本文针对挠性卫星姿态机动和振动抑制问题,给出一种基于多项式平方和(sum of squares,SOS)的非线性局部镇定控制方法.根据姿态系统结构特征,在此基础上,采用SOS结合S-procedure理论,得出相应的非线性局部可镇定条件.该条件可借助有效凸优化工具进行检验,当优化问题可解时,可构造非线性姿态控制器的解析解.最后,将文中方法应用于某型挠性卫星姿态控制.仿真结果表明,在实现大角度姿态快速机动的同时,有效抑制了挠性附件振动.
Exponential stability and robust exponential stability relating to switched systems consisting of stable and unstable nonlinear subsystems are considered in this study.At each switching time instant,the impulsive increments which are nonlinear functions of the states are extended from switched linear systems to switched nonlinear systems.Using the average dwell time method and piecewise Lyapunov function approach,when the total active time of unstable subsystems compared to the total active time of stable subsystems is less than a certain proportion,the exponential stability of the switched system is guaranteed.The switching law is designed which includes the average dwell time of the switched system.Switched systems with uncertainties are also studied.Sufficient conditions of the exponential stability and robust exponential stability are provided for switched nonlinear systems.Finally,simulations show the effectiveness of the result.
