基于非线性干扰观测器的L_2滤波反步控制

L_2 filtered backstepping control based on nonlinear disturbance observer

针对一类多输入多输出高阶不确定非线性系统,提出一种基于非线性干扰观测器的L2滤波反步控制方法。利用非线性干扰观测器对系统的未知复合干扰进行在线估计,基于李雅普诺夫稳定性理论设计指令滤波反步控制器,避免常规反步法由于对虚拟控制迭代求导造成控制器复杂的问题,设计L2干扰抑制鲁棒控制器减弱了观测器误差对控制精度带来的影响。针对某三阶不确定非线性系统进行仿真验证。研究结果表明:非线性干扰观测器能够有效估计系统的复合扰动,且L2干扰抑制方法能够在观测器存在误差时提高控制精度。

A L2 filtered backstepping control method based on the nonlinear disturbance observer for a general class of multiple input multiple output high order nonlinear system with uncertainties was proposed. The uncertainty of the system could be estimated by nonlinear disturbance observer online. The filtered backstepping controller was designed based on the Lyapunov stability theorem which could avoid the the complex iterative derivative operation of supposition of traditional backstepping approach. A L2 disturbance attenuation robust controller was adopted to decrease the influence of the control accuracy from the observer estimation error. Aiming at one kind of three-order nonlinear system with uncertainties, the simulation results were illustrated. The results show that the nonlinear disturbance observer can estimate the composite disturbances of the system effectively, and the L2 disturbance attenuation method can improve the control accuracy when there exists error in the observer.