论文部分内容阅读
随着大型航天器柔性越来越大,结构越加复杂,导致低频柔性模态密集,但同时需要极高的定向精度及姿态稳定度,这就对航天器姿态控制系统提出了更高的要求。本文采用拉格朗日法建立了柔性航天器姿态轨道耦合动力学模型,并设计了大角度机动航天器的姿态控制器。Lyapunov定理给出闭环系统的稳定性,在0.03Nm均方根的白噪声扰动下,大角度机动姿态角误差小于0.02°,均方根误差0.003°,为了抑制姿态抖振,设计了复合控制器,采用Stewart平台对敏感载荷局部高精度主动隔振和定向,局部控制后敏感载荷的定向误差小于0.0001°,均方根误差0.000036°。鲁棒Η∞控制器对Stewart平台主动镇定时,姿态抖振小于0.000002°,均方根误差小于0.0000008°,姿态稳定度优于0.00001°/s。
As the large spacecraft becomes more and more flexible, the structure becomes more and more complex, resulting in dense low-frequency and flexible modes, but at the same time, it requires extremely high orientation accuracy and attitude stability. This poses higher requirements for spacecraft attitude control systems . In this paper, Lagrange method was used to establish the attitude and orbit coupling dynamics model of flexible spacecraft, and the attitude controller of large-angle mobile spacecraft was designed. Lyapunov theorem gives the stability of the closed-loop system. Under the noise of 0.03Nm white noise, the attitude error of large-angle maneuver is less than 0.02 ° and the root-mean-square error is 0.003 °. In order to suppress the chattering, a compound controller The Stewart platform is used to actively isolate and orient the sensitive loads locally with high precision. The directional errors of the sensitive loads after the local control are less than 0.0001 ° and the root mean square error is 0.000036 °. When the robust Η∞ controller is active to stabilize the Stewart platform, the chattering is less than 0.000002 °, the root mean square error is less than 0.0000008 ° and the attitude stability is better than 0.00001 ° / s.