Robust digital controller and its designing device

Abstract

A robust digital controller is equipped with a high degree of approximation and is able to incorporate a novel two-degree-of-freedom robust digital control system without substantially considering the magnitude of the control inputs and there is provided its designing device. A control compensating means is configured as an integral type control system in which a discrete transfer function W(z) between a target value r and a controlled variable y is approximated to a higher-approximate quadratic approximate model transfer function W(z) and an arithmetic processing can be performed within the digital controller based on the model transfer function W(z). Further, the designing device automatically calculates parameters constituting the control system. Consequently, a robust digital controller can be easily realized that is equipped with a high degree of approximation as compared with a conventional approximate digital control system for realizing a first-order model and is robust against output noises.