Implementation of optimal greenhouse control: Multiple influences approach

Recently, many educated farmers have adopted automated greenhouse control systems to increase productivity while reducing their labor cost in greenhouse management. In this paper, to increase level of automation, we propose a reliable greenhouse control system that runs without human intervention based on multi-variable control scheme, which concurrently takes various inner and outer environmental factors into account. To cool or heat a greenhouse in an efficient way, we introduce a cooling and a heating load being calculated from sunlight level, outer temperature, and wind speed as well as inner temperature. Each actuator is then controlled by its own control parameters which are tightly associated with these load amounts. The proposed control scheme has been tested in a real greenhouse, and experimental results showed that inner temperature was consistently controlled according to users setting while obtaining minimum number of actuator operations (i.e., ventilation, curtain, and heater).