CN100501220C - Appearance measuring and detecting method for inner surface of space curve type long-distance microtubule - Google Patents

Abstract

The invention discloses a method for checking the surface condition of spatial curvature long-distance micro tube. The inventive machine is mainly formed by a two-dimension position sensor, a semi-conductor laser, a transparent window, a micro motor, a scanning mirror, a reflector, a convergent lens, and a receiving lens. The light of laser via two reflections will form a micro spot on the inner wall of tube, while said spot is received by the two-dimension position sensor. Via the current signal of two-dimension position sensor and the structural parameters of inventive machine, the invention calculates out the position of the spot in local three-dimension coordinate. The micro motor rotates the scanning mirror one round to obtain the positions of all sampling points of one section of inner wall of tube. The invention can be used in the defect check and three-dimension measurement of the inner wall of the curvature micro tube whose inner diameter is 9-11mm and radius is larger than 100mm, while the measurement accuracy can reach +- 0.1mm.

Description

Appearance measuring and detecting method for inner surface of space curve type long-distance microtubule

Technical field

The present invention relates to a kind of appearance measuring and detecting method for inner surface of space curve type long-distance microtubule.

Background technique

In all conglomeraties such as machinery, the energy, chemical industry, all used a large amount of pipeline-like parts, after long-term the use, defectives such as crackle just might appear, thereby cause the leakage of gas or liquid, make whole system receive damage, cause unnecessary economic loss, even critical life safety to the staff.Therefore the detection to this class part has just become a very important problem.Domestic and international many documents have all been done deep research to the problem of this respect, but major part is at the pipeline of internal diameter greater than 20mm, and for small pipeline, especially internal diameter is less less than the research report of the pipeline of 10mm.

The detection technique of large pipeline inwall is comparative maturity, and the most frequently used method is to adopt ccd video camera to the inner-walls of duct imaging, then image is carried out suitable processing, just can judge whether pipeline exists defective.Because the processing circuit complexity of CCD chip, microminiaturization be difficulty relatively, therefore concerning small pipeline, common ccd video camera is difficult to enter inside.Though and special-purpose industrial electronic endoscope can detect the small pipeline inwall, be difficult to determine the size of defective, the concrete spatial position and the inner three-dimensional appearance of pipe at place.Though the micro-tube robot of people such as Tsuruta k. development also can enter the pipeline of 10mm and detect, and can only lean on the CCD picture shot that inner-walls of duct is observed, and can not remedy the above-mentioned shortcoming of endoscope.Human position transducer PSD (Position Sensitive Detector) such as Mizunuma M realize the detection and the three-dimensional reconstruction of inner-walls of duct, but system's rotating machinery complexity of their development, only be suitable for the straight tube that internal diameter is 66～83mm, and can not detect crooked pipeline or micro fine pipe.

Summary of the invention

The purpose of this invention is to provide a kind of internal diameter that is applicable to is Φ 9～Φ 11mm, the defects detection of the curved micro fine pipe inwall that radius of curvature 100mm is above and the appearance measuring and detecting method for inner surface of space curve type long-distance microtubule of three-dimensional measurement.

The step of space curve type long distance fine pipe internal surface shape detecting method is:

1) the laser emitting light beam is behind scan mirror and reflector two secondary reflections, on inner-walls of duct, form a small hot spot D, this hot spot receives the back by lens and obtain picture point N on the two-dimensional position sensor photosensitive surface, set up an office D and some N is respectively R and r to the distance of detector medial axis, the angle of yaw of scan mirror is θ, lens interarea spacing is d, and some B is the incident point of laser beam in scan mirror, and some B ' is the symmetric points of B about mirror surface with holes; L represents the distance of a B ' to the two-dimensional position sensor photosensitive surface, and f represents the distance of lens left side interarea to the two-dimensional position sensor photosensitive surface; Then try to achieve and put the distance of D on the inner-walls of duct to the detector medial axis according to optical geometry:

