事件触发机制下的充液航天器姿态控制

Event-triggered attitude control of liquid-filled spacecraft

针对液体大幅晃动、通信资源受限的充液航天器姿态控制系统,提出一种自适应滑模控制与事件触发机制相结合的控制策略。首先,针对固-液耦合的充液航天器姿态控制系统,选用滑模变结构控制来削弱液体大幅晃动的非线性影响,并设计自适应更新律在线估计不确定参数来提高系统的鲁棒性。然后,考虑星载计算机资源的限制,设计相对阈值的事件触发机制来决定控制输入信号的更新,从而减少控制器与执行器之间的信号更新对通信网络的占用。最后,仿真结果表明,在液体大幅晃动下,所提控制策略不但可以使航天器姿态控制系统最终收敛到任意小的界内,而且可以减少96%的控制信号传输,减轻航天器的通信负载。

Aimed at the attitude system of liquid-filled spacecraft with large-amplitude liquid sloshing and limited communication resources,a control strategy combining adaptive sliding mode control and event-triggering mechanism is proposed.First,sliding mode variable structure control is used to weaken the nonlinear effect of large-amplitude liquid sloshing for a liquid-solid coupled spacecraft attitude system,and an adaptive updating law is designed to estimate the uncertain parameters online to improve the robustness of the system.Then,considering the limitation of onboard computer resources,an event-triggering mechanism with relative threshold is designed to determine the update of control input signal,so as to reduce the occupation of communication network caused by signal update between controller and actuator.Finally,the simulation results show that,under large-amplitude liquid sloshing,the control strategy can not only make the spacecraft attitude system converge to an arbitrary small boundary,but also reduce the control signal transmission by 96%and reduce the communication load of spacecraft.