CN110146449A - A kind of air compressor cylinder body face crack online test method and system based on laser-ultrasound - Google Patents
A kind of air compressor cylinder body face crack online test method and system based on laser-ultrasound Download PDFInfo
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- CN110146449A CN110146449A CN201910460629.7A CN201910460629A CN110146449A CN 110146449 A CN110146449 A CN 110146449A CN 201910460629 A CN201910460629 A CN 201910460629A CN 110146449 A CN110146449 A CN 110146449A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01N29/04—Analysing solids
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/4409—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by comparison
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
- G01N2021/1706—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in solids
Abstract
The present invention discloses a kind of air compressor cylinder body face crack online test method and system based on laser-ultrasound, detection method step are as follows: (1) pulse laser generator issues laser beam, laser beam is incident on cylinder surface to be detected and generates detection ultrasonic signal, (2) laser interferometer issues detection light beam, and detection beam reception detects ultrasonic signal；(3) detection amplified be transferred to after high-speed data acquisition card is handled of ultrasonic signal is transferred to data analysis system again；(4) data analysis system carries out image checking to detection ultrasonic signal；(5) it will test result real-time display.On-line detecting system includes PLC controller, laser interferometer, high-speed data acquisition card, data analysis system, display screen, laser pulse generator and optical path adjusting system etc..Detection method has the advantages that Entirely contactless formula, detection efficiency and precision are high, testing result is intuitive in the application, and detection system can be realized online, real-time, quick, the accurate detection of cylinder surface crackle.
Description
Technical field
The present invention relates to detection technique fields, in particular, being related to a kind of air compressor cylinder body surface based on laser-ultrasound
Crackle online test method and system.
Background technique
Air compressor (abbreviation air compressor machine) is a kind of power-equipment for generating compressed air, and air compressor machine can be by free sky
Air pressure is reduced to required pressure, to drive pneumatic equipment, such as air drill, grab loader, geomantic omen pump, pneumatic hammer, is widely used in handing over
The fields such as logical transport, weaving, food, derived energy chemical and pharmacy.Air compressor cylinder body generally by grey iron casting, be process, wrap
Containing upper and lower two parts.Upper and lower two parts are located by connecting by positioning pin and bolt.When work, air compressor cylinder body need to continue to bear high
Temperature, high pressure gas effect, thus it is extremely stringent to upper and lower cylinder surface and joint face finish, planarity requirements.In fact,
In casting and process, easily there is sand hole or fatigue crack in air compressor cylinder body surface, if cannot be in time to these crackles
It is detected, and takes the necessary measures and repair, crackle can slowly extend, and then influence single cylinder or even whole equipment system
Stability and safety, in some instances it may even be possible to lead to catastrophic burst consequence, cause huge economic loss.For safety and warp
Ji demand carries out detection to air compressor cylinder body face crack and is extremely important.
Domestic and international existing air compressor cylinder body surface crack testing method is broadly divided into two classes: contact measurement with it is contactless
Detection.Contaction measurement method mainly includes ultrasound examination, Magnetic testing, ray detection etc., non-contact detection method master
Will include infrared detection, camera imaging detect etc., wherein contaction measurement method because detection efficiency it is low, may to detection pair
As cause damage, it is unfriendly to environment the disadvantages of gradually substituted by non-contact detecting.Contaction measurement method low efficiency be because
For in measurement process sensor to be contacted with measurand, be unable to reach on-line checking purpose；Sensor when detecting, in order to
Signal-to-noise ratio is improved, needs the daubing coupling agent in measurand, couplant typically belongs to organic solvent, and it is to be measured right to corrode
As；And sensor surface is also easy to scratch subject surface to be measured, and detection is caused to damage.And Magnetic testing, ray detection are to people
Body harm is larger, these methods have been given it up mostly in factory.In non-contact detection method, at present using more
It is that infrared detection and camera imaging detect.Infrared detection is recorded on checked object surface by scanning since defect or material are different
Thermal property caused by temperature change carry out Identification of Cracks, but this method is by environment temperature, measurand surface temperature
It is affected, is easy to generate measurement error.In addition, camera imaging detection has high requirement to test environment, such as light intensity,
And because of imaging pixel reason, it is difficult to the detection for realizing fine cracks in larger area of detection, certain occasions its application also by
Certain restrictions is arrived.
In consideration of it, the air compressor cylinder body face crack online test method that it is necessary to provide a kind of based on laser-ultrasound and being
System.
Summary of the invention
It is an object of the invention to overcome the above deficiencies in the existing technologies, and provide a kind of Entirely contactless formula,
Can be achieved on-line checking, to object to be measured and it is environmental-friendly, detection efficiency is high, detection accuracy is high and testing result is intuitively visual
The air compressor cylinder body face crack online test method based on laser-ultrasound, and provide a kind of air compressor machine based on laser-ultrasound
Cylinder surface crackle on-line detecting system, the system can be realized the online, real-time, quick, smart of air compressor cylinder body face crack
Really detection.
