Comparison of PID and LQR Controllers for Dynamic Positioning of an Oceanographic Research Vessel

Author(s):  
Kunal Tiwari ◽  
P. Krishnankutty
2021 ◽  
Author(s):  
Kunal Tiwari ◽  
Krishnankutty P.

Abstract A dynamic positioning system is computer controlled system which maintains the positioning and heading of ship by means of active thrust. A DP system consist of sensors, observer, controller and thrust allocation algorithm. The purpose of this paper is to investigate the performance of proportional derivative type fuzzy controller with Mamdani interface scheme for dynamic positioning of an oceanographic research vessel (ORV) by numerical simulation. Nonlinear passive observer is used to filter the noise from the position and orientation. A nonlinear mathematical model of the ORV is subjected to the wave disturbance ranging from calm to phenomenal sea. Robustness and efficiency of the fuzzy logic controller is analysed in comparison with the multivariable proportional integral derivative (PID) and the linear quadratic regulator (LQR) controller. A simplified constrained linear quadratic algorithm is used for thrust allocation. The frequency response of the closed loop system with different controllers is analysed using the bode plot. The stability of controller is established using the Lyapunov criteria.


2001 ◽  
Vol 35 (3) ◽  
pp. 8-13
Author(s):  
Sujata S. Millick

As the oceanographic research vessel community prepares for updating its fleet of research vessels, they must consider vessel designs that improve the capability of the fleet to support science in the near and long-term. Advances in informational technologies have changed the "instruments" of science and resulted in the ability to study ocean processes in smaller time and space scales than before. While, networked structures on the ocean floor, remote sensing, and autonomous vehicles will allow oceanographers to synoptically measure the environment, ships will remain the "host-platforms" for such research. However, deployment and recovery of such systems, requires that future designs incorporate capabilities for increased speed, seakeeping, acoustic quietness, efficient power management systems, and lifecycle considerations. Consideration of such issues in the design phases will allow for the development of a technologically advanced ship that can serve the research community in the near and long-term.A major aspect of oceanography through the decades has been the availability of research vessels for science. However, the access to and the capability of such vessels under the University-National Oceanographic Laboratory System (UNOLS) must not be taken for granted. Changes in the oceanographer's ability to make measurements at smaller and smaller sampling scales are brought on by advents in computational and information technologies. These changes necessitate that the researcher's "host-platform" evolves to handle these new observing systems. This evolution can include, but is not limited to speed, seakeeping, efficient ship power arrangements, and acoustic quietness. While each subject can be the focus of detailed individual papers, this article presents a general discussion on four elements of oceanographic research vessel design—hull concepts, power systems, acoustics, and life cycle management.


1994 ◽  
Vol 31 (01) ◽  
pp. 1-19
Author(s):  
Yushu Washio ◽  
Masao Miyoshi ◽  
Katsuyoshi Takekuma ◽  
Kenji Yamada ◽  
Kazuo Kobayashi

Requirements for characteristics of a large oceanographic research vessel are extended over various fields of its design. General-purpose running work such as retrieving various kinds of fundamental data about the ocean, extensive on-board scientific research, and worldwide exploration, including the polar regions, are described. Recent developments in acoustic measurements and instrumentation, such as the multi-narrow beam, require noise abatement in the design because of both airborne and waterborne noise caused by the vessel itself. The design features and R&D achievements of such vessels are described, especially with respect to general arrangement, type of power plant, hull form, maneuvering, seakeeping, noise abatement by choice of propellers, mounting of machinery and structure, and also design and building schedule. The example case used is the Hakuho Maru, the newest and most sophisticated research vessel for the Ocean Research Institute of the University of Tokyo.


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