Environmental modelling and expert fuzzy control of climate in a miniature cropping house
Berry, Damon (1996) Environmental modelling and expert fuzzy control of climate in a miniature cropping house. Master of Science thesis, Dublin City University.
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This work describes the development of an inexpensive control system for a miniature cropping house which uses the method of crop production.
The control system was first developed in the Matlab-Simulink environment where it controlled a simulated model of the plant. The model was composed of four differential equations describing, air temperature in the cropping house, water temperature, C 0 2 concentration and inside humidity. The controller comprises a fuzzy “expert” controller which accepts inputs of light intensity and air temperature and returns fan speed and water temperature set-point as outputs. The latter was applied as a set-point for digital PID controller which controls water temperature in the cropping house.
Expert advice, as well as knowledge of the plant gained from observation of the plant and the model, were used to develop fuzzy sets and a fuzzy rule-base. The controller was implemented in Matlab simulation language and tested on the model of the plant.
Finally, the controller was implemented in “C” source and assembly for a standalone Motorola 68HC11 microprocessor based digital controller Development of software for the micro-controller was conducted using the Motorola’s Evaluation Tool-kit PCBUG. The controller circuits included two temperature sensing circuits, a light input and power control circuitry for both a DC fan and a set of aquarium heaters.
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