Research Of The Structure Design, The Routing And The Localization Algorithms Of Wireless Sensor Network In Manufacturing Shop

Digitalization and intelligentization of manufacturing shop is the inevitable development trend of manufacturing enterprise informatization. Nowadays, the problems existing in production process include i) the data collection is time-consuming and lagging; ii) the execution state cannot be fully monitored and iii) products and manufacturing resources is difficult to be tracked accurately. Only with applicating the technology of WSN, which is a representation of internet of things (IoT), the interconnections between manufacturing resources and the production process of active sensing and monitoring can be realized. Therefore, the aim of the intelligent scheduling and optimization decision of manufacturing process and resouces can be achieved. However, there still exsists some technical difficulties in the application of WSN technology in manufacturing shop because of the complexity of shop environment and the requirements of real-time, accuracy, high-quality of data collection. The technical difficulties include the design of sensor network structure, the real-time acquisition and reliable transmission of multi-type data and high precision positioning of mobile manufacturing resouces, etc. In this thesis the key technologies of WSN are researched and applied in a typical manufacturing enterprise. The detailed content is as follows:The characteristics of WSN are analyzed, which are featured as complex network properties. A local world evolving model based on energy awareness is constructed with the introduction of scale-free networks and local-world model. Statistical results show that the communication range increasing of several nodes can improve the efficiency of data transmission. On the basis of the theory above, a WSN with small world characteristics is built through adding some advanced nodes which have higher energy, more storage capacity and data processing ability. The network model can decrease the time delay of data transmission, reduce the energy consumption of communication, balance the node load and improve the fault tolerance with the random failure.The data acquisition methods and transmission modes in manufacturing shop are summarized. Then, an unequal clustering routing algorithm in WSN is proposed for the application scenario of periodic transmission. Based on the community detection method in complex network, the algorithm balances the energy consumption of nodes and improves the transmission efficiency. Furthermore, as the qualities of services (QoS) of multiple operations are quite different, a hybrid network is designed to provide various structures. Therefore, a multipath routing algorithm is presented, which can switch different path for data transmission, in order to meet the real-time requirements of multiple operations.The application requirements of wireless positioning of mobile resources in workshop are introduced firstly. In this thesis, the localization algorithm of WSN is on the basis of Monte Carlo method (MCL). Then, range-free and range-based algorithms are proposed. In range-free localization algorithm, Guass-markov motion model is used to simulate the trajectory of mobile resource. The possible range of the current moment position is predicted according to the estimated position of the previous moment and motion model. Then, enough samples are selected in the possible range to estimate the node position. In RSSI-based localization algorithm, the range information between reference nodes and mobile nodes constrains the sampling range to improve sample quality and sampling efficiency. The localization precision of the two algorithms is promoted compared to original MCL algorithm.Based on the research founding above, a manufacturing execution system on basis of IoT technologies is put forward. An example of the digital workshop project in a construction machinery enterprise is given to bulid the wirless sensor network of workshop. In addition, the application scenarios of materials status monitoring, manufacturing resources localization and automatic collection of quality information illustrate the implementation of WSN technologies in workshop.Finally, a conclusion is drawn and the trend on WSN technologies in manufacturing is anticipated.