Parameter Tuning of Two-degree of Freedom Controllers Using FRIT for the Tracking Property and the Feedback Properties

In [13], some of the authors of this paper proposed the fictitious reference iterative tuning (which is abbreviated as FRIT in the following) as one of the useful and powerful methods of parameter tuning of an implemented controller in the sense that we require only one-shot experiment for the parameter tuning in order to achieve the minimization of the squared error between the real output and the desired one. However, feedback properties like sensitivity or noise reductionability those are also required for a control system to be more practical have not been addressed yet. On the other hand, it is well known that the two-degree of freedom of control scheme is one of the effective ways those enable us to deal both of tracking property and feedback ones simultaneously. From this reason, in this paper, we expand FRIT into the two-degree of freedom control scheme in order to tune parameters of impelmented controllers in this structure for the sake of the acheivement of given specifications on not only tracking property but also feedback properties. We consider the correspondence of the minimization between desired cost function and the fictitious ones. We then provide effective procedures of FRIT in the two-degree of freedom of control scheme with two-shot experiments. Finally, we also give illustrative examples in order to show the validity of our proposed methods.