Gas Monitoring System Based on ZigBee Pro and a New Method for Safety Grade Evaluation

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1 501 Gas Montorng System Based on ZgBee Pro and a New Method for Safety Grade Evaluaton Shutao Wang 1, Meme L 2, Quanmn Zhu 3, Mnghua Lu 4, Hongjn L 5 12,4,5 Insttute of Electrcal Engneerng,Yanshan Unversty, qnhuangdao, Hebe Provnce, Chna, Department of Engneerng Desgn and Mathematcs, Unversty of the West of England, Brstol, UK, BS16 1QY Abstract Amng at the mne safety problem, ths paper proposes a gas concentraton montorng system desgn scheme based on ZgBee Pro. The scheme desgns a set of ZgBee Pro wreless network combned software wth hardware based on KGS-20 gas sensor and CC2530 chp as the controller core. Accordng to the fuzzy reasonng technology and mult-factors nformaton fuson technology, a new method for the gas safety grade evaluaton s put forward and acheves a hgh-precson predcton for gas safety grade. The system wth the merts of securty, antnterference, hgh senstvty, low power consumpton, hgh lfe expectancy and easy applcaton, has a huge advantage n practcal applcatons. Keywords: ZgBee Pro, CC2530, Gas detecton, Informaton fuson and fuzzy reasonng technology 1. Introducton In recent years, the coal mne safety ncreasngly causes the attenton of people. Coal mne accdents occur frequently, causng serous nfluence n socety [1]. Therefore, t s partcularly urgent to study the effectve safety montorng system [3]. In order to meet the needs of montorng nformaton tendng to network, the gas concentraton montorng system based on ZgBee Pro s proposed. Usng the wred way for sgnal transmsson [2], the tradtonal gas concentraton montorng equpment detects the gas concentraton on the spot wth the dsadvantages of trval wrng and strong dependence on the lne. Whle the wreless sensor network s able to accurately acqure and montor varous envronment parameters n real tme, makng up for the defcency of cable montorng mode effectvely. The wreless sensor network avods the rsk of testng personnel on ste and realzes the mult-pont contnuous measurement of montorng area wth hghrelablty data. Accordng to the fuzzy mathematcs fuson theory, a new method for mne safety grade evaluaton s put forward. The smulatons of mult-group data prove that the proposed method s practcal and hgh relable. 2. ZgBee Pro Technology and Network Overall Desgn ZgBee s a knd of wreless network technology whch works n 900 MHZ and 2.4 GHZ frequency band [6], wth the characterstcs of the medum communcaton dstance, low power consumpton, low complexty, low data rate, low cost behavor [4]. As ZgBee developng gradually, the upgraded verson ZgBee Pro comes out. "At the greatest extent ZgBee Pro enhances ZgBee s ablty to promote the ease of use and advanced support for large network [5]". The outstandng characterstcs of ZgBee Pro are usng random addressng nstead of orgnal tree addressng, puttng forward Many-to-one routng and provdng commercal-grade encrypted communcatons, etc. The commonly used network topology structures of ZgBee Pro manly nclude star network topology and mesh network topology [7]. Because n ZgBee Pro specfcatons the way to allocate network locaton s random, and there s no relatonshp between the network poston of all chld nodes and the actual relatve poston of the whole system network topology [8]. Therefore, ZgBee Pro does not support tree routng. In order to avod faults n a certan part of the network node or system not workng normally for dsrupted lnk due to envronmental reasons, the system scheme n the paper desgns the retcular network as wreless communcaton network topology. The overall frame of gas content automatc montorng system controlled by wreless network s shown as fgure 1.The system s manly composed of ZgBee Pro wreless sensor nodes, central coordnator and remote control center composton. Its workng prncple s that the moble modes and the sensor nodes of temperature,

