CN111879400B - System and method for measuring module modal parameters of spacecraft electromechanical product - Google Patents
System and method for measuring module modal parameters of spacecraft electromechanical product Download PDFInfo
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Abstract
The invention relates to a system and a method for measuring modal parameters of a component of an electromechanical product of a spacecraft, wherein the component is a high-speed rotor of a gyroscope, a high-speed rotor of a control moment gyroscope or a rotor of a flywheel, and the modal parameters comprise frequency, vibration mode and damping, and the system and the method belong to the technical field of modal measurement of small-mass mechanical components. The MEMS accelerometer is used for modal measurement of small-mass components such as a gyro high-speed rotor, so that the influence of the weight of the sensor on the mass distribution of the measured rotor is reduced, and the rotor modal measurement precision is improved. The oscilloscope is used for replacing a pre-set and analysis software of the traditional accelerometer, and modal frequency, modal vibration mode and modal damping are obtained by simple operation, so that modal measurement cost is greatly reduced. The method can be applied to the accurate measurement of the modal parameters of the components such as the rotor of the control moment gyroscope, the flywheel, the two-floating gyroscope, the three-floating gyroscope and other products. The invention can also be applied to the modal measurement of the high-speed motor rotor, and has wide market prospect.
Description
Technical Field
The invention relates to a system and a method for measuring modal parameters of a component of an electromechanical product of a spacecraft, wherein the component is a high-speed rotor of a gyroscope, a high-speed rotor of a control moment gyroscope or a rotor of a flywheel, and the modal parameters comprise frequency, vibration mode and damping, and the system and the method belong to the technical field of modal measurement of small-mass mechanical components.
Background
The high-speed rotor is a core component of products such as a spacecraft inertia actuating mechanism, a three-floating gyro, a two-floating gyro and the like. The modal design of the system influences the stability and the operation precision of the whole machine, and the measurement of modal characteristics (frequency, vibration mode and damping) is an important means for verifying the accuracy of the modal design and carrying out design iteration.
The rotor structure mode is an important design factor, the component mode analysis is one of the foundation and the core of the complete machine mode analysis, and the acquisition precision of the component mode parameters directly influences the accuracy of the complete machine mode analysis. And the modal measurement and implementation of the low-mass component are more difficult.
CMG, gyroscope and so on are assembled together by a plurality of components, the high-precision finite element analysis of the complete machine mode is difficult by the connection modeling error of the components, the processing and assembling error of the components, and under most conditions, the pure finite element analysis only has qualitative action on the acquisition of the mode parameters, so that the mode parameters need to be accurately tested. The measured modal parameters can provide feedback for design analysis to modify the finite element analysis model.
The mechanical vibration test is mainly realized by adopting a contact type accelerometer, and a test sensor is fixed on a tested piece. The currently available vibration sensors are generally piezoelectric or charge type, the weight of the vibration sensors is more than 10 grams, the self mass of the vibration sensors can change the structure of a tested piece, and the vibration sensors have great influence on the testing precision. In addition, the high-precision vibration sensor needs an external charge amplifier and a high-speed data acquisition unit, so that the cost is extremely high and the realization is complex.
The method for measuring the modal parameters of the high-precision component has the advantages of small influence on the mass distribution of the component to be measured (particularly for a small-mass component), high detection precision, light weight, high measuring range and convenience in implementation.
Disclosure of Invention
The technical problem solved by the invention is as follows: the defects of the prior art are overcome, and the system and the method for measuring the module modal parameters of the spacecraft electromechanical product are provided.
