A state-space parametrization of discrete-time two-degree-of-freedom integral controllers

Using the observer-based integral controller proposed by Ishihara, H. J. Guo and H. Takeda (1992). Automatica, 28, 599–603, as a basic controller, we propose a state-space parametrization of discrete-time two-degree-of-freedom integral controllers accounting computation delay. The proposed parametrization can easily be obtained by using the solution of an observer-based regulator problem for a plant. Clear interpretation of the parametrization as an observer-based integral controller is given. As application, we discuss the loop transfer recovery and the dead-beat control using the free parameters.