A clarifying analysis of feedback error learning in an LTI framework
Journal article, 2008

Feedback error learning (FEL) is a proposed technique for reference-feedforward adaptive control. FEL in a linear and time-invariant (LTI) framework has been studied recently; the studies can be seen as proposed solutions to a feedforward MRAC problem. This paper reanalyzes two suggested schemes with new interpretations and conclusions. It motivates the suggestion of an alternative scheme for reference-feedforward adaptive control, based on a certainty-equivalence approach. The suggested scheme differs from the analyzed ones by a slight change in both the estimator and the control law. Boundedness and error convergence are then guaranteed when the estimator uses normalization combined with parameter projection onto a convex set where stability of the estimated closed-loop system holds.

adaptive control

feedback error learning

feedforward control


Magnus Nilsson

Chalmers, Signals and Systems, Systems and control, Automatic Control

Bo Egardt

Chalmers, Signals and Systems, Systems and control, Automatic Control

International Journal of Adaptive Control and Signal Processing

0890-6327 (ISSN) 1099-1115 (eISSN)

Vol. 22 9 875-901

Subject Categories

Control Engineering



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