the infra-low and low frequencies and small amplitude values of vibrations in space, along three axes of Cartesian coordinates.

BACKGROUND OF THE INVENTION

[2] In the modern world, there is a huge number of technical systems and equipment, such as pipelines, machines, fans, rotors, pumps, etc., the failure of which can lead to adverse consequences. During the operation of such objects (equipment with reciprocating or rotational type of movement, equipment of shock and shock-rotation action, etc.), the resulting vibration can accelerate the wear of these objects, increase the gaps between internal parts, lead to the destruction of fastening structures and, in general, bring the object into disrepair. To avoid unexpected and costly breakdowns, these facilities typically install vibration monitoring devices to monitor vibrations on a regular basis.

[3] At the moment, such devices are indispensable for monitoring various equipment, technical systems and various structures (hereinafter referred to as objects). The vibration parameters measured using such devices make it possible to diagnose the state of the object under study, evaluate its technical condition and detect malfunctions by comparing the current vibration parameters created by the operating object with the norms of the vibration parameters for the specified object. Vibration level monitoring devices, as a rule, are vibration sensors of various types. Currently, the most common vibration sensors are piezoelectric, piezoresistive and microelectromechanical (MEMS) sensors based on accelerometers. In such sensors as accelerometers corresponding to the type of sensor are used for primary acceleration transducers.

[4] Tensoresistive vibration sensors are designed to measure vibrations with a frequency of several tens of hertz. In these sensors, with the help of strain gauges, the deformation of the sensitive element connecting the oscillating seismic mass with the transducer body is measured.

[5] The disadvantages include the influence of temperature on the resistance of temperature strain gauges, the impossibility of their operation under conditions of strong dynamic loads, as well as the strong dependence of the measurement accuracy on the material with which the sensor is attached to the object (the occurrence of hysteresis), which practically excludes its use for vibration level monitoring in industrial equipment and complex technical systems with high loads and high operating temperatures (for example, the cooling system of a building, etc.).

[6] Piezoelectric vibration level sensors are the most accurate, however, this type of sensors is not suitable for solving the problems of monitoring the vibration of an object in space along the three axes of Cartesian coordinates, since it is required to place 3 separate sensors on the object (due to the features of piezoelectric accelerometers), which in some situations is practically impossible. In addition, piezoelectric transducers are expensive.

[7] A wireless vibration sensor is known from the prior art, described in RF patent No. RU 2437071 C2 (Limited Liability Company Research and Production Center “Diagnostics, reliability of machines and integrated automation”), publ. 12/20/2011. Said sensor contains a housing in which signal processing devices, signal transmission devices, a power source and an accelerometer are located, fixed in said housing by means of an elastic membrane. Such a sensor provides an extended bandwidth of measured frequencies by attaching the accelerometer with an elastic membrane.

[8] The disadvantages of this solution include the impossibility of controlling vibration along three mutually orthogonal coordinate axes, as well as the presence of strong intrinsic noise (due to the design features), which does not allow accurate measurement of vibration in the region of low and infra-low frequencies and small amplitude values of oscillations in space. [9] The prior art is a device for measuring vibration parameters, disclosed in the patent of the Russian Federation No. RU 189841 U1 (Prygunov Alexander Germanovich and others), publ. 06/06/2019. Said device contains a housing, inside of which there is a MEMS-type vibration sensor connected to the microcontroller and power supply, as well as a device body base temperature sensor and a microcontroller temperature sensor connected to the microcontroller computing core. This device improves the accuracy of measuring vibration parameters by controlling temperature and correcting data when measuring vibration with a MEMS-type vibration sensor.

[10] The disadvantages of this solution include the presence of strong intrinsic noise, due to which the accuracy of measuring vibration parameters in the region of low and infra-low frequencies and small amplitude values of oscillations in space decreases.

[11] A common disadvantage of these solutions is the absence in their design of a MEMS-type vibration velocity sensor capable of accurately measuring vibration parameters in space along three axes of Cartesian coordinates, in the region of infra-low and low frequencies, as well as small amplitude values of oscillations in space, with accuracy, commensurate with sensors built on piezoelectric transducers. Also, this kind of solution should be simple and inexpensive to manufacture compared to piezoelectric sensors.

ESSENCE OF THE TECHNICAL SOLUTION

[12] This technical solution is aimed at eliminating the shortcomings inherent in existing solutions known from the prior art.

[13] The present invention is aimed at solving a technical problem or technical problem, which consists in creating a vibration velocity sensor capable of measuring vibration parameters in space with high accuracy along three mutually orthogonal coordinate axes, in the region of infra-low and low frequencies and small amplitude values of oscillations in space.

[14] The technical result achieved by solving the above technical problem is to increase the accuracy of measuring the level of vibrations in space with a vibration velocity sensor in the region of infra-low and low frequencies and small amplitude values of oscillations in space.

[15] An additional technical result achieved in solving the above problem is the expansion of the arsenal of technical means.

[16] The indicated technical results are achieved due to the implementation of the vibration velocity sensor to control the level of vibrations in the infra-low and low frequencies, including a housing, inside which a printed circuit board is installed, on which are located:

• at least two microelectromechanical three-axis accelerometers (210 and 211), made with the possibility of cyclic measurement of the instantaneous acceleration value along three mutually orthogonal axes;

• a microcontroller (220) containing: o at least two integrators (230 and 231) configured to generate at least two sets of arrays of instantaneous values of vibration velocity based on instantaneous values of acceleration along three mutually orthogonal axes obtained from microelectromechanical three-axis accelerometers ( 210 and 211); about at least two spectral analysis modules (240 and 241) configured to generate at least two sets of arrays of the spectral distribution of vibration velocity based on the array sets of instantaneous values of vibration velocity; about the spectrum cross-correlation module (250), configured to generate the resulting set of vibration velocity spectra based on at least two sets of spectral velocity distribution arrays; about the module for calculating the resulting vibration velocity values (260), configured to calculate the resulting vibration velocity vector and a set of vibration velocity values based on the resulting set of vibration velocity spectra.

