Ding Yibo, Wang Xiaogang, Bai Yuliang, Cui Naigang
School of Astronautics, Harbin Institute of Technology, Harbin 150001, China.
School of Astronautics, Harbin Institute of Technology, Harbin 150001, China.
ISA Trans. 2019 Jul;90:1-18. doi: 10.1016/j.isatra.2018.12.043. Epub 2018 Dec 29.
An improved robust fixed-time sliding mode controller (RFSMC) is presented for flexible air-breathing hypersonic vehicle (FAHV) with actuator faults, composing of a novel fast fixed-time integral sliding surface (FFIS), a continuous fixed-time super-twisting-like reaching law (CFSTL) and a uniformly convergent observer. Firstly, the nonlinear control-oriented model of FAHV is processed via input/output feedback linearization with flexible effects and actuator faults modeling as matched Lipschitz disturbances. Secondly, a novel non-singular FFIS is established based on a fast fixed-time high-order regulator (FFTR), which is improved with two gains incorporating into standard fixed-time high-order regulator via dilation rescaling. The FFTR proposed can accelerate respond speed of system by tuning values of two gains simply without complicated parameters selection and the stability is proved strictly via Lyapunov criteria. Thirdly, a CFSTL is utilized to ensure high-precision convergence of sliding mode vector and its derivative in fixed time. Afterwards, a uniformly convergent observer is applied to estimate lumped disturbances accurately in fixed time. With the estimated values compensated into controller, RFSMC can enhance fault-tolerant performance and attenuate chattering efficiently. Finally, simulations on FAHV are performed to verify the effectiveness and superiority of the method proposed.
针对存在执行器故障的柔性吸气式高超声速飞行器（FAHV），提出了一种改进的鲁棒固定时间滑模控制器（RFSMC），它由一种新型快速固定时间积分滑模面（FFIS）、一种连续固定时间超扭曲类趋近律（CFSTL）和一个一致收敛观测器组成。首先，通过输入/输出反馈线性化对FAHV的非线性面向控制模型进行处理，将柔性效应和执行器故障建模为匹配的李普希茨干扰。其次，基于快速固定时间高阶调节器（FFTR）建立了一种新型非奇异FFIS，通过尺度变换将两个增益纳入标准固定时间高阶调节器对其进行改进。所提出的FFTR可以通过简单调整两个增益的值来加快系统响应速度，无需复杂的参数选择，并且通过李雅普诺夫准则严格证明了其稳定性。第三，利用CFSTL确保滑模向量及其导数在固定时间内高精度收敛。然后，应用一致收敛观测器在固定时间内准确估计集总干扰。将估计值补偿到控制器中，RFSMC可以提高容错性能并有效减弱抖振。最后，对FAHV进行了仿真，验证了所提方法的有效性和优越性。
