Abstract
This paper proposes a new design scheme for multivariable servo control systems. By making full use of fractional representation by polynomial matrices, this scheme provides a frequency-domain version of the well-known ILQ design method, and connects the designed controller with the circle criterion in a transparent form. LQ optimality for some weightings is guaranteed by letting a parameter tend to infinity, and the lower bound for optimality in this sense can be computed by means of a generalized eigenvalue problem, together with a bisection algorithm.
