On-Line Identification of Open-Loop Frequency Response and Two-Degree-of-Freedom Design Method of PID Control Systems

Abstract

In this paper, we study the accuracy of the open-loop frequency response of control system obtained by on-line identification from the closed-loop frequency response, and show that the open-loop frequency response required for design based on the frequency response can be obtained accurately. Moreover, we consider feedforward-type two-degree-of-freedom PID control systems, and propose an on-line design method of feedback controllers, and a design method of feedforward controllers focused on the number of phase-lead elements between the reference input and the manipulated input. Furthermore, combining these design methods, an on-line design method of two-degree-of-freedom PID control systems is proposed. The efficiency of the proposed design method is evaluated by simulation.