One of the requirements for ships equipped with dynamic positioning system is the ability to maintain a given position in various hydrometeorological conditions. At the same time, efforts at reducing electricity consumption are made in order to reduce operating costs and emissions of exhaust gases, such as sulfur oxides and greenhouse gases such as carbon dioxide (CO2). For this purpose, the ship designer at the design stage must predict both how much energy the ship will theoretically use during operation and how the expenditure can be reduced. The publication presents a comparison of energy consumption with two different approaches to ship positioning: the use of classic dynamic positioning utilizing a set of thrusters and by using a set of anchors. In order to determine the energy consumption during positioning, the matrix method was used, on the basis of which the analysis of the ability to hold the position of the ship (capability plot) was performed, in accordance with the recommendations of the classification society DNV GL. Thanks to this analysis, it was possible to find such a distribution of thrust vectors on propulsors that the ship would not lose its set position under the hydrometeorological conditions specified in the analysis. As a result of comparing the two positioning systems, it turned out that using anchor-based positioning uses 24% less energy than positioning based on a set of thrusters, which translates into 24% less CO2 emissions into the atmosphere.

https://www.mdpi.com/1996-1073/14/3/524/pdf

A Comparative Analysis of Energy Consumption by Conventional and Anchor Based Dynamic Positioning of Ship

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Robust Fuzzy Sampled-Data Control for Dynamic Positioning Ships

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The article describes the process of construction and testing a floating offshore drilling platform model with focus on cooperation of its diverse subsystems in order to stabilise the position and control the movement of the platform In real-life applications, advanced off-shore oil-rigs are indeed floating without any scaffolding or concrete basis, so the waves and shore current continuously disrupt their position Since the place of drilling is fixed, those movements are able to damage or even break the drill, which leads to serious environment contamination by the emerging oil This paper considers PID controller as a dynamic positioning system with a reference system based on image recognition

Floating Oil Platform Model with Dynamic Positioning and Reference System

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Design of fuzzy PID controller for ship dynamic positioning

With the accelerating process of China’s urbanization and the gradual expansion of the city scale, the robustness and reliability of urban road traffic networks are particularly important. This paper took the public transportation network in Heping District of Shenyang as the research goal, and obtained the important public transport stations as the research object. The bus stations were used as the nodes of the complex network to analyze the degree, the degree distribution, the clustering coefficient and the average path length. Node attacks included random attack, degree attack and betweenness attack. This paper analyzed the robustness of the network by combining the changes of network efficiency ratio and accessibility index. The research results show that the accessibility index can be used to analyze the robustness of complex networks, and the public transportation network has good robustness against the random attack, poor resistance against the deliberate attack, and degree attack is more destructive than betweenness attack.

Robustness Analysis of Urban Public Transportation Network Based on Accessibility Index

It is the control problems of hydraulic servo system that parameter perturbation and the uncertainty caused by external interference difficult to solve. Based on robust control, we can still ensure good quickness and steady state performance even when the system is under ultimate conditions through designing a controller with steady structure and constant parameters. This paper focuses on applying robust control H ∞ to realizing the electro-hydraulic servo control. In connection with the production line of cold rolled sheet of some steelworks electro-hydraulic servo control system for striped steel centering, we designed a H ∞ robust controller with optimal mixed sensitivity on the basis of mixed sensitivity design method. The relative simulation results show that the controller we designed ensures that the robust stability of the closed-loop system and good follow performances, at the same time, it restrains the model perturbation and external disturbance to the influence of the system, which settled the system of anti-disturbance and model disturbance well.

Lin Xu

Papers

Design of fuzzy PID controller for ship dynamic positioning

Robustness Analysis of Urban Public Transportation Network Based on Accessibility Index

H ∞ control for striped steel centering of electro-hydraulic servo control system