Marine Propulsion Wave Control for Head-Wave Hull Stability
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Solution Overview
Problem
Existing marine propulsion systems fail to adequately stabilize the hull during waves, leading to insufficient ride comfort due to insufficient wave condition-based control and instability.
Innovation Solution
A marine propulsion system with an up-and-down movement sensor and controller that performs wave control by distinguishing between head waves and following waves, temporarily reducing vessel speed and adjusting attitude to stabilize the hull, using attitude and speed controls based on sensor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vessel speed is temporarily reduced each time the marine vessel rides over a wave, then the up-and-down attitude change of the hull is reduced and hull stability is improved, but when following waves are occurring, the hull tends to become unstable and the ride comfort deteriorates
Solution Approach 1:
The system changes the control parameter (vessel speed adjustment) based on the wave condition parameter (wave direction). When head waves are detected, the vessel speed is temporarily reduced to stabilize the hull. When following waves are detected, the speed reduction control is not applied, preventing hull instability. This conditional parameter change resolves the contradiction by adapting the control strategy to the specific wave condition.
2Device complexity
If simple control based on wave load magnitude is performed, then the control system is simple, but the stability of the hull is not sufficiently maintained and ride comfort is insufficient
Solution Approach 1:
The system uses feedback from up-and-down movement sensors to detect wave conditions and engine rotation speed to detect wave load. This feedback information is processed by the controller to determine wave direction (head wave or following wave) and to decide whether to apply speed reduction control. The feedback mechanism enables sophisticated hull stability control without requiring overly complex system architecture, as it leverages existing sensor data.
3Object-affected harmful factors
If the vessel speed is reduced to reduce impact when riding over waves, then the ride comfort is improved, but the productivity and voyage time are reduced
Solution Approach 1:
The speed reduction control is applied periodically and temporarily only when the vessel encounters head waves, not continuously. The controller temporarily reduces vessel speed each time the marine vessel rides over a wave when head waves are occurring, then restores normal speed when waves subside or when following waves are detected. This periodic, conditional application of speed reduction minimizes impact while preserving productivity during favorable conditions.
Data Source
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AI summary
A marine propulsion system (102, 202, 302 402) includes a propulsion device (1), an up-and-down movement sensor (2b), and a controller (4, 204, 304, 404) configured or programmed to control driving of the propulsion device, and perform a wave control including an attitude control to reduce an up-and-down attitude change of a hull (101) by temporarily reducing a vessel speed based on a measurement result of the up-and-down movement sensor each time a marine vessel rides over a wave when waves are occurring. The controller is configured or programmed to, in the wave control, perform the attitude control when determining that a wave condition is a head wave, and not perform the attitude control when determining that the wave condition is a following wave.