Research On Intelligent Monitoring And Control System Of Greenhouse Environment Based On WSN

Currently, most of the greenhouse monitoring and control systems use wired system which has the shortcomings of inflexible deployment and poor adjustment and so on, the systems also occur abnormalities result of the cable fault, while, the greenhouse has the features of nonlinear,strong coupling and large time delay and so on, the existing monitoring and control ways are difficult to meet the intensive monitoring requirements for lots of greenhouses. Wireless sensor network(WSN) combines the technologies of sensor perception, embedded, modern network and wireless communication, distributed information processing, and so on,it can collaboratively monitor various objects covered by the monitoring network. As one of the key technologies of the Internet of things, it is being widely used and researched. Recently, there have been found greenhouse monitoring and control systems, but they are of the nature of research, high cost, poor availability, difficult to apply to the actual production.The article carried out optimization of WSN, implemented the design of wireless sensor environment monitoring node, control node and intelligent control algorithm. The main research achievement are as follows:(1) The system used ZigBee2006 wireless transmission protolcol, optimized configuration of the ZigBee2006 from many aspects for greenhouse application characteristics, and designed coordinator, router and enddevice of WSN, set up the communication platform of wireless monitoring and control system based on WSN. (2) Designed the environment monitoring node used TI's CC2430 as micro-processing chip of the wireless sensor node,it contained main board and expansion board, the main board can monitor three basic environment factors air temperature and humidity, light. Expansion board can monitor soil temperature and humidity, soil electrical conductivity, carbon dioxide concentration, wind speed, wind direction, rainfall, ammonia concentration and so on; designed and achieved the power supply control of the sensors, the expansion board can control the sensors's power automatically to reduce power consumption; designed power supply system of the node, the node was powerd by solar-based, supplemented by adapter; developed the data collection procedures of the monitoring node, linked the acquisition programs and the ZigBee protocol, achieved the wireless transmission of data successfully.(3) Accomplished the greenhouse equipment automatic control node, it can control skylight, inside shade net, outside shade net, fan, wet screen, humidifier, heater and so on, and support device status information collection; designed I/O port expansion program based on I2C and its interface program with ZigBee protocol, achieved control commands receiving and device status information uploading of the control node. (4) Designed intelligent control algorirhm combined three control theory of PID control, fuzzy control and Smith predictor. Achieved the remote control of the central server with the fuzzy PID with Smith, meanwhile, the central server also haved two control modes of immediate intervention control and set value control.The article implemented greenhouse environment monitoring and control system based on WSN upon the applied research of wireless sensor network technology. After testing and deployment, indicating that the system is low cost, low power consumption, high reliability, extensible monitoring factor, power supply flexibility, wireless network, control mode variety and so on, it basically meets the monitoring and control needs of actual agricultural production. Meanwhile, verified the algorithm's performance superiority of the fuzzy PID with Smith predictor through simulation.