This paper describes initial work on untethered microscale flying structures as a platform for new class of aerial MEMS microrobots. We present and analyze both biomimetic structures based partially on wing designs of smallest flying insects on Earth, as well as stress-engineered structures powered by radiometric (thermal) forces. The latter devices, also called MEMS Microfliers are 300 μm × 300 μm × 1.5 μm in size, and are fabricated out of polycrystalline silicon. A convex chassis, formed through a novel in-situ masked post-release stress-engineering process, ensures their static inflight stability. High-speed optical micrography was used to image these MEMS microfliers in mid-flight, analyzing their flight profile.
Microassembly is one of the applications successfully implemented by group of individually-controllable MEMS microrobots (MicroStressBots). Although the robots are controlled using a centralized optical closed-loop control systems, i.e., a camera mounted on top of a microscope, compliance and self-alignment were used to successfully reduce the control error and permit precise assembly of planar structures. In this work, we further explore the possibility of using compliance to facilitate docking between MicroStressBots. The forces generated by the docking surfaces create a local attractor (pre-image of the goal configuration) that facilitates alignment between the two structures. Through this interaction the robot senses and aligns its position to match the desired configuration. Specifically, in this work we examine two cases: a) docking of two microrobots with straight front edges that promote sliding, and b) docking of two microrobots with patterned edges that restricted sliding between the two robots. In the former case, the robots are engaged in mutual alignment, which is akin to pairwise Self Assembly (SA). This allows generation of highly accurate seed-shapes for further assembly. In the latter case, the robots with matching pattern edges can dock and successfully align. Here, the patterned edge functions as a lock-and-key mechanism, and is akin to the selective affinity in SA-systems. The difference however between a system of MicroStressBots and SA is that MicroStressBots contain active on-board propulsion compared with passive SA systems.