针对编队卫星姿态协同控制问题,在考虑到执行机构误差的前提下,提出一种将时延控制与滑模自适应控制相结合的鲁棒控制方法。该方法通过引入自适应更新律实现对执行机构小角度安装误差的在线估计,同时通过滑模控制完成对外界干扰和执行机构随机幅值误差等随机扰动的抑制。由于引入了时延环节,只需对上一时刻控制力矩进行单位时延,达到大大简化控制器设计复杂度的目的。基于Lyapunov稳定性理论,证明了闭环系统的稳定性。最后,通过数值仿真对提出的控制方法进行了验证,仿真结果表明该方法能够有效抑制外部干扰和执行机构随机幅值误差的影响,对执行机构安装误差的自适应在线估计能够快速稳定收敛,鲁棒性强,且具有良好的过渡过程品质。
This paper develops an adaptive sliding mode attitude control system combined with time-delay control for the attitude coordination of satellite formation, especially when there exists the misalignment and magnitude error of active actuators. An adaptive update algorithm is presented to estimate the misalignment of actuators online, while the external disturbances together with random magnitude errors of an actuator are attenuated by the sliding mode controller. In addition, due to the introduction of the time-delay element, which just delays the last instantaneous control torque for a unit time, the complexity of controller design is greatly reduced. The stability of the closed-loop system is also proved based on the Lyapunov theory. Finally, the effectiveness of the corresponding controller is studied through numerical simulation. The results demonstrate that the external disturbance and random magnitude error can be attenuated by choosing appropriate control parameters, and the adaptive update algorithm can converge in a short time as well.
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