Approximation-based disturbance observer approach for adaptive tracking of uncertain pure-feedback nonlinear systems with unmatched disturbances

This paper presents an approximation-based nonlinear disturbance observer (NDO) methodology for adaptive tracking of uncertain pure-feedback nonlinear systems with unmatched external disturbances. Compared with existing control results using NDO for nonlinear systems in lower-triangular form, the ma...

Full description

Saved in:
Bibliographic Details
Published inInternational journal of systems science Vol. 48; no. 8; pp. 1775 - 1786
Main Authors Kim, Hyoung Oh, Yoo, Sung Jin
Format Journal Article
LanguageEnglish
Published London Taylor & Francis 11.06.2017
Taylor & Francis Ltd
Subjects
Adaptive control
Adaptive systems
adaptive technique
Approximation
Attenuation
Computer simulation
Control systems
Disturbance observers
Disturbances
Dynamical systems
Feedback
Mathematical analysis
Neural networks
Nonlinear disturbance observer (NDO)
Nonlinear dynamics
Nonlinear systems
Nonlinearity
Tracking
unmatched external disturbance
unmatched non-affine nonlinearities
Online AccessGet full text

Cover

More Information
Summary:This paper presents an approximation-based nonlinear disturbance observer (NDO) methodology for adaptive tracking of uncertain pure-feedback nonlinear systems with unmatched external disturbances. Compared with existing control results using NDO for nonlinear systems in lower-triangular form, the major contribution of this study is to develop an NDO-based control framework in the presence of non-affine nonlinearities and disturbances unmatched in the control input. An approximation-based NDO scheme is designed to attenuate the effect of compounded disturbance terms consisting of external disturbances, approximation errors and control coefficient nonlinearities. The function approximation technique using neural networks is employed to estimate the unknown nonlinearities derived from the recursive design procedure. Based on the designed NDO scheme, an adaptive dynamic surface control system is constructed to ensure that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and the tracking error converges to a neighbourhood of the origin. Simulation examples including a mechanical system are provided to show the effectiveness of the proposed theoretical result.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0020-7721
1464-5319
DOI:10.1080/00207721.2017.1282062