Dynamic analysis of a box-structured satellite deployment mechanism with self-actuated torsion joints

Abstract

This paper designed a kind of satellite deployment mechanism with a boxed structure and passive torsion joints. This deployment mechanism has significant strengths, including a high base frequency and stiffness, a high ratio of deployed and folded space occupation ratios, and self-actuated joints without needing any external power to drive. In order to analyze the dynamic characteristics of this mechanism, a simplified governing equation is proposed and dynamic behavior is studied systematically, including impact response, harmonic response, and modal analysis. Through systematic research, several conclusions are drawn. Firstly, when the deployment mechanism reached the ending stage of unfolding driven by passive torsional joints, the load base installed on top of the deployment mechanism generated a first-order sharp reaction force and multiple low-order shocks followed, and the system entered a stable state after a certain time of vibration. Secondly, the system can generate a high vibration magnitude at low-frequency excitation when the mechanism is in a fully deployed state and at high-frequency excitation when the mechanism is in a folded state. Thirdly, the first sixth-order natural frequency and vibration shape with different wall thicknesses are obtained by modal analysis. The result shows that only with a 2.5 mm wall thickness can the connecting rod satisfy the design requirement. Through dynamic behavior research, the structure characteristics are obtained which can be used for structure optimization and to provide an effective solution for the design of a box-structured satellite-unfolding mechanism with self-actuated torsion joints.