CN104089775A - Bearing fault diagnosis resonance demodulator based on current mode - Google Patents
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Abstract
The invention discloses a bearing fault diagnosis resonance demodulator based on a current mode, and relates to the technical field of bearing testing devices. The bearing fault diagnosis resonance demodulator comprises a high-Q band-pass filter, an envelope peak detector and an anti-aliasing filter. Compared with a resonance demodulator based on a voltage mode, the resonance demodulator based on the current mode has the advantages of being high in speed, wide in frequency band, low in voltage and low in power consumption. On the basis of stating the resonance demodulation basic principle, the bearing fault diagnosis resonance demodulator based on the current mode is realized through an improved current conveyor CCII. The demodulator can work normally at the microamp level and under high-frequency signals and can successfully extract bearing fault signals with impact characteristics from high background noise. Computer simulation and experiment results verify that signals output by the resonance demodulator have a smaller distortion factor and a higher signal-to-noise ratio and show the correctness of the demodulator.
Description
Technical field
The present invention relates to the proving installation technical field of bearing, relate in particular to the resonance and demodulation device of the bearing failure diagnosis based on current-mode that a kind of measuring accuracy is high.
Background technology
Modern industry is produced generally towards serialization, high speed and robotization equal altitudes modernization future development, the inevitable outcome of development makes the scale of modern production system increasing like this, the function of production system is more and more stronger, and mechanical performance index is more and more higher, and the composition of equipment becomes increasingly complex.The critical movements parts of heavy mechanical equipment are carried out to on-line monitoring, fault diagnosis and failure prediction and just seem very necessary.We are in the research process of bearing failure diagnosis problem, successfully resonance demodulation technique is used for to the fault diagnosis of rolling bearing, the resonance and demodulation device of voltage mode has utilized the resonance amplification of acceleration transducer impact fault-signal, makes the fault signature after processing more obvious.Resonance and demodulation device need be introduced very strong negative feedback and realize precision rectifying link, and not only circuit element parameter coupling is had relatively high expectations but also the switching rate of device requires very strict.Be subject to the impact of the limiting factors such as impedance level, switching rate and bandwidth, when processing faint, high-frequency signal, circuit can lose rectified action.
Summary of the invention
Technical matters to be solved by this invention is to provide a kind of resonance and demodulation device of the bearing failure diagnosis based on current-mode, described resonance and demodulation device rectifying part is because working in current-mode, can overcome the impact of diode threshold voltage completely, thereby can process the signal of microampere order of magnitude or the microvolt order of magnitude, when processing feeble signal, still can present good line rectification characteristic, result is obviously superior to the homogeneous circuit of voltage mode, it is adjustable that filtering part adopts same current conveyor can realize the independence of centre frequency and quality factor, due to the consistance of device, that integrated circuit is easy to is integrated.
For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of resonance and demodulation device of the bearing failure diagnosis based on current-mode, is characterized in that described resonance and demodulation device comprises: high Q bandpass filter, envelope peak wave detector and anti-mixing filter; The input termination acceleration transducer of described high Q bandpass filter, high Q bandpass filter is connected with the input end of anti-mixing filter through envelope peak wave detector, the output termination Acquisition Instrument of anti-mixing filter, described high Q bandpass filter, envelope peak wave detector and anti-mixing filter adopt current transmission device to carry out acquisition and processing to current signal;
The fault-signal of bearing impact is wiped vibration frequency place in the installation of acceleration and has been obtained significantly strengthening, after too high Q bandpass filter, retain the signal that trouble unit is larger, and conventional interference noise is eliminated because it is distributed in low-frequency range more, wherein passband central frequency is consistent with the fixing resonance frequency of acceleration transducer; Then, the fault-signal of impact, after envelope detector, obtains one and is equivalent to the train of impulses that amplifies and widen; Finally, the interference noise that this signal is rejected remaining upper frequency through anti-mixing filter inputs to Acquisition Instrument and processes.
Further, the current input terminal first via of described high Q bandpass filter is connected with the current output terminal of current transmission device U1, and the second tunnel is through resistance R 2 ground connection; The current input terminal of current transmission device U1 is through capacitor C 1 ground connection, the voltage input end of current transmission device U1 is divided into two-way, wherein the first via is through resistance R 1 ground connection, the second tunnel is connected with the forward current output terminal of modified current transmission device U2, and the current input terminal of modified current transmission device U2 is through capacitor C 2 ground connection; The voltage output end of the current input terminal of current transmission device U1, modified current transmission device U2 is connected with inverse current output terminal, and the node after connection is the output terminal of high Q bandpass filter.
