Abstract
Spacecraft instruments or components that have mechanically moving part generate undesired disturbances and thus affect spacecraft performance such as pointing stability of mission payloads. With the growing demand for high pointing accuracy in observation satellites, these disturbances are now emerging as a major cause of pointing stability deterioration. In recent years, multi-axis vibration isolation systems have been required and installed in observation satellites to attenuate complex transmission of dynamic internal disturbances. In this paper, a Stewart-platform-based vibration isolation system aiming at next-generation geostationary observation satellites is proposed. This system consists of the six isolator struts which support a mission payload against a satellite main body and isolates disturbance transmission in six degrees of freedom. To design this system, the transmissibility matrix which characterizes the performance of multi-axis vibration isolation is firstly derived from a simple dynamic model. Valid physical parameters such as single isolator dynamic stiffness and geometric layout of the platform are examined and a prototype of the vibration isolation system is developed based on this result. Experimental results show that the prototype accomplished 1/10 vibration transmissibility in six degrees of freedom above 20 Hz across the board. Also, compatibility to mechanical environment was demonstrated through the vibration and shock testing under specific environmental profiles.
