CN111307947A - System and method for positioning leakage of discontinuous structure of spacecraft based on frequency domain characteristic spectrum mapping - Google Patents
System and method for positioning leakage of discontinuous structure of spacecraft based on frequency domain characteristic spectrum mapping Download PDFInfo
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/14—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object using acoustic emission techniques
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- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/46—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by spectral analysis, e.g. Fourier analysis or wavelet analysis
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
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Abstract
The invention relates to a spacecraft discontinuous structure leakage positioning system based on frequency domain characteristic spectrum mapping, which is characterized in that: the spacecraft wall plate comprises a spacecraft wall plate, a signal emitter, a voltage amplifier, an excitation sensor, an upper computer, a signal conditioning module, a reference sensor and a receiving sensor. The invention also relates to a spacecraft discontinuous structure leakage positioning method based on frequency domain characteristic spectrum mapping, which comprises the following steps: 1) determining the range of the discontinuous structure of the spacecraft to be detected; 2) establishing a sensor network; 3) signal processing; 4) and (4) determining a leakage point. The method is scientific and reasonable in design, generates the mapping table through the characteristic spectrum of the frequency domain, does not need to obtain the initial time of the signal, and is suitable for the rapid detection and leakage positioning of the discontinuous structure of the spacecraft.
Description
Technical Field
The invention belongs to the technical field of structure detection, relates to leakage positioning of a discontinuous structure of a spacecraft, and particularly relates to a leakage positioning system and method of the discontinuous structure of the spacecraft based on frequency domain characteristic spectrum mapping.
Background
Since the first satellite in the Soviet Union, aerospace technology has been greatly developed. While convenient communication, navigation and positioning services and the like are brought, a large amount of space garbage is generated, which seriously threatens the on-orbit operation safety of the spacecraft. Once leakage occurs, the safety of the spacecraft and the astronauts can be seriously threatened, so the safety detection of the structural leakage of the spacecraft becomes an urgent problem to be solved.
For the outer shell of the spacecraft, the outer shell can be approximately seen as a plate-shaped material, and as for nondestructive detection of the material, ultrasonic detection method draws wide attention by virtue of the advantages of high sensitivity, capability of on-line detection, short detection time and the like. However, for the leak detection of spacecraft structures, there are several problems as follows:
the leakage signal is a continuous signal, the initial moment of the signal is difficult to capture, and the general method of positioning by using the sound arrival time difference is difficult to directly realize. The spacecraft structure has certain discontinuity, such as structures of a porthole, a cabin door and the like on a wall plate, the discontinuous structure has direct influence on the propagation of sound waves, and the boundary of the discontinuous structure can reflect, attenuate energy, convert wave modes and the like to the sound waves in materials, so that the characteristics of the sound waves become complex, the detection and positioning effects of the traditional ultrasonic method become poor, and a new method capable of positioning leakage of the discontinuous structure of the spacecraft is needed.
Through a search for a patent publication, no patent publication similar to the present patent application is found.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a spacecraft discontinuous structure leakage positioning system and method based on frequency domain characteristic spectrum mapping.
The technical problem to be solved by the invention is realized by the following technical scheme:
a spacecraft discontinuous structure leakage positioning system based on frequency domain characteristic spectrum mapping is characterized in that: the spacecraft wall plate comprises a spacecraft wall plate, a signal emitter, a voltage amplifier, an excitation sensor, an upper computer, a signal conditioning module, a reference sensor and a receiving sensor, wherein the excitation sensor, the reference sensor and the receiving sensor are all arranged on the spacecraft wall plate; the reference sensor and the receiving sensor amplify and condition signals through a signal conditioning module and transmit the signals to an upper computer; the signal generator provides an excitation signal, and the voltage amplifier amplifies the signal generated by the signal generator and provides an excitation source for exciting the sensor.
Moreover, the number of the receiving sensors is 2-5.
