Model free visual servoing in macro and micro domain robotic applications

Abstract

Bu calsmada, makro ve mikro duzeylerde gerceklestirilmis degisik gorevler icindeney sonuclarn degerlendirerek, modelden bagmsz gorsel geri beslemeli kontrolalgoritmalar uzerine performans arastrmas yaplmstr. Modelden bagmsz yadabir diger adyla kalibre edilmemis gorsel geri beslemeli kontrol, komposit (imge+robot)Jakobyan' cevrimici olarak kestirebildiginden sistemin kalibre edilmesine (gorme sistemi+ robotik sistem) ve incelenen ortamn modeline ihtiyac duymaz. Parametredegisimlerine ve bozucu ds etkilere kars gurbuzdur. Modelden bagmsz gorsel geribeslemeli kontrol yontemi 7 serbestlik derecesine sahip Mitsubishi PA10 robotik kolve mikromontaj is istasyonu uzerinde test edilmistir. Makro dunyada, duzlemselsekil hizalama icin yeni bir yaklasm sunulmustur. Sekil hizalama islemi, bir egrinindsbukey zarf (convex-hull) kullanlarak elde edilen, iki noktada tegetler (bitangents)yardmyla gerceklestirilmistir. Hizalama islemi kalibre edilmis ve kalibreedilmemis gorsel geri beslemeli kontrol yaklasmlar kullanlarak gerceklestirilmisve sonuclar karslastrlmstr. Buna ilave olarak, modelden bagmsz gorsel geribeslemeli kontrol kare, cember ve sinus gibi degisik yorunge takibi gorevleri icindenenmistir ve bu yorungeler kendileri boyunca ara hedeer ureten bir dogrusalaradegerleyici kullanlarak olusturulmustur. Modelden bagmsz gorsel geri beslemelikontrol metodunun, kalibrasyonu oldukca usandrc ve hata olaslg yuksek olanve ayrca her farkl yaknlastrma seviyesinde sistemin yeniden kalibre edilmesinigerektiren optik sistemlerde kullanm oldukca rahatlk saglamaktadr. Bu nedenlemakro dunyada yaplanlarn dsnda, mikrokonumlandrma ve uc farkl yorungetakip gorevi de mikro dunyada gerceklestirilmistir. Sunulan deneysel sonuclar,modelden bagmsz gorsel geri beslemeli kontrol algoritmalarnn makro ve mikroduzeylerde gerceklestirilen gorevlerde kullanlmasnda sagladg faydalar ortayakoymustur.Anahtar Kelimeler: Model bagmsz, gorsel geri beslemeli kontrol, sekil hizalama,iki noktada tegetler, mikrosistemler

This thesis explores model free visual servoing algorithms by experimentallyevaluating their performances for various tasks performed both in macro and microdomains. Model free or so called uncalibrated visual servoing does not need thesystem (vision system + robotic system) calibration and the model of the observedscene, since it provides an online estimation of the composite (image + robot) Jacobian.It is robust to parameter changes and disturbances. A model free visualservoing scheme is tested on a 7 DOF Mitsubishi PA10 robotic arm and on a microassemblyworkstation which is developed in our lab. In macro domain, a newapproach for planar shape alignment is presented. The alignment task is performedbased on bitangent points which are acquired using convex-hull of a curve. Bothcalibrated and uncalibrated visual servoing schemes are employed and compared.Furthermore, model free visual servoing is used for various trajectory following taskssuch as square, circle, sine etc. and these reference trajectories are generated by alinear interpolator which produces midway targets along them. Model free visualservoing can provide moreexibility in microsystems, since the calibration of theoptical system is a tedious and error prone process, and recalibration is requiredat each focusing level of the optical system. Therefore, micropositioning and threedierent trajectory following tasks are also performed in micro world. Experimentalresults validate the utility of model free visual servoing algorithms in both domains.Keywords: Model free, visual servoing, shape alignment, bitangents, microsystems