Stable digital control networks for continuous passive plants subject to delays and data dropouts

TitleStable digital control networks for continuous passive plants subject to delays and data dropouts
Publication TypeConference Paper
Year of Publication2007
AuthorsKottenstette, N., and P. J. Antsaklis
Conference Name46th IEEE Conference on Decision and Control
Date Published12/2007
Conference LocationNew Orleans, LA
ISBN Number978-1-4244-1497-0

This paper provides a framework to synthesize l2- stable networks in which the controller and plant can be subject to delays and data dropouts. This framework can be applied to control systems which use "soft-real-time" cooperative schedulers as well as those which use wired and wireless network feedback. The approach applies to passive plants and controllers that can be either linear, nonlinear, and (or) time-varying. This framework is based on fundamental results presented here related to passive control and scattering theory which are used to design passive force-feedback telemanipulation systems. Theorem 3 states how a (non)linear (strictly input or strictly output) passive plant can be transformed to a discrete (strictly input) passive plant using a particular digital sampling and hold scheme. Furthermore, theorem 4(5) provide new sufficient conditions for l2 (and L2)-stability in which a strictly - output passive controller and plant are interconnected with only wave-variables. Lemma 2 shows it is sufficient to use discrete wave-variables when data is subject to fixed time delays and dropouts in order to maintain passivity. Lemma 3 shows how to safely handle time varying discrete wave-variable data in order to maintain passivity. We then present a new cooperative scheduler algorithm to implement a I2-stable control network. We also provide an illustrative simulated example followed by a discussion of future research.