Further Development of a Laser Interferometer

Recen Inno a ions in Mecha onics (RIiM) Vol. 3. (2016). No. 1-2. DOI: 10.17667/ iim.2016.1-2/12. 1 Fu he De elopmen o a Lase In e e ome e László Rónai Robe Bosch Depa men o Mecha onics Uni e si y o Miskolc Miskolc, Hunga y [email protected] Abs ac —A mo e han 25 yea old lase in e e ome e has been u he de eloped in o de o handle he signals also by compu e s. A TTL signal con e e has been buil in using an analog compa a o uni ype LM319. A Na ional Ins umen s 6341 OEM measu emen ca d was implemen ed oo. The mode nized lase in e e ome e has been e i ied wi h a p ecise Renishaw XL-80 in e e ome e . A ib ome e uni has been also calib a ed wi h he upda ed in e e ome e . Keywo ds—lase in e e ome e ; measu emen ; ib ome e ; analog compa a o I. INTRODUCTION The his o y o he lase s is ela i ely sho , he i s lase was made in 1960, which was a solid ( uby) lase . The heo e ical basis o he lase s was in en ed ea lie by Albe Eins ein [7]. The e m o lase [2], [3], [7] is de i ed om he Ligh Ampli ica ion by S imula ed Emission o Radia ion wo ds ini ial le e . Nowadays lase sys ems a e used in a e y wide ield, e.g., labo a o y esea ches, measu emen s, ma e ial p ocessing. One can ead u he in o ma ion abou lase s, e.g., in [2] and [8]. In his pape u he de elopmen o a lase in e e ome ic mo ion analyse (LIMA) is discussed. The aim o he de elopmen is o handle he signals also by compu e s. Fu he mo e he uni will be used in demons a ion and educa ional pu poses. In his a icle compa a i e measu emen s a e pe o med wi h he in es iga ed de ice and a so called Lase Dopple Vib ome e [9] (LDV) and a Renishaw XL-80 [12] lase in e e ome e . This esea ch was accomplished a he Ins i u e o Physics [4] in collabo a ion wi h he Wigne Resea ch Cen e o Physics. The Renishaw in e e ome e was p o ided by he Robe Bosch Depa men o Mecha onics. The p ecision measu emen s o ib a ions a e p o ided by he lase in e e ome y. Th ee di e en lase sys ems a e desc ibed in Sec ion 2. The designing s eps o he u he de elopmen , e.g., on panel, analog compa a o ci cui a e gi en in Sec ion 3. The manu ac u ing s eps a e w i en in Sec ion 4. The las wo Sec ions a e deal wi h he es ing p ocess and he p ac ical ib a ion measu emen s. The u u e plans a e men ioned in Conclusion. II. LASER SYSTEMS The applica ion o lase s a e ela i ely popula . The lase beams a e highly monoch oma ic and spa ially cohe en . Fu he mo e lase s p o ide high spec al powe densi y ( he ene gy is concen a ed in o one poin ) and li le di e gence. The i s in e e ome e was c ea ed by Albe Ab aham Michelson in 1881, o measu e he speed o he Ea h compa ed o he ’e he ’ in 1887. The op omechanical scheme o he in es iga ed lase in e e ome e is desc ibed in Fig. 1. He-Ne lase S abilize De ec o S a iona y mi o Beam spli e Mo ing mi o Measu emen uni Head uni Fig. 1. Op omechanical scheme o LIMA The sys em is mo e han 20 yea old, which has go a He- Ne gas lase . The emi ed lase beam is passing h ough a beam spli e , hus he beam is di ided in o wo pe pendicula pa . The in ensi y o he wo beams a e emaining he same [1]. The ea e one beam is passing h ough he s a iona y mi o and he o he beam is passing o e a mo ing mi o . The wo lase beams a e coming ac oss he spli e uni , hen i will e u n o he de ec o in he head uni . The phase ela ionship o he beams a e de e mined by he pa h leng h di e ence [1]. The pa h leng h di e ence mus be wi hin he cohe ence ange o he lase uni . The o iginal measu emen and da a p ocessing module is ou da ed, which is shown in Fig. 2. The main speci ica ions o he LIMA a e gi en in Table I. Recen Inno a ions in Mecha onics (RIiM) Vol. 3. (2016). No. 1-2. DOI: 10.17667/ iim.2016.1-2/12. 