Design, Analysis and Fabrication of SAF AM, A 4 DOF Assembled Microrobot

In this paper we present a new type of 3-dimensional microrobot, the Solid Articulated Four Axes Microrobot (sAFAM). This microrobot is an evolutionary improvement of a previous microrobot utilizing microassembly of out-of-plane compliant mechanical structures. The original AFAM was a microrobot driven by two coupled in-plane MEMS X-Y stages, through an epoxied cable to an out-of-plane assembled arm. In this paper, sAFAM was designed to replace the cable traction system with an unibody arm that can be assembled into the in-plane X-Y stages, which simplifies the assembly process complexity and improves the microrobot precision. The proposed structure was simulated with finite element analysis (FEA), resulting in a $22\mu m\times 47\mu m\times 18\text{S}\mu m$ workspace, appropriate concentration of stresses during actuation, and reduced motion coupling between the microrobot degrees of freedom. Fabrication and assembly processes are discussed and demonstrated experimentally, and results closely match simulations. sAFAM has the potential to be used as an assist $\mathbf{micro}/\mathbf{nano}$ manipulation tool in the scanning electron microscope (SEM) or the atomic force microscope (AFM).