화학공학소재연구정보센터
Journal of Process Control, Vol.20, No.4, 551-558, 2010
Adaptive compensation strategy for the tracking/rejection of signals with time-varying frequency in digital repetitive control systems
Digital repetitive control is a technique which allows to track periodic references and/or reject periodic disturbances. Repetitive controllers are usually designed assuming a fixed frequency for the signals to be tracked/rejected, its main drawback being a dramatic performance decay when this frequency varies. A common approach to overcome this problem consists of an adaptive change of the sampling time according to reference/disturbance period variations. However, the sampling period adaptation implies structural changes that may degrade the closed-loop time response. This article presents a design strategy which allows to compensate for the effect of non-uniform sampling and forces the closed-loop behavior to coincide with that of the system operating under an a priori selected nominal sampling period. The stability of the overall closed-loop system is also analyzed. Experimental results obtained from a mechatronic plant model validate the proposal. (C) 2010 Elsevier Ltd. All rights reserved.