A filtering system and a method for obtaining the double-frequency amplitude and phase of a vibration signal

Abstract

The present invention relates to a filtering system and a method for obtaining the double-frequency amplitude and phase of a vibration signal. Among them, the filtering system includes: a sensor arranged on a rotating device for collecting the vibration signal of the rotating device; a hardware conditioning circuit for converting the vibration signal into a first signal that can be input to an analog-to-digital converter; an analog-to-digital converter for sampling the first signal to obtain a first sampled signal; and a digital signal processor for filtering the first sampled signal by using a preset filter to obtain a filtered first sampled signal. Since the filtering system of the present invention filters the first sampled signal by using a preset filter to obtain a filtered first sampled signal, compared with the prior art, it can filter out corresponding interference signals.

Description

Technical Field

[0001] The present invention relates to the technical field of monitoring industrial rotating mechanical equipment, and particularly to a filtering system and a method for obtaining the multiple frequency amplitude and phase of a vibration signal. Background Art

[0002] The operating state of rotating mechanical equipment in the industrial field is mainly monitored, analyzed and alarmed by a vibration monitoring system. The monitoring contents of the vibration monitoring system include vibration, displacement, rotational speed, key phase, temperature, etc., which are used to analyze and predict the operating state and health state of the equipment. The vibration monitoring function mainly performs time-domain and frequency-domain analysis on vibration signals. However, in the existing technology, the vibration signals are not filtered, so the obtained vibration signals are not accurate. At the same time, in the actual monitoring environment, due to frequency deviation, false alarms may occur for a certain multiple frequency. It is not that the vibration signal has a large component at this multiple frequency, but due to the calculation by the fast Fourier transform method. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] In view of the above-mentioned disadvantages and deficiencies of the existing technology, the present invention provides a filtering system and a method for obtaining the multiple frequency amplitude and phase of a vibration signal, which solve the technical problems such as inaccurate vibration signals in the existing technology.

[0005] (2) Technical Solutions

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] In the first aspect, an embodiment of the present invention provides a filtering system, including:

[0008] A sensor disposed on a rotating device for collecting vibration signals of the rotating device;

[0009] A hardware conditioning circuit for converting the vibration signal into a first signal that can be input to an analog-to-digital converter;

[0010] An analog-to-digital converter for sampling the first signal to obtain a first sampled signal;

[0011] A digital signal processor for filtering the first sampled signal by using a preset filter to obtain a filtered first sampled signal.

[0012] Preferably,

[0013] The preset filter is: a low-pass filter with a cut-off frequency of MHz;

[0014] Wherein, M is a preset value.

[0015] Preferably,

[0016] the preset filter is: a band-pass filter with a cut-off frequency of N Hz;

[0017] wherein, N is a preset value.

[0018] Preferably,

[0019] the preset filter is: an elliptic filter or a Butterworth filter.

[0020] Preferably, the system further includes:

[0021] a key phase monitoring module, configured to collect the rotation frequency of the rotating device and generate a rectangular wave signal having the same frequency as the rotation frequency of the device;

[0022] a vibration monitoring frequency domain analysis module, configured to obtain the preset multiple-frequency amplitude and phase of the vibration signal by using a fast Fourier transform method according to the vibration signal and the rectangular wave signal.

[0023] Preferably,

[0024] the preset filter is: a band-pass filter with a cut-off frequency of the rotation frequency of the rotating device.

[0025] Preferably,

[0026] the obtaining of the preset multiple-frequency amplitude and phase of the vibration signal by using a fast Fourier transform method according to the vibration signal and the rectangular wave signal specifically includes:

[0027] obtaining the number n of signal zero-crossings passed by the vibration signal within a preset first time period;

[0028] the first time period is m cycles of the rectangular wave signal;

[0029] based on the n and m, obtaining the preset multiple-frequency amplitude and phase of the vibration signal by using a fast Fourier transform method.

[0030] Preferably,

[0031] the preset multiple-frequency amplitude and phase of the vibration signal are:

[0032] the fundamental frequency amplitude and phase of the vibration signal; or, the half fundamental frequency amplitude and phase of the vibration signal; or, the second harmonic amplitude and phase of the vibration signal.

[0033] Preferably, the obtaining of the preset multiple-frequency amplitude and phase of the vibration signal based on the n and m by using a fast Fourier transform method specifically includes:

[0034] When \(2m - 1\leq n\leq2m + 1\), the fundamental frequency amplitude and phase of the vibration signal are obtained by using the fast Fourier transform method;

[0035] When \(m - 1\leq n\leq m + 1\), the half - frequency amplitude and phase of the vibration signal are obtained by using the fast Fourier transform method;

[0036] When \(4m - 1\leq n\leq4m + 1\), the second - harmonic frequency amplitude and phase of the vibration signal are obtained by using the fast Fourier transform method.

[0037] In a second aspect, an embodiment of the present invention provides a method for obtaining the harmonic frequency amplitude and phase of a vibration signal, and the method is executed by the system described above.

