This article is devoted to global adaptive stabilization for a class of uncertain nonlinear systems. Notably, the systems under investigation admit unknown control directions and unknown input powers, and particularly the latter, which are a new type of system uncertainties, largely challenge the feasibility of continuous feedbacks. This spurs us to pursue a switching adaptive feedback which is actual a discontinuous one with high feedback capability. To solve the control problem, a parameterized controller in a specified form is first introduced, which can globally stabilize the system once the design parameter involved belongs to a certain set. However, the controller cannot directly be implemented since the set depends heavily on the unknown input powers. To make the parameterized controller implementable, a new switching strategy is delicately proposed, which can instantly update the parameters of the controller to compensate the serious system uncertainties. It turns out that the parameterized controller with switching updating mechanism guarantees that all the signals of the closed‐loop system are globally bounded and ultimately converge to zero. Simulation examples demonstrate the effectiveness of the proposed design scheme.

中文翻译：

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具有未知控制方向和未知输入功率的非线性系统的自适应控制器

本文致力于一类不确定非线性系统的全局自适应镇定。值得注意的是，所研究的系统允许未知的控制方向和未知的输入功率，尤其是后者，这是一种新型的系统不确定性，极大地挑战了连续反馈的可行性。这促使我们追求一种开关自适应反馈，它实际上是具有高反馈能力的不连续反馈。为了解决控制问题，首先引入指定形式的参数化控制器，一旦涉及的设计参数属于某个集合，该控制器就可以全局稳定系统。但是，由于该集合在很大程度上取决于未知的输入功率，因此无法直接实现该控制器。为了使参数化控制器可实施，精心提出了一种新的切换策略，该策略可以立即更新控制器的参数以补偿严重的系统不确定性。事实证明，带有开关更新机制的参数化控制器可确保闭环系统的所有信号都具有全局范围，并最终收敛到零。仿真实例证明了所提出设计方案的有效性。