Study On Key Technology Of Wireless Monitoring Network And Fault Diagnosis For Underground Workface Device

As a new and highly interdisciplinary research field, Wireless sensor network isattracting more and more attention at home and abroad. The basic application of WSNis to gather and transfer the perceptive information of sensor nodes in the monitoredregion. How to build a reliable network infrastructure, reduce network data traffic andimprove the efficiency of information transmission are the biggest challenges inwireless sensor network. Therefore, the methods of topology control, routing protocoland coverage control are aiming at the improvement of network performance, andbecoming important research focus.Since the technical characteristics of wireless sensor network, it has broadapplication prospects in military, environment, security, medical treatment, industrialand agricultural production, intelligent living, etc. The research of WSN be applied tothe machine fault diagnosis is still in initial stage. Especially for large complexmechanical devices underground, it can establish the monitoring system with wirelessmonitoring network. The monitoring system can reduce the downtime and costs ofdevice inspection, improve efficiency, what’s more, it can find the signs of earlyfailure and the fault feature existed, avoid the security accident caused by mechanicalfailure.This thesis given an in-depth study on topology control, routing protocol andcoverage control in WSN, and proposed some new improved methods. The faultmodel and fault diagnosis methods are analyzed in detail, and researched the faultfeature extraction and fault type classification. The chief main work and innovation ofpresent study can be drawn as follows.(1) To the actual demands of workface underground, the devices (shearer,scraper conveyor, and hydraulic support group) and environment (temperature,humidity, gas concentration, etc.) need to be monitored, it analyzed the monitoringequipment-Shearer, Scraper and hydraulic support group, listed the importantparameters and device status, and the important environmental parameters needmonitored. According to monitoring parameters of environment and key devices,designed the general architecture of wireless monitoring network underground,analyzed the network requirements and level structure, and established the wirelesstransmission channel model for the special conditions underground. (2) In order to ensure the reliability and connectivity of wireless sensormonitoring network underground, reduce power consumption and time consumptionin the process of network start-up. This thesis proposed a topology control algorithmbased on PID with self-adaptive hierarchical genetic (SAHGA-PID), introduced thehierarchical search strategy to self-adaptive genetic algorithm, divided into two-layersearch, and improved the optimization result of the algorithm. The algorithm used theclosed-loop control theory, and introduced the self-adaptive hierarchical geneticalgorithm. The result shown that the algorithm can reduce the energy consumption ofnetwork boot. Using the topology control based on SAHGA-PID to establish thenetwork topology underground, it will be faster and better in the boot process, and canreduce the energy consumption and time consumption, meet the requirements ofnetwork connectivity quickly.(3) By establishing the model of wireless transmission energy consumption, andon this basis, this thesis proposed a multiclass hierarchical routing protocol based onself-adaptive clustering, it combined distributed clustering mechanism and centralizedclustering mechanism, introduced distance factor to the distributed clustering, makedclusterhead distributing more balance. At the same time, it introduced the redundancymechanism of double-clusterhead. When there are excessive nodes in some cluster, itcan balance the network load; when there is some clusterhead failure, it can guaranteenetwork reliability and connectivity. For searching the optimization path transmit data,cosidered the energy and time consumption, designed the algorithm of constructingthe Min-path tree based on power control. The result shown that the proposed routingprotocol can clustering more uniform, control the number of nodes in the cluster,improve the network load balance, extend the network life cycle, and enhancenetwork reliability.(4) Coverage control and task scheduling of wireless sensor network is analyzedand attributed to the problem of search the best solution. This thesis did a study ofwireless sensor network coverage optimize algorithm existed, and considered theadvantages and disadvantages, purposed the coverage optimization algorithm basedon hybrid frog-leaping and ant colony. The result shown that, by the fusion of hybridfrog-leaping algorithm and ant colony algorithm, to search the greatest damage pathof the network, it can optimize the coverage performance of network effectively, andadjust the position of the node to improve network coverage. Meanwhile, for thenarrow feature of devices area in the workface underground, this thesis establish the task scheduling model of chain-type wireless monitoring network, and optimized themodel with intelligent genetic algorithm. The result shows that, the time consumptionand energy consumption achieve the optimization when entire chain networkcompleted the task with optimizing the model.(5) Described the development of mechanical fault and the classificationdiagnosis methods. Thorough analyzed the rolling bearing that the critical componentsof shearer, and established the model of fault feature. Then, this thesis analyzed thefault signals with multilateral band frequency by Cepstrum. Through did a study oflog-linear, principal component analysis and support vector machine. A method offault feature extraction based on PPCA with Logarithm-linear Ratios is proposed forextracting bearing fault feature, and a classification method based one-to-one supportvector machine classifier for bearing fault feature. The test result is shown that, thefault diagnosis algorithm based on L-PPCA and improved SVM classifier, can workwell for the bearing fault of shearer, and get very good results of fault featureextraction and classification.