Virtual reference direct design method: An off-line approach to data-basedcontrol system design

This paper presents a direct model reference approach to the off-line desig n of linear controllers, suited to deal with plants described by a single s et of open-loop I/O measurements only. The method is direct inasmuch as the controller parameters are directly estimated with no preliminary identific ation of any model to describe the plant. The design can be carried out off -line and, in the present formulation, lends to a nonadaptive controller. T he basic idea is that of interpreting the open-loop I/O measurements of the plant as closed-loop data produced by a "virtual" reference signal that ca n be computed by backpropagating the measured output of the plant through t he reference model; thus, the controller design reduces to a standard ident ification problem, in which the "output" signal to be matched is the measur ed input of the plant. Both a deterministic (noise free) and a stochastic s etting are considered.