高阶非线性不确定系统的复合有限时间控制

Composite finite-time control for a high order nonlinear uncertain system

中文关键词  非线性系统  有限时间干扰观测器  复合趋近律  非奇异终端滑模控制  有限时间稳定

英文关键词  nonlinear system  finite time disturbance observer  hybrid reaching law  non-singular terminal sliding mode control  finite time stability

中文摘要

      本文针对一类带有外界干扰的高阶非线性不确定系统, 提出基于有限时间干扰观测器的复合有限时间控制策略, 为了解决终端滑模的奇异性问题, 设计改进的非奇异终端滑模面. 同时, 双曲正切函数和指数型函数相结合, 构造新型复合趋近律. 为了处理外界干扰, 设计非奇异终端滑模观测器, 将观测到的干扰值前馈到滑模控制中, 进一步提高系统的抗干扰性. 最后, 将设计的复合趋近律与其他5种趋近律进行仿真对比, 验证复合趋近律的收敛速度和削弱抖振能力, 并通过非线性系统的数值仿真验证所提出控制策略的有效性和优越性.

英文摘要

      A composite finite-time control strategy based on finite time disturbance observer is proposed for a class of high-order nonlinear uncertain systems with external disturbances. In order to solve the singularity problem of terminal sliding mode, an improved non-singular terminal sliding mode (NSTSM) surface is designed. Meanwhile, the hyperbolic tangent function and the exponential function are combined to construct a new hybrid reaching law. A NSTSM observer is designed to deal with external disturbances, and the observed disturbance value is fed forward into the sliding mode control to further improve the anti-disturbance performance of the control system. Finally, the proposed reaching law is simulated and compared with other five reaching laws to verify the convergence speed and free-chattering ability of the hybrid reaching law. The effectiveness and superiority of the proposed control strategy are verified by numerical simulation of nonlinear system.