  The motion of biological micro-robots -- similar to that of swimming
microorganisms such as bacteria or spermatozoa -- is governed by different
physical rules than what we experience in our daily life. This is particularly
due to the low-Reynolds-number condition of swimmers in micron scales. The
Quadroar swimmer, with three-dimensional maneuverability, has been introduced
for moving in these extreme cases: either as a bio-medical micro-robot swimming
in biological fluids or a mm-scale robot performing inspection missions in
highly viscous fluid reservoirs. Our previous studies address the theoretical
modeling of this type of swimmer system. In this work, we present the
mechatronic design, fabrication, and experimental study of a mm-scale Quadroar
swimmer. We describe the design methodology and component selection of the
system based on the required performance. A supervisory control scheme is
presented to achieve an accurate trajectory tracking for all the actuators used
in the swimmer. Finally, we have conducted experiments in silicone oil (with
5000 cP viscosity) where two primary modes of swimming - forward translation
and planar reorientation - have been tested and compared with the theoretical
model.
