一类带液体晃动的航天器滑模姿态控制器设计

Sliding-mode Attitude Controller Design for a Kind of Spacecraft with Fuel Slosh

针对一类带液体晃动的航天器,在建立系统数学模型的基础上,利用一种增量滑模的设计方法来设计控制器。将系统状态变量分成可自行到达平衡位置和需要施加控制才能到达平衡位置两部分,对于需要施加控制达到预定平衡位置的状态变量,用增量滑模控制来设计控制律,将其分解成两个子系统,选取一个子系统的状态变量构造第一层滑模面,然后将第一层滑模面看成一个状态变量与另外一个子系统的状态变量构造第二层滑模面,最后采用Lyapunov方法求取总控制量。当系统接近平衡位置时,增量滑模控制器可以在保证最后一级稳定的情况下实现整个系统各个状态的控制,在30s内可以保证系统能够稳定在最终的平衡位置上。仿真结果表明,该方法能很好地达到控制效果。

An incremental sliding-mode control design method was proposed for a kind of spacecraft with fuel slosh. The whole system was divided into two parts. The incremental sliding-mode control method was mainly used for the states which are not relative equilibrium ones. Two state variables of a subsystem were chosen to construct the first-layer sliding surface, and then the first-layer sliding surface and one of the left state variables were used to construct the second-layer sliding surface. Using the Lyapunov method, a sliding-mode control law can be derived. When the states reach the equilibrium position, the incremental sliding- mode controller was degraded into the monolayer controller which ensured the system stabilized at the uppermost equilibrium position within 30 seconds. Simulation results are given to illustrate the validity.