| Safety is the top priority of the coal mine production. Today, accidents in coal mine that caused great casualties and property loss still occur occasionally. Thus, mining safety is highly desired in coal industry. Coal mine monitoring system can monitor multiple environmental parameters in underground mines and plays an important role in the coal mine work safety. However, coal mine monitoring system at present is mainly based on cable networks or single wireless protocol. Due to the limitation of the communicational cable, it is difficult for the cable monitoring system itself to comprehensively and effectively monitor the environmental parameters of the coal mines. Besides, the additional cable may become the new hidden danger and stop working under the harsh conditions. Coal mine monitoring based on ZigBee can only adopt the method of single strand and relay, the huge communication pressure of the relay node may severely reduce the working life of the relay node and lead to the failure of the whole system. As a low rate of wireless communication technology, a single node of the ZigBee cannot bear the data flow of the whole coal mine nodes, which limit the extension of high transmission rate. Whereas, by using new type of wireless methods based on the underground industrial Ethernet and combined the technology of ZigBee and WiFi, a mixing wireless monitoring system can effectively, instantly and flexibly monitor variety of environmental parameters.Furthermore, the system realize coal mine informatization due to its easy installation, mobile collection, big transmission channel capacity and the background data processing systemThe main contents of this thesis include the following three parts:Firstly, design and realize the miniaturization and low power consumption of the nodes. The system consists of multiple-parameter wireless sensor network nodes and ZigBee-WiFi gateway nodes. The former can strengthen monitoring and collecting data of the coal mine environmental parameters, such as gas, carbon monoxide, oxygen, temperature and humidity, and then transport data to ZigBee-WiFi gateway nodes. The latter nodes complete the transformation from ZigBee agreement to WiFi protocol and the environmental data eventually transmit through underground Ethernet.Secondly, design and realize ZigBee-WiFi mixing wireless communicational networks. Realization of comprehensively and effectively monitoring the environmental parameters is attributed to the ZigBee and WiFi in the system, which can combine the advantages of flexibility, low power consumption of ZigBee and large capacity, easy import to Ethernet of WiFi.Thirdly, design the background data processing system. a single PC data processing program based on serial port communication can realize scene real-time handling of the environmental parameters. Beside, we design the B/S data processing system based on MVC architecture to achieve remote network data processing. |
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