Grrrnhouse Temperature Control Based On Embeded System

With the development of industrial technology, the greenhouse control technologyhas been great progress. It controls various parameters in greenhouse by modern methodsinstead of manual control. Optimized production is the technology that adopts a variety ofcontrol methods to achieve high quality, high efficiency, andlow power consumption ofagricultural production system, then completes the economic revenue maximization. Dueto the temperature is the most affected to crop in greenhouse, so this thesis focuses on thegreenhouse temperature control. The traditional industrial control typically uses the PIDcontrol algorithm, which can only achieve a good control performance for the system withan accurate mathematical model. It is difficult to apply PID control algorithm to theagricultural control because that greenhouse is a complex system has nonlinear and purelag, so we adopted the intelligent control algorithm to meet the requirements.Fuzzy control algorithm has a good solution to the uncertainty of the system model,and accurate control of the system can be achieve. But the rules of the formulation hasgreat dependence on expert knowledge, it is difficult to make effective fuzzy rules in thesituation that control strategy makers is not very familiar to greenhouse canopy control. So,in order to effectively solve the above problems, PID control was combined with fuzzycontrol in this thesis, achieve the optimization of greenhouse temperature control throughthe method of online adjusting PID parameters. Control block diagram of system was builtin the Matlab Simulink, and simulation results show that the designed fuzzy PID controllercan accurately control the temperature in greenhouse, and control parameters can meetrequirements of crop growth.In this thesis, Cortex-M3was selected as the kernel of STM32F103processor, theIAR development environment for system implementation of programming, and completethe controller hardware realization through the J-link downloader to download workprogram. The design of control system includes the following four modules: processormodule, analog circuit module, display module, computer communication module. Analogvoltage signal was collected by using the sensor, and data was processed through the fuzzy PID control algorithm, LCD display real-time displayed temperature in greenhouse. Finally,the hot and cold water heating refrigerator valve opening was controlled by D/A outputanalog voltage signal, to realize the temperature control in the greenhouse canopy.