Development Of Intelligent Water-saving Irrigation Control System Based On WSN In Facility Agriculture

The subject comes from the major projects of Shanxi department of science and technology(NO: 20131101029).Based on analysis of the existing study of farmland irrigation,this paper focuses on intelligence technology and integrates wireless sensor network technology,automatic control technology,artificial intelligence technology and database technology.Intelligent and networked water-saving irrigation has been further investigated in order to help reduce labor intensity,reduce water loss,boost crop yields and increase farmers’ income continuously.Combined with the development direction of intelligent irrigation,taking intelligent water-saving irrigation as research target,the research scheme was designed based on wireless sensor network.The main research works are as follows:The sensor node based on sensor and DTU was designed,which is responsible for transmitting the soil moisture to the remote monitoring service center.The geographical restriction was broken through,which is convenient for farmer to know whether farmland needs irrigation anywhere.The deploy method of sensors in the farmland was elaborated,which improve the utilization of the sensing nodes in the network coverage area and cut down the development costs.The transport layer built upon the foundation of Local Area Network(LAN),Wide Area Network(WAN)and internet is a wireless data transmission channel,which can solve the problems of sensor distribution and network wiring difficulties in a large area field.In the design of network communication,port mapping between inner net and outer is built by NAT123,which solves the problem of instability in data transmission.In order to improve the ability of human-machine interaction,The application layer is designed based on LabVIEW.The communication between LabVIEW and field controller PLC was built by NI OPC.On the basis of LabSQL toolkit,the communication between LabVIEW and SQL Server 2008 was built by open database connectivity(ODBC).In addition,real-time weather forecast information from web browser was implanted into fuzzy expert system in order to water loss after the rain,which improves the practicability of the irrigation control system.On the intelligent control algorithm,a control method for farmland irrigation based on fuzzy expert system was put forward.Linguistic control rules rather than numerical values were used to describe irrigation experience.The expert system was established after setting up its expert knowledge base,knowledge acquisition department,integrated database,human-machine interface and reasoning engine combined with fuzzy control algorithm.After the design of the reasoning machine was completed,the control effect of the controller was simulated in the fuzzy system designer toolkit.The simulation result verified validity of control strategy,which change the traditional irrigation method.The intelligent water-saving irrigation system was designed based on LabVIEW,including parameters monitoring,data analysis and storage,network communication and management decision.After completing the system design,the whole system was adjusted with long running operations.The experimental results showed that the performance of the fuzzy expert system was quite stable and the design requirement in irrigation precision was satisfied.The test result showed that the wireless sensor network has features of accurate data collection and reliable communication.The collection errors were less than 1%,which meet the performance index and design requirements.This system can complete automatically irrigation without the intervention of person according to crop water requirements.The error between target value and test value is less than 5%,which ensure the irrigation accuracy and timeliness.