Angular accuracy improvement for industrial grade pedestal

This paper describes a way of upgrading a low-cost industrial grade pedestal, based on a direct drive motor and a geared resolver, to a high accuracy system. The upgraded pedestal could be utilized as a platform for a narrow field of view (FOV) optical surveillance unit. The pedestal angular position error is analyzed and experimentally evaluated. Then a method for compensating the major error sources is presented. It addresses the gear and resolver systematic errors. Proper choice of the gear is also discussed. Finally, actual results of the compensation algorithm integration into the servo loops, which yields an angular accuracy of less than 100 ¿Rad RMS, are presented.