  We designed and constructed an A-sized base autonomous underwater vehicle
(AUV), augmented with a stack of modular and extendable hardware and software,
including autonomy, navigation, control and high fidelity simulation
capabilities (A-size stands for the standard sonobuoy form factor, with a
maximum diameter of 124 mm). Subsequently, we extended this base vehicle with a
novel tuna-inspired morphing fin payload module (referred to as the Morpheus
AUV), to achieve good directional stability and exceptional maneuverability;
properties that are highly desirable for rigid hull AUVs, but are presently
difficult to achieve because they impose contradictory requirements. The
morphing fin payload allows the base AUV to dynamically change its
stability-maneuverability qualities by using morphing fins, which can be
deployed, deflected and retracted, as needed. The base vehicle and Morpheus AUV
were both extensively field tested in-water in the Charles river,
Massachusetts, USA; by conducting hundreds of hours of operations over a period
of two years. The maneuvering capability of the Morpheus AUV was evaluated with
and without the use of morphing fins to quantify the performance improvement.
The Morpheus AUV was able to showcase an exceptional turning rate of around
25-35 deg/s. A maximum turn rate improvement of around 35% - 50% was gained
through the use of morphing fins.
