Research On Intelligent Multifunction Monitoring And Control System Platform For Grain Storage

Global food production can not keep pace with the rapid population growth, additionally the accelerating process of urbanization makes food supplies much more difficult to meet food demands. Thus, reducing post-product loss of grains, especially the loss during grain storage has become a very important policy ensuring national food security. For these purposes, one of the significant researches is to reveal and validate the heat and mass transfer models of grain storage in order to find the integration point between the model and practical monitoring and control system for grain storage in order to achieve the objective of grain quality, energy saving, and green grain storage; otherwise, high-tech measures should be take into application in modern grain monitoring and control system to improve the level of current extensive grain management. For the objectives above, the research is carried on combining wireless sensor networks, embedded systems, virtual instrument and automatic control theory to construct a new intelligent multifunction monitoring and control system for grain storage. In this paper, the main research contents as follows:1. Initially propose a solution of research platform based on wireless sensor network both for validating the heat and mass transfer model of grain storage, and for grain monitoring system (RP-AMMCS).2. Facing the demand of long life span and the situation of high wireless signal attenuation when passing though the grain, a wireless sensor node (Grain-Node) for grain monitoring is designed which has the low-power consumption and can monitor multi-parameter of grain. It can be flexibly placed either on grain surface or in grain heap to construct wireless sensor network for real-time monitoring. Tests on the reliable communication distance in air and the grain heap show that Grain-Node is suitable for both the demand of model validity research and practically usage in barn monitoring. The validity of hardware and software design of Grain-Node is verified by both theoretical analysis and practical test, and the life of Grain-Node is given in the condition of the sleep-wake mechanism and time synchronous algorithm function.3. A remote data sink node (Server-Node) is designed and realized based on embedded processor. Data of grain states is transmitted to the Server-Node though wireless sensor network based on 802.15.3/ZigBee, and then sent by the GPRS module to the monitoring administration system running in the remote host computer. Meanwhile, it receives commands from the remote host computer, and distributes the commands to each wireless sensor nodes.4. Controlled temperature-and-humidity cabin is a nonlinear, coupled hysteresis, and multiple input multiple output control system. According to the requirements of temperature and humidity control, corresponding control strategy is put forward. PID control algorithm is employed to achieve the coupling control of temperature and humidity. The control parameters have been further optimized, through the process of actual operation of the system.5. Z-AODV routing protocol and AODV protocol are simulated on NS2 platform. Combining Z-AODV routing protocol and the node's dynamic energy consumption, a new energy efficient routing algorithm EEZ-AODV is proposed. Simulation results show that, comparing with Z-AODV, EEZ-AODV protocol improves the efficiency of data transmission and prolongs the survival time of node.6. On RP-AMMCS, a predict module is build for forecast the variation of temperature and humility of grain. A set of data management and conrol system based on Lab VIEW and Matlab in PC is developed for real-time data display, data management, ventilation control, and temperature and humidity control of the cabin.