PID, LQG and sliding mode controllers design for antenna servo system and performance comparison

Antennas are system elements that make use of electromagnetic waves and provide data communication between long distances. At the present time, antennas which are widely used in civil and military applications, especially in communication and radar systems. Servo control systems that direct the antenna unit in azimuth and elevation axes are used in these studies where sensitivity and tracking accuracy are important. Direct current motor is an important drive element in servo system applications that require speed and position control. Thanks to their successful performance, high efficiency and ease of control, direct current motors are used in many applications for various purposes. In practical applications, systems can be exposed to various disturbances such as noise and vibration. Again, due to similar factors, parameters may change over time in system units, or uncertainties may occur in the system due to modeling with unknown parameters. For this reason, the control method that is used in servo systems that require precision should be chosen well. In this context, it is required that the control methods behave quick response, robust against disturbances and uncertainties. In this study, controller design has been made with PID, which is a traditional control type, with sliding mode control, which is a nonlinear control type and with linear quadratic Gaussian (LQG), which is an optimal control type for position output of the antenna servo system whose mathematical model has been determined. The designed controllers have been implemented in simulation environment by using MATLAB/Simulink application. Similar applications have been carried out in simulation environments, which can be encountered in practice, which are disturbance and uncertainty, with results the robustness of the controllers have been evaluated. The results that are obtained after simulations have been analyzed by using various performance analyses methods. After comparing the results of designed controllers, the most appropriate control method that can be used in the antenna servo system has been determined as sliding mode controller.