Design of Novel 3-dof Nano Precision Stage

INSTRUCTIONS Precision nano-positioning techniques have become very important for biomedical science, optics and microscopy. PZT and flexure compliant mechanisms are widely used in these various fields and applications within these fields. Compliant mechanisms are flexible structures, which can generate the desired motions by undergoing elastic deformation instead of through rigid linkage/joints as in rigid body mechanisms [1]. The advantages of flexure mechanisms include the lack of backlash, the lack of non-linearity, a simply monolithic structure, and ease of manufacturing. These advantages would have enabled ultra-highprecision positioning. Therefore, it is suitable to be used in the fields of biomedical nano-stage. The stage in the field of biomedical is required to design as a hollow type and compact size for the measurement of biological specimens. Several in-plane motion (3-DOF) flexure stages were designed for precision stage. Hua designed a 3DOF ( Z XYθ ) compliant micro positioning stage with amplification mechanism and performed optimal design and input coupling analysis [1]. Tian presented the mechanical design and dynamics of a 3-DOF flexure stage with amplification mechanism [2]. And aside from these, similar parallel mechanism stages were designed for many applications. In particular, several stages have double amplification mechanism for longer working range [3, 4]. However, although above all 3-DOF stages have sufficient working range, ultra-precision accuracy and compact size, these stages are not designed as a hollow type. It is easy to design 2-DOF stage of hollow type, relatively. But, in 3-DOF parallel type stage, it is not easy to design due to triangular structure. Moreover, if the stage should have designed a hollow type maintaining a compact size, it is more difficult to arrange the PZT actuators and the flexure amplification mechanisms. Especially, design of a compact amplification mechanism was great difficulty in proposed stage. Design and modeling a various hinge lever mechanism of amplification device is presented for increasing small PZT actuator out range [5]. As before, many developed stage has an amplification mechanism basically [6, 7]. In those studies, various design conditions to achieve higher magnification ratio were considered. However, it is not suited for stage of hollow type. This paper discusses the mechanical design of a 3-DOF flexure based parallel compliant mechanism for hollow type biomedical specimen stage. Even though the proposed stage is applied both parallel compliant mechanism and hollow type, the stage have a large working range, nanometer resolution with compact size.