Abstract
The problem to be considered in this paper is to find a structural solvability condition for a disturbance rejection problem of linear multivariable systems.
Although some solvability conditions for a disturbance rejection problem have been already investigated by many authors, all these conditions depend on system parameters. The system structure for the problem to be solvable is presented by Bhattacharyya et al. But it is necessary to a suitable transformation for obtaining such a structure.
With the aid of the graph-representation of systems, a necessary and sufficient condition for structural solvability is given, which does not depend on system parameters. The new procedure, that is very simple and intutive, for deciding the solvability is also presented. Simple examples are given to illustlate this procedure.
