Title: Stress-Based Navigation for Microscopic Robots in Viscous Fluids,
Abstract: Objects moving in fluids experience patterns of stress on their surfaces
determined by their motion and the geometry of nearby boundaries. Fish and
underwater robots can use these patterns for navigation. This paper extends
this stress-based navigation to microscopic robots in tiny vessels, where
robots can exploit the physics of fluids at low Reynolds number. This applies,
for instance, in vessels with sizes and flow speeds comparable to those of
capillaries in biological tissues. We describe how a robot can use simple
computations to estimate its motion, orientation and distance to nearby vessel
walls from fluid-induced stresses on its surface. Numerically evaluating these
estimates for a variety of vessel sizes and robot positions shows they are most
accurate when robots are close to vessel walls.