Robust adaptive learning control for nonlinear systems with extended matching unstructured uncertainties |
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Authors: | Riccardo Marino Patrizio Tomei Cristiano Maria Verrelli |
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Affiliation: | ‘Tor Vergata’ University, Electronic Engineering Department, Via del Politecnico 1, 00133 Rome, Italy |
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Abstract: | The exponential output tracking problem for a class of single‐input, single‐output uncertain nonlinear systems, including systems with extended matching unstructured uncertainties and without a well‐defined global relative degree, is addressed. Conditions on the uncertain system dynamics are derived, which allow us to design a state‐feedback learning control achieving semi‐global exponential output tracking of sufficiently smooth and periodic reference signals of known period, while guaranteeing ??2 and ??∞ transient performances during the learning phase. The application of the proposed learning approach to the position tracking control problem for uncertain permanent magnet step motors with non‐sinusoidal flux distribution and uncertain position‐dependent load torque allows us to provide a solution to a yet unsolved problem. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | learning control robust adaptive control nonlinear systems extended matching ℒ ︁ 2 and ℒ ︁ ∞ robustness permanent magnet step motors |
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