Automatica, Vol.41, No.12, 2083-2089, 2005
Integral controller design based on disturbance cancellation: Partial LTR approach for non-minimum phase plants
For non-minimum phase plants, the loop transfer recovery (LTR) design of integral controllers based on the disturbance cancellation is considered. Since the design requires an unstabilizable extended plant, the standard LTR method cannot be applied. A new partial LTR method is proposed to overcome the difficulty. The target of the proposed design is a fictitious controller including a disturbance estimator based on the measurement of the minimum phase state. It is shown that the Riccati equation including the gain matrix of the disturbance estimator in the target can be used to recover the target feedback property in the output feedback controller. A simple design example is presented to show the effectiveness of the proposed method. (c) 2005 Elsevier Ltd. All rights reserved.
Keywords:linear systems;integral controllers;disturbance cancellation;loop transfer recovery;non-minimum phase plants;partial loop transfer recovery;PI observers;Riccati equations