Further, the input end of described envelope peak wave detector is the voltage input end of current transmission device U3; The current output terminal of current transmission device U3 is divided into two-way, and the first via is through diode D1 and power supply V1 ground connection, and the second tunnel is through diode D2 and resistance R 4 ground connection; The current input terminal of current transmission device U3 is connected with the current input terminal of current transmission device U4 through resistance R 3, the voltage input end ground connection of current transmission device U4, the current output terminal of current transmission device U4 is divided into two-way, the first via is through diode D4 and power supply V2 ground connection, the second tunnel connects the node of diode D2 and resistance R 4 through diode D3, the node of described diode D2 and resistance R 4 is the output terminal of envelope peak wave detector.
Further, the input end of described anti-mixing filter connects the voltage input end of current transmission device U5 successively through resistance R 5 and resistance R 6, the voltage input end of current transmission device U5 is through capacitor C 3 ground connection, the current output terminal ground connection of current transmission device U5, the current input terminal of current transmission device U5 is through the node of capacitor C 4 connecting resistance R5 and resistance R 6, the output terminal that the current input terminal of current transmission device U5 is anti-mixing filter.
The beneficial effect that adopts technique scheme to produce is: described resonance and demodulation device rectifying part is because working in current-mode, can overcome the impact of diode threshold voltage completely, thereby can process the signal of microampere order of magnitude or the microvolt order of magnitude, when processing feeble signal, still can present good line rectification characteristic, result is obviously superior to the homogeneous circuit of voltage mode, it is adjustable that filtering part adopts same current conveyor can realize the independence of centre frequency and quality factor, and due to the consistance of device, that integrated circuit is easy to is integrated.
By above analysis, can learn, described resonance and demodulation device can be removed low-frequency disturbance noise effectively, extracts bearing impact fault-signal, improves the signal to noise ratio (S/N ratio) of signal of rolling bearing, the degree of distortion of reduction signal, can highlight the fault signature of bearing.Because the signal conditioning unit of resonance and demodulation device based on current-mode extracts bearing fault signal, gets rid of interference noise, make follow-up A/D sampling process and microprocessor analysis fault more accurate, be easy to realize the on-line monitoring of rolling bearing operating mode.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
Fig. 1 is theory diagram of the present invention;
Fig. 2 is the theory diagram of modified second generation current transmission device CC II;
Fig. 3 is the schematic diagram of high Q bandpass filter;
Fig. 4 is the schematic diagram of envelope peak wave detector;
Fig. 5 is the schematic diagram of anti-mixing filter;
Fig. 6 is a data converter surface chart of writing with labview software;
Fig. 7 is the schematic diagram of CC II+current transmission device;
Fig. 8 is the schematic diagram of CC II-current transmission device;
Fig. 9 is the whole simulating schematic diagram of resonance and demodulation device;
Figure 10-21st, the Output rusults sample graph of Resonance Solutions circuit.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only a part of embodiment of the present invention, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
A lot of details have been set forth in the following description so that fully understand the present invention, but the present invention can also adopt other to be different from alternate manner described here and implement, those skilled in the art can do similar popularization without prejudice to intension of the present invention in the situation that, so the present invention is not subject to the restriction of following public specific embodiment.
The defect of pointing out in order to overcome background technology, we have developed the bearing failure diagnosis resonance and demodulation device based on current-mode.This detuner has less degree of distortion and larger signal to noise ratio (S/N ratio) in processing high frequency, feeble signal, and this resonance and demodulation device is applied to bearing fault on-line monitoring, has obtained good effect.
The ultimate principle of resonance and demodulation device
The modulation of 1.1 fault-signals
Rolling bearing, normally in service, can produce two kinds of vibrations, and a kind of is conventional vibration, by bearing element material behavior, caused, as: out-of-roundness, roughness and percent ripple; Another kind is proper vibration, and by mutually colliding and cause between rolling body and the inside and outside circle of bearing, belong to mandatory vibration, natural frequency is very large, is generally 1KHz-20KHz, sometimes up to 80kHz.
