Twin-Rudder Ship Docking Control for Parallel Quay Approach
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Solution Overview
Problem
Existing ship maneuvering technologies struggle with high accuracy in automatic docking and maneuvering, especially in congested sea areas or when affected by external forces like wind, waves, and tidal currents.
Innovation Solution
A uniaxial twin-rudder ship with an automatic docking function, equipped with a propulsion system, a maneuvering system, and an observation system, which includes a bow thruster, high-lift rudders, and sensors for precise control and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If autopilot is used for automatic steering, then navigation to preset course is automated, but position correction capability is lost due to inability to maintain course line
Solution Approach 1:
The system uses GPS to continuously measure the ship's actual position and compares it with the intended course line. When deviation is detected, the system automatically calculates correction commands and adjusts the rudder angle to return the ship to the correct position, creating a closed-loop feedback control system that maintains both automation and position accuracy.
Solution Approach 2:
The patent replaces traditional mechanical autopilot systems with an integrated electronic control system that combines GPS positioning, electronic charts, and automated steering control. This substitution enables the system to maintain course line accuracy while preserving automatic steering functionality.
2Measurement precision
If manual steering is used for high accuracy maneuvering, then position and speed control is precise, but operation complexity increases and automation is reduced
Solution Approach 1:
The system automatically performs maneuvering calculations and steering control based on input parameters such as desired position, speed, and course. The automated maneuvering support unit computes optimal rudder angles and thrust commands without requiring manual intervention, enabling precise maneuvering while simplifying operation through automated decision-making.
3Speed
If large rudder angle is used for quick course change, then response speed increases, but steering stability decreases due to rapid changes
Solution Approach 1:
The system dynamically adjusts rudder angle changes based on real-time ship state and maneuvering requirements. Instead of applying maximum rudder angle immediately, the system calculates optimal progressive adjustments that balance response speed with steering stability, preventing excessive oscillations while maintaining quick course correction capability.
Solution Approach 2:
The automated system uses periodic control cycles to adjust rudder angle gradually, applying small corrections at regular intervals rather than large abrupt changes. This periodic adjustment pattern enables the ship to respond quickly to course changes while maintaining steering stability through controlled, incremental maneuvers.
4Device complexity
If external forces like wind and waves are not compensated, then simple steering is maintained, but position accuracy deteriorates
Solution Approach 1:
The system continuously monitors the ship's actual position via GPS and compares it with the expected position based on course and speed. When external forces cause deviation, the feedback mechanism automatically calculates compensation commands and adjusts steering parameters to counteract wind, wave, and current effects, maintaining position accuracy without requiring complex manual compensation procedures.
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
The system enables precise automatic docking and maneuvering with high accuracy, even in challenging conditions, by correcting steering angles for external forces and maintaining the ship's fore-and-aft direction parallel to the target quay.
Implementation Method 1
a bow thruster, and a thruster controller that controls the bow thruster
Implementation Method 2
a pair of right and left high-lift rudders disposed behind the propulsion propeller, a pair of steering engines that drive the respective high-lift rudders
Implementation Method 3
a propulsion propeller disposed at the stern of the ship
Data Source
AI summary
A hull motion control unit performs steering for a pinwheeling swing such that a bow distance and a stern distance that are measured by a quay separation distance measuring device are made equal to each other and the fore-and-aft direction of a ship is parallel to a target quay, and then the ship is caused to laterally approach and dock in the target quay while keeping the parallel state.