[17] In one particular embodiment of the sensor, a connector is additionally located on the printed circuit board for connecting a power source. [18] In another particular embodiment of the sensor, the connector is a wired serial interface.

[19] In another particular embodiment of the sensor, the wired serial interface is an interface selected from the group: RS485, U ART, RS422, SPI, 1 ² C.

[20] In another particular embodiment of the sensor, a transceiver module is additionally located on the printed circuit board, configured to exchange data with an external device

[21] In another particular embodiment of the sensor, at least two MEMS three-axis accelerometers (210 and 211) are at least accelerometers selected from the group: capacitive accelerometers, multi-axis accelerometers.

[22] In another particular example of the implementation of the sensor, the measurement of instantaneous values of vibration velocity by microelectromechanical three-axis accelerometers along three mutually orthogonal coordinate axes is carried out without adjusting the structure.

[23] In another particular embodiment of the sensor, the accelerometers (210 and 211) comprise an analog-to-digital converter (ADC).

[24] In another particular embodiment of the sensor, as measured by the accelerometers (210 and 211), the instantaneous acceleration values include the sum of the intrinsic noise value and the measured signal value.

[25] In another particular embodiment of the sensor, each of at least two sets of arrays of instantaneous vibration rates formed in integrators (230 and 231) contains at least three arrays of instantaneous vibration rates along mutually orthogonal axes.

[26] In another particular embodiment of the sensor, the formation of each of at least two sets of arrays of instantaneous values of vibration velocity is performed in parallel in each of the integrators (230 and 231).

[27] In another particular embodiment of the sensor, the formation of each of the at least two arrays of the spectral distribution of vibration velocity is performed in parallel in each of the spectral analysis modules (240 and 241).

[28] In another particular embodiment of the sensor, the formation of arrays of the spectral distribution of vibration velocity by the spectral analysis modules (240 and 241) is performed using a fast Fourier transform (FFT). [29] In another particular embodiment of the sensor, each of at least two sets of vibration velocity spectral distribution arrays formed in the spectral analysis modules (240 and 241) contains at least three vibration velocity spectral distribution arrays along mutually orthogonal axes.

[30] In another particular embodiment of the sensor, the spectrum cross-correlation module (250) is configured to calculate the RMS of the vibration velocity.

[31] In another particular embodiment of the sensor, the resulting set of vibration velocity spectra in the cross-correlation module (250) of the spectra is formed based on the multiplication of the values of the first of at least two sets of arrays of the spectral distribution of vibration velocity by the complex conjugate values of the second of at least two sets arrays of spectral distribution of vibration velocity.

[32] In another particular embodiment of the sensor, the resulting set of vibration velocity spectra generated in the spectrum cross-correlation module (250) contains at least three resulting vibration velocity spectra along mutually orthogonal axes.

[33] In another particular embodiment of the sensor, the set of vibration velocities calculated in the computing module (260) contains at least three vibration velocities along mutually orthogonal axes.

[34] In another particular embodiment of the sensor, the sensor housing is made dust- and moisture-proof.

[35] In another particular embodiment of the sensor, the housing is explosion-proof.

[36] In another particular embodiment of the sensor, the explosion-proof housing is made of a material selected from the group of polyester-coated mild steel, AISI 304 stainless steel, polyester, carbon-filled fiberglass reinforced, powder-coated cast aluminum.

[37] In another particular embodiment of the sensor, the housing further comprises a magnetic mount for attaching the sensor to an object.

[38] In addition, the claimed technical results are achieved by implementing a method for measuring vibration velocity to control the level of vibrations in areas of infra-low and low frequencies, performed using a vibration velocity sensor, and containing the steps in which: a) activate the vibration velocity sensor; b) receiving cyclic measurement data of the instantaneous acceleration value from at least two microelectromechanical triaxial accelerometers along three mutually orthogonal axes; c) forming at least two sets of arrays of instantaneous values of vibration velocity based on the obtained instantaneous values of acceleration along three mutually orthogonal axes; d) generating at least two sets of velocity spectral distribution arrays based on the arrays of instantaneous velocity values generated in step (c); e) generating the resulting set of vibration velocity spectra based on at least two sets of vibration velocity spectral distribution arrays, f) calculating the resulting vibration velocity vector and a set of vibration velocity values based on the resulting set of vibration velocity spectra, g) transmitting the values calculated in step (f) to an external device.

[39] In another particular embodiment of the method, the vibration velocity sensor is activated based on a predetermined activation time period.

[40] In another particular embodiment of the method, after the calculated values are transmitted to an external device, the vibration velocity sensor is turned off.

[41] In another particular embodiment of the method, the first and second sets of arrays of instantaneous values of vibration velocity contain at least three arrays of vibration velocity values along mutually orthogonal axes.

[42] In another particular embodiment of the method, the first and second set of spectral distribution arrays of vibration velocity contain at least three arrays of spectral distribution of vibration velocity along mutually orthogonal axes.

[43] In another particular embodiment of the method, the resulting set of vibration velocity spectra contains at least three resulting vibration velocity spectra along mutually orthogonal axes. [44] In another particular embodiment of the method, the set of vibration velocity values contains at least three vibration velocity values along mutually orthogonal axes.

[45] In another particular embodiment of the method, the resulting set of vibration velocity spectra is formed based on the multiplication of the values of the first of at least two sets of vibration velocity spectral distribution arrays by the complex conjugate values of the second of at least two sets of vibration velocity spectral distribution arrays.

[46] In another particular example of the implementation of the method, the vibration level of the object is controlled in the infra-low and low frequencies in the range from 2 Hz to 1000 Hz with a dynamic range from 0.01 to 50 mm/s.

[47] In another particular example of the implementation of the method, data is transferred to an external device via an interface selected from the group: RS485, U ART, RS422, SPI, 1 ² C.

