Abstract
This paper is concerned with discrete-time direct closed-loop identification based on an output inter-sampling scheme to construct a plant model when the plant is directed by a feedback controller. The ordinary identifiability condition requires that the order of the controller is higher than that of the plant order, however, this is hardly satisfied in practical cases. This paper proposes a new direct method using data set of the input and inter-sampled output of the plant and clarifies that the ordinary restrictive identifiability conditions can be removed by using the single input multiple output model description, and then the consistency of the parameter estimate is assured even without using any external test signal with PE condition.
