A Modeling of Lettuce Growth by System Identification (Part 2)

System Identification of Lettuce Growth with Light Input

Abstract

Using the results of the identification experiments which was explained in the previous report, a transfer function between the photon flux density and the flesh weight of a lettuce, which is a single input-single output model, was derived by means of the system identification method. The ARX, ARMAX and BJ model could express the lettuce growth precisely. The system parameters were derived by the recursive least squared method. It was found that a transition of growth phase could be detected by the time course of the system parameters. Consequently, the system identification, which considered the dense planting and the leaf overlap between the two stocks as well seen in the plant factory, was found to be feasible.