Ding Yibo, Yue Xiaokui, Liu Chuang, Dai Honghua, Chen Guangshan
School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China.
Shanghai Aerospace Control Technology Institute, Shanghai 201109, China.
ISA Trans. 2022 Mar;122:96-113. doi: 10.1016/j.isatra.2021.04.038. Epub 2021 Apr 30.
An adaptive anti-saturation robust finite-time control algorithm (AARFTC) is designed for flexible air-breathing hypersonic vehicle (FAHV) under actuator saturations. Firstly, an adaptive fixed-time anti-saturation compensator (AFAC) is presented to drive system to faster leave the saturated region Compared to traditional anti-saturation compensators, the auxiliary variable of AFAC is able to realize faster and more accurate convergence when saturation disappears, which avoids the influence on convergent characteristics of tracking error. In addition, the novel adaptive law in AFAC can further shorten the duration of saturation and improve the convergent speed of tracking error via adjusting gain in AFAC according to saturation of actuator. Then, dynamic inversion control is combined with AFAC to establish anti-saturation controller for velocity subsystem. Secondly, differentiator-based backstepping control is combined with AFAC for height subsystem. Two recursive fixed settling time differentiators are utilized to approximate derivatives of virtual control signals exactly in fixed time, which avoids the complex computational burden residing in traditional backstepping control and improves convergent accuracy compared to command filtered backstepping control. Meanwhile, AFAC is utilized to suppress the influence of elevator saturation. Ultimately, multiple sets of simulations on FAHV subject to external disturbances, parametric uncertainties and actuator saturations are carried out to show the superiorities of AFAC and AARFTC.
针对存在执行器饱和的柔性吸气式高超声速飞行器（FAHV），设计了一种自适应抗饱和鲁棒有限时间控制算法（AARFTC）。首先，提出了一种自适应固定时间抗饱和补偿器（AFAC），以使系统更快地离开饱和区域。与传统抗饱和补偿器相比，AFAC的辅助变量在饱和消失时能够实现更快、更精确的收敛，避免了对跟踪误差收敛特性的影响。此外，AFAC中的新型自适应律可根据执行器的饱和情况调整AFAC中的增益，进一步缩短饱和持续时间并提高跟踪误差的收敛速度。然后，将动态逆控制与AFAC相结合，为速度子系统建立抗饱和控制器。其次，将基于微分器的反步控制与AFAC相结合用于高度子系统。利用两个递归固定收敛时间微分器在固定时间内精确逼近虚拟控制信号的导数，避免了传统反步控制中复杂的计算负担，与指令滤波反步控制相比提高了收敛精度。同时，利用AFAC抑制升降舵饱和的影响。最后，对受外部干扰、参数不确定性和执行器饱和影响的FAHV进行了多组仿真，以展示AFAC和AARFTC的优越性。
