LQG/LTR controller design improved with disturbance observer for two-axis precise gimbal stabilization

Applications that include data transfer and laser operations using gimbal systems have become a popular research field in recent decades. In this context, numerous methods have been proposed that attempt to improve the health and meaning of the transferred data. In this study, first a system identification method is proposed to identify the dynamical behavior of the two inner axes of a four-axis gimbal system, where the identified axes achieve the precise tracking and targeting. Next an optimal controller augmented with a disturbance observer structure is designed. This controller is an LQG/LTR controller which overcomes the robustness problems of the classical LQG design. The main goal of the controller is to provide a robust line of sight (LOS) controller that achieves the design criteria while rejecting disturbances. The controller is expected to reject disturbances caused by aerodynamic and mechanical effects, as well as minimize unmodeled nonlinearities and provide robustness in the frequency range of operation. The improved LQG/LTR controller is also verified on an actual experimental setup and it is observed that the design goals are met successfully. The main contribution of this thesis is the improvement of the classical LQG/LTR structure with a disturbance observer and the verification of the results of an actual physical system.