BRIEF DESCRIPTION OF THE DRAWINGS

[48] The features and advantages of the present technical solution will become apparent from the following detailed description and the accompanying drawings, in which:

[49] FIG. 1 - illustrates an example of the implementation of the vibration velocity sensor.

[50] FIG. 2 - illustrates the block diagram of the vibration velocity sensor.

[51] FIG. 3 - illustrates a block diagram of the implementation of the claimed method for measuring vibration velocity to control the level of vibrations in the infra-low and low frequencies.

[52] FIG. 4 - illustrates the general view of the computing modules.

DETAILED DESCRIPTION

[53] The terms and concepts necessary for the implementation of the present technical solution will be described below.

[54] Sensor is a collective term that can mean: measuring transducer; primary measuring transducer; sensitive element. [55] A measuring transducer is a technical device with normalized metrological characteristics that is used to convert a measured quantity into another quantity or a measuring signal that is convenient for processing, storage, further transformations, indication or transmission.

[56] Explosion-proof electrical equipment - electrical equipment in which design measures are provided to eliminate or hinder the possibility of ignition (during operation) of the surrounding explosive mixture.

[57] The claimed technical solution makes it possible to measure the values of the vibration velocity of the object under study in space, along three mutually orthogonal axes, in the region of infra-low and low frequencies and small amplitude values of oscillations with high accuracy by compensating for the intrinsic noise of the vibration sensor. Controlling the vibration level of an object with the help of the claimed technical solution can be carried out in the frequency range from 2 Hz to 1000 Hz (the region of infra-low and low frequencies) with a dynamic range from 0.01 to 50 mm/s.

[58] In addition, this solution allows the use of the vibration sensor in explosive environments due to the implementation features described in more detail below. Also, the implementation of the specified sensor on MEMS accelerometers (microelectromechanical accelerometers) allows you to measure the vibration velocity values along three mutually orthogonal coordinate axes without adjusting the structure.

[59] FIG. 1 shows an example of the implementation of the vibration velocity sensor 100. The specified sensor 100 is made in an explosion-proof housing 110 containing a mount (not shown) designed to install the sensor 100 on the object under study. In a private embodiment, the sensor 100 may further comprise a connector for connecting an external power source.

[60] The explosion-proof enclosure of the software can be made of, but not limited to, polyester coated mild steel, AISI 304 stainless steel, carbon-filled fiberglass reinforced polyester, powder coated cast aluminum, and the like.

[61] Also, the sensor 100 may have dust and moisture resistance (the degree of protection is not lower than IP 65). The degree of protection is understood as a method of protection, verified by standard test methods, which is provided by the enclosure from access to dangerous parts (dangerous current-carrying and dangerous mechanical parts), ingress of external solid objects and / or water inside shells. This is achieved, for example, by coating the current-carrying elements of the circuit with varnish and / or coating the components of the software package with a rubber layer, which prevents moisture from entering inside.

[62] The mount used to mount the probe 100 on the object of interest can be, for example, a magnetic mount for metal surfaces, a threaded stud mount for even and smooth surfaces, a screw mount via an adapter for uneven and/or painted surfaces, and etc., but not limited to. The mount may be located on the base of the sensor 100. In addition, in private implementations, the sensor 100 can be installed on the object under test using an adhesive, such as epoxy. For a person skilled in the art, it is obvious that any type of mounts designed to install the sensor 100 on the object of interest can be used as a mount.

[63] The object under investigation in this decision should be understood as any equipment and technical systems or installations that cause vibration. For example, the investigated object (or object) may be a gas cleaning fan, a compressor, a motor, a drilling rig, railroad tracks, etc., without being limited.

[64] The sensor 100 is designed to measure vibration velocity values on the equipment under test. A more detailed operating principle of said sensor 100 and a detailed block diagram are shown in FIG. 2 and are disclosed in more detail below.

[65] The choice of the measured vibration parameter (vibration velocity) is determined by vibration standards and regulations. So, as a normalized vibration parameter for monitoring the technical condition of an object, most standards and regulatory documents establish the vibration velocity RMS (root mean square value), because this parameter gives the most accurate assessment of the technical condition of objects in the most common frequency range of vibration sources. In addition, ISO 10816-3 also requires the Root Mean Square (RMS) of the vibration velocity to evaluate the vibration level.

[66] For a person skilled in the art it will be obvious that with the measured vibration velocity parameters, the vibration displacement and vibration acceleration parameters can be easily obtained. To convert vibration velocity to vibration acceleration, the measured parameters need to be differentiated. To convert the vibration velocity into vibration displacement, the signal must be integrated.

[67] FIG. 2 shows a structural diagram of the sensor 100. The specified sensor 100 contains an explosion-proof housing, inside which is a printed circuit board, on which are located: two microelectromechanical three-axis accelerometers 210 and 211, a microcontroller 220 containing: two integrators 230 and 231, two spectral analysis modules 240 and 241 , spectrum cross-correlation module 250, module for calculating the resulting vibration velocity values 260.

[68] The elements of the claimed vibration velocity sensor 100 are fixed between themselves and the supporting structural elements, using a wide range of assembly operations, for example, screwing, articulation, soldering, riveting, etc., depending on the most suitable method of fastening the elements.

[69] The microcontroller 220 may be an on-board computer, controller, computer (electronic computer), CNC (computer numerical control), PLC (programmable logic controller) and any other device capable of performing a given, well-defined sequence of computing operations (actions, instructions). Microcontroller 220 may be implemented as a device or module, described in more detail in FIG. 4. Microcontroller 220 is configured to simultaneously receive and process information from accelerometers 210 and 211. As noted above, microcontroller 220 may include a set of modules, which may be logic or firmware modules, such as modules 230, 231, 240, 241, 250, 260, configured to generate sets of arrays of instantaneous values of vibration velocity based on information from accelerometers 210 and 211, generate sets of arrays of spectral distribution of vibration velocity, generate the resulting set of spectra of vibration velocity based on sets of arrays of spectral distribution of vibration velocity, calculate the resulting vector of vibration velocity and a set of vibration velocity values based on the resulting set of vibration velocity spectra.

