Applications of nonlinear, time variant, and variable parameters represent a big challenge in a conventional control systems, the control strategy of the fuzzy systems may be represents a simple, a robust and an intelligent solution for such applications.
This paper presents a design of fuzzy control system that consists of three sub controllers; a fuzzy temperature controller (FC_T), a fuzzy humidity controller (FC_H) and a ventilation control system; to control the complicate environment of the greenhouse (GH) using a proposed multi-choice control system approach. However, to reduce the cost of the crop production in the GH, the first choice is using the ventilation system to control the temperature and humidity of the GH environment according to the external climate if it is possible, if it is not possible then the second choice uses the FC_T to actuate the cooling-heating system to control the temperature and FC_H to actuate the humidifier-dehumidifier to control the humidity of the GH environment. The resultant is a robust, multi choice and multi-mode capability system. The designed system reflects the fuzzy system capability to deal with complicated environments and its flexibility to use the same design in controlling different applications.
