On Pointing Accuracy and Pointing Stability of Disturbance-Free Payload Using Umbilical Connection

摘要

Pointing accuracy and pointing stability play an important role in gravitational wave detection spacecraft. This paper presents dynamics model, pointing accuracy and stability analysis of a payload-spacecraft system connected using umbilical and non-contact actuators. Accurate model of payload-umbilical-spacecraft is proposed which takes into account the translational stiffness and damping effects, as well as the torsional stiffness effect. The Lagrangian approach is applied to derive the rigid-flexible coupling dynamics model. Both of the open-loop and closed-loop simulation studies are conducted to investigate the pointing accuracy and stability of the payload. The results indicate that the umbilical significantly degrades the vibration isolation performance of the payload at low frequencies between 0.01 Hz and 1 Hz. Simulation of two other cases, the payload without umbilical and the payload with umbilical considering only the translational stiffness effect, are also performed. The results of these three cases show that the umbilical greatly degrades the pointing accuracy of the payload and lowers the pointing stability. The torsional stiffness also has a slight effect on the pointing accuracy of the payload.