[70] The term "instructions" as used in this application may refer, in general, to instructions in a program that are written to perform a particular function, such as receiving data from the accelerometers 210 and 211, processing the received data (integration, fast Fourier transform etc.), data transformation. The instructions may be implemented in a variety of ways, including, for example, object-oriented methods. For example, the instructions may be implemented using the C++ programming language, Java, various libraries (eg, “MFC”; Microsoft Foundation Classes), etc. The instructions that carry out the processes described in this solution can be transmitted over both wired and wireless transmission lines.

[71] The accelerometers 210 and 211 may be microelectromechanical three-axis accelerometers (MEMS accelerometers) and are designed to generate arrays of instantaneous acceleration values and convert the obtained values into an electrical signal. These accelerometers 210 and 211 have three measuring axes at once, directed perpendicular to each other, which makes it possible to measure the acceleration of a body in any direction. Thus, when measuring instantaneous acceleration values, each of said accelerometers 210 and 211 generates an array of instantaneous acceleration values along each of the axes. These operations can occur in parallel. It is also worth noting that accelerometers 210 and 211 may also include an analog-to-digital converter (ADC) to convert the measured acceleration values.

[72] In a particular implementation, capacitive MEMS accelerometers can be used, based on a measuring cell, which is a silicon case, inside which a console with a suspended inertial mass is placed. Electrodes are applied to the inner surfaces of the case and the surface of the mass, which turns the structure into a system of two capacitors. Under the action of acceleration, the inertial mass oscillates on the console, which leads to a change in the distance between the plates of both capacitors and, as a result, a change in their capacitance. In this case, the total capacitance of the composite capacitor remains unchanged. The capacitance variation of capacitors is reflected by a change in the potentials on their plates, which, in fact, can be measured as a signal proportional to the applied acceleration. In turn, the three-axis MEMS accelerometer uses a separate test mass for each axis, which is displaced along this axis when acceleration occurs (fixed by capacitive sensors). In another frequent implementation, a multi-axis accelerometer built on the above-described principles and differing by the principle of manufacturing an inertial mass, which allows it to oscillate in several planes at once.

[73] For a person skilled in the art it will be obvious that as three-axis MEMS accelerometers can be used any type of MEMS accelerometer design that measures the instantaneous values of the object's acceleration and converts them into electrical signals.

[74] As triaxial MEMS accelerometers 210 and 211, for example, triaxial accelerometers from Analog Devices™ such as ADXL375, LIS2DW12 triaxial accelerometers from STMicroelectronics™, etc. can be used without limitation.

[75] Integrators 230 and 231 are designed to generate sets of arrays of vibration velocity values based on the arrays of instantaneous acceleration values from accelerometers 210 and 211, respectively. Each of these integrators 230 and 231 generates an independent set of arrays of vibration velocity values as a function of time based on the obtained instantaneous acceleration values. Moreover, a set of arrays of vibration velocity values means three arrays of vibration velocity values along mutually orthogonal axes in accordance with the measured acceleration values along the indicated axes. So, if the accelerometer 210 is connected to the integrator 230, then the specified integrator 230 will perform the process of integrating the arrays of values (three arrays of instantaneous acceleration values along the three corresponding axes) received from the accelerometer 210, and accordingly the integrator 231 will perform a similar integration process for the accelerometer 211. For a specialist , it is obvious that the number of integrators and the scheme of their connection to accelerometers depends on the number of used accelerometers. These integration operations can be performed simultaneously by parallelizing the integration operations. It is also worth noting that the integration process is widely known and used, including for converting acceleration values into velocity values. A more detailed description of the integration processes is given in [1].

[76] Spectral analysis modules 240 and 241 are designed to form arrays of the spectral distribution of vibration velocity. These modules 240 and 241 perform a Fast Fourier Transform (FFT) of the arrays of vibration velocities received from modules 230 and 231 to form arrays of the spectral vibration velocity distribution. Fourier transform processes by different modules can also occur in parallel. So, module 240, when receiving an array of vibration velocity values from module 230, can perform a fast Fourier transform, while module 241 will perform a similar operation with data received from module 231. Fast Fourier transform is the process of converting a function of a real variable x(t) into its spectrum is described in more detail in [2].

[77] Spectrum cross-correlation module 250 is designed to compute the resulting velocity spectrum array. The specified module 250 is configured to receive the arrays of the spectral distribution of vibration velocity from modules 240 and 241, and multiply the values of one array by the complex conjugate values of the second array to obtain the resulting array of the vibration velocity spectrum. At the same time, the multiplication process makes it possible to reduce the inherent noise in the region of low and infra-low frequencies and small amplitude values that occur in the accelerometers 210 and 211 and to improve the accuracy of measuring the vibration velocity values due to the resulting array of the vibration velocity spectrum, which levels the own noises.

[78] When the two accelerometers 210 and 211 are operated in parallel, the measured acceleration values include the sum of the intrinsic noise value and the useful (measured) signal value. Since the useful signal is caused by an external force that is simultaneously applied to both accelerometers, the output data streams from the accelerometers contain in-phase components that determine the degree of signal similarity (correlation). To quantify the degree of similarity of the measuring signals, the cross-correlation function (CCF) is used, which can be calculated, for example, using the following formula:

Bxy(T) = f x(t)-y(t-T)-dt (1) where, x(t) - set of instantaneous accelerometer acceleration values 210, y(t) - set of instantaneous accelerometer acceleration values 211, - time shift of function x regarding u.

[79] When multiplying the instantaneous values x(t) and y(t), the magnitude of the correlated (useful) signal increases significantly with respect to chaotic noise. Thus, as a result of calculating the function B _X y, the signal-to-noise ratio increases. The parameter in this case is chosen equal to 0. In order to obtain the magnitude of the vibration velocity in a certain frequency range based on the spectral distributions of the vibration velocity obtained from the modules 240 and 241, the cross-correlated spectrum of the vibration velocity is calculated using the following formula:

F(Bxy) = (F|x|)* • (F|y|) (2) where F is the Fourier transform,

(F(x|)* is the complex conjugate function for x.

