Optimal Control of Greenhouse Climate Using a Short Time Climate Model and Evolutionary Algorithms

Abstract

The use of evolutionary algorithms for calculation of the optimal control of the states of a greenhouse system will be presented. The integrated model employed (greenhouse climate, crop growth, outside weather conditions and control equipment) predicts temperature, air humidity and CO 2 concentration in a time interval of 15-60 minutes (short time-scale model). The paper presents the optimization of the control of the greenhouse climate to maximize the profit under certain constraints (for instance, prevention of stress for the crops) using evolutionary algorithms. By incorporation of problem specific knowledge into the evolutionary algorithm better results were produced in a shorter time. The results of optimization for optimal control using real world weather data are shown.

Optimal control of greenhouse climate using minimal energy and grower defined bounds

“…However, collecting data using a neural net requires an extremely large amount of data. Other authors proposed optimal control in order to maximize profit [14,15,13,[16][17][18][19]. Gutman et al [20] minimized heating costs by exploiting deviations allowed from the standard blueprints expressed in temperature sums and, based on perfect weather predictions.…”

Analysis and modeling of control tasks in dynamic systems

“…This approach is not used widely, mainly because it requires a quite long response time, because of the time-consuming evolution of the control signals. However, the strategy has been used to control a multiple-burner boiler system [11], a sugar beet press [12], and a greenhouse [10]. In more advanced applications, the EA acts as the tuning algorithm for another control strategy.…”

What are dynamic optimization problems?

“…One update of the control parameters corresponds to one decision. Other examples in this category can also be found [16] [12]. In the other category, decisions are being made over time in an event-triggering manner.…”