航天器姿态的非线性鲁棒分散控制器设计

Nonlinear Robust Decentralized Controller Design for Spacecraft Attitude Control System

研究了具有外部干扰力矩及参数不确定性的航天器姿态控制问题。针对这类多输入-多输出的不确定非线性系统,基于一种非线性鲁棒分散控制理论,设计了结构简单而易于实现的控制器。该控制器中包含的积分环节可以补偿系统的各种未知因素,同时确保恒值调节系统不存在稳态误差。仿真结果表明：所设计的鲁棒分散控制器与非线性动态逆控制器相比,具有更优越的抗干扰能力和对模型不确定的适应能力。即使系统存在外部干扰及模型不确定性,仍可在闭环系统中实现精确的姿态控制。该控制器有效地提高了航天器姿态控制的鲁棒性和适应性。

This paper deals with the attitude control problem of the spacecraft with external disturbance torques and parameters perturbations. For this class of MIMO uncertain nonlinear system, based on a kind of nonlinear robust decentsalized control theory, a simple and easy-to-realize controller was designed. The proposed controller included integral actions for the compensation of the entire dynamics system assumed to be unknown. In addition, these integral actions ensured that the steady state error in the regulation of the output variables in some constant reference outputs was equal to zero. Simulation results are presented to show that, compared with nonlinear dynamic inversion controller, nonlinear robust decentralized controller designed is superior in resisting external disturbances and adapting the uncertainties of system model. In the closed-loop system, even if external disturbances and model uncertainties exist, precise attitude control call still be accomplished. Nonlinear robust decentralized controller can effectively improve robustness and adaptability of the spacecraft attitude control systems.