The technical solution of the invention is as follows:
a measurement system for the modal parameters of the components of the electromechanical products of the spacecraft comprises a vibration detection module, a signal processing module, a modal vibration type analysis module and a modal damping analysis module;
the vibration detection module is a PCB type micro-vibration measurement module based on an acceleration chip and comprises the acceleration chip, a filter module and a PCB, wherein the acceleration chip and the filter module are fixed on the PCB, the acceleration chip selects an MEMS acceleration chip with small volume, weight, high bandwidth and wide measuring range, a CMG rotor is taken as an example, the vibration detection module is fixed on the measured rotor in an adhesion mode, the adhesion positions are bearing supporting points (two), a node, a maximum value point and the like of a rotor modal vibration type determined by Ansys pre-analysis, the CMG rotor is suspended and fixed by cotton wires (or soft thin wires), and the fixed point is the node of the rotor modal vibration type;
when the end part (vibration mode maximum point) of the CMG rotor is knocked by a modal hammer, an acceleration chip in a vibration detection module at a sticking point is sensitive to vibration, converts the vibration into a voltage signal and outputs the voltage signal to a filtering module, and the filtering module carries out filtering processing on the received voltage signal and outputs the filtered voltage signal to a signal processing module;
the signal processing module is used for receiving the filtered voltage signal output by the vibration detection module, performing FFT analysis on the received filtered voltage signal to obtain a filtered voltage signal peak frequency and a corresponding amplitude, and outputting the obtained filtered voltage signal peak frequency and the obtained filtered voltage signal corresponding amplitude to the modal vibration type analysis module and the modal damping analysis module;
the modal shape analysis module is used for receiving the filtered voltage signal peak frequency and the corresponding amplitude sent by the signal processing module, and performing point tracing and cubic spline interpolation calculation according to the received amplitudes of the peak frequencies of different pasting points at the same moment to obtain the rotor modal shape;
the modal damping analysis module is used for receiving the filtered voltage signal peak frequency and the corresponding amplitude sent by the signal processing module, and carrying out analysis operation according to the received amplitude change of the peak frequency of the same pasting point at different moments to obtain rotor modal damping;
the filter module is realized by RC filter, the filter bandwidth is 5-10 times of the measured peak frequency, and the acceleration chip senses the vibration force of the measured piece and converts the vibration force into a vibration electric signal;
the signal processing module takes a four-channel oscilloscope as an example, a voltage signal U1 output by a vibration detection module pasted at a bearing support point position is taken as a reference signal to be connected into an oscilloscope channel 1, FFT conversion is carried out on the voltage signal U1 to obtain the amplitude of modal frequency F1 of the rotor and is taken as M11, a voltage signal U2 output by a vibration detection module pasted at another bearing support point position is taken as a reference signal to be connected into an oscilloscope channel 2, a voltage signal U3 output by a vibration detection module pasted at a node position of the rotor modal shape is taken as a reference signal to be connected into an oscilloscope channel 3, a voltage signal U4 output by a vibration detection module pasted at the maximum point position of the rotor modal shape is taken as a reference signal to be connected into an oscilloscope channel 4, FFT conversion is respectively carried out on a voltage signal U2, a voltage signal U3 and a voltage signal U4, and the amplitude of modal frequency F1 of the rotor is respectively obtained and is taken as M12, a voltage signal, The amplitude of the modal frequency F1 of the rotor is recorded as M13, and the amplitude of the modal frequency F1 of the rotor is recorded as M14, then the phase of the voltage signal U2 input by the oscilloscope channel 2, the phase of the voltage signal U3 input by the oscilloscope channel 3 and the phase of the voltage signal U4 input by the oscilloscope channel 4 on the frequency F1 scale are respectively compared with the phase of the voltage signal U1 input by the oscilloscope channel 1 on the time domain, if the phases are the same, no processing is carried out, and if the phases are reversed, a negative sign is added before the amplitude of the corresponding modal frequency;
the amplitude of each measuring point of the mode frequency F2 and F3 … … can be measured by the steps;
if the residual measuring points exist, testing according to the steps until the measuring is finished to obtain M15 and M16 … …;
the modal shape analysis module firstly normalizes vibration amplitudes of test modal frequencies corresponding to the test points obtained by the signal processing module, normalizes the amplitude M11 to 1 to obtain an amplitude sequence [1, M12 ', M13 ', … … ], and fits the amplitude sequence [1, M12 ', M12 ', … … ] by a cubic spline interpolation function, namely the normalized amplitude of the amplitude M11 is 1, the normalized amplitude of the amplitude M12 is M12 ', and so on;
the method comprises the following steps that the internal resistance of a rotor material can be formed by the strain hysteresis stress of the rotor material, the material needs to be tested, the vibration attenuation speed of the rotor is tested by the modal damping analysis module by adopting a time domain method, the damping of a corresponding vibration mode is obtained, in order to eliminate the disturbance in the hammering action process, timing is started from a period of time (>5ms) after the vibration starts, and the relation of the change of the modal amplitude along with time is as follows:
where F1 is the rotor modal frequency, ξ is the corresponding modal damping, and A (t) is U (t) at time t in amplitude at the F1 modal frequency.
