Ship Steering Device Oblique Sailing Rotation Correction
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Solution Overview
Problem
Conventional ship steering methods fail to prevent unintended rotation during oblique sailing due to mismatch between the pressure center and centroid of the hull, requiring unique correction values that vary by ship type and size, making lateral movement without turning challenging.
Innovation Solution
A ship steering method that uses a control device to determine and apply a correction value based on the elevation angle and hull speed, adjusting the rotation speeds and steering angles of outdrive devices to ensure the propulsion power acts on the hull's centroid, thereby preventing unintended rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ship sails obliquely with conventional steering methods, then the ship can move in the desired direction, but unintended rotation (yawing) occurs due to mismatch between pressure center and centroid
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the rotation angles of the outdrive devices based on detected hull rotation. The control device modifies steering parameters (rotation angles) in real-time to compensate for unintended yawing, transforming the static steering approach into a dynamic parameter-adjustment system that maintains hull orientation stability during oblique sailing
Solution Approach 2:
The patent implements feedback control by using a rotation detection sensor to continuously monitor hull rotation and feeding this information back to the control device. The control device processes this feedback and adjusts the outdrive device rotation angles accordingly, creating a closed-loop control system that automatically corrects unintended rotation while maintaining lateral movement
2Reliability
If unique correction values are determined for each ship type and size, then unintended rotation can be canceled, but the system complexity and calibration requirement increase
Solution Approach 1:
The patent applies self-service by enabling each ship to automatically determine its own correction values through actual sailing operations. The control device measures the ship's unique characteristics (centroid position, hydrodynamic properties) during operation and autonomously calculates correction values, eliminating the need for external calibration services or complex pre-calibration procedures
Solution Approach 2:
The patent implements preliminary action by pre-determining correction values during the ship's initial operation or setup phase. The system performs automatic calibration by measuring hull rotation responses to standardized steering inputs and computing correction values in advance, so that the steering system is ready for accurate oblique sailing without requiring complex real-time adjustment mechanisms
3Measurement precision
If the reference steering angle and reference propulsion power ratio are set by actual sailing, then accurate lateral movement control is achieved, but the calibration process requires time and operational art
Solution Approach 1:
The patent replaces manual calibration procedures with an automated electronic measurement and calculation system. The rotation detection sensor and control device automatically measure hull rotation characteristics and compute reference steering angles and propulsion power ratios, substituting complex manual calibration art with straightforward electronic measurement and computation processes that reduce both time and skill requirements
Data Source
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AI summary
The purpose of the present invention is to provide a ship steering device capable of steering a hull in an intended direction by correcting an unintended rotation that occurs during an oblique sailing operation regardless of the type and size of the hull. A ship steering device 1 is provided with an elevation angle sensor 36 for detecting the elevation angle α of a hull 2, a hull speed sensor 37 for detecting the speed V of the hull 2, a storage means 33 storing the relation among the elevation angle α of the hull 2, the speed V of the hull 2, and a correction value K, and a calculation means 32 serving as a correction value determination means, and an operation amount by which a joystick 21 is operated such that the hull 2 does not turn in the state in which the hull 2 is obliquely sailed is determined by the calculation means 32 and used as the correction value K.