Technical solution used by the present invention solves the above problems is: a kind of air compressor cylinder body surface based on laser-ultrasound
Crackle online test method, it is characterised in that: steps are as follows:
Step 1: pulse laser generator launches high energy pulse laser beam, high energy pulse laser beam is through optical path adjusting system
System is divided into two bundles: first laser beam is incident on the Scanning Detction point of cylinder surface to be detected, and excites and produce in the Scanning Detction point
Raw laser ultrasonic signal, the laser ultrasonic signal are radiation center to four as detection ultrasonic signal and using Scanning Detction point
Week diffusion；Second laser beam is incident on the enabled mouth of high-speed data acquisition card, and high-speed data acquisition card is made to enter working condition；
Step 2: laser interferometer issues detection light beam, which is incident on a fixation of cylinder surface to be detected
Point, the fixed point are not overlapped with any Scanning Detction point, detect the detection ultrasonic signal in the beam reception first step；
Step 3: the signal output end of laser interferometer is connected with signal amplifier input terminal, laser interferometer first will
Collected detection ultrasonic signal is transmitted to signal amplifier, then will test ultrasonic signal transmission after signal amplifier amplifies
High-speed sampling is carried out to high-speed data acquisition card to handle to obtain sampled signal, and sampled signal is finally transferred to data analysis system
It is analyzed and processed；
Step 4: data analysis system carries out image checking to collected detection ultrasonic signal；
Step 5: by image checking result real-time display on a display screen.
Preferably, the optical path adjusting system includes the first convex lens, spectroscope, the second convex lens and scanning galvanometer；
First convex lens is placed on the high energy pulse laser beam optical path that pulse laser generator is launched, and is used to high energy pulse
Laser beam is focused；The spectroscope is placed at the focal position of the first convex lens, and spectroscope is by incident high energy pulse
Laser beam is divided into the first laser beam of horizontal direction transmission and the second laser beam of vertical direction transmission；First laser beam is by the
Two convex lenses are incident on the center of scanning galvanometer after focusing, the scanning galvanometer control first laser beam is existed with certain speed
It is scanned incidence in cylinder surface a certain range to be detected, incident first laser beam is scanned in cylinder surface to be measured and excites production
Raw laser ultrasonic signal；Second laser beam is transmitted to the enabled mouth of high-speed data acquisition card by optical fiber, adopts high-speed data
Truck enters working condition.
Preferably, the eyeglass inside the scanning galvanometer is freely overturn in the angular region of 20 ° of space by setting rate, thus
The incident first laser beam of control is transmitted to the Scanning Detction point of cylinder surface to be detected by certain path.
Preferably, the laser beam spot diameter for being incident on scanning galvanometer center is 0.1mm.
Preferably, when scanning galvanometer control detection light beam treats detection cylinder surface and is scanned detection, road is scanned
Diameter is period shape square wave, and distance is 0.1mm between adjacent two scanning element.
Preferably, described step 4: data analysis system to it is collected detection ultrasonic signal carry out image checking tool
Body step are as follows:
(1) preliminary noise reduction process is carried out to the collected detection ultrasonic signal of institute first, to remove ambient noise, raising is adopted
Collect Signal-to-Noise；
(2) extract institute it is collected detect ultrasonic signal in by cylinder surface crackle non-linear modulation function influence characteristic
Value, and then according to characteristic value knots modification inverting crack information；
(3) imaging is carried out according to crack information.
Preferably, in described (2) step, the specific steps of inverting crack information are as follows:
1) speed and acceleration of the laser interferometer acquisition air compressor cylinder body after by incident laser ultrasonic exciting；
2) phase space for characterizing air compressor cylinder body dynamic characteristic, phase space are constructed according to speed and acceleration
Each of point all one by one map cylinder body a kind of behavioral characteristics, and these points in phase space along specific trajectory line move
It is dynamic, one or more specified point positions in phase space finally all can be gradually converged to along trajectory line, which is referred to as
Singular point in phase space；The phase space is a hyperspace to indicate practical all possible states of cylinder body,
The hyperspace is made of each dimension motion vector of the practical cylinder body, for example cylinder body phase space can be swashed by cylinder body by incidence
Speed and acceleration after light ultrasonic exciting are reconstructed, and laser interferometer can collect the speed of cylinder body response
Degree and acceleration, signal collected laser interferometer is vector signal needed for reconstruct cylinder body phase space；
3) cylinder body dynamic characteristic is obtained by the trend of the point set moving rail trace in phase space, when cylinder body is cracked,
The trajectory line that the point set of characterization cylinder body dynamic characteristic converges to singular point in cylinder body phase space can change, specific by defining
Characteristic ginseng value define knots modification, and it is it is associated with crack information, so that it may inverting obtains crack information, wherein
The characteristic ginseng value for describing the point set trajectory line knots modification in cylinder body phase space is Pasteur's distance (Bhattacharyya
Distance, BD).