[0038] (III) Beneficial effects

[0039] The beneficial effects of the present invention are as follows: A filtering system of the present invention filters the first sampled signal by using a preset filter to obtain the filtered first sampled signal. Compared with the prior art, it can filter out corresponding interference signals. And because a key - phase monitoring module is adopted to collect the rotation frequency of the rotating equipment and generate a rectangular wave signal with the same frequency as the rotation frequency of the equipment; a vibration monitoring frequency - domain analysis module is adopted to obtain the preset harmonic frequency amplitude and phase of the vibration signal by using the fast Fourier transform method according to the vibration signal and the rectangular wave signal, which can filter out interference to the greatest extent and avoid false alarms. Description of the drawings

[0040] Figure 1 It is a schematic structural diagram of a filtering system of the present invention;

[0041] Figure 2 It is a schematic structural diagram of the filtering system in the embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram corresponding to the vibration signal and the rectangular wave signal in an ideal state;

[0043] Figure 4 It is a schematic diagram corresponding to the vibration signal and the rectangular wave signal in an actual situation.

[0044]

Description of the reference numerals

[0045] 1: Vibration signal;

[0046] 2: Rectangular wave signal;

[0047] 3: Signal zero point. Detailed implementation manners

[0048] For better explaining the present invention and facilitating understanding, the present invention will be described in detail below in conjunction with the accompanying drawings and through specific embodiments.

[0049] To better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more clear and thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0050] See Figure 1 , this embodiment provides a filtering system, including:

[0051] A sensor disposed on a rotating device for collecting vibration signals of the rotating device.

[0052] The vibration signal in this embodiment is a signal converted by the sensor from the vibration of the rotating device.

[0053] A hardware conditioning circuit for converting the vibration signal into a first signal that can be input to an analog-to-digital converter.

[0054] An analog-to-digital converter for sampling the first signal to obtain a first sampling signal.

[0055] A digital signal processor for filtering the first sampling signal using a pre-set filter to obtain a filtered first sampling signal.

[0056] In the prior art, the signal frequency range supported by vibration monitoring for collection is generally 1 Hz to 30 kHz. The filtering parameters of the hardware are usually selected to be relatively large and the parameters are fixed and cannot be changed. To solve the limitations of hardware filtering and improve the anti-interference ability of vibration signals, a pre-set filter is used for filtering before the digital signal processor performs calculations.

[0057] In an implementation manner of this embodiment, the pre-set filter is: a low-pass filter with a cut-off frequency of MHz; where M is a pre-set value. Specifically, M in this embodiment is 1.

[0058] In an implementation manner of this embodiment, the pre-set filter is: a band-pass filter with a cut-off frequency of NHz; where N is a pre-set value.

[0059] In an implementation manner of this embodiment, the pre-set filter is: an elliptical filter or a Butterworth filter.

[0060] See Figure 2, in the specific application of this embodiment, the system further includes: a key phase monitoring module, configured to collect the rotation frequency of the rotating device and generate a rectangular wave signal having the same frequency as the rotation frequency of the device.

[0061] A vibration monitoring frequency domain analysis module, configured to obtain the preset multiple frequency amplitudes and phases of the vibration signal by using a fast Fourier transform method according to the vibration signal and the rectangular wave signal.

[0062] In an implementation manner of this embodiment, the preset filter is: a band-pass filter with a cut-off frequency being the rotation frequency of the rotating device.

[0063] See Figure 3 , in an ideal state, the frequencies of the vibration signal 1 and the rectangular wave signal 3 are the same. At this time, the 1x multiple frequency amplitude and the corresponding phase, 1 / 2x multiple frequency amplitude and the corresponding phase, and 2x multiple frequency amplitude and the corresponding phase of the vibration signal can be accurately calculated by using the fast Fourier transform method. However, in an actual monitoring environment, there may be a certain frequency difference between the vibration signal 1 and the rectangular wave signal 2. At this time, the result calculated by the fast Fourier transform method is not only the 1x multiple frequency amplitude, but also components of 1 / 2x multiple frequency, 2x multiple frequency and other multiple frequencies. Therefore, in the case of the frequency deviation between the two, it may cause a false alarm for a certain multiple frequency. It is not that there is a large component of the vibration signal at this multiple frequency, but rather caused by the calculation of the fast Fourier transform method.

[0064] See Figure 4 , to avoid errors, in the specific application of this embodiment, the obtaining of the preset multiple frequency amplitudes and phases of the vibration signal 1 by using the fast Fourier transform method according to the vibration signal 1 and the rectangular wave signal 2 specifically includes:

[0065] Obtaining the number n of times the signal zero point 3 passed by the vibration signal 1 within a preset first time period; in this embodiment, the signal zero point refers to when the vibration signal is zero.

[0066] The first time period is m periods of the rectangular wave signal 2; see Figure 4 , m in this embodiment is 3, that is to say, the first time period is 3 periods of the rectangular wave signal.

[0067] Based on the n and m, using the fast Fourier transform method to obtain the preset multiple frequency amplitudes and phases of the vibration signal.

