Experimental characterization and modeling of telescope behavior at low velocities

Astronomical telescopes are large systems which are designed to accurately track the objects in sky at very low velocities. In this paper we characterize the behavior of a telescope and employ Monte-Carlo technique to analyze robustness of parameter estimation. We present overall model of telescope with the LuGre model for friction and synthesis a feedback linearizable controller for the system. At very low speeds the effects like dynamics of nonlinear friction, flexure in gears, flexure in rotating axis and backlash start dominating the system behavior. Hence, we propose a new model to capture the observed behavior for such large systems operating at very low speeds.