[80] The execution of the Fourier transform for the cross-correlation function of two signals is performed based on the product of their spectral functions, one of which is subjected to complex conjugation. The result is a distribution of the spectrum of cross-correlation (cross-correlation) of the original signals.

[81] The module for calculating the resulting vibration velocity values 260 is designed to calculate the resulting vibration velocity vector and a set of vibration velocity values based on the resulting set of vibration velocity spectra. The specified module 260 is configured to receive the resulting vibration velocity spectrum from the module 250 and calculate the RMS value of the vibration velocity based on it. At the output of module 260, the vibration velocity value is formed along the corresponding measurement axis. The vibration velocity values for the X, Y, Z axes are used to calculate the scalar value of the resulting vibration velocity vector.

[82] Further, the calculated values of the vibration velocity can be used to determine the anomalous operation of the object under study, determine the deviations of the vibration level from the permissible vibration level, etc. Vibration level control, as mentioned above, is carried out on the basis of calculated vibration velocity values, which can be interpreted into appropriate diagnostic indicators for a specific type of object under study.

[83] The calculated values of the vibration velocity along the axes are then transferred to an external device. After that, the cycle of measurement of vibration values is completed.

[84] Thus, by measuring two independent arrays of instantaneous acceleration values simultaneously with two independent accelerometers 210 and 211, as well as further parallel processing of the measured data, which consists in integration and FFT, and further calculation of the cross-correlated spectrum, increases the accuracy of measuring the vibration velocity values in the region of infra-low and low frequencies and small amplitude values, and reduces the intrinsic noise that occurs when measuring the primary instantaneous acceleration values, which makes it possible to provide high-precision control of the vibration level for the studied object.

[85] The following is a description of the scenario of the sensor 100, which is given as an example and does not limit the options for implementing the specified sensor.

[86] The scenario of the sensor 100 begins with the installation of the specified sensor on the object under study. As mentioned above, a technical installation that creates vibration can be used as an object under study. Depending on the type of installation, the type of attachment of the sensor 100 to the object under study is selected. So, for example, to install the sensor on an industrial fan, a magnetic mount located at the base of the sensor software housing 100 can be used. In another embodiment of the claimed solution, a threaded stud mount can be used as a mount.

[87] Activation of the sensor 100 occurs by applying power to said sensor 100. In one particular embodiment, the sensor can be powered from an external power source connected to the vibration velocity sensor 100 via a power supply connector. The operating range of the supply voltage is from +2.7V to +3.7V. As a power source, for example, a lithium cell can be used. The power supply filters the input power supply, protects against transient voltage spikes, and provides power to the internal busses of the sensor 100. In another particular embodiment, the sensor 100 may further comprise a power supply equipped with a transceiver.

[88] When the sensor 100 needs to be activated, for example, both in the case of a scheduled measurement of the vibration level of an object, and a measurement of the vibration level on demand from an external device, the sensor 100 is energized. It should be noted that the vibration level is the results of measuring the vibration indicators that the object under study creates and their further comparison with the corresponding permissible values of these indicators for a particular type of the object under study. Measurement of vibration parameters allows identify deviations in the normal operation of equipment in a timely manner, identify defects at an early stage, etc. Thus, the vibration level of the object can be determined based on the vibration velocity index, etc., without being limited. As described above, power can be supplied from an external device according to its activation periods (both scheduled and on demand).

[89] After power-up, the microcontroller 220 initializes all necessary software and hardware resources, namely the internal and peripheral modules of the microcontroller and the three-axis MEMS accelerometers 210 and 211.

[90] Next, the microcontroller 220 sends a control signal to start the measurement cycle in the accelerometers 210 and 211 and receives the measurement data. The cycle of measurement of instantaneous acceleration values lasts until the arrays of primary data are filled. So, for example, in a particular embodiment, the measurement cycle lasts until the arrays of primary data are filled, each with a size of 8192 readings. After receiving arrays of primary data from the accelerometers 210 and 211 in one embodiment, the microcontroller deactivates these accelerometers 210 and 211 to save power supply.

[91] The resulting arrays of instantaneous acceleration values are input to the integrators 230 and 231. As mentioned above, the integrators 230 and 231 can be, without limitation, software or firmware modules and are located directly on the printed circuit board and/or in the microcontroller 220, for example , on FPGA (programmable logic integrated circuit) type FPGA, etc. These integrators 230 and 231 are configured to form sets of arrays of instantaneous values of vibration velocity from the obtained arrays of primary acceleration values. Thus, the array of vibration velocity values generated by each of the integrators 230 and 231 is the result of integrating the instantaneous vibration acceleration values, i.e. is obtained by converting acceleration values into speed, and is an array of instantaneous vibration velocity values.

[92] Since each accelerometer 210 and 211 generates an array of primary acceleration values along three axes in the Cartesian coordinate system, each set of arrays of instantaneous vibration velocity values also contains at least three arrays of vibration velocity values along mutually orthogonal axes (along the X, Y axes , Z). As described above, depending on the type of accelerometers 210 and 211, the formation of a primary array of instantaneous acceleration values for each axis can occur using MEMS accelerometers manufactured using planar (surface) or volumetric technology. Thus, at the output of integrators 230 and 231, two sets of arrays of instantaneous values of vibration velocity are formed, each of which contains three arrays of instantaneous values of vibration velocity along three corresponding measurement axes.

[93] The generated sets of arrays of instantaneous values of vibration velocity are then fed to the inputs of modules 240 and 241, which perform a fast Fourier transform to obtain sets of arrays of the spectral distribution of vibration velocity. These modules 240 and 241 can also be both software and firmware modules and are located directly on the printed circuit board and/or in the microcontroller 220. Each of these arrays of the spectral distribution of vibration velocity contains three arrays of the spectral distribution of vibration velocity along three mutually orthogonal axes.

