Prasad Singh, Nagendra (Professor0Negese, Bekele2018-06-282023-11-282018-06-282023-11-282016-06http://etd.aau.edu.et/handle/12345678/4493This thesis is focused towards the studies on Vertical Take-Off and landing (VTOL) Unmanned Aerial Vehicle (UAV) quad rotor control. The quad rotor is controlled by four BLDC motors which act in different directions to control the yaw angle, roll angle and pitch angle and z-axis position. The control action basically depends on the controlled voltages fed to the four motors. The dynamic modelling of quad rotor is discussed and the design of Linear Quadratic Gaussian (LQG) is presented. A simulator based on MATLAB/SIMULINK model of UAV quad rotor is developed to carry out simulation studies. The effectiveness of the proposed LQG control algorithm to control the hovering position and cruising position in the presence of disturbances such as plant noise and sensor noise is investigated through simulation studies on the simulator. The effectiveness of the proposed controller is tested with and without disturbance through simulation studies. The first test is observed from model verification of open loop response. It is observed from the open loop response that the altitude control is done through three conditions. This was done by controlling the four input controls through rotors frequencies which are compared with the hovering frequencies. Closed loop simulation studies are carried out with the proposed LQG controller. It is observed that the desired tracking is achieved almost within 9 seconds after giving the step input command signals. Similarly, it is observed that the hovering position is achieved almost within 8 seconds after giving the step input command signals. It is further observed that the quad rotor tracks the command signals almost after 10 seconds under the influence of disturbance of covariance value 0.9. It is further observed that the quad rotor attains the desired hovering position after 9 seconds under the influence of disturbance of covariance value 0.9. Key words: VTOL, UAV, LQG, LQR, Kalman Filter, Tracking control, Hovering position StabilizationenVTOL;UAV;LQG;LQR; Kalman Filter;Tracking control; Hovering position StabilizationThesis