The Electromechanical Fuzzy Control Research Of The Temperature In A Solar Greenhouse

It is not only an important but also a difficult task to control the greenhouse climate. On the one hand, the greenhouse temperature is associated with many factors such as: the ambient temperature, illuminance, wind, snow, rain, house materials and so on. Moreover, the factors interact and the growth of crop affects the climate factors. The processes are both physical and physiological. So the greenhouse is a multi-variable coupled, time-varying and non-linear complicated system.The modeling of greenhouse climate is the key to the control of greenhouse temperature. The main thermo-dynamical processes related to greenhouse climate are analyzed systemically, and the control of the greenhouse temperature is achieved with hot water. According to the principle of thermal equilibrium and piping thermorytic characteristics, the relationship between the flow velocity in the heating pipe and the greenhouse climate has been set up.The fuzzy control theory is applied to the fuzzy control of the greenhouse temperature. On account of the complexity and high expense of the measurement and control to the solar radiation intensity, the solar radiation is considered as an interference, and set up the control model of the greenhouse temperature.A fuzzy controller for the greenhouse is designed, and the fuzzy control system of the greenhouse temperature is built up. With calculating the different parameters of the greenhouse, generating the random curves imitating the natural environment by limiting the maximum and the minimum of the ambient temperature and the solar radiation intensity, determining the suitable quantification and proportion factors, a simulating environment is set up. The simulation results show that the fuzzy controller has a very brilliant performance on controlling the greenhouse temperature and the intense robustness and adaptability.