At bearing, without local defect in the situation that, vibration signal is mainly conventional vibration frequency (being that axletree turns frequently) and the each harmonic composition thereof of rolling element, and fault vibration signal can be expressed as by x (t):
F
nrepresent that wheel is to turning frequently, while there is damage class fault or distribution defect on rolling bearing, bearing fault vibration signal generation modulation phenomenon.Fault bearing often circles with axle, and defect is passed through once, and amplitude modulated signal model can be expressed as
Wherein
, f
kfor bearing fault characteristics frequency.
Trouble-shooting characteristic frequency f in frequency spectrum generally
kand frequency multiplication, according to the size of fault signature spectral line spectrum value, determine whether monitored parts exist certain class fault.Due to the existence of the frequency band variation class influence factors such as stage difference that traction electric machine power input is different, fault Present site is different, fault forms, make axle f frequently
nthe function that is a change can make fault-signal resonant frequency move.This just makes signal generation aliasing and migration, and it is very complicated that barrier signal content becomes, and comprises axle f frequently
nwith fault characteristic frequency f
keach harmonic time become modulated process.
The basic comprising of 1.2 resonance and demodulation devices, as shown in Figure 1
Because bearing fault damage has shock pulse characteristic, can evoke the proper vibration (resonance) of bearing.This resonance signal can access a series of shock pulse sequences after processing by resonance and demodulation device, to carry out the subsequent treatment work of A/D conversion and microprocessor.Resonance and demodulation device mainly consists of following several parts:
(1) high Q bandpass filter: the fault-signal of impact is wiped vibration frequency place in the installation of acceleration and obtained significantly strengthening, after too high Q bandpass filter (passband central frequency is consistent with the fixing resonance frequency of acceleration transducer), retain the signal that trouble unit is larger, and conventional interference noise because being distributed in low-frequency range more, it is eliminated.
(2) envelope peak wave detector: the fault-signal of impact, after envelope detector, obtains and is equivalent to the train of impulses that amplifies and widen.
(3) anti-mixing filter: the interference noise of rejecting remaining upper frequency through this wave filter.
The principle of work of 1.3 second generation current conveyors and characteristic
Modified second generation current transmission device CC II is the active integrated device of a kind of current mode four port, as shown in Figure 2.It has adopted new technology and the complementary type bipolar technology such as unity gain buffer, current mirror and current-mode, has broad passband, high-speed and high-precision current transmission characteristic.New type of current forwarder can be realized current feedback and fall low impedance current output, thereby is conducive to cascade.Symbol X, Y represent respectively electric current and voltage input end,
with
represent two complementary current output terminals.The input of CC II, output port characteristic can be described with following hybrid matrix equation,
In fact CC II comprise simultaneously CC II+and CC II-, CC II+Z end output current is identical with X end current polarity, and CC II-Z end output current and X hold current polarity contrary.
The hardware circuit design of the resonance and demodulation device based on current-mode
1, the high Q bandpass filter of muting sensitivity
Current-mode bandpass filter as shown in Figure 3, consists of two CC II, two stake resistances and direct earth capacitance.Adopt current mirror reproduction technology to draw again an output terminal at the z of the 2nd current conveyor end, can obtain thering is the output port compared with strong current drive ability.The current transfer function that can obtain high Q bandpass filter according to Fig. 3 analysis is:
I
infor input signal, the centre frequency of wave filter
and quality factor q is respectively
with
, obviously
independent adjustable with Q.According to Calculation of Sensitivity formula
analytical calculation can obtain, and in diagram circuit, each passive element parameter is with respect to filter characteristic parameter
all meet with the sensitivity of Q
, illustrate that circuit has the low feature of sensitivity.
2, the design of envelope peak wave detector
The envelope peak wave detector being formed by two CCll+ be one with the non-linear irrelevant precision linear rectification circuit of diode, it is mainly comprised of two CCll+ modules and four diodes, as shown in Figure 4.The current conveyor of take is subject to the restriction of dV/dt as the distortion situation of basic envelope peak wave detector, and this circuit provides a kind of AB class bias voltage, makes on all diodes under zero input condition in critical conduction mode.When particularly diode D1/ D3 and D1/ D3 exchange are conducted, this condition guarantees to be presented in Z terminator impedance ratio, and whenever all low other is, improved load capacity and cascade level.