2 502 methane, carbon monoxde and other gas as RFD (reduced functon equpment), the center coordnator as FFD (full functon equpment), each sensor node sends data to the center coordnator, that the center coordnator collectng data from each sensor node transmts data to the remote control center to be processed and dsplayed n real-tme; and then the PC evaluates the densty collected usng the mult-nformaton fuson technology and fuzzy reasonng technque; and fnally the PC ssues a warnng nformaton evaluatng the possblty of the current gas exploson and concludes that rsk rate[9]. Fgure1 Automatc montorng system overall structure Fgure2 Schematc dagram of the system hardware

3 The System Hardware and Software Desgn The system manly conssts of sensors collecton part and wreless communcaton module. The sensor collecton part s manly responsble for gatherng the CH4 and CO, CO2 and H2S, dust, temperature, ar output acquston from the external envronment. The acqured sgnal after denosng, temperature compensaton, the I-V crcut converson, sgnal amplfcaton and a seres of operatons wll be sent drectly to the communcaton module. Wreless communcaton module s responsble for sendng the real-tme data collected n the front of the sensor to ZgBee coordnator and then ZgBee coordnator deals wth the data correspondngly, and the data s transmtted by ZgBee coordnator to host computer for dsplay and wreless montorng. Hardware desgn schematc dagram s shown n fgure 2. Software s the center of the montorng system, and hardware crcut can realze ts functon smoothly only under the correct gudance of the software. Ths system uses IAR7 as development envronment, adoptng the protocol Stack for TI. Z - Stack software whch has been open for free download. The protocol stack acheves ZgBee allance reference platform level, and s already wdely adopted by global ZgBee developers at present. By testng the system's overall layout, t s known that the sensor module and coordnator module play a man role. Fnally the nformaton s transmtted from the coordnator to the control center and receved and dsplayed by the upper computer n real tme. Fgure4 Coordnator program flow chart Fgure3 Sensor program flow chart The sensor node ntalzes hardware and network after startng, and attempts to jon the network. When the equpment jons the network, the jont network address wll be sent to coordnator. On recevng nstructon, the nstructon wll be analyzed and then be carred on. At the same tme the sensor node starts to acqure data through the sensor module. After the acquston of the data completely, the sensor node sends data to the coordnator node. Then the node steps nto watng for nstructon state after the sensor node sends successfully. Program flow chart below 3, 4 fgure.

4 Gas Safety Grade Evaluaton Model of Fuzzy Data Fuson The tradtonal gas safety assessment standard only smply uses a gas concentraton threshold lmt to judge whether the mne s safe. However the gas s compounded and gas safety grade evaluaton also needs to consder CO, CO 2, H 2 S and others concentraton whch are related to each other. Therefore, the author evaluates the mne gas concentraton by usng the fuzzy data fuson, whch effectvely uses mathematcal theory of fuzzy language non-determnsm. And the detected sgnal s transformed from qualtatve nformaton nto quanttatve nformaton, so that the montorng personnel can montor more ntutvely. Fuzzy comprehensve evaluaton method [10] s a knd of comprehensve evaluaton method based on the fuzzy mathematcs [12]. The comprehensve evaluaton method based on fuzzy membershp degree theory translates the qualtatve evaluaton nto the quanttatve, whch uses fuzzy mathematcs to make an overall evaluaton restrcted by varous factors thngs or objects. It has the characterstc that the result s clear and the systemc s strong, to solve the problem whch s fuzzy and dffcult to quantfy. It s sutable to solve all knds of uncertan problems [9]. Fuzzy comprehensve evaluaton method regards the