Similarly, modal damping of the response at modal frequencies F2 and F3 … … can be found.
A method for measuring component modal parameters of spacecraft electromechanical products comprises the following steps:
(1) and Ansys pre-analyzes to determine the node, the maximum point and the like of the rotor modal shape. The vibration detection module is adhered to a bearing supporting point, a node of a rotor modal vibration mode and a maximum point, and a rotor is suspended and fixed by cotton threads (or soft thin wires), wherein a fixed point at one end is the node of the rotor modal vibration mode, and a suspension point at the other end;
(2) knocking the end part (vibration mode maximum point) of the CMG rotor by using a modal hammer, filtering voltage signals converted from rotor response by vibration detection modules positioned at different sticking points, and simultaneously sending the voltage signals to a signal processing module; there are two kinds of data, one group is response signal of different paste point at the same time; a set of response signals which change with time after each paste point is hammered;
(3) the signal processing module carries out FFT analysis on the filtered voltage signal output by the detection module after receiving the vibration to obtain the peak frequency and the corresponding amplitude of the filtered voltage signal, and outputs the obtained peak frequency and the corresponding amplitude of the filtered voltage signal to the modal vibration type analysis module and the modal damping analysis module;
(4) the modal shape analysis module performs point tracing and cubic spline interpolation calculation according to the peak frequency of the voltage signal output by the signal processing module, the corresponding amplitude and the amplitude of the peak frequency of the received different pasting points at the same moment to obtain the rotor modal shape;
(5) the modal damping analysis module performs analysis operation according to the peak frequency and the corresponding amplitude of the voltage signal output by the signal processing module and the received amplitude change of the peak frequency of the same pasting point at different moments, and obtains rotor modal damping through the following formula;
where F1 is the rotor modal frequency, ξ is the corresponding modal damping, and A (t) is U (t) at time t in amplitude at the F1 modal frequency.
Similarly, modal damping of the response at modal frequencies F2 and F3 … … can be found.
Compared with the prior art, the invention has the advantages that:
(1) the PCB type vibration sensor is a mems vibration sensor which is miniature, light in weight, wide in measuring range and high in precision.
(2) The PCB type vibration sensor has small mass, small influence on the mass distribution of the tested component (especially for a small-mass component), and high detection precision.
(3) The invention can obtain parameters such as modal frequency, vibration mode, damping and the like of the measured structure body, and can realize accurate measurement of the modal of the measured body.
(4) The invention uses the oscilloscope to replace a pre-set and analysis software of the traditional accelerometer, realizes acquisition of modal frequency, modal vibration mode and modal damping by simple numerical calculation, is simple to realize and greatly reduces the modal measurement cost.
