%0 Journal Article
%T Adaptive fuzzy backstepping output feedback control of nonlinear time-delay systems with unknown high-frequency gain sign<br>
%A Chang-Liang Liu
%A Shao-Cheng Tong
%A Yong-Ming Li
%A Yuan-Qing Xia
%A <br>
%J 国际自动化与计算杂志
%D 2011
%I 
%X In this paper, an adaptive fuzzy robust feedback control approach is proposed for a class of single-input and single-output (SISO) strict-feedback nonlinear systems with unknown nonlinear functions, time delays, unknown high-frequency gain sign, and without the measurements of the states. In the backstepping recursive design, fuzzy logic systems are employed to approximate the unknown smooth nonlinear functions, K-filters is designed to estimate the unmeasured states, and Nussbaum gain functions are introduced to solve the problem of unknown sign of high-frequency gain. By combining adaptive fuzzy control theory and adaptive backstepping design, a stable adaptive fuzzy output feedback control scheme is developed. It has been proven that the proposed adaptive fuzzy robust control approach can guarantee that all the signals of the closed-loop system are uniformly ultimately bounded and the tracking error can converge to a small neighborhood of the origin by appropriately choosing design parameters. Simulation results have shown the effectiveness of the proposed method.
%K Nonlinear systems
%K adaptive fuzzy control
%K time-delay
%K high-frequency gain sign
%K backstepping
%K K-filters&prev_q=K-filters')"> K-filters" target="_blank">K-filters')"> K-filters
%K stability<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=8240383F08CE46C8B05036380D75B607&jid=7139AD613512F4F05F6D525B914296AA&aid=DB46A6CEBF73B81EC82776750A34E3B6&yid=9377ED8094509821&vid=5D311CA918CA9A03&iid=CA4FD0336C81A37A&sid=F3583C8E78166B9E&eid=BC12EA701C895178&journal_id=1476-8186&journal_name=国际自动化与计算杂志&referenced_num=0&reference_num=24