A Novel Dynamic Model of a Reaction Wheel Assembly for High Accuracy Pointing Space Missions

Abstract

This paper proposes a novel dynamic model of a Reaction Wheel Assembly (RWA) based on the Two-Input Two-Output Port framework, already presented by the authors. This method allows the user to study a complex system with a sub-structured approach: each sub-element transfers its dynamic content to the other sub-elements through local attachment points with any set of boundary conditions. An RWA is modelled with this approach and it is then used to study the impact of typical reaction wheel perturbations on a flexible satellite in order to analyze the microvibration content for a high accuracy pointing mission. This formulation reveals the impact of any structural design parameter and highlights the need of passive isolators to reduce the microvibration issues. The frequency analysis of the transfer between the disturbance sources and the line-of-sight (LOS) jitter highlights the role of the reaction wheel speed on the flexible modes migration and suggests which control strategies can be considered to mitigate the residual micro-vibration content in order to fulfil the mission performances.

Micro-Vibration Analysis, Suppression, and Isolation of Spacecraft Flywheel Rotor Systems: A Review

“…Aiming at the parameter identification problem involved in the hybrid model, Kim [106] proposed a two-step sequential optimization method, and verified the effectiveness of the proposed method through numerical and test results. Sanfedin et al [107] applied the dual input-dual output method for hybrid modeling of the RWA, and combined it with the dynamic model of a space telescope with two flexible solar panels and antennas to investigate the possible coupling effect between the structural and RWA flexible modes. The analysis results have certain guiding significance for passive vibration isolation scheme design.…”