A spacecraft discontinuous structure leakage positioning method based on frequency domain characteristic spectrum mapping is characterized by comprising the following steps: the positioning method comprises the following steps:
1) determining the range of the discontinuous structure of the spacecraft to be detected: the discontinuous structure of the spacecraft wallboard is generally smaller than 3 square meters, the area of the discontinuous structure is smaller than 20 percent of that of the spacecraft wallboard, the spacecraft wallboard is subjected to grid division in the orthogonal direction, and the size of each grid is 5-20 mm2；
2) Establishing a sensor network: placing a reference sensor at the center of a spacecraft wallboard, placing a receiving sensor and an excitation sensor in the range to be measured of the discontinuous structure established in the step 1), providing an excitation source for the excitation sensor by a signal generator, connecting the receiving sensor with a signal conditioning module for signal amplification, and then sending a time domain signal to an upper computer;
3) signal processing: the upper computer processes the time domain signal in a period of time, performs fast Fourier transform on the time domain signal, and extracts a frequency domain characteristic spectrum;
4) and (3) determining a leakage point: and comparing the frequency domain characteristics of the unknown leakage signals with the established frequency domain characteristic spectrum mapping table, calculating the result by using a minimum variance method, and taking the grid corresponding to the minimum value as a leakage point.
Furthermore, in step 3), the frequency domain characteristic spectrum is the ratio of the frequency domain spectrum of the signals received by the receiving transducer and the reference transducer, and the leakage will generate a continuous acoustic signal, which is received by the transducer through the wall plate, and the signals received by the receiving transducer are:
Sn(f)＝Gn(f)En(f)A(f)exp(jφ(f)-jk(f)dn)
wherein: gn(f) Represents the attenuation of propagation in the plate;
En(f) is the amplitude-frequency response factor of the sensor;
a (f) is the amplitude spectrum of the leakage excitation sound signal;
phi (f) is the phase spectrum;
k (f) represents wave number;
dnindicating the distance of the sensor from the leak;
forming a characteristic spectrum by the ratio of the frequency domain amplitudes, wherein the characteristic spectrum of the sensor with the number n and the reference sensor can be represented as follows:
moreover, the method for establishing the frequency domain characteristic spectrum mapping table in the step 3) comprises the following steps:
1) sequentially utilizing an excitation sensor to generate an excitation signal to simulate a leakage sound source in each grid established on a wall plate of the spacecraft to be tested; the excitation sensor can select a piezoelectric ultrasonic transducer, the excitation signal adopts a frequency sweeping signal of 100-403kHz, and the signal time length is selected to be 6 ms;
2) each receiving sensor can receive a response signal after the transmission of the excitation signal and calculate a frequency domain characteristic spectrum corresponding to each grid point;
3) and establishing a frequency domain characteristic spectrum mapping table corresponding to the grid points according to the obtained frequency domain characteristic spectrum Q.
The invention has the advantages and beneficial effects that:
1. the positioning method generates the mapping table through the characteristic spectrum of the frequency domain, is irrelevant to the propagation rule of the signal, does not need to obtain the initial time of the signal, and is suitable for the leakage positioning of the discontinuous structure of the spacecraft.
2. Before the positioning method is used, a mapping table needs to be established for real-time comparison, and quick detection and leakage positioning can be realized in application.
Drawings
FIG. 1 is a schematic diagram of a positioning system according to the present invention;
FIG. 2 is a flow chart of a positioning method according to the present invention.
Detailed Description
The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.
A spacecraft discontinuous structure leakage positioning system based on frequency domain characteristic spectrum mapping is innovative in that: the spacecraft wall plate comprises a spacecraft wall plate, a signal emitter, a voltage amplifier, an excitation sensor, an upper computer, a signal conditioning module, a reference sensor and a receiving sensor, wherein the excitation sensor, the reference sensor and the receiving sensor are all arranged on the spacecraft wall plate; the reference sensor and the receiving sensor amplify and condition signals through a signal conditioning module and transmit the signals to an upper computer; the signal generator provides an excitation signal, and the voltage amplifier amplifies the signal generated by the signal generator and provides an excitation source for exciting the sensor.
