Dynamic analysis and composite robust control for detumbling non-cooperative flexible satellites

Abstract

For the non-cooperative satellite, the use of detumbling approaches to reduce its angular velocity can facilitate capturing missions. A servicing spacecraft mounted with flexible operation rod is considered to be a promising detumbling approach. Mounting numbers of studies have been devoted to the detumbling dynamics and control of the servicing spacecraft. However, almost all studies on the dynamics do not simultaneously consider the effects of flexible solar panels of the satellite and the spacecraft. Moreover, due to the contact-induced disturbance with fast time-varying characteristics, the most existing controllers make the spacecraft unable to realize efficient and safe operations. To solve these problems, a dynamic model of the non-cooperative flexible satellite is established via the absolute coordinate based method, and a dynamic model of the flexible servicing spacecraft is established via the Lagrangian multipliers approach. Besides, a novel composite robust detumbling control method is proposed to significantly improve convergence performance and tracking accuracy, wherein a predefined-time disturbance observer is constructed to accurately estimate the disturbance without requiring the information of the disturbance and its derivative. Extensive simulations are conducted to demonstrate the key dynamic behavior of the spacecraft and the effectiveness of the control method.