Research On Integration And Control System Based On Wireless Sensor Networks

With the continuous improvement and development of fieldbus technology, the network integrated control system emerged on the basis of distributed control of building automatic control system. The characteristic of the network integrated control system is that the data communication network extends to the bottom of system. Wireless sensor networks(WSN) shows unique advantages as the bottom network nodes in monitoring situations where targets move usually and building control applications of which real-time requirement is not strict and wiring is difficult.Aimed at smart home environment, a clustered wireless sensor network with wireless communication was designed, and this wireless sensor network was formed by the indoor environmental information monitoring nodes and electrical equipment nodes. The whole network was integrated by a gateway based on ARM processor for acquiring data and controling equipment.Firstly, the research background and the domestic and overseas development states were summarized in the paper. The characteristics, structure and research difficulties of WSN were introduced in detail. Through the study of communication mechanism of data link layer in wireless sensor network protocol stack, a communication protocol based on Time Division Multiple Access (TDMA) mechanism was designed for clustered wireless sensor network. In this mechanism, time is divided into periodic time frames, each of which is divided into several time slots, and each node in the network takes at least one time slot. This mechanism requires synchronize the time of the nodes in the network. DMTS was adopted in time synchronization algorithm. The cluster head node broadcasted synchronization message periodically, child nodes adjusted their own local clock according to delay time after receiving synchronization message and completed synchronization process. The master-slave communication mode was adopted. The master node initiated communication and one-hop child nodes executed operation or collected data which would be returned to the head node finally after receiving network command. The nodes away from the head node completed the communication by multi-hop through their higher level relay nodes.Smart home gateway was designed to integrate the wireless sensor nodes. Samsung Advanced RISC Machine Processor S3C2410 was adopted as the controller of the gateway. Embedded Linux system was ported and applications based on Qtopia were designed on top of the operating system. Users can observe environmental data information and control devices directly through the LCD touch screen of gateway. Embedded Web Server was ported. HTML files and CGI applications programs were designed. Users can complete related operations by accessing the gateway remotely through Internet.