[94] The sets of spectral velocity distribution arrays are then fed to the input of the spectrum cross-correlation module 250, which provides the formation of the resulting set of vibration velocity spectra based on the obtained sets of spectral distribution of vibration velocity arrays. To obtain the resulting set of vibration velocity spectra, the values of the first of two sets of vibration velocity spectral distribution arrays are multiplied by the complex conjugate values of the second of two sets of vibration velocity spectral distribution arrays. Thus, at the output of module 250, the resulting set of vibration velocity spectra is formed, which contains three resulting vibration velocity spectra along mutually orthogonal axes.

[95] Based on the resulting set of vibration velocity spectra obtained from module 250, the resulting vibration velocity vector and the set of vibration velocity values are calculated. These calculations are performed in the module for calculating the resulting vibration velocity 260. The specified module 260 is configured to calculate the RMS vibration velocity to obtain vibration velocity values for each measurement axis (X, Y, Z), as well as to calculate the scalar value of the resulting vibration velocity vector. [96] After calculating the scalar value of the resulting vibration velocity vector and the vibration velocity values for each axis, these data are transmitted to an external device. Data transfer to an external device can be carried out via the interface of the RS485 standard. For a person skilled in the art, it is obvious that, depending on the requirements for an external data acquisition device, UART, RS422, SPI, 1 ² C, etc. interfaces can be used, without limitation. In one particular embodiment, the sensor 100 further comprises a transceiver module that transmits measured data to an external device. A personal computer, a server, a smartphone, a tablet, a wearable smart device, a router, a communication center, etc. can be used as an external device.

[97] As a data transmission standard, any means of wireless data transmission can be used, for example, a GSM modem, a GPRS modem, an LTE modem, a 5G modem, a satellite communication module, an NFC module, a Bluetooth and/or BLE module, a Wi-Fi module, and etc. In addition, the sensor 100 may additionally contain satellite navigation tools, such as GPS, GLONASS, BeiDou, Galileo.

[98] Thus, due to the formation of two independent primary arrays of instantaneous acceleration values and their subsequent processing and transformation, as well as the formation of the resulting set of vibration velocity spectra, the intrinsic noise of MEMS accelerometers is compensated, which makes it possible to increase the accuracy of measuring the vibration level in the infra-low and low frequencies and in the region of small amplitude values of oscillations in space, where the noise level is especially strong.

[99] FIG. 3 shows the steps of a method 300 for measuring vibration velocity to monitor the level of vibrations in the infra-low and low frequency region. Said method 300 is performed using the vibration velocity sensor 100 as described above.

[100] In step 301, the sensor 100 is activated. The sensor 100 is powered from an external power source through the power connector on the body 110 of the sensor 100. A lithium battery can be used as an external power source. In another particular embodiment, power is supplied from an external device via a wired serial interface such as RS485, etc. not limited. The periods of power supply to the sensor 100 can be set on an external device. The activation period of the sensor 100 can is the planned period of measurements of the values of the vibration velocity of the object under study, set on an external device by means of a human-machine interface of interaction. In another particular embodiment, sensor 100 may be activated by an external device at the request of a user through a human-machine interface. One of ordinary skill in the art will appreciate that any known method of energizing sensor 100 may be used.

[11] After power is applied, all the necessary software and hardware resources are initialized, namely the internal and peripheral modules of the microcontroller 220 and the three-axis MEMS accelerometers 210 and 211.

[102] At step 302, instantaneous acceleration value cyclic measurement data is obtained from at least two MEMS triaxial accelerometers 210 and 211. At this step 302, microcontroller 220 activates accelerometers 210 and 211, which begin the instantaneous acceleration value measurement cycle. The specified cycle lasts until the primary data arrays are filled. So, for example, in a particular embodiment, the measurement cycle lasts until the arrays of primary data are filled, each with a size of 8192 readings. After receiving arrays of primary data from the accelerometers 210 and 211 in one embodiment, the microcontroller deactivates these accelerometers 210 and 211 to save power supply. The resulting arrays of instantaneous acceleration values are transferred to modules 230 and 231 for further processing.

[SW] In step 303, at least two sets of arrays of instantaneous vibration rates are formed by modules 230 and 231 based on the received arrays of instantaneous vibration rates. Sets of arrays of instantaneous values of vibration velocity are formed based on the integration of arrays of instantaneous values of vibration acceleration over a time interval, each set of arrays of vibration velocity values containing three arrays of vibration velocity values along mutually orthogonal axes. This is due to the fact that the three-axis accelerometers 210 and 211 form an array of instantaneous acceleration values along three mutually orthogonal axes (X, Y, Z) to control the level of vibrations in space. As mentioned above, the indicated process of integrating each of the arrays of instantaneous acceleration values can occur in parallel in each of the modules 230 and 231. Integrated sets of arrays of vibration velocity values are then sent to modules 240 and 241.

[J4] In step 304, at least two sets of velocity spectral distribution arrays are generated by modules 240 and 241 based on the array sets of instantaneous velocity values obtained in step 303. These modules perform a fast Fourier transform to obtain spectral velocity distribution array sets. Modules 240 and 241 can also be both software and firmware modules and are located directly on the printed circuit board and / or in the microcontroller 220. Each of these arrays of the spectral distribution of vibration velocity also contains three arrays of the spectral distribution of vibration velocity along three mutually orthogonal axes. The received sets of arrays of the spectral distribution of the vibration velocity are sent to module 250.

[Y5] At step 305, in module 250, the resulting set of vibration velocity spectra is formed based on at least two sets of spectral distribution of vibration velocity arrays obtained at step 304. values of the second of two sets of arrays of spectral distribution of vibration velocity. Thus, at the output of module 250, the resulting set of vibration velocity spectra is formed, which contains three resulting vibration velocity spectra along mutually orthogonal axes.

