A Parametrization of the Discrete-Time Two-Degree-of-Freedom Integral Controllers with Computation Delays and its Applications

Abstract

Using the observer-based integral controller proposed by Ishihara, et al. as a basic controller, we propose a state-space parametrization of discrete-time two-degree-of-freedom integral controllers accounting general computation delays. The proposed parametrization can easily be obtained by using the solution of an LQG problem for a plant and does not require constraints on the two free parameters. The role of the free parameters are clarified in connection with the basic controller. As applications of the proposed parametrization, we discuss the loop transfer recovery and the pole assignment using the free parameters. A numerical example is presented to show the effectiveness of the proposed methods.