$R=\frac{r(L-f-d+a+b)}{f+r/\mathrm{<figure-callout\; id="2"\; label="tan"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">tan</figure-callout>}2\mathrm{\&theta;}}$

The formula of α and b is:

$\left\{\begin{array}{c}a=t(\tan {\mathrm{\&alpha;}}_1-\tan {\mathrm{\&alpha;}}_2)\\ b=t(\tan {\mathrm{\&beta;}}_1-\tan {\mathrm{\&beta;}}_2)\end{array}\right.$

T is the thickness of transparency window, α ₁, α ₂Be respectively laser reference angle and refraction angle by transparency window behind the reflector back reflection, β ₁, β ₂Be respectively laser refraction angle and reference angle by transparency window after the inner-walls of duct reflection, formula is respectively:

α ₁＝90°-2θ，

α ₂＝arcsin(sinα ₁/i _r)，

β ₁＝arcsin(i _rsinβ ₂)，

β ₂＝arctan(r/f)

Wherein, i _rRefractive index for transparency window;

2) center O with the two-dimensional position sensor receiver lens is an initial point, and detector medial axis OC is the z axle, the portion's three-dimensional system of coordinate of founding the bureau, and the location tables of 1 D is shown on the inner-walls of duct:

$\left\{\begin{array}{c}x=R\cos \mathrm{\&omega;}\\ y=R\sin \mathrm{\&omega;}\\ z=L+a-f-R/\tan 2\mathrm{\&theta;}-d/2\end{array}\right.$

Wherein ω is O _PN and O _PThe angle of u, the angle of swing of expression scan mirror, O _PBe two-dimensional position sensor photosensitive surface center, O _PU is the principal direction of two-dimensional position sensor photosensitive surface;

3) inner surface of pipeline topography measurement instrument transfixion in pipeline, and micro motor drives scan mirror around 360 ° of detector medial axis rotations, calculates the position coordinate that cross section ring of inner-walls of duct is gone up each sampled point;

4) when adjacent two sampled points to the range difference of detector medial axis during less than 0.1mm, then there is not defective in this sampling location; When adjacent two sampled points to the range difference of detector medial axis greater than 0.1mm, then there is defective in this sampling location

Beneficial effect of the present invention:

1) this topography measurement instrument is applicable to that internal diameter is Φ 9～Φ 11mm, the defects detection and the three-dimensional measurement of the curved micro fine pipe inwall that radius of curvature 100mm is above, and measuring accuracy can reach ± 0.1mm.

1) laser convergence is after overscanning mirror and twice reflection of reflector with holes arrive inner-walls of duct, and the length of having dwindled whole detector makes it and can the bend pipe of small radii of curvature be detected.

3) two-dimensional position sensor has only four signaling lines and a power line, its output is current signal, attenuation ratio is less after the long Distance Transmission, therefore processing circuit and two-dimensional position sensor can be separated, thereby reduced the weight of whole detection system, enable under the driving of micro-tube robot, to enter the inside of long pipeline, detect duct length and can reach 10m.

4) the micro motor rotating speed is regulated by waveform generator, thereby can regulate the sampling number on cross section of inner-walls of duct.

5) micro motor drive scan mirror rotates a circle, and can finish the detection of a pipeline section, can calculate the three-dimensional coordinate of corresponding hot spot point on the pipeline section according to the structural parameter of detector.

6) feeler is regulated the subtended angle that sea whelk can be regulated feeler, enables to adapt to the pipe survey of certain limit internal diameter.

7) the laser adjusting screw can be finely tuned for laser, thereby effectively eliminates laser itself and assemble the centring error that brings.

8) laser adopts the rectangular wave modulation, and the difference that optical signal and no optical signal will be arranged is as useful signal, thereby has eliminated the influence of bias light and dark current

9) under the collaborative work of the driving of micro-tube robot and curvature sensor, can finish the measuring three-dimensional morphology and the three-dimensional reconstruction of inner surface of pipeline.

