针对含模型不确定性和外部扰动的高超声速飞行器(HFV)巡航飞行的控制问题,提出一种基于线性扩张状态观测器(LESO)的动态面控制方法。首先,建立高超声速飞行器的纵向运动模型,并采用非线性动态逆(NDI)技术实现了飞行器速度和高度通道的解耦;其次结合传统反演设计方法,采用基于反双曲正弦函数的跟踪微分器(IHSTD)求取虚拟控制量的微分信号,避免了"微分爆炸"的问题;然后设计了LESO,能够实现对模型不确定项和外部扰动组成的"总和扰动"的精确估计,进而在控制器中动态补偿,大幅增强了系统的扰动抑制能力;最后,采用Lyapunov稳定性理论对所提出的控制方法进行了稳定性分析。本文所提出的控制方法保证了系统的渐近稳定性和较强的鲁棒性,仿真结果校验了本文所设计控制器的有效性。
A linear estended state observer(LESO)-based dynamic surface controller is proposed in this paper for the cruising control problem of a hypersonic flight vehicle(HFV) with model parametric uncertainties and external disturbances. First of all,the longitudinal model of the HFV is denoted,and the decoupling of the altitude and velocity is realized via the nonlinear dynamic inversion(NDI) technique. Then,combining with the conventional back-stepping technique,a tracking differentiator based on the inverse hyperbolic sine function(IHSTD) is adopted to attain the derivatives of the virtual control laws,which avoids the problem of "differentiation explosion". And then a LESO is designed for the precise estimation and compensation of the "lumped disturbance " containing parametric uncertainties and external disturbances,which tremendously improves the ability of the disturbance rejection of the system. Finally,the stability of the proposed approach is analyzed by means of the Lyapunov stability theory. The exploited approach guarantees the asymptotic stability and robustness of the system,and the simulation results demonstrate the validity of the proposed method.