Preferably, the method for extracting characteristic ginseng value Pasteur distance BD is as follows:
(1) preparing one piece of surface first does not have the cylinder body of crackle, and the cylinder body of crackle not can use electron microscope pair
Cylinder surface is checked to obtain；
(2) there is no response signal of the cylinder body of crackle under laser-ultrasound incentive action using laser interferometer measurement；
(3) phase space that the not cylinder body of crackle is rebuild according to collected response signal, referred to herein as intact cylinder body
Phase space；
(4) Q basic point y (i) is randomly selected from the point set motion profile of intact cylinder body phase space, wherein i=1,2 ...,
Q should make to predict that error calculation value is not changed interference by its points when choosing Q value；
Wherein Q=N/100, N are the corresponding data points that high-speed data acquisition card measurement obtains；
(5) response signal of cylinder body to be measured, and phase space reconstruction are acquired using laser interferometer, in the phase space point set rail
It is that each basic point y (i) finds P space point of proximity x (j) on mark, wherein j=1,2 ..., P, the selection of space point of proximity x (j)
It is directly chosen according to Euclidean distance, i.e., distance y (i) nearest each point will be taken as point of proximity in trajectory line；P value, which is chosen, to be needed really
Protecting attractor local feature can be characterized completely, while calculated value is insensitive to ambient noise, and taking P=N/1000, N is height
The corresponding data points that fast data collecting card measurement obtains；
(6) by each basic point and point of proximity along respective track advance L step pitch from this point, each point of proximity matter of point y (i)
The heart indicates are as follows:
Calculating prediction error value PE indicates are as follows:
Characteristic ginseng value Pasteur's distance BD can be indicated are as follows:
Wherein u, δ are respectively the mean value and variance of prediction error value PE, subscript b, c respectively indicate intact cylinder body phase space with
Cylinder body phase space to be measured；
(7) know that crackle is smaller by formula (1-2), two phase space Point Set motion profiles are more similar, and PE value is smaller, and BD is calculated
Value also just it is smaller, according to practical BD calculated value can inverting obtain crack information value.
Preferably, the image processing method step are as follows:
Firstly, carrying out cycle square wave Scanning Detction to cylinder surface to be measured using scanning galvanometer control first laser beam, sweep
During retouching, in cylinder surface fixed point to be measured, the fixed point and first swashs the detection beam irradiation that laser interferometer issues
Any Scanning Detction point of light beam is not overlapped；
Then, the response signal on each Scanning Detction point of cylinder surface to be measured is acquired using laser interferometer, and then by
One calculates the BD value of each point,
Finally, characterizing each point BD value size degree using shade degree, imaging can be carried out to crackle.
In order to solve the above technical problems, the present invention also provides another technical solutions: a kind of air compressor machine based on laser-ultrasound
Cylinder surface crackle on-line detecting system, it is characterised in that: including PLC controller, cylinder body conveyer, driving motor, detection work
Make platform, laser interferometer, signal amplifier, high-speed data acquisition card, data analysis system, display screen and is integrated with laser pulse
The detection of generator and optical path adjusting system controls box.The cylinder body conveyer and driving motor are arranged in the case where detecting workbench
Side, driving motor drivig cylinder conveyer, cylinder body conveyer are used to be delivered to cylinder body to be detected immediately below detection workbench
Detection station, the laser interferometer and detection control box are arranged on detection workbench；The optical path adjusting system includes
First convex lens, spectroscope, the second convex lens and scanning galvanometer；First convex lens is placed on pulse laser generator hair
On the high energy pulse laser beam optical path of injection, for being focused to high energy pulse laser beam；The spectroscope is placed on first
At the focal position of convex lens, spectroscope by incident high energy pulse laser beam be divided into the first laser beam of horizontal direction transmission with
The second laser beam of vertical direction transmission；First laser beam is incident on the centre bit of scanning galvanometer after the focusing of the second convex lens
Set, scanning galvanometer control first laser beam be scanned in cylinder surface a certain range to be detected with certain speed into
It penetrates, generation laser ultrasonic signal can be excited in cylinder surface to be measured by scanning incident first laser beam；Second laser beam passes through
Optical fiber is transmitted to the enabled mouth of high-speed data acquisition card, and high-speed data acquisition card is made to enter working condition；The laser interferometer
Light beam is detected for issuing, which is incident on a fixed point of cylinder surface to be detected, and detection light beam acquisition laser is super
Acoustic signals, the signal output end of laser interferometer are connected with the signal input part of signal amplifier；The signal amplifier can
To amplify the collected laser ultrasonic signal of laser interferometer, and it is transmitted to high-speed data acquisition card entrance；At a high speed
Data collecting card can carry out high-speed sampling to amplified signal, and will acquire data transmission to data analysis system；The data point
Analysis system and display screen communicate to connect, and data analysis system will inspection after carrying out analytical calculation to collected laser ultrasonic signal
It surveys result and is transmitted to display screen；The PLC controller and driving motor, laser interferometer and the equal communication link of laser pulse generator
It connects.
