Data/hora: 24/06/2024 01:26:53

Biblioteca(s): | Embrapa Agroindústria Tropical.
Data corrente: | 09/11/2006
Data da última atualização: | 16/06/2017
Autoria: | MIRANDA, F. R. de.
Título: | A distributed control system for priority-based site-specific irrigation.
Ano de publicação: | 2003
Fonte/Imprenta: | 2003. 137 f.
Idioma: | Inglês
Notas: | Doctor of Philosophy Thesis (Biosystems Engineering) - University of Tennessee, Knoxville.

Conteúdo:

Site-specific irrigation enables maximizing yields and water use efficiency for fields with
variation in soil water availability. Distributed control for fixed irrigated systems, with
controIlers cIose to the sensors and actuators in the field, is easier to instaIl and maintain,
and less susceptible to damage by lightning strikes compared to centralized control, but is
only economicaIly viable with affordable, low-power controIlers. A low cost, solar
powered, feedback irrigation controIler for distributed control of fixed irrigation systems
was developed and tested. The system used soil water potential measurements to control
the amount of water applied to each specific zone of a field. Priority scheduling and
hydraulic pressure measurements were used to aIlocate water resources among irrigation
controIlers. Each irrigation controlIer was autonomously powered, minimizing
maintenance and eliminating hard-wire connections among control units. The study
methodology involved system design (hardware and software), experimental
implementation, performance evaluation, and power supply optimization. The irrigation
controIler proved to be effective in maintaining the soil water potential in the root zone
cIose to a predetermined set point. Performance of the priority scheduling approach for
water aIlocation among the irrigation controlIers was satisfactory, with irrigation of
management zones always occurring according to the priority rank, and under adequate
operating pressure. Advantages of the control system compared to centralized control
systems incIude significant reduction in wiring costs, lower risk of system shut down, and
higher flexibility.

Thesagro: | Irrigação.
Categoria do assunto: | --
Registro original: | Embrapa Agroindústria Tropical (CNPAT)
Exemplares: | CNPAT - (9576-1) - UPA - TS - -- - 2003.0008 -  - 2003.0008 - DIS