Date of Award

Winter 2025

Project Type

Thesis

Program or Major

Ocean Engineering

Degree Name

Master of Science

First Advisor

May-Win Thein

Second Advisor

Yuri Rzhanov

Third Advisor

Martin Renken

Abstract

The development of biomimetic robotic fish has been an ongoing research topic for the last 30 years. Here, researchers have explored biomimetic propulsion and maneuverability mechanisms, studied energy efficiency in comparison to live fish, and developed autonomous control algorithms for these extremely nonlinear systems. This work studies a multi-linkage, single-actuator propelled biomimetic robotic fish, the Ghost Uncrewed Performance Platform Submersible (GUPPS), developed at the University of New Hampshire. A set of symmetrically driven, static pectoral fins are added to the original platform to enable diving and surfacing capabilities by controlling the vehicle Angle of Attack (AoA) through pitch and yaw maneuverability. The future intent is to provide a controllable multi-nodal sensor array comprised of a school of robotic fish. A five Degree-of-Freedom (5-DOF) dynamic model is developed to analytically study GUPPS' motion, specifically to observe the response of the body pitch angle with specified pectoral fin inputs. These simulation results are compared to that of lab experiments that implement static fin trials and open-loop control sequences actuated with pre-scripted robotic autonomy. Equipped with an onboard Inertial Measurement Unit (IMU) and a dual-pressure sensor array to measure pitch angle, the simulation and experimental data show consistent alignment. The analytical model is used to tune a Proportional-Integral-Derivative (PID) controller for GUPPS' pitch control regulation. It is observed that the starting depth in relation to the robotic fish's neutral buoyancy point has a significant impact on the success of the controller in maintaining a constant angle. Regardless, the results show that the measured experimental pitch angles in the PID control trials also closely align with those in the analytical simulation.

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