Description of drawings

Fig. 1 is the measuring instrument for space curve type long distance fine pipe internal surface shape structural representation;

Fig. 2 is a two-dimensional position sensor fundamental diagram of the present invention;

Fig. 3 is that inner-walls of duct of the present invention detects schematic diagram;

Fig. 4 is an inner surface of pipeline measuring three-dimensional morphology schematic representation of the present invention.

Embodiment

As shown in Figure 1, measuring instrument for space curve type long distance fine pipe internal surface shape has the two-dimensional position sensor pedestal 17 that is connected successively, transparency window 3, laser pedestal 7, at transparency window 3 internal fixation motor retaining ring 4 is arranged, on motor retaining ring 4, be fixed with the micro motor 15 that connects successively, scanning microscope base 14, scan mirror 5, two-dimensional position sensor trim ring 1 is installed on two-dimensional position sensor pedestal 17 successively, two-dimensional position sensor 19, receiver lens group 16, be fixed with feeler retaining ring 18 in two-dimensional position sensor pedestal 17 outsides, feeler is regulated sea whelk 12 and be fixed with elasticity feeler 2 on feeler retaining ring 18, laser adjusting screw 10 is installed on laser pedestal 7 successively, laser trim ring 9, semiconductor laser 8, elastic washer 11, convergent lens 6, reflector 13 is fixed with feeler retaining ring 18 in laser pedestal 7 outsides, feeler is regulated sea whelk 12 and be fixed with elasticity feeler 2 on feeler retaining ring 18.

Above-mentioned two-dimensional position sensor is a kind of lateral effect silicon photoelectric device, luminous energy can be converted into electric energy.But it has the fast continuous sampling of speed of response, detect characteristics such as data are only relevant with the center of energy of luminous point.When incident illumination is to the two-dimensional position sensor photosensitive surface, produce four tunnel electric current I ₁, I ₂, I ₃, I ₄As Fig. 2, with the center O of photosensitive surface _PFor initial point is set up plane coordinate system O _PUv, then the position of launching spot N on photosensitive surface can be expressed as:

$u=\frac{s(I_1-I_3)}{2(I_1+I_3)},$ $v=\frac{s(I_2-I_4)}{2({\mathrm{<figure-callout\; id="2"\; label="I"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">I</figure-callout>}}_2+I_4)}---\left(1\right)$

Wherein, s is the length of side of photosensitive surface.

Then put the distance of N to two-dimensional position sensor photosensitive surface center:

$r=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">u</figure-callout>}}^2{+v}^2}---\left(2\right)$

The used two-dimensional position sensor of this inner surface of pipeline detector is 3mm * 3mm type position transducer that Zhejiang company of Futong produces, and its boundary dimension is Φ 7.5mm * 2.5mm.Semiconductor laser adopt Chongqing to navigate AL650T10 type laser that big photoelectricity Co., Ltd produces, its wavelength is 650nm, power is 10mW.The 4ZK751Q type motor that micro motor adopts Lufa Micromoter Co., Ltd., Zhejiang to produce, its size of main body is Φ 4.1mm * 7mm, voltage rating 3.0V, no-load speed 25000r/m.

The inner-walls of duct of topography measurement instrument detects principle as shown in Figure 3.The laser emitting light beam is behind scan mirror and reflector two secondary reflections, on inner-walls of duct, form a small hot spot D, this luminous point receives the back by lens and obtain picture point N on the two-dimensional position sensor photosensitive surface, set up an office D and some N is respectively R and r to the distance of detector medial axis, the angle of yaw of reflector is θ, lens interarea spacing is d, and some B is the incident point of laser beam in scan mirror, and some B ' is the symmetric points of B about mirror surface with holes; L represents the distance of a B ' to the two-dimensional position sensor photosensitive surface, and f represents the distance of lens left side interarea to the two-dimensional position sensor photosensitive surface; Then try to achieve and put the distance of D on the inner-walls of duct to the detector medial axis according to optical geometry:

$R=\frac{r(L-f-d)}{f+r/\mathrm{<figure-callout\; id="2"\; label="tan"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">tan</figure-callout>}2\mathrm{\&theta;}}---\left(3\right)$

