CN203132688U - Device for realizing synchronous order-domain trace analysis on rotating mechanical vibration signals - Google Patents

Abstract

The utility model relates to a device for realizing synchronous order tracking and analysis of vibration signals of rotating machinery, comprising a multi-channel signal acquisition A/D conversion circuit and a signal processing circuit, and the multi-channel signal acquisition A/D conversion circuit is provided with a multi-channel signal Receiving interface, one of the multi-channel signal receiving interfaces is the key phase pulse signal interface for receiving the key phase pulse of the rotating machine, and at least four other channels are the vibration signal interface of the rotating machine; the signal processing circuit includes a central processing unit chip and a An FPGA chip, the FPGA chip is provided with a filter processing channel and a sampling frequency generator correspondingly connected to multiple signal interfaces in the A/D conversion circuit. The utility model has a simple structure and overcomes the shortcomings of the traditional hardware method that the collected waveform data has intervals and discontinuities due to the need for continuous adjustment of the sampling frequency; it can realize continuous and uninterrupted collection of waveforms without adding any other components such as phase-locked loops and frequency multipliers. Hardware such as circuits can realize accurate equiangular sampling.

Description

A device for realizing synchronous order tracking analysis of rotating machinery vibration signals

technical field

The utility model relates to the field of mechanical vibration analysis and measurement, in particular to a device for realizing synchronous order tracking and analysis of vibration signals of rotating machines. the

Background technique

The traditional vibration order tracking method of rotating machinery is realized by hardware, which requires a phase-locked loop, a frequency multiplication and frequency division circuit, and an anti-aliasing filter with a real-time adjustable cut-off frequency. The circuit is complex and the cost is high. In particular, equiangular resampling has been studied intensively. The main problems of the hardware implementation method are: 1) The sampling frequency needs to be pre-estimated by the last rotation speed of the rotating machinery, and there are errors in the estimation, so it is impossible to achieve accurate synchronous sampling of the entire cycle, resulting in spectral leakage of the FFT results; 2) The hardware method The required anti-aliasing filter with adjustable cut-off frequency has a complex structure. Since the sampling frequency needs to be adjusted continuously, the collected waveform data has the disadvantage of interval and discontinuity. The Chinese patent with the notification number CN102175439 discloses a "method for realizing the order analysis of rotating machinery", and its resampling at the same angle is "according to the low-speed pulse of the update frequency and the speed pulse of the current high-speed shaft respectively output to the acquisition card The signal is equiangularly resampled". This method is quite effective when the rotation speed of the rotating machinery is constant or changes little, but when the rotation speed changes greatly at any time, the update frequency at this time is calculated from the frequency at the first sampling; therefore, when using this update frequency and the current Equiangular resampling of the speed pulses on the high-speed axis will cause the update frequency to be out of sync with the current speed pulses on the high-speed shaft. the

Contents of the invention

In order to solve the problems of the prior art, the utility model proposes a device for realizing the synchronous order tracking analysis of the vibration signal of the rotating machinery. The device realizes accurate equal-angle sampling by a fixed sampling frequency, and there is no frequency confusion phenomenon, that is, Every time the rotating shaft rotates, the sampling point is consistent with the angle difference on the rotating shaft, and the position on the rotating shaft is fixed, so as to realize accurate synchronous sampling of the whole period. the

The purpose of this utility model is achieved in this way: a device for realizing synchronous order tracking analysis of vibration signals of rotating machinery, including a multi-channel signal acquisition A/D conversion circuit and a signal processing circuit, the multi-channel signal acquisition A/D conversion The circuit is provided with multiple signal receiving interfaces, and one of the multiple signal receiving interfaces is a key phase pulse signal interface, which is used to receive the rotating mechanical key phase pulse analog signal transmitted by the photoelectric sensor; All the other at least four roads are vibration signal interfaces, which are used to receive the rotating mechanical vibration signal transmitted by the vibration sensor; the signal processing circuit includes a central processing unit chip and an FPGA chip, and the FPGA chip is provided with a corresponding connection A/D The filter processing channel and the sampling frequency generator of the multi-channel signal interface in the conversion circuit, the control port of the FPGA chip is connected with the control port of the CPU chip, the data port of the CPU chip is connected with the data port of the FPGA chip, and the FPGA chip Connect a monitor. the

Further, a cascaded integral comb filter processor is set in the path of the filter processing channel corresponding to the key phase pulse signal interface, and an FIR digital filter processor is set in the path of the filter processing channel corresponding to the vibration signal interface. the

Further, the multi-channel signal acquisition A/D conversion circuit is a 16-bit 8-channel A/D acquisition module modeled as AD7606. the

The contribution of the utility model to the prior art is:

1. The structure is simple, and accurate equal-angle sampling can be realized without adding any other hardware such as phase-locked loops and frequency multiplication circuits. There is no frequency confusion, that is, every time the rotating shaft rotates, the sampling point corresponds to the angle difference on the rotating shaft It is consistent, and the position on the rotating shaft is fixed, so as to realize accurate synchronous sampling of the whole cycle.

