Adaptive output tracking control for nonlinear systems with unknown high frequency gain
具有未知输入增益的非线性系统的跟踪控制(英文)

An adaptive controller is proposed for output tracking of nonlinear systems with unknown high frequence gain. The control design is achieved by introducing the Nassbaum gain in the backstepping design scheme. It is shown that the proposed controller can achieve asymptotic tracking without any growth conditions and any a priori knowledge on the sign of the high frequency gain.