  A formulation of a multi-input single-output closed-loop subspace method for
system identification is employed for the purpose of obtaining control-relevant
model of the vacuum-plasma response in the Damavand tokamak. Such a model is
particularly well suited for robust controller design. The accuracy of the
estimate of the plant dynamics is estimated by different experiments. The
method has been described in this paper is a worst-case identification
technique, that aims to minimize the error between the identified model and the
true plant. The fitness of the identified model around defined operating point
is more than 90% and compared with physical-based model it has better root mean
square measure of the goodness of fit.
