基于MFTESO的可重复使用运载火箭多变量有限时间控制方法

MFTESO Based Multivariable Finite-time Control for Reusable Rocket

针对可重复使用运载火箭一子级返回过程中大气层内无动力减速段姿态控制问题,考虑模型不确定性和外界干扰因素的影响,提出了一种基于多变量有限时间扩张状态观测器(multivariable finite-time extended stateobserver, MFTESO)的多变量有限时间控制方法。基于绕质心运动模型建立面向姿态控制的模型,利用MFTESO对系统状态和总扰动进行估计,并将估计值引入多变量有限时间控制器,以保证对姿态角期望值的准确和快速跟踪控制。基于Lyapunov理论证明了闭环系统有限时间稳定性;将基于MFTESO的多变量有限时间控制方法与非奇异快速终端滑模控制方法作对比,结果表明,前者使运载火箭一子级动态响应过程中的超调量、稳态误差更小,且能在有限时间内跟踪姿态角期望值,为实现垂直回收提供了必要条件。

To solve the attitude control problem for the first-stage of a reusable rocket in atmosphere unpowered deceleration phase, considering the influence of the model uncertainty and external disturbance, a multivariable finite-time control method based on multivariable finite-time extended state observer was proposed. Firstly,the attitude control model is established based on the model of rotational motion. Secondly,the multivariable finite-time extended state observer is used to estimate the system states and the lumped disturbance, and the estimations are introduced into the multivariable finite-time controller to ensure accurate and fast tracking control of the attitude angle expectation value. Then,the finite-time stability of the closed-loop system is guaranteed through Lyapunov theory. The MFTESO based multivariable finitetime control method was compared with the singularity-free fast terminal sliding mode control method. Numerical simulation shows that the former method gives smaller overshoot and steady-state error rates in the dynamic response process, and can track the attitude angle expectation value within a finite time, which also provides the necessary conditions for first-stage of reusable rocket vertical recovery.