3, the design of anti-mixing filter
In measurement and control system, the transport function of the low-pass filter of widespread use is
The anti-mixing filter that this detuner adopts is second order Butterworth type low-pass filter, and as shown in Figure 5, this filter gain cutoff frequency when-3dB is its schematic circuit diagram
.Because the output impedance of wave filter is low, during multi-section serial, do not need isolation level, and feeble signal is had to amplification.
3 experimental demonstrations
3.1 Data Source
In the present embodiment, fault data derives from the rolling bearing that model is 352226x2-2RZ, and its each main structure parameters is as table 1.Experiment collecting device adopts the INV36DF signal sampler of Beijing vibration and noise technique Research Institute.
Table 1 352226x2-2RZ profile shaft holds important technological parameters
| Central diameter D/mm | Roller diameter d/mm | Contact angle α/° | Roller number z |
| 176.29 | 24.74 | 8.833 | 20 |
Inner peripheral surface damage is mainly chosen in experiment, peel off outer ring has carried out feature extraction with rolling body galvanic corrosion three quasi-representative faults, and wherein, the first has occurred pit at rolling bearing inner ring, and diameter is about 18mm, belongs to inner peripheral surface damage class fault.The second, one of them roller surface of rolling bearing has a 5mm strip evidence of corrosion, belongs to rolling body galvanic corrosion class fault.The third, several, housing washer surface paint body peels off situation, belongs to outer ring and peels off class fault.
3.2 hardware experiments circuit are built
3.2.1multisim the signal of the resonance and demodulation circuit based on current-mode under environment input
In order to test the detection effect of resonance and demodulation device, need input signal, by labview power module by the actual True Data input circuit of adopting.We are by utilizing acceleration transducer that actual signal is recorded and is kept in TXT file, then will in this signal input circuit, analyze Output rusults.
The signal format that it should be noted that I1 input is xx.lvm.Conventionally the data that experiment is adopted are xx.txt forms, so wanted translation data form before input actual samples signal, Fig. 6 is a data converter of writing with labview software.
3.2.2 Modified current conveyor CC II builds
In order to meet the demand of frequency band, switching rate and the DC and AC characteristics of circuit design, experiment adopts on the market the current feedback high speed operation amplifier AD844 of better performances to build CC II+and CC II-structure, CC II+as shown in Figure 7, CC II-as shown in Figure 8
.
3.3.3 simulation parameter is set
Build the resonance and demodulation device practical circuit based on current-mode, comprising centre frequency is that 4.5khz bandwidth is the bandpass filter of 1k, envelope detection circuit based on current-mode and Anti-aliasing Filter Circuits and corresponding anti-jamming circuit, whole circuit simulation structure as shown in Figure 9.
3.3.4 rolling bearing interpretation
During experiment, rolling bearing only has place's fault, and other parts are normal, and rotating speed is 467r/s, and equipment sample frequency is 51200Hz, and the sampling time is 10s.By the Output rusults of the Resonance Solutions circuit to through based on current-mode, do fft analysis and just obtain the experimental result of Figure 10-21 below.
What feature Figure 10 Central Plains signal waveform do not see; Original signal obtains Figure 11 after bandwidth-limited circuit, and Figure 11 has mainly intercepted the resonance paragraph of 4.5Khz, does not also see fault signature; Former letter obtains its envelope signal after envelope detection circuit, to envelope signal, asks envelope spectrum to obtain Figure 12, and Figure 12 intermediate frequency spectrum concentration of energy, below 800Hz, effectively eliminated the impact of high-frequency carrier signal, but fault signature is not obvious; Envelope signal input frequency overlapped-resistable filter, result is carried out to fft analysis and obtain Figure 13, Figure 13 has obvious crest at frequency 68.3747Hz place, and occurs frequently and also occurred crest 2 frequencys multiplication and 3 times, and known 68Hz is fault characteristic frequency.
For the ease of observing, by Figure 15-17, the result of Figure 19-21 only shows that 0-800Hz is with interior part.All there is obvious crest at 90Hz, 180Hz and 270Hz frequency place in Figure 17, known 83Hz is outer ring and peels off class bearing fault characteristic frequency.All there is obvious crest at 27.5Hz, 55Hz and 82.5Hz frequency place in Figure 21, known 27.5Hz is rolling body galvanic corrosion class bearing fault characteristic frequency.