[0068] In the specific application of this embodiment, the preset multiple frequency amplitudes and phases of the vibration signal are:

[0069] The amplitude and phase of the fundamental frequency of the vibration signal; or, the amplitude and phase of the half fundamental frequency of the vibration signal; or, the amplitude and phase of the second harmonic frequency of the vibration signal.

[0070] In the specific application of this embodiment, the obtaining of the preset harmonic amplitude and phase of the vibration signal by using the fast Fourier transform method based on n and m specifically includes:

[0071] When 2m - 1 ≤ n ≤ 2m + 1, the amplitude and phase of the fundamental frequency of the vibration signal are obtained by using the fast Fourier transform method.

[0072] When m - 1 ≤ n ≤ m + 1, the amplitude and phase of the half fundamental frequency of the vibration signal are obtained by using the fast Fourier transform method.

[0073] When 4m - 1 ≤ n ≤ 4m + 1, the amplitude and phase of the second harmonic frequency of the vibration signal are obtained by using the fast Fourier transform method.

[0074] A filtering system of the present invention filters the first sampled signal by using a preset filter to obtain the filtered first sampled signal. Compared with the prior art, it can filter out corresponding interference signals. And because a key phase monitoring module is adopted to collect the rotation frequency of the rotating device and generate a rectangular wave signal with the same frequency as the device rotation frequency; a vibration monitoring frequency domain analysis module is adopted to obtain the preset harmonic amplitude and phase of the vibration signal by using the fast Fourier transform method according to the vibration signal and the rectangular wave signal, it can filter out interference to the greatest extent and avoid false alarms.

[0075] Since the system described in the above embodiments of the present invention is the system adopted for implementing the method in the above embodiments of the present invention, based on the method described in the above embodiments of the present invention, those skilled in the art can understand the specific structure and deformation of the system, so it will not be elaborated here. Any system adopted for the method in the above embodiments of the present invention belongs to the scope protected by the present invention.

[0076] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can be implemented in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can be implemented in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0077] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions.

[0078] It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a claim listing several means, several of these means can be embodied by one and the same piece of hardware. The use of the terms first, second, third, etc. is for convenience of expression only and does not denote any order. These terms can be understood as part of the name of the element.

[0079] In addition, it should be noted that in the description of this specification, the descriptions of the terms "an embodiment", "some embodiments", "embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without conflict, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0080] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications after learning the basic creative concepts. Therefore, the claims should be construed to cover the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0081] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention should also include these modifications and variations.

Claims

1. A filtering system, characterized in that, Including: A sensor disposed on a rotating device for collecting vibration signals of the rotating device; A hardware conditioning circuit for converting the vibration signals into first signals that can be input into an analog-to-digital converter; An analog-to-digital converter for sampling the first signals to obtain first sampling signals; A digital signal processor for filtering the first sampling signals by using a preset filter to obtain filtered first sampling signals; The system further includes: A keyphasor monitoring module for collecting the rotation frequency of the rotating device and generating a rectangular wave signal having the same frequency as the rotation frequency of the device; A vibration monitoring frequency-domain analysis module for obtaining preset multiple-frequency amplitudes and phases of the vibration signals according to the vibration signals and the rectangular wave signals by using a fast Fourier transform method; The obtaining preset multiple-frequency amplitudes and phases of the vibration signals according to the vibration signals and the rectangular wave signals by using a fast Fourier transform method specifically includes: Obtaining the number n of signal zero-crossings passed by the vibration signals within a preset first time period; The first time period is m periods of the rectangular wave signal; Based on the n and m, obtaining preset multiple-frequency amplitudes and phases of the vibration signals by using a fast Fourier transform method.

2. The system according to claim 1, wherein The preset filter is: a low-pass filter with a cut-off frequency of MHz; Wherein, M is a preset value.

3. The system according to claim 1, wherein The preset filter is: a band-pass filter with a cut-off frequency of NHz; Wherein, N is a preset value.

4. The system according to claim 1, wherein The preset filter is: an elliptic filter or a Butterworth filter.

5. The system according to claim 4, wherein The preset filter is: a band-pass filter with a cut-off frequency of the rotation frequency of the rotating device.

6. The system according to claim 5, wherein The preset multiple-frequency amplitudes and phases of the vibration signals are: The 1× frequency amplitude and phase of the vibration signals; or, the 1 / 2× frequency amplitude and phase of the vibration signals; or, the 2× frequency amplitude and phase of the vibration signals.

7. The system according to claim 6, wherein The obtaining preset multiple-frequency amplitudes and phases of the vibration signals based on the n and m by using a fast Fourier transform method specifically includes: When 2m - 1 ≤ n ≤ 2m + 1, obtaining the 1× frequency amplitude and phase of the vibration signals by using a fast Fourier transform method; When m - 1 ≤ n ≤ m + 1, obtaining the 1 / 2× frequency amplitude and phase of the vibration signals by using a fast Fourier transform method; When 4m - 1 ≤ n ≤ 4m + 1, obtaining the 2× frequency amplitude and phase of the vibration signals by using a fast Fourier transform method.

8. A method for obtaining the frequency-doubled amplitude and phase of a vibration signal, characterized in that, The method is executed by the system according to any one of claims 5 - 7.

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