(5) A method for measuring modal parameters of a miniature high-precision component adopts an MEMS accelerometer to carry out modal measurement on a small-mass component such as a gyro high-speed rotor, reduces the influence of the weight of a sensor on the mass distribution of the measured rotor, and improves the rotor modal measurement precision. The oscilloscope is used for replacing a pre-set and analysis software of the traditional accelerometer, and modal frequency, modal vibration mode and modal damping are obtained by simple operation, so that modal measurement cost is greatly reduced. The method can be applied to the accurate measurement of the modal parameters of the components such as the rotor of the products such as a control moment gyroscope, a flywheel, a two-floating gyroscope, a three-floating gyroscope and the like. The invention can also be applied to the modal measurement of the high-speed motor rotor, and has wide market prospect.
Drawings
FIG. 1 is a schematic diagram of the vibration detection module of the present invention;
FIG. 2 is a block diagram of the vibration detection module of the present invention;
FIG. 3 is a schematic diagram of a signal processing module according to the present invention;
FIG. 4 is a schematic view of a modal shape analysis module according to the present invention;
FIG. 5 is a schematic diagram of a modal damping analysis module according to the present invention.
Detailed Description
As shown in fig. 1, the present invention is a structural block diagram, and includes a vibration detection module, a signal processing module, a modal shape analysis module, and a modal damping analysis module. The vibration detection module is a PCB type micro vibration measurement module based on an acceleration chip. The device comprises an acceleration chip and a filtering module, and is installed on a PCB. The acceleration chip is selected to be a MEMS acceleration chip with small volume and weight, high bandwidth and wide measuring range). Taking the CMG rotor as an example, the vibration detection module is fixed on the measured rotor in an adhesion mode, the adhesion positions are a bearing supporting point, a node, a maximum value point and the like of a modal vibration mode determined by Ansys pre-analysis, and a modal hammer is used for knocking the end part of the rotor (the maximum value point of the vibration mode). The vibration detection module acquires a rotor vibration signal of the sticking point and transmits the rotor vibration signal to the general oscilloscope, the oscilloscope performs FFT analysis on the vibration signal detected by the vibration detection module to obtain the peak frequency and the corresponding amplitude of the vibration signal, the peak frequency and the corresponding amplitude are sent to the modal vibration pattern analysis module and the modal damping analysis module, and the modal vibration pattern analysis module performs point tracing and cubic spline interpolation calculation according to the amplitude of the peak frequency of different test points at the same moment, which is acquired by the signal processing module, to obtain the rotor modal vibration pattern. And the modal damping analysis module performs analysis operation according to the amplitude change of the peak frequency of the same test point at different moments, which is acquired by the signal processing module, so as to obtain the rotor modal damping.
As shown in fig. 2, the structural block diagram of the vibration detection module of the present invention includes an acceleration chip and a filter module, which are mounted on a PCB. The acceleration chip selects the MEMS acceleration chip with small volume and weight, high bandwidth and wide measuring range. The filtering module is realized by RC filtering, and the filtering bandwidth is 5-10 times of the measured modal frequency. The acceleration chip senses the vibration force of the measured piece, converts the vibration force into a vibration electric signal and sends the vibration electric signal into the oscilloscope module.
As shown in fig. 3, which is a schematic diagram of the signal processing module of the present invention, taking a four-channel oscilloscope as an example, a vibration signal at a measurement point at one end is selected as a reference signal to be connected to an oscilloscope channel 1, and FFT transformation is performed on the signal, so as to obtain an amplitude of the measured modal frequency F1, which is recorded as M11. And connecting the measuring point 2-4 into an oscilloscope channel 2-4, performing FFT (fast Fourier transform) on each signal successively, and obtaining the amplitude of the measured modal frequency as M12-M14. And compares the phase of the channel 2-4 signal to the channel 1 signal on the frequency F1 scale in the time domain. If the phase is reversed, a negative sign is added before the amplitude of the corresponding modal frequency. If the residual measuring points exist, the testing is carried out according to the steps until the measuring is finished, and M15 and M16 … … are obtained. The amplitude of each point of the modal frequencies F2 and F3 … … can be measured by the above steps.
