Characterisation and Control of Micro-vibration on-board Satellite

Abstract

Reliable working of spacecraft components and assemblies requires no external mechanical disturbances like vibration. However, due to various mechanical components mounted on- board like momentum wheel assembly, reaction wheel assembly and cryocooler assembly, the vibrations are produced which are usually low amplitude and low frequency in nature. The effect of gravity in the spacecraft moving in orbits is minimal. Hence the vibration generated in a microgravity environment is referred as microvibrations. Due to unavailability of earthy environment in the spacecraft, the generated unwanted micro vibrations prevails for longer duration which can hinder the performances of delicate electronic and optical components. This dissertation aims to develope an active isolation system to attenuate microvibration. The feasibility of the same is to be checked before employing it in the spacecraft systems. For the same, the laboratory model has been developed which contains a simple plate mounted on the vibration shaker fixture with Piezoelectric actuators. The vibration performance is evaluated using Finite Element analysis to evaluate the region of micro-vibration numerically. The same has been tested experimentally using Low-Level Sine (LLS) test. The identified frequency response for the micro-vibration domain has been attenuated actively through programming piezo actuators. Thus, the feasibility of the active isolation has been successfully demonstrated experimentally on the laboratory scale.