System Identification of a Spacecraft Antenna Pointing Mechanism

This paper describes results of identification of a spacecraft antenna pointing mechanism. Accurate modelling of the physical effects that occur during the mechanism operation is mandatory for the realistic assessment of the microvibration budget as well for the control design of the mechanism electronics. System identification is seen as a very attractive methodology in characterizing the entire mechanism, including stepper motor electronics, electromagnetic effects that occur during stepping and microstepping operation and accurate modelling and parameterization of the mechanical drive train. The results achieved throughout model identification show a very good agreement between the model and experimental data in wide operational ranges in time and in frequency domains.