It is well known that unknown modeling errors cannot be avoided in practice. Such unmeasured uncertainties are usually denoted as unknown nonlinear functions that exist in every channel of the system equation. This paper aims to develop an output feedback adaptive control scheme by constructing state estimation filters to address such unknown modeling errors. In the controller design, these uncertainties caused by modeling errors will be accumulated to the last step for compensation. Unknown parameters existing in the upper bound functions of unknown nonlinear functions and system parameters are estimated synchronously based on tuning function approaches. It is shown that the designed output feedback controller can ensure the stability and tracking performance of the closed-loop system, and the transient performance in terms of a truncated norm is also established.

中文翻译：

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具有未知建模误差的不确定非线性系统的自适应输出反馈控制

众所周知，未知的建模错误在实践中是无法避免的。这种无法测量的不确定性通常表示为存在于系统方程的每个通道中的未知非线性函数。本文旨在通过构建状态估计滤波器来开发输出反馈自适应控制方案，以解决此类未知的建模误差。在控制器设计中，这些由建模误差引起的不确定性将累积到最后一步进行补偿。基于整定函数方法对未知非线性函数上界函数中存在的未知参数和系统参数进行同步估计。结果表明，设计的输出反馈控制器能够保证闭环系统的稳定性和跟踪性能，并且还建立了截断范数的瞬态性能。