A spacecraft discontinuous structure leakage positioning method based on frequency domain characteristic spectrum mapping is innovative in that: the positioning method comprises the following steps:
2) determining the range of the discontinuous structure of the spacecraft to be detected: the discontinuous structure of the spacecraft wallboard is generally smaller than 3 square meters, the area of the discontinuous structure is smaller than 20 percent of that of the spacecraft wallboard, the spacecraft wallboard is subjected to grid division in the orthogonal direction, and the size of each grid is 5-20 mm2；
3) Establishing a sensor network: placing a reference sensor at the center of a spacecraft wallboard, placing a receiving sensor and an excitation sensor in the range to be measured of the discontinuous structure established in the step 1), wherein the number of the receiving sensors is 2-5, a signal generator provides an excitation source for the excitation sensor, the receiving sensor is connected with a signal conditioning module to amplify signals, and then, time domain signals are sent to an upper computer;
3) signal processing: the upper computer processes the time domain signal in a period of time, performs fast Fourier transform on the time domain signal, and extracts a frequency domain characteristic spectrum;
4) and (3) determining a leakage point: and comparing the frequency domain characteristics of the unknown leakage signals with the established frequency domain characteristic spectrum mapping table, calculating the result by using a minimum variance method, and taking the grid corresponding to the minimum value as a leakage point.
Step 3) the frequency domain characteristic spectrum is the ratio of the frequency domain spectrum of the signals received by the receiving sensor and the reference sensor, the leakage will generate continuous acoustic signals which are received by the sensor through the wall plate, and the signals received by the receiving sensor are as follows:
Sn(f)＝Gn(f)En(f)A(f)exp(jφ(f)-jk(f)dn)
wherein: gn(f) Represents the attenuation of propagation in the plate;
En(f) is the amplitude-frequency response factor of the sensor;
a (f) is the amplitude spectrum of the leakage excitation sound signal;
phi (f) is the phase spectrum;
k (f) represents wave number;
dnindicating the distance of the sensor from the leak;
forming a characteristic spectrum by the ratio of the frequency domain amplitudes, wherein the characteristic spectrum of the sensor with the number n and the reference sensor can be represented as follows:
step 3) the method for establishing the frequency domain characteristic spectrum mapping table comprises the following steps:
1) sequentially utilizing an excitation sensor to generate an excitation signal to simulate a leakage sound source in each grid established on a wall plate of the spacecraft to be tested; the excitation sensor can select a piezoelectric ultrasonic transducer, the excitation signal adopts a frequency sweeping signal of 100-403kHz, and the signal time length is selected to be 6 ms;
2) each receiving sensor can receive a response signal after the transmission of the excitation signal and calculate a frequency domain characteristic spectrum corresponding to each grid point;
3) and establishing a frequency domain characteristic spectrum mapping table corresponding to the grid points according to the obtained frequency domain characteristic spectrum Q.
Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.
Claims (5)
1. A spacecraft discontinuous structure leakage positioning system based on frequency domain characteristic spectrum mapping is characterized in that: the spacecraft wall plate comprises a spacecraft wall plate, a signal emitter, a voltage amplifier, an excitation sensor, an upper computer, a signal conditioning module, a reference sensor and a receiving sensor, wherein the excitation sensor, the reference sensor and the receiving sensor are all arranged on the spacecraft wall plate; the reference sensor and the receiving sensor amplify and condition signals through a signal conditioning module and transmit the signals to an upper computer; the signal generator provides an excitation signal, and the voltage amplifier amplifies the signal generated by the signal generator and provides an excitation source for exciting the sensor.
