No abstract

Micro-vibration on board a spacecraft is an important issue that affects payloads requiring high pointing accuracy. Although isolators have been extensively studied and implemented to tackle this issue, their application is far from being ideal due to the several drawbacks that they present, such as limited low-frequency attenuation for passive systems or high power consumption and reliability issues for active systems. In the present study, a novel 2-collinear-DoF strut with embedded Electromagnetic Shunt Dampers (EMSD) is modelled, analysed and the concept is physically tested. The combination of high-inductance components and negative-resistance circuits is used in the two shunt circuits to improve the EMSD micro-vibration mitigation and to achieve an overall strut damping performance that is characterised by the elimination of the resonance peaks and a remarkable FRF final decay rate of −80 dB/dec. The EMSD operates without requiring any control algorithm and can be comfortably integrated on a satellite due to the low power required, the simplified electronics and the small mass. This work demonstrates, both analytically and experimentally, that the proposed 2-collinear-DoF strut with embedded EMSD 2 strut is capable of producing better isolation performance than other well-established damping solutions over the whole temperature range of interest.

No abstract

Due to constantly increasing requirements for more precise and high-resolution instrumentations, microvibration prediction represents an issue of growing importance. Hence the need of reliable analysis tools which can evaluate microvibrations effects efficiently. This paper describes how to tackle the issue of structural uncertainties in microvibration predictions. In particular, uncertainties related to the microvibration sources are analysed as well as those linked to the modelling of the structure. A methodology to define the worst case of vibration produced by on board sources is presented and compared to experimental data. Additionally, an approach to quantify the uncertainties in the Finite Element model is also described.

No abstract