Vessel Thruster Bias Mode Control for Energy and Motion Stability
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Solution Overview
Problem
Manual activation and deactivation of the non-directional bias mode in vessels lead to inefficient energy consumption and compromised motion performance due to improper timing, resulting in increased wear and tear on thrusters and potential deviations from target positions or velocities.
Innovation Solution
A control system that estimates operational conditions and automatically commands the activation, deactivation, or bias level change of the bias mode, ensuring optimal use of the bias mode to enhance motion performance and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual activation and deactivation of non-directional bias mode is used, then motion performance can be improved when needed, but energy consumption increases and thruster wear increases due to improper timing
Solution Approach 1:
The control system performs preliminary estimation of operational conditions (wave forces, wind forces, current) to predict when bias mode activation will be beneficial. By proactively determining optimal activation/deactivation timing based on forecasted conditions rather than reactive manual operation, the system prevents unnecessary bias mode usage that would waste energy while ensuring timely activation when motion performance is needed.
Solution Approach 2:
The control system continuously monitors actual operational conditions and compares them with estimated conditions to evaluate the effectiveness of bias mode activation. This feedback loop allows the system to learn from past decisions and optimize future activation timing, reducing energy consumption from premature or prolonged bias mode usage while maintaining reliable motion performance when required.
2Reliability
If manual activation and deactivation of non-directional bias mode is used, then motion performance can be improved when needed, but thruster wear increases due to improper timing
Solution Approach 1:
The control system estimates operational conditions in advance to determine optimal moments for bias mode activation, preventing unnecessary thruster cycling that would increase wear. By proactively identifying situations where bias mode will provide meaningful motion performance improvement, the system minimizes redundant thruster adjustments and extends thruster lifetime while maintaining reliability when needed.
3Speed
If non-directional bias mode is activated to improve responsiveness, then motion performance increases, but energy consumption increases
Solution Approach 1:
The control system estimates operational conditions including wave forces and wind forces to predict when high responsiveness will be needed. By activating non-directional bias mode only when estimated conditions indicate significant external forces requiring rapid response, the system achieves high responsiveness when necessary while avoiding continuous activation that would waste energy during calm conditions.
Data Source
AI summary
A method of controlling a vessel having a plurality of thrusters, where the vessel is configured to operate in a bias mode where at least two of the thrusters provide thrust forces at least partly in opposite thrust directions, the method including estimating, by a control system, an operational condition associated with the vessel; and commanding, by the control system and based on the estimation, execution of a countermeasure associated with an activation of the bias mode, a deactivation of the bias mode or a change of a bias level of the bias mode. A control system and a vessel are also provided.