Morpheus: An A-sized AUV with morphing fins and algorithms for agile maneuvering

TL;DR

This paper presents Morpheus, a compact AUV with morphing fins inspired by tuna, enabling dynamic stability and maneuverability adjustments, validated through extensive field testing and demonstrating significant improvements in turning performance.

Contribution

The introduction of a modular, tuna-inspired morphing fin system for an A-sized AUV to enhance agility and stability, with extensive real-world testing validating performance gains.

Findings

Maximum turn rate of 25-35 deg/s achieved

35-50% improvement in turn rate with morphing fins

Extensive two-year field testing conducted

Abstract

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.