Variable Aspect Ratio Stabilizing Fin for Watercraft Roll Control

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Solution Overview

Problem

Existing anti-roll stabilization systems for watercraft face challenges in providing optimal performance during both navigation and anchoring, as they struggle to efficiently counter roll motions induced by wave motion, particularly at anchor where lift cannot be exploited, and require larger actuation surfaces and different fin aspect ratios for effective stabilization.

Innovation Solution

A control method and system that predicts the roll oscillation of a watercraft using detected roll values and estimates destabilizing and stabilizing moments, determining a path for the stabilizing fin's movement to optimize anti-roll stabilization, incorporating adaptive mechanisms to adjust control parameters based on real-time sea conditions and actuator performance, and calculates the path of the fin to counteract destabilizing torque effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If stabilizing fins exploit lift during navigation, then high stabilizing moments are generated with relatively small actuation surface, but at anchor lift cannot be exploited and considerably greater actuation surface is necessary

Engineering Contradiction:

Improvestabilizing momentVSAvoidactuation surface

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The fin aspect ratio is made variable through a mechanism that allows transformation between high aspect ratio and low aspect ratio configurations. This dynamic adjustment enables the system to optimize fin geometry based on operational conditions (navigation vs. anchoring), resolving the contradiction between achieving high stabilizing moments with small surface area during navigation versus requiring larger effective surface area when anchored.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the aspect ratio of the fin is increased for anchoring, then efficiency for stabilization at anchor is improved, but the system becomes less adaptable to navigation conditions

Engineering Contradiction:

Improvestabilization efficiency at anchorVSAvoidadaptability to different conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

3Device complexity

If conventional control systems use fixed control parameters, then system simplicity is maintained, but performance optimization under varying sea conditions is limited

Engineering Contradiction:

Improvecontrol system simplicityVSAvoidstabilization performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control system incorporates feedback mechanisms that continuously monitor sea conditions, fin position, and watercraft roll motion. Based on this feedback, the controller dynamically adjusts control parameters including fin angle, fin aspect ratio configuration, and actuation frequency to optimize stabilization performance under varying operational conditions while maintaining system reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control system dynamically changes operational parameters including fin angle, fin aspect ratio, and actuation frequency based on detected sea conditions and watercraft motion characteristics. This parameter adaptation enables optimized stabilization performance across different scenarios (navigation, anchoring, various wave conditions) while managing system complexity through structured control algorithms.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances anti-roll stabilization by optimizing fin movement paths, improving comfort and stability during navigation and anchoring by accurately predicting and countering roll oscillations, ensuring effective torque application and adapting to varying conditions, thereby providing superior performance across different marine scenarios.

Implementation Method 1

at anchor it is not possible to exploit the lift but it is necessary to exploit the inertial forces (acceleration and deceleration) and the forces of viscous resistance

Methodology Applied

Scientific EffectInertial forces: Inertia

Implementation Method 2

at anchor it is not possible to exploit the lift but it is necessary to exploit the inertial forces (acceleration and deceleration) and the forces of viscous resistance (linked to the velocity of actuation of the fin)

Methodology Applied

Scientific EffectViscous resistance: Viscous Damping

Implementation Method 3

during navigation the stabilizing fins exploit the phenomenon of lift for generating high stabilizing moments with a relatively exiguous surface of actuation

Methodology Applied

Scientific EffectLift: Aerofoil

Data Source

PatentUS10077098B2Control method for anti-roll stabilization of watercraft, and corresponding stabilization system and computer program product

Publication Date: 2018.09.18 CMC MARINE

AI summary

A method for controlling a stabilizing fin for anti-roll stabilization of watercraft standing at anchor, comprising the steps of: detecting at least one value identifying roll of the watercraft; estimating the expected oscillation of roll of the watercraft as a function of the value detected; determining a path for the movement of the stabilizing fin as a function of the expected roll; and controlling the movement of the stabilizing fin as a function of the path.