Control Relevant Identi cation for H 1 - norm based Performance Speci cations

For consecutive model-based control design, approximate identication of linear models should be performed on the basis of a feedback-relevant criterion, compatible with the control design. For an H1-norm based control design, a procedure is presented to estimate a possibly unstable and feedback controlled plant by using an H1-norm based feedback-relevant identi cation criterion. It is shown that the formulated identi cation problem can be handled by taking (noisy) closed loop frequency domain measurements of the plant and tting a model of a prespeci ed McMillan degree, which is parametrized in a stable factorization, using a certain non{linear constrained minimization. The procedure is illustrated by an example.