CN1719222A - Non contact optical digital guide extension meter - Google Patents
Non contact optical digital guide extension meter Download PDFInfo
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- CN1719222A CN1719222A CN 200410062273 CN200410062273A CN1719222A CN 1719222 A CN1719222 A CN 1719222A CN 200410062273 CN200410062273 CN 200410062273 CN 200410062273 A CN200410062273 A CN 200410062273A CN 1719222 A CN1719222 A CN 1719222A
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- extensometer
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- test specimen
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Abstract
The present invention relates to a non-contact optical digital tensiometer. It is composed of two groups of optical lens, two imagers, two linear image sensors, comparison logic and counting circuit, clock pulse generator, microcontroller and two reflecting marks fixed on the sample to be measured. Said invention also provides its working principle and application method.
Description
Technical field
The invention belongs to the device of measuring test specimen stretching and compression deformation in the mechanics of materials, in particular for measuring the device of test specimen microdeformation in the mechanical property test of metal material and part nonmetallic materials.Belong to the measurement mechanism class.
Technical background
Extensometer is the vitals of Material Testing Machine, is used for measuring the miniature deformation amount of test specimen in stretching, compression, vibrational state and fracture process, requires extensometer to have high precision, high reliability, high sensitivity, antidetonation.Current crowd knows that adopting strain ga(u)ge formula extensometer and photo-electric to extend to take into account carries out contact type measurement, and for example: Chinese patent ZL93219143.6 strain ga(u)ge formula extensometer, the not spacing photo-electric extensometer of Chinese patent ZL92218236.1, Chinese patent ZL02115729.4 extensometer use new method.This class extensometer has fixing gauge length, can not adaptation material in the test to the different requirements of gauge length, common way is to prepare the extensometer of various gauge lengths, thereby has increased the spare part quantity and the complicacy of testing equipment.This class extensometer must carry out mechanical connection with test specimen, and the vibrations and the variation of temperature of test specimen impact measuring accuracy.This class extensometer converts the deformation quantity of test specimen to faint simulating signal, must dispose high precision, high gain analog signals multiplying arrangement, is coupled computer data acquisition and control, also must configuration analog quantity/digital quantity conversion equipment. the auxiliary device complexity.The mechanical clearance of temperature drift and zero point drift and mechanical connection influences measuring accuracy, and particularly the accident of test specimen fracture and flexural deformation also can cause having carried out with it the permanent damage of the extensometer of mechanical connection in the process of the test.
Summary of the invention
In order thoroughly to solve influence such as test specimen vibration and test specimen temperature variation and mechanical clearance etc. to measuring accuracy, eliminate fixedly gauge length to the restriction of extensometer application, avoid the accident fracture of test specimen in the process of the test and the permanent damage that flexural deformation causes extensometer, the invention provides a kind of non contact optical digital guide extension meter device, this extensometer measurement device gauge length can be regulated, directly do not contact with test specimen, method by optical imagery is converted into the deformation quantity of the gauge length part of test specimen the variation of position of the picture of two reflecting signs, again by two linear imaging sensors, Compare Logic and counting circuit detect the position of the picture of two reflecting signs simultaneously, and send microcontroller with the position numerical value of the picture of two reflecting signs, microcontroller with the position numerical value of the picture of detected two reflecting signs during with on-test the position numerical value of the picture of two reflecting signs compare, calculate the deformation quantity of test specimen gauge length part, and by serial communication interface digitizing output.Adopt the LIS-1024 linear imaging sensor, cooperate 5 times optics to amplify, the Measurement Resolution of this extensometer can reach 2 microns.
A kind of non contact optical digital formula extensometer, this extensometer comprises reflecting sign, lens combination, imager imager adjusting support, two imageing sensor linear arraies, Compare Logic and counting circuit plate and controllers, two groups of optical lenses are imaged on two reflecting signs respectively on two linear imaging sensors, two imageing sensors are connected with counting circuit with two Compare Logic respectively, and two Compare Logic are connected with a microcontroller circuit with counting circuit.
