Ship Engine and Rudder Control Using External Force Estimation
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Solution Overview
Problem
Existing ship control systems face increased control errors and fuel consumption due to the influence of external force vectors, which are not adequately accounted for in current navigation methods.
Innovation Solution
A ship control system that includes a route command unit, an information detector, an external force vector estimation unit using a hull motion model, and a control command unit to control the main engine and rudder angle based on the estimated external force vector, thereby reducing the impact of external forces on ship position and attitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If correction is made after positional deviation becomes large, then the ship can return to the scheduled position, but the control error increases and fuel consumption increases
Solution Approach 1:
The system performs preliminary action by estimating external force vectors (wind, waves, currents) in advance and using these estimates to proactively adjust the steering command. This prevents large positional deviations from occurring in the first place, rather than correcting after deviations become large, thereby reducing both control errors and the fuel consumption required for correction.
2Reliability
If external force vector estimation is not taken into account, then the control system is simpler, but the control error due to external force vector increases
Solution Approach 1:
The system introduces an external force vector estimation unit as an intermediary component that estimates environmental forces (wind, waves, currents) and provides this information to the steering command generator. This intermediary allows the control system to compensate for external forces without requiring direct complex interaction between all system components, thereby improving control accuracy while managing system complexity through modular architecture.
Data Source
AI summary
In a ship control system of one embodiment, a route command unit outputs a route command including a target ship position and a target bow direction of a ship. An information detector detects ship information including an actual ship position and an actual bow direction of a ship. An external force vector estimation unit estimates an external force vector received by a ship, using the ship information and a hull motion model related to a hull motion of the ship. A control command unit controls both rotational frequency of a main engine and a rudder angle of a ship, based on the route command, the ship information, and the external force vector.