基于固定时间扩张状态观测器的底栖式AUV点镇定控制

Point stabilization control of benthic AUV based on fixed-time extended state observer

[目的]针对受未知干扰和不确定性因素影响的底栖式自主水下航行器(AUV)点镇定控制问题,设计一种基于固定时间扩张状态观测器(FTESO)的固定时间反步控制器。[方法]首先,根据AUV点镇定跟踪误差模型提出一种固定时间扩张状态观测器,用于估计未知的集中扰动以及不可测量的速度,并使观测误差在固定时间内收敛至0;然后,在上述观测器的基础上使用反步法设计一种固定时间点镇定控制器;最后,通过加入一阶滤波器,解决反步控制器固有的“复杂性爆炸”问题,并通过李雅普诺夫稳定性分析证明闭环控制系统的半全局固定时间一致最终有界性。[结果]经仿真分析,验证了所提方案的可行性和优越性。[结论]研究表明所提方案可以解决受未知干扰与不确定性因素影响下的底栖式AUV的点镇定控制问题,并能提高控制系统的收敛时间。

[Objectives]Aiming at the problem of the point stabilization control of a benthic autonomous underwater vehicle(AUV)under unknown disturbances and uncertainties,a fixed-time backstepping controller based on a fixed-time extended state observer(FTESO)is designed.[Methods]First,according to the point stabilization tracking error model of AUVs,a new FTESO is proposed to estimate the unknown disturbances and unmeasurable velocity,and the observation error can be converged to zero in a fixed time.Based on the above observer,a fixed-time point stabilization controller is then designed using the backstepping method.Finally,by adding a first-order filter,the inherent complexity explosion of the backstepping controller is solved,and the semi-global fixed-time uniform ultimate boundedness of the closed-loop system is proven by Lyapunov stability analysis.[Results]The feasibility and superiority of the proposed scheme are verified by simulation experiments.[Conclusions]The results show that the proposed scheme can solve the point stabilization control problem of a benthic AUV affected by unknown disturbances and uncertainties,and improve the convergence time of the control system.