Sun Lichao, Huang Yanpei, Fei Haolin, Xiao Bo, Yeatman Eric M, Montazeri Allahyar, Wang Ziwei
School of Education, Communication & Society, King's College London, London, United Kingdom.
Department of Bioengineering, Imperial College London, London, United Kingdom.
Front Robot AI. 2023 Feb 14;10:1138115. doi: 10.3389/frobt.2023.1138115. eCollection 2023.
On-orbit service spacecraft with redundant actuators need to overcome orbital and attitude coupling when performing proximity maneuvers. In addition, transient/steady-state performance is required to fulfill the user-defined requirements. To these ends, this paper introduces a fixed-time tracking regulation and actuation allocation scheme for redundantly actuated spacecraft. The coupling effect of translational and rotational motions is described by dual quaternion. Based on this, we propose a non-singular fast terminal sliding mode controller to guarantee fixed-time tracking performance in the presence of external disturbances and system uncertainties, where the settling time is only dependent on user-defined control parameters rather than initial values. The unwinding problem caused by the redundancy of dual quaternion is handled by a novel attitude error function. Moreover, optimal quadratic programming is incorporated into null space pseudo-inverse control allocation that ensures the actuation smoothness and never violates the maximum output capability of each actuator. Numerical simulations on a spacecraft platform with symmetric thruster configuration demonstrate the validity of the proposed approach.
具有冗余执行器的在轨服务航天器在进行接近操作时需要克服轨道和姿态耦合。此外，还需要瞬态/稳态性能来满足用户定义的要求。为此，本文介绍了一种用于冗余驱动航天器的固定时间跟踪调节和驱动分配方案。平移和旋转运动的耦合效应由对偶四元数描述。在此基础上，我们提出了一种非奇异快速终端滑模控制器，以保证在存在外部干扰和系统不确定性的情况下的固定时间跟踪性能，其调节时间仅取决于用户定义的控制参数而非初始值。由对偶四元数的冗余性引起的展开问题通过一种新颖的姿态误差函数来处理。此外，将最优二次规划纳入零空间伪逆控制分配中，以确保驱动的平滑性，并且永远不会违反每个执行器的最大输出能力。在具有对称推进器配置的航天器平台上进行的数值模拟验证了所提方法的有效性。
