Adaptive hierarchical control of greenhouse crop production

This paper addresses the problem of the greenhouse crop growth control using a hierarchical control approach. The proposed control scheme consists of two layers. In the lower one, adaptive and predictive controllers are used. The system dynamics at this level are described with hybrid models that arise due to the different modes of operating/controlling the greenhouse climate (heating and ventilation). As a result, different choices for the state of the system can be considered where inner temperature, solar radiation, and optimized set-points will act as logical conditions in the description of the hybrid system. The hybrid dynamics are described both in a general way and using a MLD representation, this result being useful for control purposes in the greenhouse climate control community. The upper layer calculates optimal climate set-points based on economic criteria. An optimization algorithm is used with a receding horizon strategy to provide the desired climate to the lower layer during the whole campaign. Representative experimental results of the implementation of the hierarchical control architecture are presented and discussed in the paper. Copyright (c) 2007 John Wiley & Sons, Ltd.