2. The utility model overcomes the disadvantages of intervals and discontinuity in the collected waveform data due to the continuous adjustment of the sampling frequency in the traditional hardware method, and can realize continuous and uninterrupted collection of waveforms. the

The present invention will be described in detail below in conjunction with the embodiments and accompanying drawings. the

Description of drawings

Fig. 1 is a schematic diagram of the circuit structure of the utility model. the

Detailed ways

An embodiment of a device for realizing synchronous order tracking analysis of vibration signals of rotating machinery, referring to Fig. 1, comprising a multi-channel signal acquisition A/D conversion circuit 1 and a signal processing circuit, the multi-channel signal acquisition A/D conversion circuit is provided with A multi-channel signal receiving interface, one of the multi-channel signal receiving interfaces is a key phase pulse signal interface, which is used to receive the rotating mechanical key phase pulse analog signal transmitted by the photoelectric sensor 2; the rest of the multi-channel signal receiving interfaces are at least Four roads are vibration signal interfaces, which are used to receive the rotating mechanical vibration analog signal transmitted by the vibration sensor 3; the signal processing circuit includes a central processing unit chip 4 and an FPGA chip 5, and the FPGA chip is provided with a corresponding connection A The filter processing channel and the sampling frequency generator of the multi-channel signal interface in the /D conversion circuit, the control port of the FPGA chip is connected with the control port of the central processing unit chip, and the data port of the central processing unit chip is connected with the data port of the FPGA chip, The FPGA chip is connected to the display 6, and at the same time, the FPGA chip is also connected to SDRAM and SRAM memory respectively. the

In the embodiment, a cascaded integral comb filter processor is arranged in the path of the filter processing channel corresponding to the key phase pulse signal interface, and an FIR digital filter processor is arranged in the path of the filter processing channel corresponding to the vibration signal interface of the rotating machine . the

In an embodiment, the multi-channel signal acquisition A/D conversion circuit is a 16-bit 8-channel synchronous A/D acquisition module modeled as AD7606. the

Using the above-mentioned embodiment to realize the synchronous order tracking analysis method of the rotating machinery vibration signal by the fixed sampling frequency is: adopting the fixed sampling frequency to synchronously collect the rotating machinery vibration signal and the speed key phase pulse signal, select a vibration order ratio M, and use interpolation filtering The key-phase pulse is interpolated by 2*M times to obtain the equiangular vibration sampling signal, and after processing the equiangular vibration sampling signal, the harmonic waveform of each order of vibration is finally obtained; the specific steps are:

1) Continuously and synchronously collect rotating machinery vibration signals and speed key phase pulse signals with a fixed sampling frequency greater than the maximum speed frequency * order ratio M;

2) Identify the arrival time of the rising edge and falling edge of the key phase pulse signal according to a threshold, and calculate the time difference between each two pulses through the arrival time, so as to determine the rotational speed and instantaneous frequency of each revolution of the rotating machinery;

3) Using an FPGA-based cascaded integral comb filter (CIC, Cascaded Integrator Comb filter) as an interpolation filter to perform (N=2*M) times interpolation filtering on the fixed sampling frequency between two key phase pulses, Obtain the time series corresponding to the vibration mean angle signal of the vibration signal;

4) Based on the instantaneous frequency and time series of the rotating machinery, the vibration signal is digitally filtered and interpolated to obtain an equiangular sampling signal (corresponding to the time series).

