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Hydrodynamics Modeling and Self Orginizing Control of Marine Vehicles

Taghi, Amir Hossein | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48448 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Sayyadi, Hassan
  7. Abstract:
  8. Dynamic positioning system is a controller system used to maintain the position and heading of a vessel with no use of anchors, jack ups but only using the propellers installed on the vessel. A vessel has six degrees of freedom, including three rotations and three transfer. In dynamic positioning systems, the vessel is controlled only on the horizontal plane such that its position and heading are controlled according to predetermined values. To achieve this, position and heading of the vessel is determined and the controller system computes the direction and required power of each propeller. Preliminary systems utilized PID controllers. As the control science has advanced, model based controllers and theories of optimal control have been adopted. Considering the non-linear hydrodynamic model of the vessel, non-linear controllers have been later used on positioning systems. In spite of the advantages of non-linear controllers, they require an accurate model of the system and knowing of its parameters. Today, fuzzy controllers are mainly used in controlling non-linear systems. On the one hand, the fact that the vessel model is complicated and non-linear, and on the other hand the difficulty with which the hydrodynamic and physical parameters of the vessel may be determined make controllers that do not require a model to function superior. In addition, the conditions under which position of the vessel is controlled include resistive forces of wind, currents in the sea and waves. These conditions are constantly changing and the controller has to adapt itself with the new conditions. Therefore, the controller that is used should be able to control non-linear systems, be adaptable and not need to have a model of the system. To achieve this, the notions of self-organizing fuzzy controllers have been used. In this project, after introducing the subject and presenting its importance and applications, basic concepts and existing research on position locking control systems are reviewed. Then, the hydrodynamic model of the vessel is developed by real time solving of hydrodynamic equations and developing a vessel simulation software under MATLAB, and the structure of the proposed controllers is explained. In the end, by constructing numerous experiments, the behavior of the controller under different conditions is evaluated. The structure resulting from the proposed controller, can be used to control the position of different vessels. Also, given the parametric simulation that is performed, simulating the behavior of vessels whose parameters are available is now possible
  9. Keywords:
  10. Control System ; Fuzzy Controller ; Intelligent Systems ; Hydrodynamic Modeling ; Self Organized Control ; Marine Vehicle

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