Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis On Improving the Performance of Repetitive Leaning Controllers(Izmir Institute of Technology, 2019) Çobanoğlu, Necati; Tatlıcıoğlu, EnverRobot manipulators are widely used to perform pre–defined tasks repetitively. Nearly all of the mass production factories use the robot manipulators to perform specific operations over and over again. In such a system, the control design may contain some difficulties, unavailabilities and/or there would be additive disturbances due to the periodic motion. Moreover, cost reduction may be vital, hence sensor usage has to be reduced. In the first part of this thesis, to address those restrictions, a model free full state feedback repetitive learning controller which is fused with a one–layer neural network is proposed for robot manipulator which performs a periodic motion. Stability of the system is ensured via Lyapunov based techniques. Numerical simulations and experimental results are introduced to demonstrate the performance of the proposed controller. In the second part of the thesis, under the additional constraint that velocity measurements being unavailable, output feedback repetitive learning controller fused with a neural network term is investigated. The dynamic model of the robot manipulator is again considered as uncertain to avoid its usage as part of the control design, and the reference position vector is still considered to be periodic. The stability of the closed loop system is investigated via Lyapunov based techniques. Numerical simulations are added to demonstrate the proposed controller performance.Master Thesis Thrust Control Design for Unmanned Marine Vehicles(Izmir Institute of Technology, 2012) Alkan, Buğra; Dede, Mehmet İsmet CanIn conventional electrically driven propulsion systems with fixed pitch propellers, thruster controllers are usually aimed at controlling propeller shaft speed only. Especially in unmanned marine vehicles which operate in dynamic flow conditions, these type thruster controllers provide unsatisfactory thrust responses. The reason for this is that the thrust force is simultaneously affected by dynamic effects like, variable ambient flow velocity and angle, thruster-thruster interaction and ventilation. It is aimed to achieve acceptable thrust tracking accuracy in all kind of dynamic flow conditions in this thesis work. A novel feed-back based thruster controller which includes the effect of incoming axial flow velocity, is designed for this purpose. In controller design, first, thruster propeller's open water characteristics in four-quadrant flow states are measured. Data collected from open water tests are then non-dimensionalized and embedded in the controller's thrust model code. Relation between ideal shaft speed and desired thrust is derived by using the four-quadrant propeller model. The proposed method is evaluated in the experimental test-setup designed for this study to simulate open water conditions. Results indicate that thrust tracking performance of novel controller is acceptable in all four-quadrant flow tests.