Engineering shapes and instability in thin structures: Towards self-assembling micro-robots

Helical structures are the basic building blocks in biological systems, and have inspired the design and manufacturing of helical devices with applications in nanoelectromechanical systems (NEMS) , bio-chemical sensing, magnetic field detection, optoelectronics, micro-robotics and drug delivery devices. Meanwhile, multi-stable structures, represented by the Venus flytrap and spring tape, have attracted increasing attention due to their applications in making artificial muscles, bio-inspired robots, deployable aerospace components and energy harvesting devices. Here we address the mechanical principles of self-assembly in spontaneous bending and twisting structures, which can be employed to manufacture self-assembling robotics at various scales. The established theoretical framework provides a means of guiding the on-demand design of self-assembling systems with potential actuating mechanisms. Experimental designs of such structures at both macroscopic and microscopic scales, supported by finite element modeling results, demonstrate the feasibility of creating self-assembled micro-robots with desirable mechano-sensing and actuating capability.