Date of Award

5-4-2026

Degree Type

Capstone Project

First Advisor

Professor Bahram Nassersharif

Abstract

This report presents the final design, fabrication, and validation of a Mechanical Securing Arm System (MSAS) and associated test fixture for recovering an Unmanned Underwater Vehicle (UUV) into a submerged, launch-tube-like structure. Sponsored by the Naval Undersea Warfare Center (NUWC), the project addressed the need for a reliable, low cost, scalable, and mechanically simple UUV recovery method while also reducing hydrodynamic interference caused by the existing tow tank armature setup.

A structured engineering design process was followed, beginning with literature and patent research, customer requirement development, engineering specification generation, and concept evaluation. The team generated 150 total concepts, with 30 concepts per team member, and evaluated the concepts using feasibility analysis, Quality Function Deployment (QFD), and Pugh decision matrices. The selected final concept was the MSAS, a passive mechanical recovery system that uses the incoming motion of the UUV to actuate securing arms and slow the UUV inside the retrieval tube without requiring sensors, optical guidance, or powered actuation.

The final prototype was fabricated primarily from PETG 3D printed components, with steel pins used in the updated MSAS assembly. The model UUV was also printed from PETG and included an internal steel cylinder to improve neutral buoyancy. A separate guide wire and Arduino driven winch test fixture was developed to replace the original vertical tow tank armature. The physical prototype tests pulled the UUV at approximately 1 in/s, while future calculations used a representative speed of 1 knot. The guide wire test fixture reduced the frontal area of the testing apparatus and is estimated to reduce recovery hardware drag by 90% or greater, with an estimated total UUV & test fixture drag reduction of approximately 50%.

Final testing demonstrated that the MSAS successfully recovered the model UUV in 10 out of 10 trials, achieving a 100% recovery success rate and exceeding the original 90% target. The average time to secure the UUV was 5.72 s, and the average pressure applied by each MSAS arm was calculated as 5.448 × 10-3 psi. SolidWorks CFD analysis showed pressure values of 14.695 psi before the tube and 14.718 psi at the retrieval tube opening, corresponding to a pressure difference of approximately 0.023 psi.

Overall, the final design demonstrated reliable prototype scale UUV recovery, low mechanical complexity, and improved test repeatability. Future work should focus on full scale testing, direct drag and force measurement, corrosion resistant materials, expanded hydrodynamic validation, and refinement for potential naval or research based recovery applications.

Comments

Team Name: Team 1

Company Sponsor: Naval Undersea Warfare Center

Sponsor Representatives: Ian Millspaugh, Jaxon Royal

Document Reference: URI-MCE-402-001-2026

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