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Comparison of architectures and robustness of model reference adaptive controllers and L 1 adaptive controllers
Author(s) -
Kharisov Evgeny,
Hovakimyan Naira,
Åström Karl J.
Publication year - 2013
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.2419
Subject(s) - robustness (evolution) , control theory (sociology) , adaptive control , computer science , reference model , control engineering , computation , closed loop , robust control , control system , engineering , control (management) , artificial intelligence , algorithm , biochemistry , chemistry , software engineering , gene , electrical engineering
SUMMARY The paper compares direct and indirect model reference adaptive controllers (MRAC) with theL 1 adaptive controller. The architectures of the closed‐loop systems are first compared in a simple setting that clarifies the similarities and differences of the controllers. The indirect MRAC and theL 1 controller have identical state predictors, but they differ in the computation of the control signal, which inL 1 is carried out by solving a feedback loop. The special case, where the controllers only adapt to a parameter representing input disturbances, is discussed. In this case, the closed‐loop system is linear, so it may not be appropriate to call the controllers adaptive. The special case does, however, give good insight into similarities and differences of the controllers and the effects of various modifications. In particular, the analysis gives good understanding of the robustness properties.Copyright © 2013 John Wiley & Sons, Ltd.