Hydroponics water management using adaptive scheduling with an on-line optimiser

Sigrimis, N; Arvanitis, KG; Pasgianos, GD; Ferentinos, K

dc.contributor.author	Sigrimis, N	en
dc.contributor.author	Arvanitis, KG	en
dc.contributor.author	Pasgianos, GD	en
dc.contributor.author	Ferentinos, K	en
dc.date.accessioned	2014-03-01T01:16:37Z
dc.date.available	2014-03-01T01:16:37Z
dc.date.issued	2001	en
dc.identifier.issn	0168-1699	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14129
dc.subject	Intelligent control	en
dc.subject	Irrigation	en
dc.subject	Models	en
dc.subject	Optimisation	en
dc.subject.classification	Agriculture, Multidisciplinary	en
dc.subject.classification	Computer Science, Interdisciplinary Applications	en
dc.subject.other	Adaptive control systems	en
dc.subject.other	Algorithms	en
dc.subject.other	Control system analysis	en
dc.subject.other	Control system synthesis	en
dc.subject.other	Error analysis	en
dc.subject.other	Greenhouse effect	en
dc.subject.other	Mathematical models	en
dc.subject.other	Online systems	en
dc.subject.other	Optimal control systems	en
dc.subject.other	Feedforward control loop	en
dc.subject.other	Hydroponics water management	en
dc.subject.other	Powell direction set method	en
dc.subject.other	Irrigation	en
dc.title	Hydroponics water management using adaptive scheduling with an on-line optimiser	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0168-1699(00)00172-1	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0168-1699(00)00172-1	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	An optimisation-based methodology for irrigation control and nutrient supply is developed using common measurements of greenhouse climate. The process measurement has a long time delay, and a feedforward (FF) control loop based on a model-based estimate of water losses is used. A long feedback loop, by which the FF model is adapted using output error feedback, is the mechanism used to minimise the control error. To read the output error, a drain measuring device, or soil moisture meter, is necessary. The optimisation method used is a general tool developed for real-time application and is capable of optimising linear and non-linear systems. The minimisation algorithm used is based on a variant of the Powell direction set method in multiple dimensions. It compares favourably in speed of convergence and accuracy when compared with linear regressors for linear systems. It is therefore used as a generalised tool embedded in a modern greenhouse management system. The method allows on-site on-line identification of plant water needs. As an added benefit, the method provides information for the creation of crop transpiration models. © 2001 Elsevier Science B.V.An optimisation-based methodology for irrigation control and nutrient supply is developed using common measurements of greenhouse climate. The process measurement has a long time delay, and a feedforward (FF) control loop based on a model-based estimate of water losses is used. A long feedback loop, by which the FF model is adapted using output error feedback, is the mechanism used to minimise the control error. To read the output error, a drain measuring device, or soil moisture meter, is necessary. The optimisation method used is a general tool developed for real-time application and is capable of optimising linear and non-linear systems. The minimisation algorithm used is based on a variant of the Powell direction set method in multiple dimensions. It compares favourably in speed of convergence and accuracy when compared with linear regressors for linear systems. It is therefore used as a generalised tool embedded in a modern greenhouse management system. The method allows on-site on-line identification of plant water needs. As an added benefit, the method provides information for the creation of crop transpiration models. © 2001 Elsevier Science B.V.	en
heal.publisher	Elsevier Science Publishers B.V., Amsterdam, Netherlands	en
heal.journalName	Computers and Electronics in Agriculture	en
dc.identifier.doi	10.1016/S0168-1699(00)00172-1	en
dc.identifier.isi	ISI:000167408800004	en
dc.identifier.volume	31	en
dc.identifier.issue	1	en
dc.identifier.spage	31	en
dc.identifier.epage	46	en