柔性航天器振动主动抑制及姿态控制

Active vibration suppression and attitude control for flexible spacecraft

针对柔性航天器柔性附件振动主动抑制及姿态高精度快速稳定问题,研究了一种输入成形器(IS)-自适应有限时间干扰观测器(FDO)-有限时间积分滑模控制器综合的设计方法。首先,基于柔性模态的频率及阻尼信息,获得能够有效抑制柔性振动的输入成形器形式,并与系统参考输入进行卷积,得到期望参考输入;其次,基于航天器动力学模型,设计一种新型的自适应有限时间干扰观测器,避免了综合干扰上界必须已知的约束,且保证干扰估计误差有限时间收敛至零,实现对干扰及残余振动影响的快速精确估计;最后,基于观测器的估计值,设计多变量有限时间积分滑模控制器,保证对期望参考输入的高精度快速跟踪控制,并进行严格的稳定性证明。仿真结果表明,该综合设计策略能够保证柔性附件振动抑制75%,姿态稳定度达到10^(-4)数量级。

A comprehensive design of input shaper(IS)-Finite time Disturbance Observer(FDO)-integral sliding mode controller is proposed for the active vibration suppression of flexible appendages and attitude control of flexible spacecraft,with high accuracy and fast convergence time.Firstly,an IS,which can be used to reduce flexible vibration,is obtained based on the frequency and damping information of flexible modes.The IS is convolved with reference inputs to get the desired reference commands.Then,based on the spacecraft dynamic model,a novel adaptive FDO is designed to guarantee accurate estimation of disturbance and residual vibration,which avoids the constraint that the upper bound must be known in advance and drives the estimation errors to zero in finite time.Finally,multivariable finite-time integral sliding mode controller is designed based on the estimations of FDO,which ensures the fast and high-precision tracking control of desired reference commands,and the strict stability proof is given.Simulation results show that the comprehensive design strategy can guarantee that the flexible vibration is suppressed by 75% and the attitude stability degree is up to 10-4.