Adaptive output feedback control for a class of nonlinear systems with unknown virtual control coefficients signs

作者：Zheng Yunfeng^*; Yang Yansheng

来源：International Journal of Adaptive Control and Signal Processing, 2007, 21(1): 77-89.

DOI：10.1002/acs.925

• adaptive output feedback
• nonlinear systems
• unknown virtual control directions
• Nussbaum gain
• backstepping

This paper presents a global output-feedback control scheme for a class of nonlinear systems that are transformed via a parameter-independent change of co-ordinates into a form in which there exist three kinds of unknown parameters: one is the unknown virtual control coefficients, one is the unknown parameters that multiply output nonlinearities and the other kind is the unknown parameters that multiply affine functions of the derivative of the measured output with coefficients that are smooth nonlinear functions of the measured output. We use two parameter-dependent changes of co-ordinates to transform the system considered into parametric output-feedback form. One transformation is used to eliminate the difficulty in dealing with unknown virtual control coefficients and the other transformation is used to remove the nonlinearities which are affine functions of the derivative of the measured output with coefficients that are smooth nonlinear functions of the measured output. Then the scheme presented by Ye (IEEE Trans. Automat. Control 2001; 46:112-115) can be applied to the new system. Global results can be obtained for the overall closed-loop systems without any constraints on the nonlinear terms.

• 出版日期2007-2
• 单位大连海事大学