Abstract
In this paper, we discuss the property of the limiting form derived from a standard linear optimal regulator problem by letting the weighting matrix tend to zero. It is shown that there exists an explicit relationship between limiting form of discrete-time systems linear optimal regulators and block decoupling control in discretetime systems. Based this property, we present a new procedure for deriving the decoupling control law without calculation of interactors and canonical decoupled form. The block decoupled system with maximum number of blocks is automatically constructed by the proposed designing procedure.
