Spatial flexure elements in a compliant motion stage

Abstract

2D flexure elements fulfil a pivotal role in the field of precision positioning systems as they do not suffer from backlash, friction or play and exhibit highly repeatable behaviour. However, planar building blocks are characterized by a limited design space as the majority of the flexure elements are flat and straight. In this thesis, it is proposed to investigate another type of flexure element that features spatial (3D) properties. More specifically, it considers the use of helical flexure geometries in motion stages. Insight into the linear kinematic behaviour of various helical surfaces with varying curvature is provided with the usage of parametric optimization, screw theory, unified stiffness method and a performance metric. The newly acquired insights served as a prerequisite for selecting a suitable topology capable of guiding a stage. For demonstration purposes, a motion stage prototype was fabricated consisting of three helical flexure elements. Additionally, an eigenfrequency analysis was performed and experimentally validated with a model vibration test. This has led to the successful realization of a helical based compliant motion stage.