Robust adaptive control for uncertain nonlinear systems with unknown control directions and actuator nonlinearity  

作　　者：Jianhao WANG Jianbo HU 

机构地区：[1]Engineering College,Air Force Engineering University

出　　处：《控制理论与应用（英文版）》2012年第4期441-450,共10页

基　　金：supported by the Scientific Innovation Foundation of Air Force Engineering University(No.XS0901008);Shanghai Leading Academic Discipline Project(No.J50103)

摘　　要：A robust adaptive control scheme is proposed for a class of uncertain nonlinear systems in strict feedback form with both unknown control directions and non-symmetric dead-zone nonlinearity based on backstepping design. The conditions that the dead-zone slopes and the boundaries are equal and symmetric are removed by simplifying nonlinear dead-zone input model, the assumption that the priori knowledge of the control directions to be known is eliminated by utilizing Nussbaum-type gain technique and neural networks （NN） approximation capability. The possible controller singularity problem and the effect of dead-zone input nonlinearity are avoided perfectly by combining integral Lyapunov design with sliding mode control strategy. All the signals in the closed-loop system are guaranteed to be semi-globally uniformly ultimately bounded and the tracking error of the system is proven to be converged to a small neighborhood of the origin. Simulation results demonstrate the effectiveness of the proposed control scheme.A robust adaptive control scheme is proposed for a class of uncertain nonlinear systems in strict feedback form with both unknown control directions and non-symmetric dead-zone nonlinearity based on backstepping design. The conditions that the dead-zone slopes and the boundaries are equal and symmetric are removed by simplifying nonlinear dead-zone input model, the assumption that the priori knowledge of the control directions to be known is eliminated by utilizing Nussbaum-type gain technique and neural networks （NN） approximation capability. The possible controller singularity problem and the effect of dead-zone input nonlinearity are avoided perfectly by combining integral Lyapunov design with sliding mode control strategy. All the signals in the closed-loop system are guaranteed to be semi-globally uniformly ultimately bounded and the tracking error of the system is proven to be converged to a small neighborhood of the origin. Simulation results demonstrate the effectiveness of the proposed control scheme.

关 键 词：Uncertain nonlinear system Robust adaptive control Actuator nonlinearity BACKSTEPPING Sliding modecontrol DEAD-ZONE 

分 类 号：TP13[自动化与计算机技术—控制理论与控制工程]