Modeling And Simulation Of Temperature Of Greenhouse Environment Temperature

The modern greenhouse is the representative of facilities agricultural, it creates a suitable microclimate environment through the material covered in the subrange, there are many Influence factors in greenhouse microclimate environment such as solar radiation, temperature, humidity, CO2concentration and ventilation etc, and temperature is one of the dominant factors on greenhouse microclimate environment, Greenhouse microclimate control is the most important part for modern greenhouse control. To establish a good control system for greenhouse environment, it has very important sense to reduce energy loss and promoting plant growth, and in the establishment of greenhouse environment control system, it is necessary to be modeling and simulation because the greenhouse microclimate has the characteristics of nonlinear, large time delay, and time-varying, etc.System identification method is the commonly method in the system modeling, it can construct a static or dynamic mathematic model of the system based on measurement of the input and output data, both linear system and nonlinear system can be identified. This paper aims to build agricultural greenhouse environment system temperature model based on ARX(Auto regressive exogenous) model because it has some advantages, such as simple structure, robust and high identification precision.Firstly, the data monitored both inside and outside of the greenhouse was analyzed by using the correlation analysis and significantly related inspection to determine the major influence factors of outdoor meteorological, which are temperature、relative humidity、the sun and the wind speed of radiation intensity. Secondly, the residual analysis method was used in model order identification, the recursive least squares method was applied in model parameter-estimated process, And the correctness of the model was verified through the experiment.The main work of this paper as the following aspects:(1) The important significance of the greenhouse temperature model for the development of China’s modernization greenhouse is described. The greenhouse environments modeling methods and the research situation deficiencies in the domestic and foreign at present are analyzed and the current existence deficiency is also indicated.(2) System identification technology application in modeling was studied, and agricultural greenhouse environmental temperature model was established based on ARX model, the analysis results show that the model can describe the change of the temperature in greenhouse correctly, and it can provide reference for the designing of greenhouse control system.(3) The greenhouse temperature modeling and simulation system were established by the MATLAB graphical user interface.(4) the research meaning was summarized, and the existing work must continue to improve was pointed out.