Zong Qun, Shao Shikai
School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China.
School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China.
ISA Trans. 2016 Nov;65:150-163. doi: 10.1016/j.isatra.2016.08.009. Epub 2016 Sep 13.
This paper investigates decentralized finite-time attitude synchronization for a group of rigid spacecraft by using quaternion with the consideration of environmental disturbances, inertia uncertainties and actuator saturation. Nonsingular terminal sliding mode (TSM) is used for controller design. Firstly, a theorem is proven that there always exists a kind of TSM that converges faster than fast terminal sliding mode (FTSM) for quaternion-descripted attitude control system. Controller with this kind of TSM has faster convergence and reduced computation than FTSM controller. Then, combining with an adaptive parameter estimation strategy, a novel terminal sliding mode disturbance observer is proposed. The proposed disturbance observer needs no upper bound information of the lumped uncertainties or their derivatives. On the basis of undirected topology and the disturbance observer, decentralized attitude synchronization control laws are designed and all attitude errors are ensured to converge to small regions in finite time. As for actuator saturation problem, an auxiliary variable is introduced and accommodated by the disturbance observer. Finally, simulation results are given and the effectiveness of the proposed control scheme is testified.
本文考虑环境干扰、惯性不确定性和执行器饱和等因素，利用四元数研究了一组刚体航天器的分布式有限时间姿态同步问题。采用非奇异终端滑模（TSM）进行控制器设计。首先，证明了一个定理：对于四元数描述的姿态控制系统，总是存在一种比快速终端滑模（FTSM）收敛更快的TSM。具有这种TSM的控制器比FTSM控制器具有更快的收敛速度和更少的计算量。然后，结合自适应参数估计策略，提出了一种新型终端滑模干扰观测器。所提出的干扰观测器不需要集总不确定性及其导数的上界信息。基于无向拓扑结构和干扰观测器，设计了分布式姿态同步控制律，并确保所有姿态误差在有限时间内收敛到小区域。针对执行器饱和问题，引入了一个辅助变量并由干扰观测器进行调节。最后，给出了仿真结果，验证了所提控制方案的有效性。