evaluaton target as the fuzzy set (called factor set q) made up of a varety of factors, and then sets evaluaton level of these factors selected, formng the fuzzy set of comments (called evaluaton set v)[11]. After that the membershp grade of each sngle factor to each evaluaton grades (called fuzzy matrx) s respectvely calculate. Accordng to weghts dstrbute of varous factors n the evaluaton target, the quanttatve value of the evaluaton s obtaned through the fuzzy matrx synthess. Its prncple s expressed as: Q W R (1) Where W =(w1,w2,w3, w wm) s fuzzy vector or called fuzzy converter, and t s the weght dstrbuton of evaluaton factor X = {x1, x2,..., x,..., xm}. R s a fuzzy relaton matrx composed of the evaluaton factors X = {x1, x2,..., x,..., xm} and the evaluaton set U = {u1, u2,..., u,..., un}. After gettng the set Q, t s fuzzy processed by the maxmum membershp degree. To the gas test system, we can evaluate comprehensvely from CH4, CO, CO2 and H2S, temperature, ar output as the sx aspects. The above sx domans are: CH4 concentraton A, CO concentraton B, CO2 concentraton C, H2S concentraton D, temperature F, exhaust ar volume G. Evaluaton factor X = {A, B, C, D, F, G}.The gas safety state evaluaton s set V: {safety S, warnng W, alarm D}. In order to transform the evaluaton ndex from qualtatve to quanttatve analyss, the evaluaton set of varous ndex s determned. S-coal mne exploson won't happen, where the nterval of the score s [80,100] and medan s 90. W-coal mne exploson may occur, where the nterval of the score s 60,79 a medan s69.5. D-coal mne gas exploson wll occur, where the nterval of the score s 40,59 a medan s Select the medan n each nterval as the parameters of the level, and then the three grades of the correspondng parameter are: 90, 69.5, 49.5, and ts column vector u 90,69.5, are To determne weght coeffcents, analytc herarchy process (AHP) s adopted. Through the coal mne experts nvestgaton, the moreover weghts are determned and successfully get passed from the one-tme test. Fnally the scentfc and reasonable weghts are acqured, as shown n table 1. Table.1 The judgment matrx of Gas exploson rsk X A B C D F G A B 1/ C 1/5 1/ /3 3 D 1/3 1/ /3 1 F 1/ G 1/5 1/5 1/3 1 1/2 1 Normalze the matrx X by columns: xj bj (, j 1,2,..., n) = n xj Sum the matrx X by lnes: (2)

5 (3) v b j j Normalze: (4) v w n v Calculate the maxmum characterstc root of the judgment matrx n max ( XW ) nw (5) The consstency ndex of the judgment matrx: CI ( max n) ( n 1) (6) Calculate the consstency rato CR,smulate the analytc herarchy above usng Mat lab mathematcal smulaton. The sample capacty s calculated to be ~ 10 order RIs are obtaned as the followng. Table.2 RI order judgment matrx average random consstency ndex rank RI rank RI CR CI RI (7) CR<0.1, the consstency of the X s acceptable. Otherwse t needs to readjust the judgment matrx, untl meets consstency check. After all experts have made the evaluaton of the mne gas exploson rsk, the fuzzy relaton matrx processed wth the normalzaton wll be obtaned R Therefore, the Q W R draws the fuzzy evaluaton matrx Q ( , , ) Based on the fuzzy evaluaton matrx Q and the parameters column vector u of the evaluaton set, system comprehensve evaluaton result Z wll be obtaned: Z Q u (8) Accordng to the evaluaton level regulaton, s n the possbly dangerous nterval, and n lne wth the actual stuaton. 5. Conclusons Ths system use ZgBee Pro wreless communcaton technology to be able to complete real-tme vbraton montorng, alarmng and other functons. Before underground ppelne facltes are destroyed t can predct the arrval of the rsk, and notfy the emergency mantenance personnel n tme, gvng them more tme. It s found that the method can play the advantages of the multple sensor nformaton fuson by usng the fuzzy data fuson method for the early warnng research on coal mne gas after carryng the experments on the method to be verfed. To a certan extent, t can reduce not-reportng and msreportng for the lmtatons of sngle sensor nformaton, and reduce the uncertanty, so as to mprove the safety performance of the gas system. Therefore, ZgBee pro wreless communcaton technology and data fuson method used n coal mne gas warnng study s feasble. Acknowledgements Ths work s supported by the Key Program of Natonal Natural Scence Foundaton of Chna ( , ) and Program of Natonal Natural Scence Foundaton of Hebe Provnce (F ). References [1] Hafeng Duan, Lje Wang, and Quanzhong Jng. Defnton of Investment n Coal Mne Safety and Securty Costs, Journal of safety scence of Chna,Vol. 16, No. 6, 2006, pp