For micro fine pipe, the light refraction that transparency window causes can bring very big deviation to result of calculation, therefore must pay attention to.As can be seen from Figure 3, the refraction action of transparency window is equivalent to some B ' is displaced to a B ", the right principal point E of lens is displaced to E ', and the bias size of establishing them is respectively a, b, then (3) formula is modified to:

$R=\frac{r(L-f-d+a+b)}{f+r/\mathrm{<figure-callout\; id="2"\; label="tan"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">tan</figure-callout>}2\mathrm{\&theta;}}---\left(4\right)$

Wherein

$\left\{\begin{array}{c}a=t(\tan {\mathrm{\&alpha;}}_1-\tan {\mathrm{\&alpha;}}_2)\\ b=t(\tan {\mathrm{\&beta;}}_1-\tan {\mathrm{\&beta;}}_2)\end{array}\right.$

The t here represents the thickness of transparency window, α ₁=90 °-2 β, β ₂=arctan (r/f), and α ₂, β ₁Can be according to the refractive index i of transparency window _rObtain: α ₂=arcsin (sin α ₁/ i _r), β ₁=arcsin (i _rSin β ₂).

Center O with the two-dimensional position sensor receiver lens is an initial point, and detector medial axis OC is the z axle, sets up partial 3 d system of coordinates shown in Figure 3, and the position of 1 D can be expressed as on the inner-walls of duct:

$\left\{\begin{array}{c}x=R\cos \mathrm{\&omega;}\\ y=R\sin \mathrm{\&omega;}\\ z=L+a-f-R/\mathrm{<figure-callout\; id="2"\; label="tan"\; filenames="C200610166837E00101.png"\; state="\{\{state\}\}">tan</figure-callout>}2\mathrm{\&theta;}-d/2\end{array}\right.---\left(5\right)$

Wherein ω is O _PN and O _PThe angle of u, the angle of swing of expression scan mirror.

According to following formula,, can calculate the position of corresponding points in the detector local coordinate system on the inner-walls of duct by a sampled data of two-dimensional position sensor.If topography measurement instrument transfixion in pipeline, and scan mirror revolves three-sixth turn around the detector medial axis, then can finish the detection of a cross section ring of inner-walls of duct, calculates the position of all sampled points in the partial 3 d system of coordinates.For straight tube, the medial axis of pipeline medial axis and topography measurement instrument overlaps in the testing process, the R that is tried to achieve by (4) formula is exactly the radius of inner-walls of duct, if therefore a certain inner wall section does not have defective to exist, then the R value of each point correspondence should equate on this cross section.And in the crooked pipeline, intersect two medial axis, and the internal diameter of pipeline needs the data in several cross sections, comprehensive front and back just can calculate.But no matter the sort of situation so long as the size of R takes place to change suddenly, just means that this place exists crackle, pit or other defect.

In order to obtain final data, need handle image data.At first the position signal that two-dimensional position sensor is produced carries out processing such as I/V conversion, amplification, A/D conversion, filtering, removal bias light and noise current, according to the demarcation of PSD data is proofreaied and correct again.At last data are cut apart, fitted, thereby obtain the final position of cross section discrete point in the partial 3 d system of coordinates.

In Fig. 4, use O _iXyz represents the detector partial 3 d system of coordinates of topography measurement instrument when the i time sampling, O _iInitial point for respective coordinates system.If if O _I-1Be known, then carry out when sampling the i time, if 1 P that surveys on the inner wall section ring at detector partial 3 d system of coordinates O _iPosition among the xyz then has to obtain:

$\stackrel{\&RightArrow;}{O_{i-1}P}=\stackrel{\&RightArrow;}{O_{i-1}{O}_i}+\stackrel{\&RightArrow;}{O_i}P---\left(6\right)$

$\stackrel{\&RightArrow;}{O_{w}P}=\stackrel{\&RightArrow;}{O_w{O}_{i-1}}+\stackrel{\&RightArrow;}{O_{i-1}}P---\left(7\right)$

$\stackrel{\&RightArrow;}{O_w{O}_i}=\stackrel{\&RightArrow;}{O_{w}P}+\stackrel{\&RightArrow;}{O_i}P---\left(8\right)$

Wherein

Step-length for the topography measurement instrument advances is provided by the pipeline robot that drives.