[S6] In step 306, a resulting velocity vector and a set of velocity values are determined based on the resulting set of velocity spectra. The necessary calculations are performed in the module for calculating the resulting vibration velocity values 260. The specified module 260 is configured to calculate the RMS vibration velocity to obtain the vibration velocity values for each measurement axis (X, Y, Z), as well as to calculate the scalar value of the resulting vibration velocity vector. As mentioned above, the RMS value characterizes the vibration energy, which makes it possible to assess the destructive effect of vibration on the object under study. It should also be noted that the set of vibration velocity values obtained using module 260 contains three vibration velocity values along mutually orthogonal axes, which makes it possible to assess the effect of vibration on the object under study in space. [107] In step 307, the calculated values of the vibration velocity for each axis and the resulting vibration velocity vector are transmitted to an external device for further translation. Data transfer to an external device can be carried out via the interface of the RS485 standard. For a person skilled in the art, it is obvious that, depending on the requirements for an external data acquisition device, UART, RS422, SPI, 1 ² C, etc. interfaces can be used, without limitation. In one particular embodiment, the sensor 100 further comprises a transceiver module that transmits measured data to an external device. A personal computer, a server, a smartphone, a tablet, a wearable smart device, a router, a communication center, etc. can be used as an external device.

[108] Thus, the submitted application materials describe a vibration velocity sensor and a method for measuring vibration velocity to control the level of vibrations in the region of infra-low and low frequencies and the region of small amplitude values of vibrations, providing high measurement accuracy by reducing the intrinsic noise of accelerometers. Also, the use of three-axis MEMS accelerometers makes it possible to measure the level of vibration in space along three mutually orthogonal axes without changing the design of the accelerometers.

[Y9] In FIG. 4 shows an example of a general view of the modules (400) that provide the implementation of the presented solution. On the basis of modules (400), a different range of computing modules and microcontrollers can be implemented, for example, a human-machine interaction module, integrators, a microcontroller, a cross-correlation module, spectral analysis modules, a module for calculating the resulting vibration velocity values, a server, an external device, etc. .

[IO] In general terms, the module (400) contains one or more processors (401), memory facilities such as RAM (702) and ROM (403), input / output interfaces (404), input / output devices connected by a common information exchange bus. output (405), and a device for networking (406).

[111] The processor (401) (or multiple processors, multi-core processor, etc.) can be selected from a range of devices currently widely used, for example, manufacturers such as: Intel™, AMD™, Apple™, Samsung Exynos ™, MediaTEK™, Qualcomm Snapdragon™, etc. Under the processor or one of the processors used in the module (400), it is also necessary to understand the graphics processor, for example, an NVIDIA or Graphcore GPU, the type of which is also suitable for the full or partial execution of the method (300), and can also be used to train and apply machine learning models in various information systems.

1112] RAM (402) is a random access memory and is designed to store machine-readable instructions executable by the processor (401) to perform the necessary data logical processing operations. The RAM (402) typically contains the executable instructions of the operating system and associated software components (applications, program modules, etc.). In this case, the RAM (402) may be the available memory of the graphics card or graphics processor.

[FROM] ROM (403) is one or more permanent storage media, such as a hard disk drive (HDD), solid state drive (SSD), flash memory (EEPROM, NAND, etc.), optical storage media (CD-R/RW, DVD-R/RW, BlueRay Disc, MD), etc.

[114] Various types of I/O interfaces (404) are used to organize the operation of the module components (400) and organize the operation of external connected devices. The choice of appropriate interfaces depends on the particular design of the computing device, which can be, but not limited to: PCI, AGP, PS/2, IrDa, FireWire, LPT, COM, SATA, IDE, Lightning, USB (2.0, 3.0, 3.1, micro, mini, type C), TRS/ Audio jack (2.5, 3.5, 6.35), HDMI, DVI, VGA, Display Port, RJ45, RS232, etc.

[115] Various means (405) of I/O information are used to provide user interaction with the panoramic image creation tool, for example, a keyboard, a display (monitor), a touch display, a touch pad, a joystick, a mouse, a light pen, a stylus, a touch panel, trackball, speakers, microphone, augmented reality tools, optical sensors, tablet, indicator lights, projector, camera, biometric identification tools (retina scanner, fingerprint scanner, voice recognition module), etc.

[116] The network communication means (406) provides data transmission via an internal or external computer network, for example, an Intranet, the Internet, a LAN, and the like. As one or more means (406) may used but not limited to: Ethernet card, GSM modem, GPRS modem, LTE modem, 5G modem, satellite communication module, NFC module, Bluetooth and / or BLE module, Wi-Fi module, etc.

[117] Additionally, satellite navigation tools can also be used as part of the module (400), for example, GPS, GLONASS, BeiDou, Galileo.

[118] The specific choice of elements of the module (400) for the implementation of various software and hardware architectural solutions may vary while maintaining the required functionality provided from a particular type of device.

[119] Some functions of the vibration velocity sensor can also be implemented on the firmware of the user's personal device, which can be a module (400) in the form of a set of hardware or logic modules capable of performing a given, well-defined sequence of computational operations (actions, instructions), or a computer-readable medium containing instructions, such as software, to perform the above functions.

[120] The submitted application materials disclose preferred examples of the implementation of the technical solution and should not be construed as limiting other particular examples of its implementation that do not go beyond the scope of the requested legal protection, which are obvious to specialists in the relevant field of technology.

Information sources:

1) V.I. Belousova, G.M. Ermakova, M.M. Mikhaleva, N.V. Chuksina, I.A. Shestakova, "Higher Mathematics, Part II", Ural Federal University, 2017.

2) V.P. Kandidov, S.S. Chesnokov, S.A. Shlenov, "DISCRETE

FOURIER TRANSFORM, Faculty of Physics, Moscow State University, 2019

Claims

FORMULA

1. Vibration velocity sensor (100) for monitoring the level of vibrations in the infra-low and low frequencies, including a housing, inside which a printed circuit board is installed, on which are located:

2. The sensor according to claim 1, characterized in that the printed circuit board additionally has a connector for connecting a power source.

