Design and implementation of a Real-Time data acquisition system for the identification of dynamic temperature models in a hydroponic greenhouse.

摘要

This paper describes a Real-Time data acquisition and identification system implemented in a soilless greenhouse located at the University of Algarve (south of Portugal). Using the Real Time Workshop, Simulink, Matlab and the C programming languagea system was developed to perform real-time data acquisition from a set of sensors, both inside and outside the greenhouse, connected to a data logger. Because the dynamic discrete-time models of systems like the greenhouse inside air temperature are time varying, a system was also developed to recursively identify the parameters of the dynamic transfer functions based in the input/output data of the system to be identified. Using the real-time data acquisition and the identification system together, itis possible to have real-time estimates of the transfer function parameters and the identified system output estimate. The software developed was executed in real-time to identify parameters of a second-order model of the greenhouse inside air temperature as a function of the outside air temperature and solar radiation, and the inside relative humidity. The estimated temperature curve showed very close fitting to the values measured by the sensor. The software developed will be used to perform real-time climate control in the greenhouse.