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针对挠性欠驱动航天器的姿态系统的镇定问题,提出了一种基于自适应观测器的容错控制方法,使得航天器的角速度和姿态收敛到有界的区域.所考虑的挠性航天器几乎是轴对称的,其中小参数ε给出了航天器关于欠驱动轴的非对称性的度量程度.首先,利用齐次系统的思想简化系统的模型,消除部分难以处理的耦合项;其次,设计自适应观测器实现对挠性非线性项的未知信息进行估计,并给出观测值与真值的范数界限;进而设计容错控制器使得系统的输出对于耦合项的估计是输入状态稳定的.最后,仿真结果验证了所提方法的有效性.
Aiming at the problem of stabilization of the attitude system of flexible under-actuated spacecraft, a fault-tolerant control method based on adaptive observer is proposed, which makes the angular velocity and attitude of the spacecraft converge to a bounded region. The considered flexible spacecraft almost Is axisymmetric, where the small parameter ε gives the degree of measurement of the spacecraft’s asymmetry about the underdrive shaft.Firstly, by using the idea of homogeneous system, the system model is simplified and some of the coupling terms that are difficult to handle are eliminated. Secondly, The adaptive observer realizes the unknown information of the flexible nonlinear term and gives the norm limit of the observed value and the true value. Furthermore, the fault-tolerant controller is designed to make the output of the system stable to the input state of the coupled term. Finally, the simulation results verify the effectiveness of the proposed method.