Optimal kinematic design of a link-drive mechanism with prescribed velocity characteristics

The paper presents an example of a link-drive mechanism for a deep drawing mechanical press. Because of its characteristics such a drive is much more appropriate than conventional crankshaft or eccentric drive. The existing design of the drive has proved unsatisfactory and does not meet all the demands and constraints, which are ideal for deep drawing process. Optimization of the drive is therefore necessary. The intention is to achieve the required velocity characteristics in a defined area of movement. Firstly, the drive is analyzed and a mathematical model is made and prepared for optimization procedure. The process is time-dependent, so it cannot be used directly in the optimization algorithm. Mathematical model is transformed intoa form suitable for the standard non-linear optimization procedure and then optimization is carried out. The method used is sequential quadratic programming. The final objective of the optimization process is to find such dimensions of link-drive members that the given requirements are satisfied in the best possible manner

Computer simulation of needle and take-up lever mechanism using the ADAMS software package

A knowledge of the interactions between a sewing machinećs mechanisms and the sewing thread in the stitch formation process should help us to understand thread loadings in the sewing process. The aim of this work is to analyse the needle bar\u27s kinematics with the thread take-up lever by using computer simulation. A cyclogram was drawn on the basis of modelling and kinematic simulation of a needle bar with a thread take-up lever, and measurements of the thread tension forces in the sewing process. This cyclogram enables analysis of the interactions between the thread and the elements of the sewing machine. The results of these simulations are curves that describe the movements at characteristic points on the mechanism. These give the possibility of pinpointing the exact positions of the mechanism\u27s elements with respect to the main shaft rotation in the sewing machine

Optimization of link-drive mechanism for deep drawing mechanical press

V prispevku se ukvarjamo z optimiranjem večzgibnega pogona paha stiskalnice za globoki vlek pločevine. Sedanja konstrukcija ne izpolnjuje vseh postavljenih zahtev, zato jo želimo čimbolj prilagoditi idealnim zahtevam tehnološkega postopka. Osnovni namen je prilagoditi sedanjo hitrostno karakteristiko paha zahtevam delovanja v določenem območju. Zato je bilo treba izdelati analizo pogona in njegov matematični model ter izvesti optimizacijo. Uporabljena metoda za nelinearno optimizacijo je sekvenčno kvadratno programiranje. Ker je postopek časovno odvisen, optimizacijskega modela ni moč uporabiti neposredno, ampak je treba primer prevesti v časovno neodvisno obliko, ki je primerna za reševanje s standardnim optimizacijskim postopkom. Cilj optimiranja je določiti takšne izmere pogonskega mehanizma, ki bi čimbolj izpolnile zahteve. V sklepu je prikazana primerjava doseženih rezultatov optimirane konstrukcije večzgibalnega pogona z začetnim stanjem pred optimizacijo.This paper deals with an example of a link-drive for a deep-drawing mechanical press. The existing design has proved unsatisfactory and does not meet all the demands and constraints which are required for this metal-forming process. Optimization of the drive is therefore necessary. Firstly, the drive is analysed and a mathematical model is made. The whole process is time-dependent, so it cannot be used directly in the optimization algorithm. This mathematical model has first to be transformed into a form suitable for the standard non-linear optimization procedure and then the optimization is carried out. We use the method of sequential quadratic programming. The final objective of the optimization process is to find the dimensions of the link-drive members such that the gives requirements are satisfied in the best possible manner. In conclusion, the results are described and compared with the initial design

Projektno delo študentov na programu Mehatronika

Na bolonjskem programu Mehatronika smo na prvi stopnji uvedli projektno delo študentov. Prva bolonjska stopnja traja šest semestrov in s projekti začnemo včetrtem semestru, nadaljujemo v petem in končamo v šestem semestru, kjer se zadnji projekt praviloma konča z diplomskim delom. Projektno delo je vrednoteno z 8 ECTS v vsakem semestru. To znese skupaj 24 ECTS. Polovica točk je namenjena kontaktnim uram, druga polovica pa samostojnemu delu študentov. Projekte vsako leto razpišemo in jih v začetku semestra ponudimo študentom. Ti izberejo, kar se jim zdi zanimivo in kar jih priteguje. Projekti so organizirani tako, da sinergijsko povezujejo teoretična znanja, ki so si jih študenti pridobili pri teoretičnih in strokovnih predmetih z aplikacijami, ki so v projektnih nalogah zahtevane. Bistvo projektnega dela je rezultat, ki pa ni omejen na javno predstavljeno poročilo na koncu semestra, temveč je poudarek na mehatronskem izdelku, ki praviloma mora biti realiziran. Kot dober primer projektnega dela študentov je v prispevku prikazan primer projekta, ki se razvija iz leta v leto z vedno novimi študenti in nalogami. Delo temelji na gradnji in stalnih modifikacijah robotizirane proizvodne celice za točkovno varjenje, ki ji bo letošnja generacija študentov dodala novo aplikacijo, to je frezanje poljubnih 3D oblik za izdelke do velikosti 2m3. Robotizirana proizvodna celica je ob tem namenjena tudi za pedagoško delopri laboratorijskih vajah, prav tako pa za najrazličnejše raziskovalne aplikacije v robotiki in robotizaciji