Fig. 4 is a schematic diagram of a modal shape analysis module according to the present invention. Firstly, the vibration amplitudes of the test mode frequencies corresponding to the test points obtained by the signal processing module are normalized, and are normalized to be 1 by taking the reference signal as a reference, so that amplitude sequences [1, M11 ', M12', … … ], [1, M21 ', M22', … … ], … … are obtained.
Then, the amplitude sequence [1, M11 ', M12', … … ] is fitted with a cubic spline interpolation function, and the rotor mode shape after fitting is compared with the original data.
Fig. 5 is a schematic diagram of a modal damping analysis module according to the present invention. The strain hysteresis stress of the rotor material can form the internal resistance of the material, and the test is needed. The time domain method is adopted to test the vibration attenuation speed of the rotor, and the damping of the corresponding vibration mode is obtained. To eliminate the disturbance of the hammer action process, a time count was started 10mS after the start of vibration.
The modal amplitude over time relationship is:
where F1 is the rotor modal frequency, ξ is the corresponding modal damping, and A (t) is U (t) at time t in amplitude at the F1 modal frequency.
The amplitude of the rotor first-order mode F1 is 11.3dB higher than 10mS at 110mS, and the following formula is derived from the formula (1):
solving to obtain xi-0.004776.
Examples
Taking a CMG rotor as an example, firstly determining a node and a maximum value point of a rotor modal shape through Ansys pre-analysis; the vibration detection module is pasted on a bearing supporting point 1, a bearing supporting point 2 and a node and a maximum value point of a rotor modal shape shown in figure 1. The rotor is suspended and fixed by cotton threads (or soft thin threads), one end of the fixed point is a node of the rotor modal vibration mode, and the other end of the fixed point is a suspension point.
The CMG rotor end (mode shape maximum point) is hit by a mode hammer, and the vibration detection module output at the bearing support point 1 is U1(t), and the vibration detection module outputs at other sticking points are U2(t), U3(t) and U4 (t). U1(t), U2(t), U3(t) and U4(t) are simultaneously fed to the signal processing module. A voltage signal U1(t) output by a vibration detection module pasted at the position of a bearing supporting point 1 is taken as a reference signal to be connected into an oscilloscope channel 1, and U2(t), U3(t) and U4(t) are connected into oscilloscopes channels 2, 3 and 4.
The signal processing module performs FFT analysis on the U1(t), the U2(t), the U3(t) and the U4(t) output by the received vibration detection module to obtain the peak frequency and the corresponding amplitude of the filtered voltage signal, and finds the frequency with the highest amplitude by the FFT analysis of the U1(t) to obtain the modal frequency 702Hz of the rotor; the amplitude is recorded as M11 being 1.2V; carrying out FFT analysis on U2(t) to obtain the amplitude and marking as M12 ═ 1.2V; carrying out FFT analysis on U3(t) to obtain the amplitude and marking as M13 ═ 0.1V; carrying out FFT analysis on U4(t) to obtain the amplitude of the rotor, and recording as M14 as 1.4V; and then comparing the phase of the voltage signal U2 input by the oscilloscope channel 2, the voltage signal U3 input by the oscilloscope channel 3 and the voltage signal U4 input by the oscilloscope channel 4 with the phase of the voltage signal U1 input by the oscilloscope channel 1 on the scale of the frequency 702Hz in a time domain, if the phases are the same, not performing any processing, and if the phases are reversed, adding a negative sign in front of the amplitude of the corresponding modal frequency.
Outputting the obtained filtered voltage signal peak frequency and the corresponding amplitude to a modal shape analysis module and a modal damping analysis module; the modal shape analysis module performs dotting and cubic spline interpolation calculation according to the voltage signals U1(t), U2(t), U3(t) and U4(t) output by the signal processing module, the peak frequency 702Hz and the corresponding amplitude M11 of 1.2V, M12 of 1.2V, M13 of 0.1V, M14 of 1.4V, firstly, the vibration amplitude of each test point corresponding to the test modal frequency obtained by the signal processing module is normalized, the amplitude M11 is normalized to 1, and an amplitude sequence [1, 1, 0.1/1.2, 1.4/1.2] is obtained, namely the normalized amplitude of the amplitude M11 is 1, the normalized amplitude of the amplitude M12 is 1, and so on, and the rotor modal shape is obtained.