Compared with prior art, the present invention having the following advantages that and effect:
1, detect the excitation of signal and receive all can long-range non-contact realization, therefore entire detection process is contactless
, and the energy density of incoming laser beam can control 107W/cm2Once, not damaged to cylinder surface to be measured, it may be implemented
The online non-destructive testing of cylinder body；
2, the use of scanning galvanometer, which ensures to detect light beam, can quickly be incident on cylinder surface any position to be measured, therefore be
Scanning Detction speed of uniting is fast, detection efficiency is high；
3, laser pulse generator and the optical path adjusting system integration can ensure that detection control box in a detection control box
Interior optical path fix stably effectively prevents shaking the influence to optical path；
4, detection Light beam spot diameter is small, and distance is small between adjacent two detection laser beams scanning element, extracted characteristic parameter
BD is more sensitive to micro-crack, so that system detection precision is high；
5, crack detection results real-time visual can be shown on a display screen, facilitate the convenient and efficient judgement of testing staff
Testing result；
6, this detection method has Entirely contactless formula, on-line checking can be achieved, to object to be measured and environmental-friendly, detection
High-efficient, detection accuracy is high and the intuitive visual advantage of testing result；
7, this on-line detecting system perfect in shape and function, can be realized air compressor cylinder body face crack it is online, real-time, quick,
Accurate detection.
Detailed description of the invention
Fig. 1 is the schematic perspective view of air compressor machine cylinder surface crackle on-line detecting system in the embodiment of the present invention.
Fig. 2 is that the stereochemical structure of the pallet in the embodiment of the present invention in air compressor machine cylinder surface crackle on-line detecting system is shown
It is intended to.
Fig. 3 is optical path adjusting system structure schematic diagram in the embodiment of the present invention.
Fig. 4 is the practical air compressor cylinder body surface sand hole defect shot using Keyemce electron microscope and fatigue crack
Figure.
Fig. 5 is the ultrasonic wave response diagram of laser interferometer measurement cylinder body in the embodiment of the present invention, and wherein Fig. 5 (a) is surface
The ultrasonic wave response diagram of intact cylinder body without crackle, if Fig. 5 (b) is cylinder body ultrasonic wave response diagram of the surface containing crackle.
Fig. 6 is by the characterization air compressor cylinder body dynamic that utilizes laser ultrasonic response signal figure to reconstruct in the embodiment of the present invention
The phase space plot of characteristic, wherein Fig. 6 (a) is the intact cylinder body phase space reconfiguration figure that surface is free of crackle, and Fig. 6 (b) contains for surface
The cylinder body phase space reconfiguration figure of crackle.
Fig. 7 is that practical air compressor cylinder body surface sand hole defect and fatigue crack detect image in the embodiment of the present invention.
Description of symbols: cylinder body conveyer 1, driving motor 2, pallet 3, positioning pin 31, positioning bolt 32, cylinder to be detected
Body 4, detection control box 5, laser interferometer 6, high-speed data acquisition card 7, data analysis system 8, display screen 9, detection workbench
10, the first convex lens 11, spectroscope 12, the second convex lens 13.
Specific embodiment
The present invention is described in further detail with reference to the accompanying drawing and by embodiment, and following embodiment is to this hair
Bright explanation and the invention is not limited to following embodiments.
Embodiment.
Referring to Fig. 1 to Fig. 7.
In the present embodiment, the air compressor cylinder body face crack on-line detecting system based on laser-ultrasound include PLC controller,
Cylinder body conveyer 1, driving motor 2, detection workbench 10, laser interferometer 6, high-speed data acquisition card 7, data analysis system 8,
Display screen 9 and the detection control box 5 for being integrated with laser pulse generator and optical path adjusting system.
Cylinder body conveyer 1 and driving motor 2 setting detection workbench 10 below, cylinder body conveyer 1 by driving motor 2 into
Row driving, cylinder body conveyer 1 are used to for cylinder body 4 to be detected to be delivered to the detection station immediately below detection workbench 10, detect work
It is provided at position close to switch, the pallet 3 for support cylinder body 4 to be detected is provided on cylinder body conveyer 1, is arranged on pallet 3
There are the positioning pin 31 and positioning bolt 32 to cylinder body 4 to be detected positioning.
Laser interferometer 6 and detection control box 5 are arranged on detection workbench 10.PLC controller and close switch pass
Dynamic motor 2, laser interferometer 6 and laser pulse generator communicate to connect.Laser pulse generator is the generation of Nd:YAG laser
Device, laser interferometer 6 are API-XD laser interferometer.
Cylinder body conveyer 1 belongs to a station on air compressor machine process line, when cylinder body 4 to be detected completes a upper station
Processing tasks, under the control of PLC controller, driving motor 2 starts running, and cylinder body conveyer 1 starts turning, and drives pallet 3
And be placed on the cylinder body to be detected 4 of the top of pallet 3 while moving, cylinder body 4 to be detected above pallet 3 by positioning pin 31 and
Positioning bolt 32 is positioned, is fixed, and when pallet 3 drives cylinder body 4 to be detected to reach detection station, is placed on connecing for detection station
Nearly switch is triggered, and sends high level signal to PLC controller close to switch, PLC controller sends instruction control driving motor 2
Stop motion, pallet 3 and cylinder body to be detected 4 thereon just stop at the fixed position of detection station, and cylinder surface crackle is waited to exist
Line detection.
