Modeling, design and analysis of low frequency flexible platform for attenuating micro-vibrations in spacecrafts
- Paper number
IAC-08.C2.3.11
- Author
Mr. Kamesh D., ISRO Satellite Centre,Bangalore, India
- Coauthor
Dr. Venkateswarlu Andra, Indian Space Research Organization (ISRO), India
- Coauthor
Prof. Ashitava Ghosal, Indian Institute of Science, India
- Coauthor
Dr. Agrawal V.K., Indian Space Research Organisation (ISRO), India
- Year
2008
- Abstract
The paper addresses the design, modeling and analysis of low frequency space frame platform for passive and active attenuation of low amplitude vibrations. Low amplitude vibrations less than 1 kHz are termed as ‘micro-vibrations’ and have been of great importance in the space platforms and satellites. Micro-vibrations are caused by equipments and devices such as reaction wheels or cyrocoolers and are propagated through the primary structure of the satellite to sensitive equipments and payloads causing degradation in their output performance. To suppress such mico-vibrations, a very low frequency space frame platform is designed with folded continuous beams and beam elements spread over three dimensions. The frame elements with three components of translation and three components of rotation are chosen and modeled by finite element method (FEM) considering Euler-Bernoulli beam theory for the flexural portion. This low frequency platform is analyzed for static and dynamic load cases. The frequency and mode shape analysis for four different fold cases have been done and the results show that the lower frequencies could be achieved with the increase in number of folds. The modal analysis techniques have been used to simulate the response of each mode and simulation has been carried out for free and forced vibration cases. It is demonstrated that vibration isolation of disturbances on-board spacecraft could be achieved passively through this kind of platform. Further studies have taken up involving the active vibration control using piezoelectric sensor and actuators which are planned to be embedded as collocated pair on flexible folded beam arm to control first few modes of interest in order to be able to control and suppress the vibration. It is also planned to incorporate the launch restraint during the launch phase, in case it is necessary, and adequate provisions will be made in the design to release the restraint in the space. Alignment stability would be addressed in the design & fabrication of this platform. Different control schemes are being tried out with various performance objectives and preliminary simulation results show that it is possible to attenuate the disturbance vibrations on-board spacecraft. In this paper we address only the passive control of vibration with this newly designed low frequency space frame platform.
- Abstract document
- Manuscript document
(absent)