Said two groups of optical lenses are removable, and removable optical lens group can make the imaging ratio 1: 5-5: regulate in 1 the scope.
Said two reflecting signs that are fixed on the test specimen have the pattern of black and white boundary.
Said Compare Logic and counting circuit are converted to digital signal with the position of the picture of reflecting sign.
What the present invention solved that its technical matters adopts is to fix two chequered with black and white reflecting signs respectively at test specimen gauge length two ends, be fixed on two imagers regulating on the support with reflecting sign be imaged on respectively two independently the linear array formed of the photosensitive unit of linear imaging sensor as on the plane, when test specimen generation deformation, subtle change takes place in the distance on the test specimen between two reflecting signs in gauge length two ends, the position of the picture of reflecting sign also is moved on as the plane, Compare Logic and counting circuit detect first position on the imageing sensor linear array, black and white separatrix in the picture of reflecting sign in real time, send position numerical value to microcontroller, microcontroller with the position numerical value of the picture of detected two reflecting signs during with on-test the position numerical value of the picture of two reflecting signs compare, calculate on the test specimen deformation quantity of part (gauge length part) between two reflecting signs.Microcontroller is by the deformation quantity Direct Digital output of serial communication interface with test specimen gauge length part.Removable lens combination makes the picture of reflecting sign amplify 1--5 doubly, corresponding, measure the resolution of reflecting sign displacement and amplified 1--5 doubly.Removable lens combination can also make the picture of reflecting sign dwindle 1--5 doubly, corresponding, the range of measuring the reflecting sign displacement has amplified 1--5 doubly.Movable reflector and imaging screen and the eyepiece that matches with it are set between lens combination and imaging surface, are used for observing image quality, adjustment equipment.
The invention has the beneficial effects as follows the noncontact digitized measurement of having realized the microdeformation of test specimen, avoided the influence to measuring accuracy such as the temperature drift of mechanical clearance, specimen temperature, vibration, simulating signal and zero point drift.By adjust two between the imager distance and the distance between two reflecting signs, can satisfy the requirement of multiple test specimen gauge length.By changing lens combination, can adjust the resolution and the range of displacement measurement.The accident fracture of test specimen in the process of the test and the technical barrier that flexural deformation causes the permanent damage of extensometer have thoroughly been solved.The precision height becomes local, easy to use, safe.
Description of drawings
Below in conjunction with accompanying drawing this invention is further described
Fig. 1 is the optical imaging device synoptic diagram of extensometer
Fig. 2 is the optical imaging device left view of extensometer
Fig. 3 is the imager cut-away view
Fig. 4 is a reflecting sign
Fig. 5 is that the photosensitive unit of imageing sensor linear array is arranged
Fig. 6 is the Circuits System block diagram
Among the figure, 1. reflecting sign, 2. lens combination, 3. imager, 4. the picture of reflecting sign, 5. imageing sensor linear array, 6. picture plane, 7. imager is regulated support, 8, fastener, 9. test specimen, 10. circuit board, 11. level crossing turnover panels, 12. the imaging screen of band scale mark, 13. eyepieces, 14. rotating shafts, 15. signal connector, 16. handles, 17. controllers.
Embodiment
In Fig. 1, fastener 8 is separately fixed at two reflecting signs 1 that chequered with black and white pattern arranged at the gauge length two ends of test specimen 9, lens combination 2 is connected with imager 3, imageing sensor linear array 5 is fixed in the imager 3, wherein adopt between lens combination 2 and the imager 3 and be threaded, thereby, can regulate the distance between lens and the imageing sensor linear array 5.The picture of reflecting sign is on the picture plane 6 of imageing sensor linear array 5.
In Fig. 3, circuit board 10 is installed in the imager 3, circuit board one end is connected with imageing sensor linear array 5, and the other end links to each other with signal connector 15.Mobilizable level crossing turnover panel 11 is placed between lens combination 2 and the imageing sensor linear array 5, is connected with imager through rotating shaft 14.When level crossing turnover panel and lens combination and imageing sensor linear array be wired to 45 the time, level crossing is imaged on the picture of reflecting sign on the imaging screen 12, can the Direct observation image quality by eyepiece 13.Adjust the position of lens combination and imager, make the central authorities of reflecting sign blur-free imaging at imaging screen.