Optical path adjusting system includes the first convex lens 11, spectroscope 12, the second convex lens 13 and scanning galvanometer.Laser arteries and veins
High energy pulse laser beam can be emitted under the effect of the high level pulse of PLC controller by rushing generator, and the first convex lens 11 is placed
On the high energy pulse laser beam optical path that pulse laser generator is launched, for being focused to high energy pulse laser beam；Point
Light microscopic 12 is placed at the focal position of the first convex lens 11, and incident high energy pulse laser beam is divided into level side by spectroscope 12
The second laser beam transmitted to the first laser beam and vertical direction of transmission.
First laser beam is incident on the center of scanning galvanometer, scanning galvanometer control after the focusing of the second convex lens 13
First laser beam is scanned incidence in 4 surface a certain range of cylinder body to be detected with certain speed, scans incident second and swashs
Light beam excites in cylinder surface to be measured and generates laser ultrasonic signal.Second laser beam is transmitted to high-speed data acquisition by optical fiber
The enabled mouth of card 7 makes high-speed data acquisition card 7 enter working condition.
Eyeglass inside scanning galvanometer is freely overturn in the angular region of 20 ° of space by setting rate, to control incidence
First laser beam is transmitted to the Scanning Detction point on 4 surface of cylinder body to be detected by certain path.It is incident on scanning galvanometer center
Laser beam spot diameter be 0.1mm.Scanning galvanometer control detection light beam treats detection 4 surface of cylinder body when being scanned detection,
Scan path is period shape square wave, and distance is 0.1mm between adjacent two scanning element.
Laser interferometer 6 is incident on a fixation on 4 surface of cylinder body to be detected for issuing detection light beam, the detection light beam
Point, detection light beam acquire laser ultrasonic signal, the signal output end of laser interferometer 6 and the signal input part of signal amplifier
It is connected；The signal amplifier can amplify the collected laser ultrasonic signal of laser interferometer 6, and be transmitted to height
Fast 7 entrance of data collecting card, the amplification factor of signal amplifier are 40dB；High-speed data acquisition card 7 can carry out amplified signal
High-speed sampling, and data transmission will be acquired to data analysis system 8, the sample frequency of high-speed data acquisition card 7 is 100MHz, can
It is corresponding with laser-ultrasound high-frequency domain characteristic to meet high frequency sample requirement；Data analysis system 8 and display screen 9 communicate to connect,
Data analysis system 8 will test result and be transmitted to display screen 9 after carrying out analytical calculation to collected laser ultrasonic signal.
In the present embodiment, using the method for above-mentioned on-line detecting system progress air compressor cylinder body face crack on-line checking
Step are as follows:
Step 1: the cylinder body of practical sand hole defect and fatigue crack is contained as cylinder body 4 to be detected in one surface of selection, it is somebody's turn to do
The real image of cylinder surface sand hole defect and fatigue crack is as shown in figure 4, Fig. 4 is shot to obtain by Keyemce electron microscope；
Step 2: successively opening data analysis system 8, pulse laser generator, laser interferometer 6, display screen 9, PLC control
The power supply of device processed, initialization scan galvanometer and high-speed data acquisition card 7 control transport motor 2 by PLC controller and start to turn
It is dynamic, it drives pallet 3 and cylinder body to be measured 4 to reach detection station, triggers close to switch, send high level close to switch and controlled to PLC
Device, subsequent PLC controller stop driving motor 2, and pallet 3 and cylinder body to be measured 4 is made to be parked in detection station, at the same PLC controller to
Pulse laser generator sends instruction；
Step 3: pulse laser generator launches high energy pulse laser beam, high energy pulse laser beam is through the first convex lens
11 focus after be incident on spectroscope 12, what incident high energy pulse laser beam was divided into horizontal direction transmission by spectroscope 12 first swashs
The second laser beam of light beam and vertical direction transmission；First laser beam is incident on scanning galvanometer after the focusing of the second convex lens 13
Center, scanning galvanometer control first laser beam week is carried out in 4 surface a certain range of cylinder body to be detected with certain speed
The scanning of phase square wave is incident, scans incident first laser beam and excites generation laser super at the Scanning Detction point of cylinder surface to be measured
Acoustic signals, the laser ultrasonic signal are around spread as detection ultrasonic signal and using Scanning Detction point as radiation center；
Second laser beam is incident on the enabled mouth of high-speed data acquisition card 7, and high-speed data acquisition card 7 is made to enter working condition；
Step 4: laser interferometer 6 issues detection light beam, which it is one solid to be incident on 4 surface of cylinder body to be detected
Fixed point, the fixed point are not overlapped with any Scanning Detction point, and detection beam reception detects ultrasonic signal；
Step 5: the signal output end of laser interferometer 6 is connected with signal amplifier input terminal, laser interferometer 6 is first
Collected detection ultrasonic signal is transmitted to signal amplifier, then will test ultrasonic signal biography after signal amplifier amplifies
It is defeated to handle to obtain sampled signal to the progress of high-speed data acquisition card 7 high-speed sampling, sampled signal is finally transferred to data analysis
System 8 is analyzed and processed；
Step 6: data analysis system 8 carries out image checking to collected detection ultrasonic signal；
Step 7: by image checking result on display screen 9 real-time display.
