基于滑模输出反馈与输入成形控制相结合的挠性航天器主动振动抑制方法

针对挠性航天器大角度姿态机动的振动抑制问题，提出了一种基于输出反馈滑模控制和输入成形振动抑制方法相结合的主动振动控制策略。输入形成器作为前馈控制器作用在反馈回路的前相通道，通过改变输入命令的作用形式，在保证参考模型（标称对象）完成指定的姿态机动的同时抑制掉对系统影响较大的挠性结构的振动；而对于闭环控制回路，考虑挠性结构模态不可测、模型参数具有不匹配不确定性以及外干扰力矩的作用，在输出反馈滑模控制的基础上，给出了仅利用输出信息的滑模控制器设计方法，保证跟踪参考模型的输出以获得要求的闭环系统的性能。将该方法应用于单轴挠性航天器的大角度rest—to—rest（静止到静止）姿态机动控制进行了仿真研究，结果表明，所提出的方法是可行而有效的。

Active Vibration Suppression in Flexible Spacecraft with Mismatched Uncertainty Via Sliding Mode/Shaped Input Control

A generalized scheme based on output feedback sliding mode control(OFSMC)in conjunction with input shaping technique is discussed for a linear uncertain system with an unknown but bounded parametric uncertainty and external disturbance,and is utilized in a flexible spacecraft for rotational nameuver control and active reduction of elastic vibration during maneuvering operation.The configuration of the proposed approach is that the input shaper is implemented outside the feedback loop,which is designed for the reference model and achieves the exact reduction of residual vibration by modifying the existing command;while for the feedback loop,the feedback controller based on the sliding mode control is implemented to make the closed-loop system behave like the reference model with input shaper and suppress the residual vibrations.The robustness against the parametric uncertainty and external disturbance is achieved through the proper selection of control gains.An attractive feature of this OFSMC algorithm is that the parametric uncertainties of the system need not satisfy the so-called matching condition or invariance conditions provided certain bounds are known.Simulation results for the spacecraft model show precise trajectory control and satisfactory vibration suppression.