3. Sensor according to claim 2, characterized in that the connector is a wired serial interface.

25

4. The sensor according to claim 2, characterized in that the wired serial interface is an interface selected from the group: RS485, U ART, RS422, SPI, 1 ² C.

5. The sensor according to claim 1, characterized in that the printed circuit board additionally houses a transceiver module configured to exchange data with an external device.

6. The sensor according to claim 1, characterized in that at least two microelectromechanical three-axis accelerometers are at least accelerometers selected from the group: capacitive accelerometers, multi-axis accelerometers.

7. The sensor according to claim 1, characterized in that the measurement of instantaneous values of vibration velocity by microelectromechanical three-axis accelerometers (210 and 211) along three mutually orthogonal coordinate axes is carried out without adjusting the structure.

8. The sensor according to claim. 1, characterized in that the accelerometers (210 and 211) contain an analog-to-digital converter (ADC).

9. The sensor according to claim 1, characterized in that, measured by the accelerometers (210 and 211), the instantaneous acceleration values include the sum of the intrinsic noise value and the measured signal value.

10. The sensor according to claim 1, characterized in that each of at least two sets of arrays of instantaneous vibration rates formed in integrators (230 and 231) contains at least three arrays of instantaneous vibration rates along mutually orthogonal axes.

11. The sensor according to claim 1, characterized in that the formation of each of at least two sets of arrays of instantaneous values of vibration velocity is performed in parallel in each of the integrators (230 and 231).

12. The sensor according to claim 1, characterized in that the formation of each of the at least two arrays of the spectral distribution of vibration velocity is performed in parallel in each of the spectral analysis modules (240 and 241).

13. The sensor according to claim 1, characterized in that the formation of arrays of the spectral distribution of vibration velocity by the spectral analysis modules (240 and 241) is performed using the fast Fourier transform (FFT).

14. The sensor according to claim 1, characterized in that each of at least two sets of vibration velocity spectral distribution arrays formed in the spectral analysis modules (240 and 241) contains at least three vibration velocity spectral distribution arrays along mutually orthogonal axes.

15. The sensor according to claim 1, characterized in that the spectrum cross-correlation module (250) is configured to calculate the vibration velocity RMS.

16. The sensor according to claim 1, characterized in that the resulting set of vibration velocity spectra in the cross-correlation module (250) of the spectra is formed on the basis of multiplying the values of the first of at least two sets of vibration velocity spectral distribution arrays by the complex conjugate values of the second of at least at least two sets of arrays of the spectral distribution of vibration velocity.

17. The sensor according to claim 1, characterized in that the resulting set of vibration velocity spectra formed in the spectra cross-correlation module (250) contains at least three resulting vibration velocity spectra along mutually orthogonal axes.

18. The sensor according to claim 1, characterized in that the set of vibration velocity values calculated in the computing module (260) contains at least three vibration velocity values along mutually orthogonal axes.

19. Sensor according to claim. 1, characterized in that the sensor housing is made dust and moisture resistant.

20. Sensor according to claim. 1, characterized in that the housing is explosion-proof.

21. The sensor according to claim 20, characterized in that the explosion-proof housing is made of a material selected from the group: polyester-coated low-carbon steel, AISI 304 stainless steel, polyester plastic, carbon-filled glass fiber reinforced, powder-coated cast aluminum.

22. The sensor according to claim. 1, characterized in that the housing additionally contains a magnetic mount designed to secure the sensor to the object.

23. A method for measuring vibration velocity to control the level of vibrations in the region of infra-low and low frequencies, performed using a vibration velocity sensor (100) according to any one of paragraphs. 1-22 and comprising the steps of: a) activating the vibration velocity sensor; b) receiving cyclic measurement data of the instantaneous acceleration value from at least two microelectromechanical three-axis accelerometers along three mutually orthogonal axes, c) forming at least two sets of arrays of instantaneous vibration velocity values based on the obtained instantaneous acceleration values along three mutually orthogonal axes, d) forming at least two sets of vibration velocity spectral distribution arrays based on the instantaneous velocity value array arrays generated in step (c), e) generating a resulting vibration velocity spectra set based on at least two velocity spectral distribution array sets, f) calculating the resulting vibration velocity vector, and a set of vibration velocity values based on the resulting set of vibration velocity spectra, g) transmitting the values calculated in step (f) to an external device.

24. The method of claim. 23, characterized in that the activation of the vibration velocity sensor is based on a predetermined time period of activation.

25. The method according to claim 23, characterized in that after the calculated values are transmitted to an external device, the vibration velocity sensor is turned off.

26. The method according to claim 23, characterized in that the first and second set of arrays of instantaneous vibration rates contain at least three arrays of vibration rates along mutually orthogonal axes.

27. The method according to claim 23, characterized in that the first and second set of spectral velocity distribution arrays contain at least three vibration velocity spectral distribution arrays along mutually orthogonal axes.

28

28. The method according to claim 23, characterized in that the resulting set of vibration velocity spectra contains at least three resulting vibration velocity spectra along mutually orthogonal axes.

29. The method according to claim 23, characterized in that the set of vibration velocity values contains at least three vibration velocity values along mutually orthogonal axes.

30. The method according to claim 23, characterized in that the resulting set of vibration velocity spectra is formed on the basis of multiplying the values of the first of at least two sets of vibration velocity spectral distribution arrays by the complex conjugate values of the second of at least two sets of vibration velocity spectral distribution arrays.

31. The method according to claim 23, characterized in that the vibration level of the object is controlled in the region of infra-low and low frequencies in the range from 2 Hz to 1000 Hz with a dynamic range from 0.01 to 50 mm/s.

32. The method according to claim 23, characterized in that data is transferred to an external device via an interface selected from the group: RS485, UART, RS422, SPI, 1 ² C.

29