Referring to Fig. 1,3,6, controller 17 is connected with two signal connectors 15 respectively, signal connector is connected with counting circuit plate 10 with Compare Logic.
Zero point correction: consult Fig. 3, before on-test, the position of writing down the picture of two reflecting signs simultaneously by microcontroller is promptly at the ordinal number of the photosensitive unit of the position imageing sensor linear array of the picture at the edge of first bright wisp, as initial zero position, note is N10 and N20.LIS-1024 imageing sensor linear array has 1024 photosensitive units, and possible photosensitive unit ordinal number is 1-1024.
Measure: after on-test, microcontroller detects the position of two reflecting signs in real time, and note is N11 and N21, is calculated the deformation quantity Hx micron of test specimen between two reflecting signs by following formula:
Hx＝(N11-N10+N21-N20)*M/K
Wherein:
1) M is the pel spacing of imageing sensor linear array, and the photosensitive unit spacing of LIS-1024 imageing sensor linear array is 7.8 microns (um),
2) K is an optical magnification.Selecting the lens combination photocentre is 20 centimetres to the distance as plane 6,10 centimetres of the focal lengths of lens combination, then K=1.
3) when test specimen extends, Hx＞0, when test specimen compresses, Hx＜0.
Claims (4)
1, a kind of non contact optical digital formula extensometer, it is characterized in that: this extensometer comprises reflecting sign (1), lens combination (2), imager (3), imager is regulated support (7), two imageing sensor linear arraies (5), Compare Logic and counting circuit plate (10) and controller (17), two groups of optical lenses (2) are imaged on two reflecting signs (1) respectively on two linear imaging sensors (5), two imageing sensors (5) are connected with counting circuit (10) with two Compare Logic respectively, and two Compare Logic are connected with a microcontroller circuit (17) with counting circuit (10).
2, according to claims 1 described a kind of non contact optical digital formula extensometer, it is characterized in that: said two groups of optical lenses (2) are removable, and removable optical lens group (2) can make the imaging ratio 1: 5-5: regulate in 1 the scope.
3, according to claims 1 described a kind of non contact optical digital formula extensometer, it is characterized in that: said two reflecting signs (1) that are fixed on the test specimen have the pattern of black and white boundary.
4, according to claims 1 described a kind of non contact optical digital formula extensometer, it is characterized in that: said Compare Logic and counting circuit (10) are converted to digital signal with the position of the picture of reflecting sign (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410062273 CN1719222A (en) | 2004-07-05 | 2004-07-05 | Non contact optical digital guide extension meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410062273 CN1719222A (en) | 2004-07-05 | 2004-07-05 | Non contact optical digital guide extension meter |
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| Publication Number | Publication Date |
|---|---|
| CN1719222A true CN1719222A (en) | 2006-01-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 200410062273 Pending CN1719222A (en) | 2004-07-05 | 2004-07-05 | Non contact optical digital guide extension meter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100398983C (en) * | 2006-02-27 | 2008-07-02 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| CN107923828A (en) * | 2015-08-24 | 2018-04-17 | 航天喷气发动机洛克达因股份有限公司 | The technique for carrying out nondestructive testing using direct strain imaging |
| CN110763146A (en) * | 2019-10-31 | 2020-02-07 | 河海大学 | High-precision optical extensometer and measuring method based on double cameras |
-
2004
- 2004-07-05 CN CN 200410062273 patent/CN1719222A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100398983C (en) * | 2006-02-27 | 2008-07-02 | 王化谦 | Double-camera video frequency large-deformation measurement method and video frequency extension device based thereon |
| CN107923828A (en) * | 2015-08-24 | 2018-04-17 | 航天喷气发动机洛克达因股份有限公司 | The technique for carrying out nondestructive testing using direct strain imaging |
| CN110763146A (en) * | 2019-10-31 | 2020-02-07 | 河海大学 | High-precision optical extensometer and measuring method based on double cameras |
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