Design of A flexure-based mixed-kinematic XY high-precision positioning platform with large range

Piezoelectric stack actuators with mechanical structure are widely used in scanning probe microscope to achieve high-precision positioning. However, their positioning ranges can only reach a few hundred microns, which cannot meet the demand of large-range imaging, especially for biological samples. To overcome these shortcomings, a flexure-based decoupled XY high-precision and large-range positioning platform with simple and compact mechanical structure is proposed in this paper. Leaf-type flexure hinges are used to achieve large-range positioning. Based on the leaf-type flexure hinges, a novel mechanism called mixed-kinematic mechanism, which combines serial and parallel kinematic mechanism together, is proposed to simplify the mechanical structure of the platform to make it compact. In addition, XY decoupling is achieved by adopting a novel decoupling structure. Structural parameters and the arrangement of hinges are precisely designed to guarantee the millimeter-level positioning range within safe levels. The performances of the platform including positioning range, resonant frequency and safety are analyzed through finite-element analysis. Experimental results of the platform tests demonstrate that the platform can achieve millimeter-level positioning with good decoupling between the two axes. The eigenfrequencies obtained by experiments also indicate that the designed platform is capable of high-speed positioning with large range. (C) 2019 Elsevier Ltd. All rights reserved.