基于扩张状态观测器的航天器时延状态反馈控制

研究了刚性航天器的时延姿态稳定控制问题。首先建立了基于修正罗德里格斯参数(modified rodrigues parameters, MRPs)的航天器非线性状态模型,具有确定上界的时延项在状态反馈控制律中体现。通过构造Lyapunov Krasovskii 泛函进行稳定性分析,由此得到保证系统渐近稳定的线性矩阵不等式,依此设计状态反馈控制系数矩阵。考虑到航天器三轴间的耦合非线性项,利用扩张状态观测器(extended state observer, ESO) 方法,设计了二阶非线性扩张状态观测器,以获得航天器系统内部状态向量并用于状态反馈控制律。为便于工程实际应用,仿真中将MRPs响应输出转换为欧拉角响应,仿真结果表明,本文所设计的控制系统能保证航天器三轴姿态稳定。

Spacecraft time-delay state feedback control based on extended state observer

This paper researches the problem of rigid body spacecraft time delay attitude stabilization. Firstly, the spacecraft nonlinear state model based on modified rodrigues parameters (MRPs) is established, the time delay term with certain upper boundary is modeled in state feedback control law. Lyapunov Krasovskii functional is constructed for this nonlinear time delay system to achieve asymptotic stabilization, linear matrix inequalities are accordingly obtained and the state feedback control coefficients matrixes are thereby computed with. Concerning the three axis coupling nonlinear terms in spacecraft, the extended state observer (ESO) method is used to design a two rank nonlinear ESO, the spacecraft system internal state vector is therefore acquired and used in the aforementioned state feedback control law. For the convenience of engineering application, the MRPs state vector is converted to Euler angles in simulation. The simulation results show the efficient of the state feedback control law with three axis attitude asymptotic stabilization achieved.