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University of California, San Diego
Mechanical and Aerospace Engineering
MAE 156B: Senior Design Project
Christopher Cordano, Anast Han, Christopher Mansfield-Reid, Trevor Marshall, Wills Moore
Project Overview
Project Overview
The Active Ballast Control System for Semi-Submersible Marine Platforms aims to create a self-stabilizing platform amidst wave motion for the application moored offshore wind turbines. Multiple ballast tanks at different locations on the platform will expel and intake water to keep the platform level while counteracting wind disturbances.
The overall goal of the platform is to reduce any inefficiencies that occur from turbine shaft misalignment in the direction of wind shear. The actuation of this system relies on data collected by position sensors placed throughout the platform. An on-board microcontroller can process this data, and activate the pistons to move liquid from the ballast(s) with low vertical position to ballast(s) with high vertical position.
Over a 15-week period, our team designed, tested, and constructed a fully functional hardware prototype at approximately 1:106 scale of standard floating offshore wind turbine dimensions. This proof-of-concept will demonstrate how active ballast control can enhance the operational capabilities of semi-submersible wind turbines, a technology crucial for expanding renewable energy production into deeper waters.
Problem Definition
Traditional semi-submersible platforms rely on passive stabilization methods, which can be insufficient during extreme weather events or unusual wave patterns. While existing systems employ basic ballast management, they typically require manual intervention and cannot respond dynamically to rapid environmental changes. Current solutions often sacrifice power generation efficiency to maintain stability, as turbines must shut down during adverse conditions. This limitation particularly affects deep-water installations where fixed-bottom foundations are impractical, creating a pressing need for innovative stabilization solutions to maintain optimal turbine positioning regardless of sea state.
Final Design
Final Design
The design incorporated a three ballast configuration with a central buoyancy device to maintain floatation within the water. The central device, called the "spar," houses our main controllers and power supply, while the ballast allow the platform to change the center of buoyancy and mass.
Ballasts accomplish these dynamics using a linear actuator and piston design. Motors connected to lead screws allow the piston to slide along linear rails. An O-ring around each piston creates a barrier between the water and the air. As the pistons move upward, it draws in water underneath and effectively decreases its buoyancy. With three ballasts, the platform is able to provide two degrees of freedom along the roll and pitch axes.
To make the system actively control for disturbances, an IMU housed in the nacelle provides real time pitch and roll data to the controllers in the spar. Using a control algorithm, the controllers determine the position of the pistons at each ballast.
Poster
Stable Wind Poster Board FINAL.pptxPage updated
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