Ship Heading Control Using Gain Scheduling Against Disturbance Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automatic steering devices for ships fail to accurately represent the dynamic behavior of ships, leading to conservative control responses and inability to suppress oscillations caused by disturbances like tidal currents or wind, due to simplistic modeling and lack of consideration for varying ship speed.
Innovation Solution
A heading control device that utilizes a controller with gain scheduling based on ship motion characteristic information, including frequency response characteristics from actual rudder angles to yaw rates, to adjust control parameters and suppress oscillations, ensuring robust control and accurate heading maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple Nomoto model is used for automatic steering control, then the control system is simple and easy to implement, but the control response becomes conservative and cannot accurately represent the actual dynamic behavior of the ship
Solution Approach 1:
The patent applies dynamics by making the physical model adaptive to varying ship conditions. The oscillation pole identification unit dynamically identifies the oscillation pole based on actual ship behavior under different operating conditions (speed, load, sea state), allowing the control system to adapt its parameters rather than relying on a fixed simple model. This resolves the contradiction by maintaining system simplicity while improving accuracy through dynamic parameter adjustment.
Solution Approach 2:
The patent changes parameters by identifying and utilizing the oscillation pole parameter that varies with ship operating conditions. Instead of using a fixed Nomoto model, the system continuously identifies the oscillation pole from actual ship responses and uses this identified parameter to adjust the physical model. This allows the control system to maintain simplicity while accurately representing actual ship behavior across different conditions.
2Stability of the object's composition
If the control band is lowered to prevent oscillation, then the system becomes stable, but the control response becomes slow and conservative
Solution Approach 1:
The system dynamically adjusts the control band based on the identified oscillation pole. When the oscillation pole indicates low oscillation tendency, the control band can be widened for faster response. When oscillation tendency increases, the control band is narrowed for stability. This dynamic adjustment resolves the contradiction by allowing both fast response and stability under different conditions.
Solution Approach 2:
The patent implements feedback by continuously monitoring actual ship behavior and identifying the oscillation pole, then using this information to adjust control parameters. The feedback loop enables the system to learn from actual performance and adapt the control band accordingly, achieving both stability and responsiveness without the conservative limitations of fixed-parameter designs.
3Ease of manufacture
If a fixed physical model is used without considering oscillation pole, then the control system is simple to implement, but it cannot suppress oscillations caused by disturbances such as tidal currents or wind
Solution Approach 1:
The system performs preliminary identification of the oscillation pole under various operating conditions before actual control operations. This pre-characterization of ship behavior allows the control system to be pre-configured with appropriate parameters for different conditions, enabling effective disturbance suppression without complex real-time calculations during critical control moments.
Solution Approach 2:
The patent changes physical model parameters based on the identified oscillation pole. By adjusting the physical model to match actual ship characteristics under different conditions, the system gains the ability to suppress disturbances effectively. This parameter adaptation maintains implementation simplicity while dramatically improving disturbance rejection capability.
Data Source
AI summary
An object is to obtain a heading control device and a heading control method for ship in which a heading control system is configured on the basis of ship motion information, without promoting oscillation excited by disturbance factors to the ship, such as tidal current or wind. The heading control device for ship, which causes a ship provided with an outboard motor to sail at a desired heading, includes: a heading generator which outputs a heading command; and a controller which outputs a rudder angle command on the basis of the heading command from the heading generator, sensor group information from a sensor group, and ship motion characteristic information from a ship motion characteristic information storage unit.