Modeling, Analysis and Testing of Micro Disturbances of Solar Array Drive Assembly

Abstract

Solar Array Drive Assembly (SADA) induces micro vibrations in satellite that have pronounced effect on precision of pointing direction and its imaging quality. The present study analyses amplitude of these disturbances both in time and frequency domain using theoretical methods and experimental techniques. SADA used for investigation is a four beat and two phase hybrid stepper motor driven in 32 & 64 subdivision (SD) numbers. The formulation for frequency of active vibration disturbance and electromagnetic coupling are calculated first leading to disturbance model for 32 & 64 subdivisions SADA running with dead load. A rigid force / moment test platform consisting of piezoelectric sensors is used to validate the theoretical results that give amplitude of disturbance moments produced by SADA. A gravity unload device is added in experimental setup to simulate the working environment in space (zero gravity conditions). 0G test setup not only confirms the presence of electromagnetic stiffness but also supplies comparison for disturbance amplitude of various subdivisions SADA running with & without gravity of load. Results acquired in time and frequency domain verify that increase of subdivisions cause reduction in micro vibrations generated by SADA. Moreover, addition of gravity unload device reduces the amplitude of vibrations in the structure and smoothen the operation. The work lays a firm foundation for study on vibration damping, design of drive circuit and SADA disturbance analysis during in orbit operation.