欠驱动航天器姿态稳定的分层滑模控制器设计

Hierarchical Sliding-Mode Control for Attitude Stabilization of an Underactuated Spacecraft

利用分层滑模控制方法,为带两个控制执行机构的欠驱动刚体航天器的姿态控制系统设计了一种三轴稳定控制器。首先,给出了基于两个推力器的欠驱动航天器的姿态动力学和运动学模型,分析了其模型特点。其次,将子系统的变量进行组合定义成第一层滑模面,利用Filippov等效定理求出等效控制律。然后依次构造出第二层滑模面及第三层滑模面,根据滑模控制原理求出切换控制律,进而得到总的控制量。利用Lyapunov稳定性理论和Barbalat引理及推论证明了各层滑模面的全局渐近稳定性。仿真实验验证了该控制方法的有效性。

For an underactuated spacecraft with two control actuators,an attitude controller is proposed based on hierarchical sliding-mode control.Firstly,attitude dynamics and kinematics models are introduced and analyzed.Secondly,the first-layer sliding surface is defined by the state variables of the underactuated system,and the equivalent controller is obtained by Filippov equivalent theorem.Then,the second-layer sliding surface and the third-layer sliding surface are constructed in sequence,and the switching controller is derived by using the sliding-mode control theory.Thus the total controller is deduced by the equivalent and switching controller.The global asymptotic stability of all sliding surfaces is proved by using Lyapunov stability theory and Barbalat theory.The simulation results illustrate the feasibility of the proposed control algorithm.