5) Perform Fourier transform (FFT) on the equiangular sampling signal to obtain a continuous rotating mechanical vibration order spectrum, and perform constant bandwidth filtering or Gabor transform on the equiangular sampling signal to obtain continuous harmonic waveforms of each order. the

Realization of real-time tracking in this embodiment: signal analysis is performed every 0.25 seconds of collection, and the signal resampling frequency is adjusted according to the actual rotation frequency (because the signal has been collected and accurately calculated according to the signal), rather than under the hardware method , predict the next rotation frequency from the last rotation frequency value, and then adjust the sampling frequency. the

In an embodiment, the interpolation is one of linear interpolation, spline interpolation, Lagrangian interpolation or sinc interpolation algorithms. the

In an embodiment, the order number M is 2 to the power of X, and X is a positive integer of 4 or more. the

In an embodiment, the digital filtering uses a Kaiser window FIR filter. the

In this example:

1) According to a fixed sampling frequency; synchronously collect one speed key phase pulse signal of the rotating machinery; and four vibration signals;

2) For the key-phase pulse signal, the threshold value (threshold) is artificially specified according to the voltage value of the rising (or falling) edge, or the threshold value is automatically calculated according to a certain algorithm according to the statistical law. According to this threshold, the arrival time t0, t1, t2...tN of the rising edge (or falling edge) of the key phase pulse signal is accurately identified and recorded by the detection algorithm;

3) From the time difference between two pulses, dt0=t1-t0, dt1=t2-t1,..., dtN-1=tN-tN-1, calculate the rotational speed rpm and instantaneous frequency f;

4) Set the order ratio M (can be 16, 32, 64, 128, 256, etc.) according to the analysis needs, and use the CIC interpolation filter to interpolate the key-phase pulse by N times (N=2*M) to obtain the angle The time series corresponding to each sample of the equal-angle vibration signal in the domain;

5) Based on the instantaneous frequency of the rotor and the resampling time series, the vibration signal is digitally filtered and interpolated and resampled to obtain an equiangular sampling signal. Among them, the interpolation can use linear interpolation, spline interpolation, Lagrangian interpolation or sinc interpolation algorithm ;

6) Perform Fourier transform (FFT) on the equiangular sampling signal to obtain the vibration order spectrum of the rotating machinery, and perform constant bandwidth filtering or Gabor transform on the equiangular sampling signal to obtain harmonic waveforms of each order.

Using the method of this embodiment, use the 24-bit data acquisition card-USB4432 of NI Corporation of the United States or the 16-bit 8-channel synchronous A/D acquisition module of model AD7606, without adding any other hardware (such as phase-locked loop, frequency multiplication circuit, etc.) , a photoelectric sensor and 4 vibration sensors collect 1 speed key phase signal and 4 vibration signals respectively, which constitutes a high-precision vibration signal acquisition and analysis system, and realizes order tracking acquisition and order analysis of variable speed vibration signals Function. the

The purpose of the method in this embodiment is to achieve accurate equiangular sampling, that is, every time the rotating shaft rotates, the sampling point corresponds to the same angle difference on the rotating shaft, and the position on the rotating shaft is fixed, so as to realize accurate synchronous sampling of the entire cycle. the

Claims (3)

1. realize that the rotating machinery vibrating signal is with the device of step comparison-tracking analysis for one kind, it is characterized in that, described device comprises multiplexed signal sampling A/D change-over circuit and signal processing circuit, described multiplexed signal sampling A/D change-over circuit is provided with the multiple signals receiving interface, in the described multiple signals receiving interface a road is key phase pulse signal interface, is used for receiving the rotating machinery key phase pulse simulation signal that is transmitted by photoelectric sensor; All the other have at least four the tunnel to be the vibration signal interface in the described multiple signals receiving interface, are used for receiving the rotating machinery vibrating signal that is transmitted by vibration transducer; Described signal processing circuit comprises a central processing unit chip and a fpga chip, described fpga chip is provided with filtering treatment channel and the sample frequency generator of multiple signals interface in the corresponding A/D of the connection change-over circuit, the control mouth of described fpga chip is connected with the control mouth of central processing unit chip, the data port of central processing unit chip connects the data port of fpga chip, and fpga chip connects display.

2. a kind of rotating machinery vibrating signal of realizing according to claim 1 is with the device of step comparison-tracking analysis, it is characterized in that, be provided with the cascaded integrator-comb filter processor in the path of described filtering treatment channel corresponding keys phase pulse signal interface, be provided with the FIR digital filter processor in the path of the corresponding vibration signal interface of described filtering treatment channel.

3. a kind of device of realizing that the rotating machinery vibrating signal is analyzed with the step comparison-tracking according to claim 1 is characterized in that described multiplexed signal sampling A/D change-over circuit is that model is 16 8 passage A/D acquisition modules of AD7606.

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