A family of flexures that eliminate underconstraint in nested large-stroke flexure systems

Abstract

In this paper we introduce a family of flexure linkages that may be used to eliminate underconstraint in nested, large-stroke flexure systems. Typically such systems achieve their large ranges of motion (i.e., stroke) because they consist of nested modules that possess redundant degrees of freedom (DOFs). Unfortunately, however, these redundant DOFs result in underconstrained bodies that are susceptible to parasitic errors, unwanted vibrations, and poor controllability. The flexure linkages proposed here eliminate underconstraint by coupling these bodies in a way that improves the system's static and dynamic performance without increasing its size or decreasing its stroke. Thus, such linkages impact the design of precision motion systems that traverse large ranges with appreciable speeds in potentially dynamic environments. Examples of such systems include energy harvesters, positioning stages, and MEMS devices such as resonators, micro-mirrors, and accelerometers. In this paper, we provide example flexure linkages as well as general guidelines for synthesizing them.