Robust Adaptive Control for a Class of Uncertain Nonlinear Systems
一类不确定非线性系统的鲁棒自适应控制

A robust adaptive backstepping control scheme with a dead zone modification is proposed for a class of uncertain nonlinear systems with unknown control direction,uncertain parameters and unmodeled dynamics.A priori knowledge of the sign of the control direction is not required.With priori knowledge of the bounds of the parametric uncertainties,the smooth projection method and the discontinuous projection method are incorporated into the adaptive laws to prevent parameter drifts respectively.The number of parameter estimates is minimal for the two cases.It is proved that under the proposed control law,all the closed-loop signals are bounded and the tracking error converges to the any prescribed small interval around zero.