Adaptive robust control of a class of nonlinear systems in semi-strict feedback form with non-uniformly detectable unmeasured internal states

Lu Lu, Bin Yao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper proposes a novel control method for a special class of nonlinear systems in semi-strict feedback form. The main characteristics of this class of systems is that the unmeasured internal states are non-uniformly detectable, which means that no observer for these states can be designed to make the observation error exponentially converge to zero. In view of this, a projection-based adaptive robust control law is developed in this paper for this kind of system. This method uses a projection-type adaptation algorithm for the estimation of both the unknown parameters and the internal states. Robustifying feedback term is synthesized to make the system robust to uncertain nonlinearities and disturbances. It is theoretically proved that all the signals are bounded, and the control algorithm is robust to bounded disturbances and uncertain nonlinearities with guaranteed transient performance. Furthermore, the output tracking error converges to zero asymptotically if the system has only parametric uncertainties. The class of system considered here has wide engineering applications, and a practical example - control of mechanical systems with dynamic friction - is used as a case study. Simulation results are obtained to demonstrate the applicability of the proposed control methodology.

Original languageEnglish (US)
Title of host publication2009 American Control Conference, ACC 2009
Pages4654-4659
Number of pages6
DOIs
StatePublished - Nov 23 2009
Externally publishedYes
Event2009 American Control Conference, ACC 2009 - St. Louis, MO, United States
Duration: Jun 10 2009Jun 12 2009

Publication series

NameProceedings of the American Control Conference
ISSN (Print)0743-1619

Other

Other2009 American Control Conference, ACC 2009
Country/TerritoryUnited States
CitySt. Louis, MO
Period6/10/096/12/09

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Keywords

  • Adaptive Robust Control
  • Dynamic Friction
  • Dynamic Uncertainties
  • Nonlinear Control

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