Index of /skoge/publications/2004/faanes_ejc_feedforward

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	submitted/	2010-07-15 11:00	-
	readme.txt	2010-07-15 11:00	926
	ff.pdf	2013-07-02 08:42	7.7M
	ff-copy.pdf	2010-07-15 11:00	1.9M
	README.html	2010-07-15 11:00	935

A. Faanes and S. Skogestad,
``Feedforward control under the presence of uncertainty'',
European Journal of Control, 10 (1), 30-46 (2004).

Abstract
In this paper we study the effect of model errors on the performance of feedforward
controllers. In accordance with the sensitivity function for feedback control, we define
the feedforward sensitivities, Sff (feedforward from disturbance) and Sffr (feedforward from 
set-point), as measures for the reduction in the output error obtained by the feedforward
control. For ``ideal'' feedforward controllers based on the inverted nominal model, the
feedforward sensitivities equal the relative model errors, which must thus remain less
than 1 for feedforward control to have a positive (dampening) effect.
For some common model error classes we provide rules for when the feedforward
controller is effective, and we also design mu-optimal feedforward controllers.