Identification of a Two Degree of Freedom Tracker System: Theoretical and Experimental Discussion

In this article, the identification problem of a practical two degree-of-freedom (DOF) tracker system is investigated. The analytical modeling of two-DOF gimbal system as the main core of the tracker for both elevation and azimuth axes are introduced. By simplification and discussion on the governing equations, suitable structure of the model for identification is obtained. By performing identification procedure on the experimental system in the elevation and azimuth axes, the simplified models of this system are obtained through Recursive Least Square (RLS) approach. This is performed by using the practical data obtained from gyro in each axis of the under study system. As it can be interpreted and predicted from theoretical model, the identification process leads to a non-minimum phase model which depends on the operational points. This identified model can be used in stabilization and tracking loops in the control system design stage. The identification results in comparison with theoretical and experimental data are discussed. The adaptive or robust controllers are suitable candidates for controlling tracker system, where in the both controllers use this simplified model as the nominal or reference model.