Marine Vessel Roll Stabilisation via Predictive Wave Slope Control
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Solution Overview
Problem
Conventional active roll stabilisation systems for marine vessels are ineffective in anticipating and counteracting rolling motion caused by wave interactions, as they rely on sensors that provide output only after the vessel has already begun rolling, resulting in delayed activation and increased inertia to correct.
Innovation Solution
A system that uses sensors to characterise approaching sea conditions, processes data to predict wave slope, and generates control signals to activate active stabilisers before the rolling motion occurs, allowing for anticipatory counteraction of expected loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensors are used to detect vessel roll motion, then the stabilisation system can be activated, but the activation is delayed until the vessel has already built up rolling inertia
Solution Approach 1:
The patent applies preliminary action by using wave radar to detect and predict wave characteristics before they reach the vessel. The system calculates the predicted wave slope and generates control signals in advance, activating the stabilisers before the vessel actually encounters the waves and begins to roll. This eliminates the delay inherent in conventional systems that only react after roll motion is detected.
Solution Approach 2:
The patent implements preliminary anti-action by applying counteracting moments to the vessel before the rolling motion occurs. The control system calculates the expected roll moment from incoming waves and activates the stabilisers to create opposing moments in advance, preventing the vessel from building up rolling inertia rather than correcting it after the fact.
2Reliability
If large stabilising forces are applied to correct rolling motion, then the vessel roll is reduced, but power consumption and wear increase
Solution Approach 1:
By activating stabilisers in advance before the vessel encounters waves, the system prevents roll motion from developing rather than correcting it after it occurs. This eliminates the need to apply large corrective forces to arrest established rolling motion, thereby reducing power consumption and mechanical wear while maintaining effective roll reduction.
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
This approach enables timely and effective reduction of rolling motion, reducing the need for large stabilising forces, lowering power consumption, wear, and noise, while allowing for tailored responses to varying vessel loading conditions.
Implementation Method 1
the use of fins projecting from both sides of the vessel which are controlled to present a hydrodynamic angle of attack to the flow of water past the ship. The angle of the fins results in the generation of a restoring moment that acts to counter the direction of roll experienced by the vessel.
Data Source
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AI summary
A system for countering the rolling motion of a marine vessel, comprises one or more sensors adapted to characterise a sea condition approaching the vessel, one or more control systems, a computer, and one or more active stabilisers. The computer is adapted to receive the characterised sea condition data, is further adapted to generate one or more control signals in dependence on the characterised sea condition data, and is still further adapted to transmit the or each control signal to the or each control system. The or each control system is in turn adapted to actuate the or each active stabiliser in response to receipt of the or each control signal, to counter the rolling motion of the marine vessel.