标题：Adaptive disturbance attenuation via output feedback for nonlinear systems with polynomial-of-output growth rate
作者：Shang, Fang; Liu, Yungang
作者机构：[Shang, Fang] Shandong Jianzhu Univ, Sch Informat & Elect Engn, Shandong Prov Key Lab Intelligent Bldg Technol, Jinan 250101, Peoples R China.; [Liu 更多
通讯作者地址：[Shang, F]Shandong Jianzhu Univ, Sch Informat & Elect Engn, Shandong Prov Key Lab Intelligent Bldg Technol, Jinan 250101, Peoples R China.
来源：INTERNATIONAL JOURNAL OF CONTROL
关键词：nonlinear system; uncertain control coefficient; adaptive disturbance; attenuation; output feedback; polynomial-of-output growth rate
摘要：In this paper, the adaptive disturbance attenuation via output feedback is investigated for a class of nonlinear systems with uncertain control coefficients. Notably, the considered systems depend on unmeasured states with polynomial-of-output growth rate, and hence the systems have severe unknowns. Due to the existence of both the virtual and actual uncertain control coefficients, we first introduce a suitable state transformation, such that the control design becomes convenient. Then, we construct an appropriate and simple state observer with two important gains, and one gain is large enough to handle the constants appeared in the design procedure, and the other is updated on-line to deal with the polynomial-of-output growth rate of the system. After that, an output feedback controller is proposed based on the observer in a step-by-step manner. Finally, it is shown that, by appropriate choice of the design parameters, the states of the closed-loop system are globally bounded, and the disturbance attenuation is achieved in the sense of L-2-gain.