In the present embodiment, in the 6th step, data analysis system 8 carries out image checking to collected detection ultrasonic signal
Specific steps are as follows:
(1) preliminary noise reduction process is carried out to the collected detection ultrasonic signal of institute first, to remove ambient noise, raising is adopted
Collect Signal-to-Noise；
(2) extract institute it is collected detect ultrasonic signal in by cylinder surface crackle non-linear modulation function influence characteristic
Value, and then according to characteristic value knots modification inverting crack information；
(3) imaging is carried out according to crack information.
Wherein, in (2) step, the specific steps of inverting crack information are as follows:
1) laser interferometer 6 acquires speed and acceleration of the air compressor cylinder body after by incident laser ultrasonic exciting；
2) phase space for characterizing air compressor cylinder body dynamic characteristic, phase space are constructed according to speed and acceleration
Each of point all one by one map cylinder body a kind of behavioral characteristics, and these points in phase space along specific trajectory line move
It is dynamic, one or more specified point positions in phase space finally all can be gradually converged to along trajectory line, which is referred to as
Singular point in phase space；
3) cylinder body dynamic characteristic is obtained by the trend of the point set moving rail trace in phase space, when cylinder body is cracked,
The trajectory line that the point set of characterization cylinder body dynamic characteristic converges to singular point in cylinder body phase space can change, and (being specifically described can join
Examine document: Nichols J M.Using state space predictive modeling with chaotic
interrogation in detecting joint preload loss in a frame structure experiment
[J] .Smart Materials&Structures, 2003,12 (4): 580-601.), by defining specific characteristic ginseng value
Define knots modification, and it is associated with crack information, so that it may which inverting obtains crack information, wherein it is mutually empty to describe cylinder body
Between in point set trajectory line knots modification characteristic ginseng value be Pasteur distance (Bhattacharyya Distance, BD).
The method for extracting characteristic ginseng value Pasteur distance BD is as follows:
(1) preparing one piece of surface first does not have the cylinder body of crackle, and the cylinder body of crackle not can use electron microscope pair
Cylinder surface is checked to obtain；
(2) response signal of the cylinder body of not crackle under laser-ultrasound incentive action is measured using laser interferometer 6；Such as
Fig. 5 (a) is the ultrasonic wave response diagram of intact cylinder body of the surface without crackle；
(3) phase space that the not cylinder body of crackle is rebuild according to collected response signal, referred to herein as intact cylinder body
Phase space；If Fig. 6 (a) is the intact cylinder body phase space reconfiguration figure that surface is free of crackle；
(4) Q basic point y (i) is randomly selected from the point set motion profile of intact cylinder body phase space, wherein i=1,2 ...,
Q should make to predict that error calculation value is not changed interference by its points when choosing Q value；
Wherein Q=N/100, N are that high-speed data acquisition card 7 measures obtained corresponding data points；
(5) response signal of cylinder body 4 to be detected, and phase space reconstruction are acquired using laser interferometer 6, if Fig. 5 (b) is table
Cylinder body ultrasonic wave response diagram of the face containing crackle, 6 (b) be cylinder body phase space reconfiguration figure of the surface containing crackle；In the phase space point set
It is that each basic point y (i) finds P space point of proximity x (j) on track, wherein j=1,2 ..., P, the choosing of space point of proximity x (j)
It takes and is directly chosen according to Euclidean distance, i.e., distance y (i) nearest each point will be taken as point of proximity in trajectory line；P value, which is chosen, to be needed
Ensure that attractor local feature can be characterized completely, while calculated value is insensitive to ambient noise, takes P=N/1000, the N to be
High-speed data acquisition card 7 measures obtained corresponding data points；
(6) by each basic point and point of proximity along respective track advance L step pitch from the value of L takes 2, at this point, point y's (i) is each
Point of proximity mass center indicates are as follows:
Calculating prediction error value PE indicates are as follows:
Characteristic ginseng value Pasteur's distance BD can be indicated are as follows:
Wherein u, δ are respectively the mean value and variance of prediction error value PE, subscript b, c respectively indicate intact cylinder body phase space with
4 phase space of cylinder body to be detected；
(7) know that crackle is smaller by formula (1-2), two phase space Point Set motion profiles are more similar, and PE value is smaller, and BD is calculated
Value also just it is smaller, according to practical BD calculated value can inverting obtain crack information value.
Image processing method step are as follows:
Firstly, cycle square wave Scanning Detction is carried out to 4 surface of cylinder body to be detected using scanning galvanometer control first laser beam,
In scanning process, the detection beam irradiation that laser interferometer 6 issues in 4 surface fixed point of cylinder body to be detected, the fixed point and
Any Scanning Detction point of first laser beam is not overlapped；
Then, the response signal on each Scanning Detction point in 4 surface of cylinder body to be detected is acquired using laser interferometer 6, into
And the BD value of each point is calculated one by one,
Finally, characterizing each point BD value size degree using shade degree, it is up to red, minimum blue
Imaging is carried out to crackle, as shown in Figure 7.
The red area from being apparent that two in Fig. 7, respectively represents sand hole defect and fatigue crack defect, in Fig. 7
Defective locations, shape and trend are almost the same with actual crack Fig. 4 at two, in this way, the air compressor cylinder body surface sand hole defect
And fatigue crack is just detected.