6 506 [2] Shumng Wang, and Xuequ He, Reflectons on Enhancng the Strength of Coal Mne Safety nvestment strategy, coal economc research, Vol. 4,2006,pp [3] Yuanpng Cheng, Le Wang, Xaole Zhang, Envronmental mpact of coal mne methane emssons and respondng strateges n Chna, Internatonal Journal of Greenhouse Gas Control, Vol. 5, NO. 1, 2011, pp [4] J. Han, H. Lee, and K. Park. Remote-Controllable and Energy-Savng Room Archtecture based on ZgBee Communcaton. IEEE Trans. On Consumer Electroncs, Vol. 55, No. 1, 2009, pp [5] Guangrong Wu, and Janxong Zhang, Realzaton of Wreless Sensor Network Based on CC2430, Modern Electroncs Technque, Vol. 12,2008, pp [6] K. Gll, S. Yang, F. Yao, and X. Lu. A ZgBee-based Home Automaton System. Consumer Electroncs, Vol. 55, No. 2, 2009, pp [7] C.C. Shen, C. Srsathapornphat, C., R. Lu, Z.C. Huang, C. Jakaeo, C., E.L. Lloyd, CLTC: a cluseter-based topology control framework for ad hoc networks, Moble Computng, IEEE Transactons on. Vol. 3, No. 1, 2004, pp [8] Quan Zhou, Zhush Yang, Wegen Chen, Jan L, Xaomn Ma. Desgn of Conductor Gallopng Mult-ponts Montorng System Usng ZgBee PRO Wreless Network Technology. Hgh Voltage Engneerng, Vol. 37, No. 8, 2011, pp [9] L Zheng, Zgbee Wreless Sensor Network n Industral Applcatons, Proceedngs of Internatonal Conference on Computer Internatonal Jont Conference SICE-ICASE, Oct,2006,pp [10] Tejun L, Dal Guo, Yujun Gong, Zhhao Tang and Kequan Chen, A Research of Fuzzy Comprehensve Evaluaton on Carbonate Reservor, Advances n Intellgent and Soft Computng, Vol. 147, 2012, pp [11] Jed Sun, and Jangtao Wen, "Research on Montorng and Pre-warnng System for Securty of Ppelnes Based on Mult-Sesmc Sensors," Proceedngs of Internatonal Conference on Internatonal Conference on Electronc Measurement & Instruments (ICEMI) 2009, pp [12] Blanco A, Delgado M, Martín- Ramos JM, and Polo MP. "AIEIA: software for fuzzy envronmental mpact assessment". Expert Syst Appl, Vol. 36, No. 91, 2009, pp Shutao Wang s a professor n Yanshan Unversty, Chna. He receved hs doctor's degree n nstrument scence and technology n 2006 at the Unversty of Harbn Industral. Hs nterests are n Intellgent Informaton Processng and photoelectrc measurement. Furthermore, he s the author of two books: optoelectroncs and fber optc sensng technology (2003) and fber optc sensng technology and applcaton (2009).Currently, he s a teacher at Yanshan Unversty, Qnhuangdao, Chna. Meme L s a Master of Yanshan Unversty Currently. The topcs of her research are n Intellgent Informaton Processng and photoelectrc measurement. Quanmn Zhu receved a doctor's degree n the unversty of Warwck engneerng nsttute n From 1989 to 1994, he was a postdoctoral n the Unversty of Sheffeld automatc control and system engneerng nsttute. Professor Zhu s the member of the nternatonal federaton of automatc control, the Brtsh engneerng professor councl and Brtan technology trade assocaton commttee. He s also the UK regstered engneer. Professor Zhu as the edtor and assocate edtor for many magaznes, he s also the member of the Brtsh engneerng and natural scence research revew commttee. He s the consultant of a number of companes and assocatons. In addton to the above ttles, Professor Zhu s also the founder and edtor of the Int. J. of Modelng, dentfcaton and Control, the founder and charman of the Int. Conference of Modelng, dentfcaton and Control.