Development Of Intelligent Control System Based On Multivariable Controlin Facilities Agricultural Greenhouse

This project comes from Taiyuan science and technology support new rural construction project(No: 120157):“The development and demonstration of adaptive control system in facilities agricultural greenhouse”.This project is proposed for the existing problems in the greenhouse control systems in China,such as the backward communication mode,the single controlled environment variable,the low intelligence level,and the lack of self-adaptability.Based on multivariable control,a set of intelligent control system for greenhouse was developed,which integrates intelligent control technology,wireless communication technology and Internet of things technology.The system can realize accurate collection of environmental parameters in greenhouse,centralized monitoring of greenhouse state and intelligent control of equipment,which can realize the intelligentized,scientific and networked management of greenhouse.The main contents of this paper are as follows:On the basis of summarizing the research status of greenhouse at home and abroad,and analyzing the control demand of the planting demonstration base,the overall design scheme and frame structure of the greenhouse intelligent control system were determined,and the functions of each part were refined.It was determined that the system structure is distributed structure,that is,a set of upper computer control multiple sets of lower computers.The communication mode chose Zig Bee wireless communication,and determines the wireless sensor network was the star topology.According to the specific requirements of the overall design scheme,the software and hardware of the lower computer are designed.According to the technical indicators and functional requirements,the selection and configuration of sensors,control cabinets and external expansion modules were carried out.The related PLC program is compiled to achieve system initialization,wireless data polling,data processing and automatic control.Based on the basic structure of the designed hardware,we designed the software of the host computer.The function and interface of the whole centralized monitoring platform are designed and optimized on the Lab VIEW software,and the functions include user login,monitoring of environmental parameters,control of output equipment,historical data management,disease and insect pests inquiry,network data publishing and security alarm.We collected and collate relevant experts' knowledge,and set up an expert database for disease and insect pests knowledge.On the centralized monitoring platform,an insect pest query module with knowledge query,image query,prevention and control method query and type diagnosis function was added to realize the defense,diagnosis and treatment guidance for crop diseases and insect pests.On the basis of the air temperature and relative humidity in the existing greenhouse control system,the intensity of light and the concentration of carbon dioxide were added as the control quantity of the system.An adaptive control method based on the dual mode paste controller was proposed.The fuzzy expert control strategy was formed according to the actual planting situation and the expert library.This control strategy divides the control mode into day and night mode,and adopts the four time temperature control.In order to verify the feasibility of the developed software and hardware,the greenhouse experiment platform was designed and improved in the laboratory,and the system designed in this paper was debugged and tested.The experimental results showed that:The intelligent control system has reasonable structure,accurate data acquisition,stable communication state and fully functional centralized controlplatform.The greenhouse control method designed by this project can accurately control the greenhouse environment,and has some advanced characteristics.It has certain reference significance for the research of greenhouse intelligent control.