Identification of the water status of the plant - identification of ar model

To control the water stress to the plant requires one of the advanced technologies for the greenhouse and the field cultivation. The highest quality of the crops is obtained when the optimal water stress is provided. In this study, the plant's responses to the randomly varying two levels of light intensity were measured, and the frequency characteristics of the plant were calculated. For the mathematical model of the plant, auto-regressive model (AR model) was assumed, and its parameters were identified. From this model, the simulation of the experiment and the frequency characteristics were calculated. The results of the simulation corresponded to those of the experiment. The step response of the lighting to the plant was also measured, and the frequency response functions were calculated. The frequency characteristics under random lighting condition, from step response, and by AR model showed good agreement. These results showed that the AR model would be a possible model to explain the plant responses.