2. The frequency domain signature mapping-based spacecraft discontinuous structure leakage localization system of claim 1, wherein: the number of the receiving sensors is 2-5.
3. The frequency domain signature spectrum mapping-based spacecraft discontinuous structure leakage positioning method according to claim 1, characterized in that: the positioning method comprises the following steps:
1) determining the range of the discontinuous structure of the spacecraft to be detected: the discontinuous structure of the spacecraft wallboard is generally smaller than 3 square meters, the area of the discontinuous structure is smaller than 20 percent of that of the spacecraft wallboard, the spacecraft wallboard is subjected to grid division in the orthogonal direction, and the size of each grid is 5-20 mm2；
2) Establishing a sensor network: placing a reference sensor at the center of a spacecraft wallboard, placing a receiving sensor and an excitation sensor in the range to be measured of the discontinuous structure established in the step 1), providing an excitation source for the excitation sensor by a signal generator, connecting the receiving sensor with a signal conditioning module for signal amplification, and then sending a time domain signal to an upper computer;
3) signal processing: the upper computer processes the time domain signal in a period of time, performs fast Fourier transform on the time domain signal, and extracts a frequency domain characteristic spectrum;
4) and (3) determining a leakage point: and comparing the frequency domain characteristics of the unknown leakage signals with the established frequency domain characteristic spectrum mapping table, calculating the result by using a minimum variance method, and taking the grid corresponding to the minimum value as a leakage point.
4. The frequency domain signature spectrum mapping-based spacecraft discontinuous structure leakage positioning method according to claim 3, characterized in that: in the step 3), the frequency domain characteristic spectrum is a ratio of frequency domain spectrums of signals received by the receiving sensor and the reference sensor, the leakage will generate a continuous acoustic signal, the continuous acoustic signal is received by the sensor through the wall plate, and the signals received by the receiving sensor are as follows:
Sn(f)＝Gn(f)En(f)A(f)exp(jφ(f)-jk(f)dn)
wherein: gn(f) Represents the attenuation of propagation in the plate;
En(f) is the amplitude-frequency response factor of the sensor;
a (f) is the amplitude spectrum of the leakage excitation sound signal;
phi (f) is the phase spectrum;
k (f) represents wave number;
dnindicating the distance of the sensor from the leak;
forming a characteristic spectrum by the ratio of the frequency domain amplitudes, wherein the characteristic spectrum of the sensor with the number n and the reference sensor can be represented as follows:
5. the frequency domain signature spectrum mapping-based spacecraft discontinuous structure leakage positioning method according to claim 3, characterized in that: the method for establishing the frequency domain characteristic spectrum mapping table in the step 3) comprises the following steps:
1) sequentially utilizing an excitation sensor to generate an excitation signal to simulate a leakage sound source in each grid established on a wall plate of the spacecraft to be tested; the excitation sensor can select a piezoelectric ultrasonic transducer, the excitation signal adopts a sweep frequency signal of 100-403kHz, and the signal time length is selected to be 6 ms;
2) each receiving sensor can receive a response signal after the transmission of the excitation signal and calculate a frequency domain characteristic spectrum corresponding to each grid point;
3) and establishing a frequency domain characteristic spectrum mapping table corresponding to the grid points according to the obtained frequency domain characteristic spectrum Q.
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| CN112254891A (en) * | 2020-10-22 | 2021-01-22 | 北京卫星环境工程研究所 | Spacecraft reinforcing rib structure leakage positioning method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109695821A (en) * | 2019-01-21 | 2019-04-30 | 天津大学 | A kind of stiffened panel leakage locating method based on amplitude spectrum index |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109695821A (en) * | 2019-01-21 | 2019-04-30 | 天津大学 | A kind of stiffened panel leakage locating method based on amplitude spectrum index |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112254891A (en) * | 2020-10-22 | 2021-01-22 | 北京卫星环境工程研究所 | Spacecraft reinforcing rib structure leakage positioning method |
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