It is any ripe although the present invention is disclosed as above with embodiment, its protection scope being not intended to limit the invention
The technical staff for knowing this technology changes and retouches made without departing from the spirit and scope of the invention, should belong to this
The protection scope of invention.
Claims (10)
1. a kind of air compressor cylinder body face crack online test method based on laser-ultrasound, it is characterised in that: steps are as follows:
Step 1: pulse laser generator launches high energy pulse laser beam, high energy pulse laser beam is through optical path adjusting system point
For two beams: first laser beam is incident on the Scanning Detction point of cylinder surface to be detected, and generates and swash in Scanning Detction point excitation
Light ultrasonic signal, the laser ultrasonic signal around expand as detection ultrasonic signal and using Scanning Detction point as radiation center
It dissipates；Second laser beam is incident on the enabled mouth of high-speed data acquisition card, and high-speed data acquisition card is made to enter working condition；
Step 2: laser interferometer issues detection light beam, which is incident on a fixed point of cylinder surface to be detected, should
Fixed point is not overlapped with any Scanning Detction point, detects the detection ultrasonic signal in the beam reception first step；
Step 3: the signal output end of laser interferometer is connected with signal amplifier input terminal, laser interferometer first will acquisition
To detection ultrasonic signal be transmitted to signal amplifier, signal amplifier transmits after amplifying to laser interferometer transmission signal
High-speed sampling is carried out to high-speed data acquisition card, and sampling obtained signal is transferred to data analysis system being analyzed and processed；
Step 4: data analysis system carries out image checking to collected detection ultrasonic signal；
Step 5: by image checking result real-time display on a display screen.
2. the air compressor cylinder body face crack online test method according to claim 1 based on laser-ultrasound, feature
Be: the optical path adjusting system includes the first convex lens, spectroscope, the second convex lens and scanning galvanometer；Described first is convex
Lens are placed on the high energy pulse laser beam optical path that pulse laser generator is launched, and are used to carry out high energy pulse laser beam
It focuses；The spectroscope is placed at the focal position of the first convex lens, and incident high energy pulse laser beam is divided by spectroscope
The first laser beam of horizontal direction transmission and the second laser beam of vertical direction transmission；First laser beam is poly- by the second convex lens
The defocused center for being incident on scanning galvanometer, the scanning galvanometer control first laser beam is with certain speed in cylinder body to be detected
It is scanned incidence in a certain range of surface, incident first laser beam is scanned and excites generation laser super in cylinder surface to be detected
Acoustic signals；Second laser beam is transmitted to the enabled mouth of high-speed data acquisition card by optical fiber, enters high-speed data acquisition card
Working condition.
3. the air compressor cylinder body face crack online test method according to claim 2 based on laser-ultrasound, feature
Be: the eyeglass inside the scanning galvanometer is freely overturn in the angular region of 20 ° of space by setting rate, to control incidence
First laser beam is transmitted to the Scanning Detction point of cylinder surface to be detected by certain path.
4. the air compressor cylinder body face crack online test method according to claim 2 based on laser-ultrasound, feature
Be: the laser beam spot diameter for being incident on scanning galvanometer center is 0.1mm.
5. the air compressor cylinder body face crack online test method according to claim 2 based on laser-ultrasound, feature
Be: when scanning galvanometer control detection light beam treats detection cylinder surface and is scanned detection, scan path is period shape
Square wave, distance is 0.1mm between adjacent two scanning element.
6. the air compressor cylinder body face crack online test method according to claim 1 based on laser-ultrasound, feature
It is: described step 4: data analysis system carries out the specific steps of image checking to collected detection ultrasonic signal are as follows:
(1) preliminary noise reduction process is carried out to the collected detection ultrasonic signal of institute first, to remove ambient noise, improves acquisition letter
Number signal-to-noise ratio；
(2) extract institute it is collected detect ultrasonic signal in by cylinder surface crackle non-linear modulation function influence characteristic value,
And then according to characteristic value knots modification inverting crack information；
(3) imaging is carried out according to crack information.