2 TABLE I. SPECIFICATIONS OF THE LASER UNIT Name o he pa ame e Value o he pa ame e Lase ype He-Ne Uniphase-1007 [6] Cohe ence leng h 3 m The empe a u e o he lase uni in s abilized s a e 51°C Ope a ing empe a u e 15°C-25°C Lase equency 4.7375·1014 Hz The communica ion be ween he head uni and he measu emen uni is p o ided by a DB 9 connec o . Fig. 2. The o iginal ou da ed measu emen uni Fo e i ica ion pu poses a Renishaw XL-80 ype lase in e e ome e is used. The accu acy o he uni is ~1 nm, he measu emen ange is expandable o 80 m. The uni communica es wi h pe sonal compu e s ia an USB cable. This sys em is applicable o calib a ion o machine ools, e.g., milling s a ions, u ning machines. The p ecision o he measu emen is ensu ed by co ec ion uni s, e.g., humidi y, empe a u e and p essu e senso s. The hi d lase uni is an LDV, which is a Poly ec PDV 100 [10]. The uni is capable o measu e he speed and he equency componen s o he ib a ions wi h con ac less way. The s uc u e o he LDV is compac , hus i is no expandable. The head uni o he sys em is a He-Ne ype gas lase , he wa eleng h o he beam is λ=632.8 nm, he e o e he emi ed ligh is isible. The dis ance o he measu emen is a iable wi hin a ange o 0.1-30 m. The uni has some main bene i s, e.g., he mobili y and he simple ope a ion. Easy o analyze objec s which a e ha d o each. The ope a ion o he sys em is based on he Dopple E ec . This e ec was disco e ed in 1843 by Ch is ian And eas Dopple . The essence o he phenomenon is ha i he obse e and/o he sou ce o he wa e mo e(s) ela i e o each o he , changes o he wa e a e de ec ed in he wa eleng hs and he equencies. The phenomenon can also be obse ed in as onomy, he ed/blue shi ela ion [11]. III. DESIGNING PROCESSES The designing p ocesses and ma e ials o he measu emen sys em o he LIMA a e desc ibed in he sequel. Powe supply uni s and clamping elemen s o he box a e selec ed in acco dance wi h he ou da ed module and he measu ed cu en s. The Kon ak a measu emen box ype 19” was selec ed o build he measu emen uni . The box had no on panel, hus he designing p ocess has been expanded wi h planning o he layou o he on panel. The de ec o o he head uni sends signals o he measu emen box, he e o e an analog compa a o ci cui is designed o p o ide TTL signals o he measu emen ca d, which is a Na ional Ins umen s ype 6341 OEM ca d. The abo e men ioned compa a o ci cui has been made in he Eagle p in ed ci cui boa d (PCB) designe so wa e upon he a ailable li e a u e o he old measu emen box. The i s s ep is o c ea e he schema ic o he ci cui , he ea e he PCB model o he boa d had o be gene a ed in Fig. 3. Fig. 3. The gene a ed model o he PCB The posi ions o he bo es and cu ing posi ions o he on panel a e designed in he F on Design so wa e. The layou o he bo es and he labels a e shown in Fig. 4. Fig. 4. The layou o he on panel Recen Inno a ions in Mecha onics (RIiM) Vol. 3. (2016). No. 1-2. DOI: 10.17667/ iim.2016.1-2/12. 3 IV. THE MANUFACTURING PROCESSES The s eps o he cons uc ing phases a e desc ibed in his Sec ion. Fi s ly he p oduc ion o he PCB o he analog compa a o uni is deal wi h. Secondly he milling and he labeling p ocesses o he on panel a e discussed. Pe o ming he milling and he solde ing he eadymade boa d wi hou analog compa a o s is shown in he Fig. 5. Fig. 5. The eadymade PCB The hickness o he on panel is 4 mm, which consis s bo es wi h Ø 3 mm diame e . The labels o he panel a e p in ed on a anspa en adhesi e ilm oil. The ea e he inal assembly and es ing o he measu emen sys em ha e been pe o med. V. THE BUILDING AND TESTING OF THE MEASUREMENT BOX A he i s s ep he clamping o he AC connec o s, cu en me e and some o he connec o s a e made. The oppo uni y o he na u al en ila ion is an impo an ea u e o a oid o e hea ing, hus he dis ance o he elemen s a e designed ela i ely la ge. Space s a e made o ix he subassemblies in