基于模糊干扰观测器的自适应二阶动态滑模控制

Adaptive second-order dynamic sliding-mode control based on fuzzy disturbance-observer

中文关键词  近空间飞行器  滑模  克服抖振  模糊干扰观测器  自适应

英文关键词  near space vehicle  sliding-mode  suppress chattering  fuzzy disturbance-observer  adaptive

中文摘要

      针对一类存在不确定性和外干扰的非线性系统滑模控制的抖振问题, 本文首先证明了以高斯函数为隶属度函数的模糊基向量对状态向量的偏导在任意情况下有界, 解决了模糊辨识同二阶动态滑模结合的关键问题. 然后设计了二阶动态Terminal滑模, 有效克服了滑模抖振, 且能保证滑模面上的滑动在有限时间内收敛. 再基于模糊干扰观测器的输出设计自适应鲁棒补偿项. 基于李雅普诺夫理论证明了系统稳定性. 最后将本文提出的控制方案用于近空间飞行器姿态角跟踪仿真, 并分析了高阶动态滑模收敛时间增加的问题. 结果表明本文提出的控制方案跟踪速度快、精度高, 且有效去除了抖振. 与常规Terminal滑模相比, 二阶动态Terminal滑模增加的收敛时间非常有限, 适于工程应用.

英文摘要

      In the sliding-mode control of nonlinear systems with uncertainties and disturbances, we prove that the partial derivative of the Gaussian fuzzy basic function vector with respect to the state vector is bounded under any condition, thus resolving the key problem in combining a second-order dynamic sliding-mode control with the fuzzy identification. In addition, we design a second-order dynamic terminal-sliding-mode control which converges in a finite period of time without chattering. The output of the fuzzy disturbance-observer is employed as the compensation signal for the adaptive robust control. The stability of the system is proved by using Lyapunov theorem. The proposed control scheme is applied to the attitude-angles tracking of a near space vehicle; the increment of the convergence time in this application of higherorder sliding-mode control has been analyzed. Results show that this control scheme effectively suppresses the chattering and is with strong robustness, fast tracking speed, and high precision. Compared with the conventional terminal-slidingmode control, the second-order dynamic terminal-sliding-mode control causes limited increment of the convergence time, demonstrating the efficacy of this control scheme in engineering application.