Design principles and millimeter-level applications of direct-acting piezoelectric platforms utilizing flexure hinges

Abstract Direct-acting piezoelectric platforms are extensively utilized in high-precision machining and manufacturing fields due to their exceptional advantages, including high precision, fast response, and immunity to electromagnetic interference. However, the output displacement of traditional direct-acting piezoelectric platforms is often limited to the order of tens of micrometers, which is beyond the engineering requirements of millimeter-level strokes. Displacement amplification fundamentally depends on flexure hinges and displacement amplification mechanisms. Consequently, this study first classifies flexure hinges according to their notch shapes. Simultaneously, displacement amplification mechanisms are categorized based on operational principles. The core operating characteristics of both components are systematically outlined. The theoretical or numerical modeling of the piezoelectric platform based on the flexure hinge is also introduced. Following this, a variety of direct-acting piezoelectric platforms that realize millimeter to sub-millimeter strokes and their structural principles are reviewed by application area. Finally, the issues of manufacturing cost and design complexity (multi-stage amplification) are discussed. The aim of this study is to provide new ideas for the design of future millimeter-scale direct-acting piezoelectric stages, and to promote their in-depth application in engineering practice.