A nonlinear feedback technique for greenhouse environmental control

Pasgianos, GD; Arvanitis, KG; Polycarpou, P; Sigrimis, N

dc.contributor.author	Pasgianos, GD	en
dc.contributor.author	Arvanitis, KG	en
dc.contributor.author	Polycarpou, P	en
dc.contributor.author	Sigrimis, N	en
dc.date.accessioned	2014-03-01T02:42:11Z
dc.date.available	2014-03-01T02:42:11Z
dc.date.issued	2003	en
dc.identifier.issn	0168-1699	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/30844
dc.subject	Environmental control	en
dc.subject	Feedback linearization	en
dc.subject	Feedforward decoupling	en
dc.subject	Greenhouses	en
dc.subject	Nonlinear systems	en
dc.subject	Psychrometrics	en
dc.subject.classification	Agriculture, Multidisciplinary	en
dc.subject.classification	Computer Science, Interdisciplinary Applications	en
dc.subject.other	Atmospheric humidity	en
dc.subject.other	Climate control	en
dc.subject.other	Cooling	en
dc.subject.other	Crops	en
dc.subject.other	Environmental engineering	en
dc.subject.other	Feedback control	en
dc.subject.other	Greenhouses	en
dc.subject.other	Nonlinear systems	en
dc.subject.other	Moisturizing	en
dc.subject.other	Agriculture	en
dc.subject.other	greenhouse ecosystem	en
dc.title	A nonlinear feedback technique for greenhouse environmental control	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1016/S0168-1699(03)00018-8	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0168-1699(03)00018-8	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	Climate control for protected crops brings the added dimension of a biological system into a physical system control situation. The plants in a greenhouse impose their own needs, significantly affect their ambient conditions in a nonlinear way, and add long-tune constants to the system response. Moreover, the thermally dynamic nature of a greenhouse Suggests that disturbance attenuation (load control of external temperature, humidity, and sunlight) is far more important than is the case for controlling other types of buildings. This paper presents a feedback-feed forward approach to system linearization and decoupling for climate control of greenhouses and more specifically for the operation of ventilation/cooling and moisturizing. The proposed method consists of three parts: (a) a model-based feedback-feedforward compensation of external disturbances (loads) on the basis of input-output linearization and decoupling; (b) the transformation of user-defined desired settings for temperature and humidity into feasible controller setpoints, taking into account the constraints imposed by the capacities of the actuators and the psychrometric laws; and (c) additional PI outer loops to compensate for model uncertainties and deviations from expected disturbances (weather). Moreover, some tuning tests lump together several physical system parameters to be easily identified, and the method guarantees accuracy in setpoint tracking while simplifying stability issues. The proposed method is applicable to any air-conditioning system and is expected to gain wide acceptance in modern climate control systems. (C) 2003 Elsevier Science B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	Computers and Electronics in Agriculture	en
dc.identifier.doi	10.1016/S0168-1699(03)00018-8	en
dc.identifier.isi	ISI:000185173100012	en
dc.identifier.volume	40	en
dc.identifier.issue	1-3	en
dc.identifier.spage	153	en
dc.identifier.epage	177	en