A Study on Robustness of a Two-Degree-of-Freedom Servosystem with Nonlinear Type Uncertainty(II) - Rubust Stability Condition

J. Ocean Eng. Technol. 1999;13(Suppl DB Error: no such field):99-105.

Kim, Young-Bok;

비선형 불확실성에 대한 서보계의 강인성에 관한 고찰(II) - 강인 안정성 조건

김영복;

(주)신창인더스트리;

Keywords: Integral Compensator, Two-Degree-of-Freedom Servosystem, Robust Stability, Nonlinear Type Uncertainty

핵심용어: 적분 보상기, 2자유도 서보계, 강인한 안정성, 비선형 불확실성

Abstract

In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers a robust stability of this 2DOF servosystem with nonlinear type uncertainty in the system, and a robust stability condition for the servosystem is introduced. This result guarantees that if the plant uncertainty is in the permissible set defined by the condition, gain tuning can be carried out to suppress the influence of the plant uncertainties and disturbance inputs.