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Yongbo L.I.,Nanjing Agricultural University | Guoxiang S.U.N.,Nanjing Agricultural University | Xiaochan W.,Jiangsu Province Engineering Laboratory for Modern Facility | Weimin D.,Jiangsu Province Engineering Laboratory for Modern Facility
Research on Crops | Year: 2013

In order to incorporate the physiological parameters of crops into the greenhouse control system, a state space model was developed based on 20-day data of sap flow and leaf temperature for summer maturation cucumbers. The model was consisted of two output parameters (stem flow and leaf temperature), four input parameters (ambient temperature, humidity, solar irradiation and soil temperature) and random disturbing input (wind velocity, operating staff condition and instrument deviations). Using time sequence analysis technology, the data of 1920 × 6 items (20-day) were filtered and sorted, and effective data source for state space model identification was established. In this paper, we adopted sub-space theory to confirm a 6-order state space model with five constant-coefficient matrices, and then completed the model specification. Comparison between the measured and predicted values showed that the fitness of sap flow and leaf temperature was 92.873 and 93.574%, respectively. Therefore, the model proposed in this paper was effective and reasonable, which could provide the model basis for applying crop physiological parameters to the greenhouse control system by resorting to modern control theory. Source

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