Vessel Thruster Bias Mode Control for Disturbance Response
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Solution Overview
Problem
Conventional vessel position control methods using thrusters face inefficiencies due to manual activation and deactivation of bias modes, leading to increased energy consumption, wear, and reduced motion performance when responding to external disturbances.
Innovation Solution
A control system that automatically estimates operational conditions to optimize the activation, deactivation, or bias level of directional and non-directional bias modes, enhancing responsiveness and reducing energy consumption by ensuring timely and appropriate use of thruster thrust forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vessel is controlled in normal mode with all thrusters pointing in the same thrust direction to minimize power consumption, then energy consumption is reduced, but the vessel cannot respond effectively to external disturbances acting in multiple directions
Solution Approach 1:
The system dynamically switches between normal mode and bias mode based on operational conditions. In normal mode, all thrusters point in the same direction for energy efficiency. When external disturbances are detected, the system transitions to bias mode where at least two thrusters provide thrust forces in opposite directions, enabling effective response to multi-directional disturbances while minimizing energy consumption during calm conditions.
2Reliability
If thrusters cycle between different thrust directions and forces to compensate for varying external disturbances, then the vessel can maintain position, but this leads to momentary position loss and increased wear and tear
Solution Approach 1:
The system activates bias mode in advance when external disturbances are detected, establishing opposite thrust directions before position loss occurs. This preliminary action prevents the need for rapid thruster cycling and direction changes, thereby reducing mechanical stress and extending thruster lifetime while maintaining reliable position control.
3Ease of operation
If manual activation and deactivation of bias mode is used, then operator control is maintained, but this leads to increased energy consumption and reduced motion performance due to delayed response
Solution Approach 1:
The control system continuously monitors operational conditions and automatically switches between normal mode and bias mode based on detected external disturbances. This feedback mechanism eliminates delays associated with manual activation, optimizing motion performance and energy consumption while maintaining operator ability to override or adjust settings when needed.
Data Source
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AI summary
A method of controlling a vessel (10) comprising a plurality of thrusters (12a-12d), where the vessel (10) is configured to operate in a bias mode (42a, 42b) where at least two of the thrusters (12a-12d) provide thrust forces (36a-36d) at least partly in opposite thrust directions, the method comprising estimating, by a control system (14), an operational condition associated with the vessel (10); and commanding, by the control system (14) and based on the estimation, execution of a countermeasure associated with an activation of the bias mode (42a, 42b), a deactivation of the bias mode (42a, 42b) or a change of a bias level of the bias mode (42a, 42b). A control system (14) and a vessel (10) are also provided.