Vessel Steering Control for Roll Suppression With Low Computing Load
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Solution Overview
Problem
Existing vessel anti-rolling control systems require large memory capacity and high-speed computing processing units, leading to increased costs and potential instability due to insufficient model construction and erroneous correlation coefficient matrices.
Innovation Solution
A vessel anti-rolling control apparatus and method that uses an azimuth commander, yaw-angle detector, rolling-angle detector, rolling-angular-velocity detector, vessel-speed detector, azimuth controller, anti-rolling controller, and steering-angle controller to generate steering-angle command values for controlling the vessel's azimuth and reducing rolling through simple calculations, without requiring extensive memory or high-function processing units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multidimensional-autoregressive model is used for anti-rolling control with increased data amount and model order to raise accuracy, then model identification accuracy is improved, but calculation load increases and memory capacity requirements increase
Solution Approach 1:
The patent segments the control system into two distinct parts: a statistical control-gain creation means that periodically constructs control models using accumulated data, and a control execution means that applies pre-calculated control gains. This segmentation allows complex model identification to be performed only when needed, rather than requiring continuous high-speed computation during execution.
Solution Approach 2:
The control model and control gains are constructed in advance during a statistical processing period before actual anti-rolling control execution. By performing model identification preliminarily and storing the results, the system avoids excessive calculation during real-time operation, resolving the contradiction between accuracy and calculation load.
2Measurement precision
If a multidimensional-autoregressive model with increased data amount and model order is used, then model identification accuracy is improved, but memory capacity requirements increase
Solution Approach 1:
The system separates data accumulation functions from model construction functions. Detection means continuously accumulate raw sensor data in storage, but the statistical control-gain creation means only processes this data periodically to build models. This segmentation allows using existing storage infrastructure without requiring additional high-capacity memory dedicated to model construction.
3Measurement precision
If excessive calculation processing is performed for model construction, then model accuracy may be improved, but calculation completion time increases causing control system instability
Solution Approach 1:
The system performs model construction as a preliminary action during designated statistical processing periods when the vessel is operating normally. By completing model identification before control execution is needed, the system ensures both adequate calculation time for accuracy and timely availability of control parameters for stable operation.
Solution Approach 2:
The detection means continuously accumulate data in the background, and the statistical control-gain creation means periodically processes this accumulated data to update control models. This continuous data collection combined with periodic processing ensures the system maintains up-to-date accurate models without interrupting control operations, balancing accuracy and timeliness.
Data Source
AI summary
In a conventional vessel anti-rolling apparatus, because a large memory capacity and a high-speed high-function computing processing unit are required, the cost of the vessel anti-rolling apparatus is caused to rise. A vessel anti-rolling control apparatus and an anti-rolling control method according to the present disclosure includesan azimuth controller that outputs a first steering-angle command value for making the vessel turn to an azimuth to which the vessel should travel, based on an azimuth command signal and a yaw-angle signal,an anti-rolling controller that outputs a second steering-angle command value for reducing rolling of the vessel, based on a rolling-angle signal, a rolling-angular-velocity signal, and a vessel-speed signal, anda steering-angle controller that controls a steering angle, based on the first steering-angle command value and the second steering-angle command value.