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This paper presents a trajectory controller for a Hovering type Autonomous Underwater (HAUV) Vehicle to meet the demands of in-water ship hull inspection. Accomplishing this task can just be done by a vehicle that has all special requirements like high maneuverability, precise controllability and especially Hovering Capability, utility of such vehicle causes increasing precision, saving more time and money and less health hazard of divers. Thrusters' configuration in terms of number of the thrusters, position and the thrust direction of each thruster is presented to provide the most suitable formation in terms of less energy consuming, reducing complexity of control strategies and control the most degrees of freedom. In this paper, roll degree of freedom is just constrained. The controller is demonstrated, was designed upon the linearized dynamic model and then applied to the non-linear model to validate the controller's practicality. This controller consist of 3 different loops, one for horizontal plane another for the vertical plane, both where designed in state space and the last one is a PID controller which is developed to control the forward speed. In the next step, the robustness of the controller is investigated in the presence of underwater disturbance and uncertainty of the hydrodynamic coefficients. State feedback controllers have the advantages such as being suitable for non-linear models, useful for MIMO system and simplicity in application development.

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In this paper, in order to improve the control performance and increase the efficiency of Vestas 660 kW wind turbine, a research based on theory and practice, using real data is done, and a state feedback controller is designed. The actual data obtained from Binalood wind power plant, show that these turbines have a low efficiency. This is due to the poor performance of the classical controller in tracking maximum power in the partial load area, and the significant error in measurement of wind speed. In this research, to solve these problems, a state feedback controller is designed which improves the turbine performance. In this controller, in order to control the generator torque, feedback of generator speed and aerodynamic torque are taken. Also, using the rotor speed and aerodynamic torque, the wind speed is estimated much more accurately than it is measured by an anemometer. Since, an accurate model of the system is needed for controller design and simulation, wind turbine modeling is done in different subsystems, and its parameters are identified using real data. Simulations performed in MATLAB, indicate the improvement of the system performance with the designed state feedback controller, compared to the classical controller in the actual wind turbine

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Network Control Systems (NCS) arise in many real-world applications and they have been an active area over recent decades. Using NCSs instead of traditional controllers has led to significant decrease in costs, weight and power of installations, also increase in reliability of control systems. Despite these advantages, NCSs confront various challenges, such as time varying delays and data packet dropouts in control data transfer which leads to instability. In this paper, the stability analysis and stabilizing with state feedback are studied for NCSs which includes time varying delays in state equations. This goal is achieved by introducing a new functional and using the Lyapunov-Krasovskii approach. Then, an accurate estimation of derivative of functional is obtained by applying Wirtinger and Reciprocally convex combination inequalities. In the proposed method, a stability criterion is derived with less conservatism and complexity. Afterwards, the problem of controller design is examined in which the state feedback controller is designed based on stability criterion. Finally, the dynamic model of the satellite as an examples is used to demonstrate the advantages of proposed method which illustrates our proposed method has desirable influence in decreasing conservatism of results and leading to better performance.