o he measu emen box. To assembly he sys em some Ø 3 mm diame e bo es had o be d illed hen ollowed by Ø 6 mm diame e lowe ing. The eadymade measu emen and da a p ocessing uni is shown in Fig. 6. Fig. 6. The mode nized measu emen sys em The u he de eloped sys em is useable wi h a PC o pe o m p ecision measu emen s. The da a o he measu emen s a e di ec ly e alua ed in a PC [5]. VI. PRECISION MEASUREMENT OF VIBRATIONS AND CALIBRATION OF THE LDV UNIT The ope a ional accu acy o he u he de eloped measu emen uni can be checked by he Renishaw sys em. The calib a ion p ocess o he LDV uni has been done by he in es iga ed lase in e e ome e . The measu emen s o he displacemen s a e aken place a he same ime wi h he LIMA and he Renishaw sys em. The a angemen o he measu emen is shown in Fig. 7. Fig. 7. The a angemen o he displacemen measu emen A p og am had o be w i en in Scilab so wa e o c ea e he equency spec um and he displacemen - ime diag am o he ib a ions o he shocks. The esul s and he e alua ion o he measu emen s we e in es iga ed in de ail in he scien i ic s uden wo k [13]. In his pape only some esul s o he measu emen be ween he in es iga ed in e e ome e and he Renishaw XL-80 uni a e discussed. The esul s o one o he measu emen s a e shown in Fig. 8. I is impo an , ha he wo in e e ome ic sys ems measu e he opposi e side o he objec able, which is he explana ion o he opposi e signs ob ained o he displacemen s. Since he e e ence imes o he wo measu emen uni s a e no ha monized, he e o e he ime axis is shi ed ela i ely o each o he . The wo main equency componen s had o be calcula ed (1) and (2) be ween he wo black lines, which a e shown in Fig. 8. The eloci y da a o he LIMA and he LDV uni a e di e en . The eloci y esul s o he LDV a e 3.5 imes bigge han he calcula ed esul s o LIMA [9]. Du ing he calib a ing p ocess, he ecommended alue o he scaling ac o , which was gi en by he manu ac u e had o be modi ied. Recen Inno a ions in Mecha onics (RIiM) Vol. 3. (2016). No. 1-2. DOI: 10.17667/ iim.2016.1-2/12. 4 Fig. 8. Pa ial esul o he measu emen s VII. CONCLUSION In he esea ch his pape was dealing wi h he de elopmen o a lase in e e ome ic measu emen and da a p ocessing uni , which could be used o ib a ion measu emen s and also o demons a i e pu poses. Upon he a ailable li e a u e he o iginal measu emen uni was e iewed, which helped o design i s mode niza ion. Du ing he planning session he schema ic o an analog compa a o ci cui was made and om his a p in ed ci cui boa d (PCB) was also designed. As he nex s ep he plan o he on panel and i s labelling we e designed wi h a so wa e called F on Design. Then he posi ion o he bo es and cu ing posi ions o he panel we e manu ac u ed. The analog compa a o ci cui was manu ac u ed o con e he signals o TTL. The compa a i e p ecision ib a ion measu emen s ealized wi h a Renishaw XL-80 compac in e e ome e . The LIMA could be pe ec ly used o ca ying ou p ecision displacemen measu emen s up o µm esolu ion. I was s a ed ha he in e e ome e and he ib ome e also could show he dominan equency componen s. P oblems [9] wi h he calib a ion o he ib ome e we e sol ed. The calib a ion was ealized wi h he upda ed in e e ome e . Two mode n, ope able measu ing and da a-p ocessing modules we e success ully made o he lase in e e ome e head uni a he Ins i u e o Physics in collabo a ion wi h he Wigne Resea ch Cen e o Physics. The de elopmen o he so wa e o he uni and he op imiza ion o he beam expansion o he head uni a e amongs my plans o he u u e. Also mo e p ecise de ices will be used o adjus ing he p isms ins ead o he ecen ly u ilized ones. ACKNOWLEDGMENT This esea ch was ca ied ou in he amewo k o ha Cen e o Excellence o Mecha onics and Logis ics a he Uni e si y o Miskolc. 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