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Examining and Choosing the Appropriate Control Algorithm and Controller Design for a Ship in Order to Path Following

Mohebbi, Matin | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55860 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Seif, Mohammad Saeed
  7. Abstract:
  8. In this research, it has been tried to design two controllers for a KVLCC2 tanker assuming unknown hydrodynamic characteristics and its mathematical model in order to maintain its course and speed. At first, due to the lack of an experimental model of a vessel, a three-degree-of-freedom MMG model of the KVLCC2 vessel was modeled in the SIMULINK, MATLAB, to be used as a basis for other tests and simulations. Therefore, by using the designed three degree of freedom model, all parameters affecting the floating maneuver were examined. In the next section, using the DNV standard, we designed two wind and sea current systems for system input disturbances. And finally, by using dynamic models of wind and sea current, we investigated their effects at different speeds and directions on the turning maneuver parameters. In the following, an attempt was made to examine and briefly describe all the important and widely used controllers in the industry. In this thesis, an attempt has been made to select a controller that has the following features: Can be used for different vessels can be used in different marine conditions (having an adjustable parameter) Have few calculations Now, according to the comparison of the important controllers, the indirect self-adjusting regulator controller was chosen in order to maintain the speed and trajectory of the ship. Also, in order to provide the system parameters for the controller, two methods of system identification, frequency domain and time domain, were used. Finally, by using the identified parameters by identification algorithms, the adjustment of the adaptive self-adjusting regulator controller was done. According to the results of the system identification method using CIFER software, it shows that the conversion function between the propeller revolution and the floating speed can be identified with very high accuracy, but the use of this method is especially limited in degrees of freedom. which have severe non-linear factors, has very low accuracy because these non-linear factors appear as disturbances in the CIFER software and reduce the quality of identification. Therefore, in order to identify the rudder transformation function, an RLS estimator was used along with the forgetting factor, this method showed that it can identify degrees of freedom that have non-linear parameters to a suitable accuracy. Finally, a systematic method was presented to adjust the self-adjusting regulator controller for both propeller and rudder. Also, the results of the simulations show that the system can be well controlled both in terms of speed and in terms of maintaining the path by adjusting the controller of the self-adjusting regulator once
  9. Keywords:
  10. System Identification ; Mathematical Maneuvering Group (MMG)Model ; CIFER Software ; Adaptive Self-Adjusting Regulator Controller ; Path Following ; Control Algorithm

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