Geometric Self-Propelled Articulated Micro-Scale Devices

The advanced development of cyber-physical systems at the sub-millimeter scale will have a large impact on a diverse set of potential applications.  For example, targeted drug delivery or materials conveyance for micro-scale construction are two application areas that will greatly benefit from reliable microsystems.  However, conventional actuator, sensor, and computational units are generally not available at extremely small scales.  This project will thus explore the nontrivial connections between novel fabrication, intelligent design, and the active control of micro-scale, cyber-physical systems.  Specifically, this project will develop a common analytical framework that lies at the intersection of microfabrication techniques and geometric locomotion analysis and design.  The framework will be used as the basis for constructing microrobots whose magnetized bodies will be optimally designed for different locomotive objectives.  The same framework will also be used to inform online controllers about how to vary an external magnetic field that will be used as the basis for actuating the systems’ bodies.  The ultimate objective of this project will be to produce desired net motions of the swimmers when they are submerged in a viscous fluid.  The cross cutting and interdisciplinary nature of this project will thus make it highly appealing as a teaching tool for K-12 outreach as well as for STEM education. 

More specifically, the systems that will be constructed in the proposed project will form elasto-magnetic filaments composed by linked ferromagnetic beads.  The filaments will be constructed by first applying a set of geometric analysis tools to inform a template design process.  The objective of the microfabricated templates will be to “catch” individual beads in different configurations of hemispherical pockets.  While in the templates, the protein-coated beads will 1) be mechanically linked via functionalized DNA nanostructures and 2) magnetized using a strong external field.  The geometric configuration of the beads while in the templates will thus be used to “program” the distribution of magnetic dipole moments across the filaments once removed.  When subjected to a constant but oscillating weak magnetic field, the local alignment of dipole moments to the field will be used to actively “actuate” the systems.  The geometric analysis framework will be developed to both determine the “optimal” distribution of magnetization profiles across the filaments, and thus link fabrication to analysis, as well as to determine how to vary the external field to effect different maneuvers in viscous fluids, such as swimming in a straight line or turning in place.