Multirate adaptive temperature control of greenhouses

Arvanitis, KG; Paraskevopoulos, PN; Vernardos, AA

dc.contributor.author	Arvanitis, KG	en
dc.contributor.author	Paraskevopoulos, PN	en
dc.contributor.author	Vernardos, AA	en
dc.date.accessioned	2014-03-01T01:15:43Z
dc.date.available	2014-03-01T01:15:43Z
dc.date.issued	2000	en
dc.identifier.issn	0168-1699	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13686
dc.subject	greenhouse climate	en
dc.subject	temperature control	en
dc.subject	sampled-data control	en
dc.subject	multirate sampling	en
dc.subject	identification	en
dc.subject	adaptive control	en
dc.subject.classification	Agriculture, Multidisciplinary	en
dc.subject.classification	Computer Science, Interdisciplinary Applications	en
dc.subject.other	POLE-PLACEMENT CONTROL	en
dc.subject.other	OUTPUT CONTROLLERS	en
dc.subject.other	LINEAR-SYSTEMS	en
dc.subject.other	PLANT OUTPUT	en
dc.subject.other	CLIMATE	en
dc.subject.other	MODEL	en
dc.title	Multirate adaptive temperature control of greenhouses	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0168-1699(00)00082-X	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0168-1699(00)00082-X	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	A new adaptive technique is proposed for the control of the temperature in a greenhouse whose parameters vary with operating conditions. The proposed adaptive controllers are derived by solving either the pole-placement or the linear quadratic regulation (LQR) problem and use multirate controllers in which the greenhouse temperature is sampled many times over a fundamental sampling period. On the basis of the proposed control scheme, the problem is reduced to an associated discrete-time problem for which constant state feedback controllers are derived. Thus, the proposed technique essentially becomes one of computing a constant gain controller rather than one of deriving state observers or output feedback controllers, as in other indirect adaptive control techniques. As a consequence, the exogenous dynamics introduced in the control loop is of low order. Furthermore, the proposed adaptive controllers can be designed to possess any degree of stability, since their transition matrices can be chosen arbitrarily. The proposed scheme estimates the unknown parameters of the greenhouse on-line from sequential data on the greenhouse temperature and the heating power, which are recursively updated. Persistency of excitation of the controlled system is assured without making assumptions on the system under control, other than controllability, observability and known order. Simulation results of the greenhouse dynamics illustrate the effectiveness of the proposed scheme. (C) 2000 Elsevier Science B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	COMPUTERS AND ELECTRONICS IN AGRICULTURE	en
dc.identifier.doi	10.1016/S0168-1699(00)00082-X	en
dc.identifier.isi	ISI:000087274100007	en
dc.identifier.volume	26	en
dc.identifier.issue	3	en
dc.identifier.spage	303	en
dc.identifier.epage	320	en