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Design of adaptive feedforward algorithms using internal model equivalence
Author(s) -
Messner William,
Bodson Marc
Publication year - 1995
Publication title -
international journal of adaptive control and signal processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 66
eISSN - 1099-1115
pISSN - 0890-6327
DOI - 10.1002/acs.4480090207
Subject(s) - feed forward , control theory (sociology) , phase margin , algorithm , repetitive control , internal model , equivalence (formal languages) , robustness (evolution) , adaptive control , computer science , feedthrough , root locus , mathematics , control system , engineering , control engineering , control (management) , artificial intelligence , amplifier , computer network , biochemistry , chemistry , electrical engineering , operational amplifier , bandwidth (computing) , discrete mathematics , gene
Abstract The paper investigates the design of adaptive feedforward cancellation (AFC) algorithms with sinusoidal regressors for repetitive control. Such adaptive algorithms are equivalent to linear controllers based on the internal model principle (IMP). Using this equivalence and root locus rules, the phase advance of the regressor of the adaptive algorithm can be chosen to maximize the phase margin at low gains. A surprising result is that selecting the optimal phase advance is equivalent to placing a zero in the open right half‐plane in certain cases. A complete design and analysis for the compensation of a single‐frequency periodic disturbance is done. A new variation of the AFC algorithm is also developed in which the adaptive portion acts in parallel with a feedthrough term. the IMP equivalent of this algorithm has two zeros instead of one. Analysis and simulation show this method to have superior convergence and robustness properties when compared with the method having no feedthrough term. Discrete time versions of the algorithms are briefly considered.