充液挠性航天器时变滑模控制及振动抑制

Time-Varying Sliding Mode Control and Vibration Suppression of Liquid-Filled Flexible Spacecraft

针对存在外界未知干扰、参数不确定问题的刚-液-柔多体耦合航天器姿态控制进行了研究.将液体燃料的晃动等效为球摆模型,挠性附件假设为欧拉-伯努利梁,建立了多体耦合航天器动力学方程.首先,设计了积分滑模干扰观测器,使其能够在有限的时间范围内对控制系统的集总扰动实现准确估计;其次,以此干扰观测器为基础,设计了一种时变滑模控制方法,该控制运用双曲正切函数;最后,结合光滑整形技术,设计出零振动指令光滑器,从而抑制液体晃动和挠性附件振动.数值仿真结果表明:本文所设计的控制方案具有可行性和有效性,多模态充液挠性航天器在姿态机动过程中所引起的残余振动可以得到有效抑制.

In this paper,attitude control of rigid-liquid-flexible multi-body coupling spacecraft with unknown interference and uncertain parameters is studied.The sloth of liquid fuel is equivalent to the spherical pendulum model,the flexible attachment is assumed to be Euler-Bernoulli beam,and the dynamics equation of spacecraft is established by Lagrangian method.Firstly,an integral sliding mode disturbance observer was designed for a finite time,enabling the designed model to estimate the lumped disturbances of the control system within a specified time range.Then,based on disturbance observer,a time-varying sliding mode control method is designed,which uses hyperbolic tangent function.Finally,a zero-vibration command smoothing device is designed to suppress liquid sloshing and vibration of flexible accessories.The numerical simulation results indicate that the control scheme designed in this paper is feasible and effective,the residual vibration caused by the multi-mode flexible spacecraft during attitude maneuver can be effectively suppressed.