In sum, there is obvious crest through the signal spectrum after the resonance and demodulation device based on current-mode at fault characteristic frequency place in signal of rolling bearing, has verified the applicability of this detuner.
(1) the resonance and demodulation device based on current-mode can be removed low-frequency disturbance noise effectively, extracts impact fault-signal, improves the noise acoustic ratio of signal of rolling bearing, the degree of distortion of reduction signal, can highlight the fault signature of bearing.
(2) because the signal conditioning unit of resonance and demodulation device based on current-mode extracts bearing fault signal, gets rid of interference noise, make follow-up A/D sampling process and microprocessor analysis fault more accurate, be easy to realize the on-line monitoring of rolling bearing operating mode.
Claims (4)
1. the resonance and demodulation device of the bearing failure diagnosis based on current-mode, is characterized in that described resonance and demodulation device comprises: high Q bandpass filter, envelope peak wave detector and anti-mixing filter; The input termination acceleration transducer of described high Q bandpass filter, high Q bandpass filter is connected with the input end of anti-mixing filter through envelope peak wave detector, the output termination Acquisition Instrument of anti-mixing filter, described high Q bandpass filter, envelope peak wave detector and anti-mixing filter adopt current transmission device to carry out acquisition and processing to current signal;
The fault-signal of bearing impact is wiped vibration frequency place in the installation of acceleration and has been obtained significantly strengthening, after too high Q bandpass filter, retain the signal frequency range that trouble unit is larger, and conventional interference noise is eliminated because it is distributed in low-frequency range more, wherein passband central frequency is consistent with the fixing resonance frequency of acceleration transducer; Then, the signal of bandpass filter intercepting, after envelope detector, obtains one and is equivalent to the train of impulses that amplifies and widen; Finally, the interference noise that this signal is rejected remaining upper frequency through anti-mixing filter inputs to Acquisition Instrument and processes.
2. the resonance and demodulation device of the bearing failure diagnosis based on current-mode according to claim 1, is characterized in that: the current input terminal first via of described high Q bandpass filter is connected with the current output terminal of current transmission device U1, and the second tunnel is through resistance R 2 ground connection; The current input terminal of current transmission device U1 is through capacitor C 1 ground connection, the voltage input end of current transmission device U1 is divided into two-way, wherein the first via is through resistance R 1 ground connection, the second tunnel is connected with the forward current output terminal of modified current transmission device U2, and the current input terminal of modified current transmission device U2 is through capacitor C 2 ground connection; The voltage output end of the current input terminal of current transmission device U1, modified current transmission device U2 is connected with inverse current output terminal, and the node after connection is the output terminal of high Q bandpass filter.
3. the resonance and demodulation device of the bearing failure diagnosis based on current-mode according to claim 1, is characterized in that: the input end of described envelope peak wave detector is the voltage input end of current transmission device U3; The current output terminal of current transmission device U3 is divided into two-way, and the first via is through diode D1 and power supply V1 ground connection, and the second tunnel is through diode D2 and resistance R 4 ground connection; The current input terminal of current transmission device U3 is connected with the current input terminal of current transmission device U4 through resistance R 3, the voltage input end ground connection of current transmission device U4, the current output terminal of current transmission device U4 is divided into two-way, the first via is through diode D4 and power supply V2 ground connection, the second tunnel connects the node of diode D2 and resistance R 4 through diode D3, the node of described diode D2 and resistance R 4 is the output terminal of envelope peak wave detector.
4. the resonance and demodulation device of the bearing failure diagnosis based on current-mode according to claim 1, it is characterized in that: the input end of described anti-mixing filter connects the voltage input end of current transmission device U5 successively through resistance R 5 and resistance R 6, the voltage input end of current transmission device U5 is through capacitor C 3 ground connection, the current output terminal ground connection of current transmission device U5, the current input terminal of current transmission device U5 is through the node of capacitor C 4 connecting resistance R5 and resistance R 6, the output terminal that the current input terminal of current transmission device U5 is anti-mixing filter.
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| CN106198070A (en) * | 2016-06-28 | 2016-12-07 | 湖南科技大学 | Automatic resonance and demodulation device based on switch-capacitor filtering |
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