Research On Microclimate Model And Control Strategy Of Glass Greenhouse

Facility glass greenhouses are an important part of facility agriculture.Today,when computer control systems and various modern equipment are involved in greenhouse facilities,it is very necessary to establish a control system that improves indoor environmental factors through the effective operation of various equipment.The establishment of a greenhouse microclimate model is a key link to achieve effective greenhouse control.The temperature and humidity environmental factors in the greenhouse are not only affected by the greenhouse structure,greenhouse facilities and greenhouse environment,but also by the mutual influence of outdoor climatic conditions.Therefore,it is necessary to have a greater impact on the greenhouse environment.Effective regulation of environmental factors affecting.This paper proposes to establish a greenhouse fuzzy control system that is comprehensively controlled according to the optimal parameters of the growth and development of the crops in each growth period and the greenhouse microclimate model.The system combines the growth requirements of the crops and the influence of the greenhouse environment to regulate the greenhouse facilities and promote the greenhouse environment to become more cropped.Production and development environment.In this paper,greenhouse tomatoes are used as experimental materials and substrate cultivation methods are used to establish a glass greenhouse that uses microclimate models and fuzzy control methods to control the climate in the greenhouse.The main research contents and results of the subject are as follows:(1)Establish a modern temperature,room temperature and humidity prediction model suitable for the climate characteristics of northern my country.Applying the improved heat transfer theory and mass-energy balance equation to research and analyze the greenhouse microclimate environment,focusing on the heat of the greenhouse gas layer,the greenhouse cover layer,the greenhouse gas layer,the heating pipe layer,the plant cover layer and the surface soil layer Balance,establish the mass balance relationship between greenhouse crops and indoor and outdoor environmental factors,establish a dynamic prediction model of temperature and humidity of the greenhouse microclimate,and specifically analyze the impact of various environmental parameters on the greenhouse microclimate.This research aims to examine the sensitivity of greenhouse environmental parameters to the greenhouse microclimate,as well as the influence of greenhouse structure and intervention facilities.(2)Through the improved heat transfer theory and mass-energy balance equation,the indoor and outdoor solar radiation,indoor and outdoor temperature,wind speed,ventilation rate,envelope structure and other factors are used to establish a dynamic prediction model for the temperature and humidity of the greenhouse.The conclusion is that the outdoor temperature And the amount of solar radiation is the main factor that affects the indoor temperature(in winter,the intervention of heating facilities should be considered especially).The change of indoor humidity is mainly affected by plant transpiration rate,indoor temperature and ventilation.The relative error of the temperature of the model in each growth period(seedling stage,flowering stage,fruiting stage): 6.8%,6.05%,5.2%;absolute error:1.33 ℃,1.32 ℃,1.04 ℃;standard error root mean square: 1.43 ℃,1.36 ℃,1.04 ℃;relative error of humidity: 5.2%,3.3%,1.55%;absolute error: 4.94%,2.65%,1.40%;standard error root mean square: 3.46%,2.22%,1.50%,verify this The model is reliable and effective,and can provide support for subsequent fuzzy control and decision-making management of the greenhouse environment.(3)Use the optimal parameter values of temperature,humidity,and solar irradiance in each growth period of tomato to compare them with the predicted values(the environmental data collected by the microcontroller is substituted into the greenhouse microclimate prediction model),and the optimal values are obtained.The deviation of the predicted value,its rate of change,and the rate of change of its rate of change,and then use the fuzzy controller to determine the control amount,and then adjust the start and stop of the actuator to promote the greenhouse environment to become the best growth environment for crops,with good control effect.