Study Of Fruit Storage Environment Supervisory Control System Based On Wireless Sensor Network

Fruits are a kind of indispensable produce in our daily life, some nutrients which are essential to but can’t be synthesized by our body need to be attained through taking up of fruits. With seasonal and regional factors, coupled with high water density, fruits are extremely easy to lose water, resulting in withering and spoiling. Hence, storage which is the middle stage of production and consumption plays a vital role in keeping qualities of fruits, a 100 billion yuan loss happens on fruits every year in our country because of bad storage conditions.Based on wireless sensor network, with application of Generalized Predictive Control algorithm, this paper designs a fruits storage environment supervisory control system. The system adopts upper and lower computer architecture, the upper computer is supervisory control center, and the lower computer is sensor network and actuator components, communication between them is through serial port, data transmition in the network uses Zigbee protocol. In the lower computer, actuators are controlled by microcontroller platform which makes STC single-chip microcontroller the control core and conducts scheduling of devices according to instructions from upper computer. The supervisory control center software is developed by Visual Studio Ultimate 2013 integrated environment, which consists of two main modules and five functional units; program design for sensor nodes in upper computer is achieved on IAR Embedded Workbench platform, and by which debugging and downloading tasks is completed. In the meantime, analyses are done in this paper on fruits’ physiological activities in the process of storage, confirming four key environmental factors that determine storage quality of fruits, namely temperature, oxygen density, carbodioxide density and humidity, the aim to supervisory control is to make sure that the four key environmental factors do not go beyond their appropriate ranges. A miniature storage room is designed in the paper to test running process of supervisory control system, and simulation experiment is implemented towards Generalized Predictive Control algorithm utilizing MATLAB toolbox, validating the effectiveness of this algorithm.Test results indicate that the supervisory control system functions well, easy to organize network, and needs few devices, thus bringing low cost. The system can effectively supervise and control environmental factors, possessing certain automated characteristics and practical application values to some extent.