The modal damping analysis module obtains rotor modal damping through the following formula according to the peak frequency and the corresponding amplitude of the voltage signal output by the signal processing module and the received amplitude change of the peak frequency of the same pasting point at different moments; the modal amplitude over time relationship is:
the amplitude of the rotor at the first-order mode F1 ═ 702Hz is 11.3dB higher at 110mS than at 10mS, and the following is derived from equation (1):
solving to obtain xi-0.004776.
Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.
Claims (8)
1. A component modal parameter measurement system of spacecraft electromechanical products is characterized in that: the measuring system comprises a vibration detection module, a signal processing module, a modal shape analysis module and a modal damping analysis module;
the vibration detection module comprises an acceleration chip, a filtering module and a PCB (printed circuit board), wherein the acceleration chip and the filtering module are fixed on the PCB, the vibration detection module is fixed on a tested rotor in an adhesion mode, the adhesion positions are a bearing supporting point, a node of a rotor modal vibration mode and a maximum point of the rotor modal vibration mode, the rotor is in a suspension mode, and a fixed point during suspension is the node of the rotor modal vibration mode;
the vibration detection module is also used for sensing vibration, converting the vibration into a voltage signal and outputting the voltage signal to the filtering module;
the filtering module is used for filtering the received voltage signal and outputting the filtered voltage signal to the signal processing module;
the signal processing module is used for receiving the filtered voltage signal output by the vibration detection module, performing FFT analysis on the received filtered voltage signal to obtain a filtered voltage signal peak frequency and a corresponding amplitude, and outputting the obtained filtered voltage signal peak frequency and the obtained filtered voltage signal corresponding amplitude to the modal vibration type analysis module and the modal damping analysis module;
the modal shape analysis module is used for receiving the filtered voltage signal peak frequency and the corresponding amplitude sent by the signal processing module, and performing point tracing and cubic spline interpolation calculation according to the received amplitudes of the peak frequencies of different pasting points at the same moment to obtain the rotor modal shape;
the modal damping analysis module is used for receiving the filtered voltage signal peak frequency and the corresponding amplitude sent by the signal processing module, and carrying out analysis operation according to the received amplitude change of the peak frequency of the same pasting point at different moments to obtain rotor modal damping;
the signal processing module is a four-channel oscilloscope, a voltage signal U1 output by a vibration detection module pasted at a bearing supporting point position is taken as a reference signal to be connected into an oscilloscope channel 1, FFT conversion is carried out on the voltage signal U1 to obtain the amplitude of the modal frequency F1 of the rotor and is recorded as M11, a voltage signal U2 output by a vibration detection module pasted at another bearing supporting point position is taken as a reference signal to be connected into an oscilloscope channel 2, a voltage signal U3 output by a vibration detection module pasted at a node position of the modal shape of the rotor is taken as a reference signal to be connected into an oscilloscope channel 3, a voltage signal U4 output by a vibration detection module pasted at the maximum value position of the modal shape of the rotor is taken as a reference signal to be connected into an oscilloscope channel 4, and FFT conversion is respectively carried out on the voltage signal U2, the voltage signal U3 and the voltage signal U4 to obtain the amplitude of the modal frequency F1 of the rotor and is recorded as M12, The amplitude of the modal frequency F1 of the rotor is recorded as M13, and the amplitude of the modal frequency F1 of the rotor is recorded as M14, then the phase of the voltage signal U2 input by the oscilloscope channel 2, the phase of the voltage signal U3 input by the oscilloscope channel 3 and the phase of the voltage signal U4 input by the oscilloscope channel 4 on the frequency F1 scale are respectively compared with the phase of the voltage signal U1 input by the oscilloscope channel 1 on the time domain, if the phases are the same, no processing is carried out, and if the phases are reversed, a negative sign is added before the amplitude of the corresponding modal frequency;
the interpolation calculation method comprises the following steps: the modal shape analysis module firstly normalizes the vibration amplitude of the test modal frequency corresponding to each test point obtained by the signal processing module, normalizes the amplitude M11 to 1 to obtain an amplitude sequence [1, M12 ', M13 ', … … ], and fits the amplitude sequence [1, M12 ', M13 ', … … ] by a cubic spline interpolation function, namely the normalized amplitude of the amplitude M11 is 1, the normalized amplitude of the amplitude M12 is M12 ', and the like.
