Greenhouse Temperature And Humidity Control System Design Based On The ARM Microprocessor

Greenhouse control technology is one modern agricultural engineering technology that advances with development in technologies like automatic testing, process control, communication and computers. It is the combination of agricultural science, sensor technology, signal process, control theory and computer technology. The purpose of greenhouse circumstance control is to provide good growth environment for plants or animals, so it has special demand on control system. On one hand, this is represented with high demand on system stability and reliability and sensitivity on cost; and on the other hand with its control object as being a nonlinear time-variation system with distributive parameters, large time delay and multi-variables, which can not be control using conventional theories. Therefore the greenhouse circumstance control is one complicate project that still has a lot of research space despite the fact that large quantity of work has been done at home and abroad.The domestic development of facility agriculture and greenhouse control technology is firstly analyzed, and then a proposal of using the high-power 32-bit ARM processor to build a greenhouse temperature-humidity control system with friendly human-machine interface is raised in this paper. And S3C44B0X is selected as MCU of the system, and temperature and humidity is selected as the main factors to be controlled in a greenhouse. The control can adjust the temperature and humidity in the greenhouse, according to the demand on the two factors in different growing period, in order to achieve best growth for the plant and animal.As for hardware of the greenhouse temperature-humidity control system, the circuit of system controller is designed, which include circuit of ARM core microprocessor and the peripheral circuits of keyboard input, LCD display, serial communication and storage system; as for the software, the embedded real-time operation systemμC/OS-II is transplanted successfully, and the real-time operation of multi-task is realized, which enable the system a better reliability, stability and maintainability and lay good foundation for further upgrade of the applied system. And the applied software of the controller is programmed on the above foundation. The applied program contains 3 modules, the data acquisition module, which is responsible for real-time data collection of greenhouse temperature and humidity; the serial communication module, which is responsible for communication with PC; and the human-machine interface module, which conducts human-machine interaction and the real-time display and query of greenhouse temperature ad humidity status. And finally the fuzzy control querying table was established based on the integrated study of greenhouse temperature-humidity and theoretical study of greenhouse temperature and humidity decoupling control algorithm.By combining the interdisciplinary knowledge of embedded computer technology, control theory and so no, one greenhouse temperature-humidity control system targeting at the rural medium and little greenhouse is designed in this paper, which is featured with high stability and reliability and convenient operation procedure, which is proved to be a useful attempt in turn the greenhouse automation technology practicable for the farmers.