FEA-based optimization of a complete structure of a monolithic z/tip/tilt micromanipulator

Abstract

In micro/nano manipulation mechanisms, the compliant z/tip/tilt stages have proved to have enormous advantages for out-of-plane positioning. Small workspace is a challenge in designing these out-of-plane positioning systems. This deficiency can be overcome significantly by a new insight into the optimization approach of a compliant mechanism that can be implemented easily on the entire structure of any spatial mechanism and/or any spatial mechanism with n-symmetrical spatial kinematic chains. Finite Element Method (FEM) adopted by the engineering software, ANSYS, is utilized to perform the structural optimization of an entire three-way symmetric spatial compliant mechanism to achieve the best performances and overcoming deficiencies. Therefore, this paper introduces a compliant monolithic three degrees of freedom (DOFs) z/tip/tilt piezo-driven micromanipulator with a comparable large workspace. Furthermore, as compact as 201 mm × 180 mm × 75 mm and made of Acrylonitrile Butadiene Styrene (ABS) with the first natural frequency of 115.42 Hz make this design superior in comparison to its peers. Regarding the structural aspects, three Scott-Russell and six leaf parallelogram mechanisms are employed to transform horizontal piezoelectric actuators’ inputs (PEAs) to vertical inputs and transfer them to the stage. The best performances of the proposed structure are achieved by optimizing the mechanism using FEM. Due to the optimization, a large amplification ratio of 5.3 is achieved. Moreover, finite element analyses and analytical modeling are performed to verify the performance of the proposed mechanism. Finally, in a comparative study, the captured workspace and resonant frequency of the proposed micromanipulator are compared against those available in theliterature and provide an insight into the performances of the proposed monolithic mechanism.