7. the air compressor cylinder body face crack online test method according to claim 6 based on laser-ultrasound, feature
It is: in described (2) step, the specific steps of inverting crack information are as follows:
1) speed and acceleration of the laser interferometer acquisition air compressor cylinder body after by incident laser ultrasonic exciting；
2) phase space for characterizing air compressor cylinder body dynamic characteristic is constructed according to speed and acceleration, in phase space
Each point maps a kind of behavioral characteristics of cylinder body one by one, and these points move in phase space along specific trajectory line,
One or more specified point positions in phase space finally all can be gradually converged to along trajectory line, which is referred to as mutually empty
Between in singular point；
3) cylinder body dynamic characteristic is obtained by the trend of the point set moving rail trace in phase space, when cylinder body is cracked, cylinder body
The trajectory line that the point set of characterization cylinder body dynamic characteristic converges to singular point in phase space can change, and pass through and define specific spy
Parameter value is levied to define knots modification, and it is associated with crack information, so that it may which inverting obtains crack information, wherein describing
The characteristic ginseng value of point set trajectory line knots modification in cylinder body phase space be Pasteur distance (Bhattacharyya Distance,
BD)。
8. the air compressor cylinder body face crack online test method according to claim 7 based on laser-ultrasound, feature
Be: the method for extracting characteristic ginseng value Pasteur distance BD is as follows:
(1) preparing one piece of surface first does not have the cylinder body of crackle, and the cylinder body of crackle not can use electron microscope to cylinder body
Surface is checked to obtain；
(2) there is no response signal of the cylinder body of crackle under laser-ultrasound incentive action using laser interferometer measurement；
(3) phase space of the not cylinder body of crackle is rebuild according to collected response signal, it is mutually empty referred to herein as intact cylinder body
Between；
(4) Q basic point y (i) is randomly selected from the point set motion profile of intact cylinder body phase space, wherein i=1,2 ..., Q, selected
Taking should make to predict that error calculation value is not counted by it when Q value changes interference；
Wherein Q=N/100, N are the corresponding data points that high-speed data acquisition card measurement obtains；
(5) response signal of cylinder body to be measured, and phase space reconstruction are acquired using laser interferometer, on the phase space point set track
Find P space point of proximity x (j) for each basic point y (i), wherein j=1,2 ..., P, the selection of space point of proximity x (j) according to
Euclidean distance is directly chosen, i.e., distance y (i) nearest each point will be taken as point of proximity in trajectory line；The selection of P value need to ensure to inhale
Introduction local feature can be characterized completely, while calculated value is insensitive to ambient noise, and taking P=N/1000, N is high speed number
The corresponding data points obtained according to capture card measurement；
(6) by each basic point and point of proximity along respective track advance L step pitch from this point, each point of proximity mass center table of point y (i)
It is shown as:
Calculating prediction error value PE indicates are as follows:
Characteristic ginseng value Pasteur's distance BD can be indicated are as follows:
Wherein u, δ are respectively the mean value and variance of prediction error value PE, subscript b, c respectively indicate intact cylinder body phase space with it is to be measured
Cylinder body phase space；
(7) know that crackle is smaller by formula (1-2), two phase space Point Set motion profiles are more similar, and PE value is smaller, BD calculated value
With regard to smaller, according to practical BD calculated value can inverting obtain crack information value.
9. the air compressor cylinder body face crack online test method according to claim 8 based on laser-ultrasound, feature
It is: the image processing method step are as follows:
Firstly, cycle square wave Scanning Detction is carried out to cylinder surface to be measured using scanning galvanometer control first laser beam, it is scanned
Cheng Zhong, the detection beam irradiation that laser interferometer issues is in cylinder surface fixed point to be measured, the fixed point and first laser beam
Any Scanning Detction point be not overlapped；
Then, the response signal on each Scanning Detction point of cylinder surface to be measured is acquired using laser interferometer, and then counted one by one
Calculate the BD value of each point；
Finally, characterizing each point BD value size degree using shade degree, imaging can be carried out to crackle.
10. a kind of air compressor cylinder body face crack on-line detecting system based on laser-ultrasound, it is characterised in that: controlled including PLC
Device processed, cylinder body conveyer, driving motor, detection workbench, laser interferometer, signal amplifier, high-speed data acquisition card, data
Analysis system, display screen and the detection control box for being integrated with laser pulse generator and optical path adjusting system；The cylinder body conveying
Machine and driving motor setting are below detection workbench, and driving motor drivig cylinder conveyer, cylinder body conveyer is used for will be to be checked
The detection station that cylinder body is delivered to immediately below detection workbench is surveyed, the laser interferometer and detection control box are arranged at detection
On workbench；
The optical path adjusting system includes the first convex lens, spectroscope, the second convex lens and scanning galvanometer；First convex lens
Mirror is placed on the high energy pulse laser beam optical path that pulse laser generator is launched, for gathering to high energy pulse laser beam
It is burnt；The spectroscope is placed at the focal position of the first convex lens, and incident high energy pulse laser beam is divided into water by spectroscope
Square to transmission first laser beam and vertical direction transmit second laser beam；First laser beam is focused by the second convex lens
It is incident on the center of scanning galvanometer afterwards, the scanning galvanometer control first laser beam is with certain speed in cylinder body table to be detected
It is scanned incidence in a certain range of face, incident first laser beam is scanned in cylinder surface to be measured and excites generation laser ultrasonic
Signal；Second laser beam is transmitted to the enabled mouth of high-speed data acquisition card by optical fiber, and high-speed data acquisition card is made to enter work
State；
The laser interferometer is incident on a fixed point of cylinder surface to be detected for issuing detection light beam, the detection light beam,
It detects light beam and acquires laser ultrasonic signal, the signal input part phase of the signal output end and signal amplifier of laser interferometer
Even；Collected detection ultrasonic signal is transferred to high-speed data acquisition card after signal amplifier amplifies by laser interferometer；Institute
It states high-speed data acquisition card to connect with data analysis system, data analysis system divides collected laser ultrasonic signal
Analysis will test result after calculating and be transmitted to display screen；The PLC controller and driving motor, laser interferometer and laser pulse are sent out
Raw device communicates to connect.
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