Naslov
Characterization of cross-spring pivots for micropositioning applications

Autori
Marković, Kristina ; Zelenika, Saša

Izvornik
Proceedings of SPIE, the International Society for Optical Engineering (0277-786X) 9517 (2015); 951727-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
cross-spring pivots ; micropositioning ; Elastica ; FEM modelling ; parasitic displacements ; rotational stiffness

Sažetak
Compliant mechanisms gain at least part of their mobility from the deflection of flexible member. They are characterised by high precision, possibility of monolithic manufacturing (‘design for no-assembly’) and of parallel kinematics, as well as no backlash and wear. Several analytical and numerical methods are used in this work to characterise the behaviour of compliant rotational mechanisms, known as cross-spring pivots, aimed at micropositioning applications. In a typical design configuration, a cross-spring pivot allows a movable block to rotate, via the deflection of leaf springs, with respect to the fixed block. In general, the pivot is loaded with a pure bending moment. When ultra-high precision is required, the limits of applicability of approximated calculation algorithms have to be determined. The results obtained by employing these methods are thus compared with results obtained via the generalized nonlinear Elastica- type approach, results obtained by using nonlinear finite element calculations as well as the experimental data reported in literature. The finite element model, tuned to the results of the exact Elastica approach, allows also to consider the influence of lateral loads and of non- symmetrical pivot configurations where the angle or point of intersection of the leaf springs, or even the initial curvature of the springs, can be varied. The aim of this part of the work is to determine the influence of the cited design parameters on the minimisation of the parasitic shift of the geometric centre of the pivot as well as on the minimisation of the variability of the rotational stiffness of the pivot so as to ensure its stability and avoid the possible occurrence of buckling. The obtained results allow therefore determining design solutions applicable in ultra-high precision micropositioning applications, e.g. in the field of production or of handling and assembly of MEMS.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo, Temeljne tehničke znanosti, Interdisciplinarne tehničke znanosti

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