Design of compliant microleverage mechanisms

Abstract

A compliant microleverage mechanism can be used as a mechanical amplifier in micro-electro-mechanical systems (MEMS) to transfer an input to output for achieving mechanical or geometric advantages, such as amplifying force or displacement. Constrained by micro-fabrication technologies, a microleverage mechanism is formed by co-planar flexures, achieving mechanical transformation through elastic deformation. This paper presents the design theory and synthesis of compliant microleverage mechanisms including single-stage and multistage microlevers. The analysis of a single-stage microleverage mechanism is presented as the building block for the multistage microleverage mechanisms. With two-stage and other multistage microleverage mechanisms, a compliance-match theory is found between the adjoining microlever stages and, more specifically, microlever stages should become stiffer and stiffer from input to output. Also calculated are the maximum amplification factor and the optimum number of microlever stages for a given output system. A resonant accelerometer with a two-stage microleverage mechanism is designed and fabricated by a silicon-on-insulator MEMS process run.