2. The system according to claim 1, wherein the system comprises: the vibration detection module is a PCB type micro-vibration measurement module based on an acceleration chip, nodes and maximum points of the rotor modal vibration mode are determined by Ansys pre-analysis, and the rotor is suspended and fixed by cotton wires or soft thin wires.
3. The system according to claim 1, wherein the system comprises: an acceleration chip in the vibration detection module at the attachment point is used to sense vibrations when the CMG rotor end is struck with a modal hammer.
4. The system according to claim 1, wherein the system comprises: the filtering module is realized by RC filtering, and the filtering bandwidth is 5-10 times of the measured peak frequency.
5. The system according to claim 1, wherein the system comprises: the analysis operation refers to: the modal damping analysis module tests the vibration attenuation speed of the rotor by adopting a time domain method to obtain the damping of a corresponding vibration mode, timing is started after 5s from the beginning of vibration, and the change relation of modal amplitude along with time is as follows:
where F1 is the rotor modal frequency, ξ is the corresponding modal damping, and A (t) is U (t) at time t in amplitude at the F1 modal frequency.
6. A method for measuring the module modal parameters of spacecraft electromechanical products is characterized in that: with the measuring system of claim 1, the steps of the method comprising:
(1) firstly, determining a node and a maximum point of a rotor modal shape, then pasting a vibration detection module on a bearing supporting point, the node and the maximum point of the rotor modal shape, and suspending a rotor;
(2) knocking the end part of the CMG rotor by using a modal hammer, filtering voltage signals converted by rotor response by vibration detection modules positioned at different sticking points, and simultaneously sending the voltage signals to a signal processing module;
(3) the signal processing module performs FFT analysis on the received filtered voltage signal output by the vibration detection module to obtain a filtered voltage signal peak frequency and a corresponding amplitude, and outputs the filtered voltage signal peak frequency and the corresponding amplitude to the modal vibration type analysis module and the modal damping analysis module;
(4) the modal shape analysis module performs point tracing and cubic spline interpolation calculation according to the peak frequency of the voltage signal output by the signal processing module, the corresponding amplitude and the amplitude of the peak frequency of the received different pasting points at the same moment to obtain the rotor modal shape;
(5) the modal damping analysis module performs analysis operation according to the peak frequency and the corresponding amplitude of the voltage signal output by the signal processing module and the received amplitude change of the peak frequency of the same pasting point at different moments, and obtains rotor modal damping through the following formula;
where F1 is the rotor modal frequency, ξ is the corresponding modal damping, and A (t) is U (t) at time t in amplitude at the F1 modal frequency.
7. The method for measuring the modal parameters of the components of the electromechanical product of a spacecraft according to claim 6, wherein: in the step (2), the data sent to the signal processing module includes response signals of different pasting points at the same time and response signals of each pasting point changing with time after being hammered.
8. The method for measuring the component modal parameters of the spacecraft electromechanical product according to claim 6, wherein the method comprises the following steps: when the rotor is suspended, the rotor is suspended and fixed by using cotton threads or soft thin threads, the fixed point at one end is a node of the rotor modal vibration mode, and the other end is a suspension point.
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