engleski

Influence of design parameters on the behaviour of cross-spring pivots

Compliant mechanisms gain at least part of their mobility from the deflection of the flexible member. They are characterised by high precision, possibility of monolithic manufacturing, as well as the absence of backlash and wear. Numerical methods are used in this work to characterise the behaviour of compliant rotational mechanisms, known as cross-spring pivots, aimed at ultrahigh- precision positioning applications. The results obtained by using nonlinear finite element calculations are compared with experimental data reported in literature. The finite element model developed in this way makes it possible to conider the influence of lateral loads and of non-symmetrical pivot configurations where the angle or point of intersection of the leaf springs can be varied. This allows assessing the influence of the cited design parameters on the minimisation of the parasitic shifts of the geometric centre of the pivot, as well as on the minimisation of the variability of the rotational stiffness of the pivot while ensuring its stability. The obtained results allow determining design solutions applicable in ultrahigh- precision positioning applications, e.g. in the production or in handling and assembly of MEMS devices.

compliant devices ; cross-spring pivots ; ultrahigh-precision positioning ; FEA modelling ; parasitic displacements ; rotational stiffness

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