Point to the direction that this instantaneous topography measurement instrument advances, provide by the curvature sensor of collaborative work.

For the ease of determining the initial detector partial 3 d coordinate origin and the direction of advance of topography measurement instrument, connect the straight-run of pipe road at the tested pipeline starting point, and be initial point with straight tube port center, be that the z axle is set up global coordinate system with the straight tube medial axis.

Therefore, according to the position of initial detector, can obtain a P and O by above-mentioned three formula _iPosition in global coordinate system, the rest may be inferred can obtain when sampling next time, the initial point of detector partial 3 d system of coordinates and the position of any point in global coordinate system on the cross section of surveying, thus the description of each point in building global coordinate system on the tested pipeline internal surface obtained.

Claims (1)

1, a kind of space curve type long distance fine pipe internal surface shape detecting method, it is characterized in that: the step of method is:

1) the laser emitting light beam is behind scan mirror and reflector two secondary reflections, on inner-walls of duct, form a small hot spot D, this hot spot receives the back by lens and obtain picture point N on the two-dimensional position sensor photosensitive surface, set up an office D and some N is respectively R and r to the distance of detector medial axis, the angle of yaw of scan mirror is θ, lens interarea spacing is d, and some B is the incident point of laser beam in scan mirror, and some B ' is the symmetric points of B about mirror surface with holes; L represents the distance of a B ' to the two-dimensional position sensor photosensitive surface, and f represents the distance of lens left side interarea to the two-dimensional position sensor photosensitive surface; Then try to achieve and put the distance of D on the inner-walls of duct to the detector medial axis according to optical geometry:

$R=\frac{r(L-f-d+a+b)}{f+r/\tan 2\mathrm{\&theta;}}$

The formula of a and b is:

$\left\{\begin{array}{c}a=t(\tan {\mathrm{\&alpha;}}_1-{\tan \mathrm{\&alpha;}}_2)\\ b=t({\tan \mathrm{\&beta;}}_1-{\tan \mathrm{\&beta;}}_2)\end{array}\right.$

T is the thickness of transparency window, α ₁, α ₂Be respectively laser reference angle and refraction angle by transparency window behind the reflector back reflection, β ₁, β ₂Be respectively laser refraction angle and reference angle by transparency window after the inner-walls of duct reflection, formula is respectively:

α ₁＝90°-2θ，

α ₂＝arcsin(sin?α ₁/i _r)，

β ₁＝arcsin(i _r?sin?β ₂)，

β ₂＝arctan(r/f)

Wherein, i _rRefractive index for transparency window;

2) center O with the two-dimensional position sensor receiver lens is an initial point, and detector medial axis OC is the z axle, the portion's three-dimensional system of coordinate of founding the bureau, and the location tables of 1 D is shown on the inner-walls of duct:

$\left\{\begin{array}{c}x=R\cos \mathrm{\&omega;}\\ y=R\sin \mathrm{\&omega;}\\ z=L+a-f-R/\tan 2\mathrm{\&theta;}-d/2\end{array}\right.$

Wherein ω is O _PN and O _PThe angle of u, the angle of swing of expression scan mirror, O _PBe two-dimensional position sensor photosensitive surface center, O _PU is the principal direction of two-dimensional position sensor photosensitive surface;

3) inner surface of pipeline topography measurement instrument transfixion in pipeline, and micro motor drives scan mirror around 360 ° of detector medial axis rotations, calculates the position coordinate that cross section ring of inner-walls of duct is gone up each sampled point;

4) when adjacent two sampled points to the range difference of detector medial axis during less than 0.1mm, then there is not defective in this sampling location; When adjacent two sampled points to the range difference of detector medial axis greater than 0.1mm, then there is defective in this sampling location.

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