Research and Application of Expert System Skeleton for Controlling Sintering Process

Available online at www.sciencedirect.comScienceDirect-=JOURNAL OF IRON AND STEEL RBSEARCH, INTERNATIONAL. 2008, 15(5): 06-08Research and Application of Expert System Skeleton forControlling Sintering ProcessLONG Hong ming'，FAN Xiao-hui? ,JIANG Tao', DAI Lin-qing'(1. School of Metallurgy and Resource, Anhui University of Technology，Ma' anshan 243002, Anhui, China;2. School ofResources Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China)Abstract: An expert system skeleton tool of sintering process was constructed using object-oriented method, whichcan actualize two functions, i e , the shell function and the program function. The skeleton tool offered a platformto build a prototype system, to program class code, and to develop the expert system. Four branch expert systemswere developed using the skeleton tool including the control of chemical composition, the control of sintering processstate, the control of expended energy, and the diagnosis of abnormity. It is found that the performance of all systemsis satisfactory in practice.Key words: sintering process expert system; skeleton tool; knowledge base; ilation engineIron ore sintering is a process of heating ironGUI (graphic user interface) with multimedia.ore to a high temperature and then melting iron oreThe electric machinery company of J apaneseto block. The product of sintering is a poriferousFujf[J] has also developed AIMAX (AI tool for man-sinter with irregular shapel1. It is difficult to de-ufacturing automatic control system) series inscribe the real-time control of sintering process ex-1990s，which are special development tools of AIactly and solve commendably the problems that ap-and are used to control, diagnose, and project forpear in the sintering process only by mathematicalindustry production process. Their characteristicsmodel because the instance of locale is complicatedare rapid ilation, object to locale, and applicable toand the problems referred are of multiplicity and in-different clients with different knowledge expres-distinction. Therefore, many expert systems were sions, and they have perfect interface with other ap-developed on the basis of the engineers' specialtyplication programs.knowledge to actualize the optimized control of sin-Hitachi manufactorytl developed a developmenttering process. However, these expert systems usu- tool ES/ KERNEL2 (Expert System/ KERNEL2) forally used the knowledge base and ilation engine asexpert system to develop expert system efficiently.core of systems and costed much with respect to hu-This system adopted neural networks, intensifiedman resources, material resources, financial re-the fuzzy ilation, and combined AI functions andsources, and time if they were developed one by oneobject- oriented techniques. It can be used as an ef-for each sinter plant.fective development tool, which was formed fromThe ART' Enterprise developed by Americanrapid prototyping approach and was used extensivelyInference Company in 199352] is an intelligent in- in general software development.tegrate application developing tool, which has theIt can be seen that the expert system skeleton ischaracteristics of object- oriention, management with formed from some expert systems that were devel-several kinds of database, case based reasoning, andoped successfully and proved to be effective in prac-Foundation Item,ltem Sponsored by National Natural Science Foundation of Chin中国煤化Iosgrnduate Edueation ofCentral South University (042310011):MYHCNMHGBiography.LONG Hong rming(1979-), Male, Doctor; E-mail; yafhm@126. (Issue 5Research and Application of Expert System Skeleton for Controlling Sintering Process●7●tice, with the removal of idiographic knowledge con-(1) Collect, analyze, sum up knowledge suchtent and only preserving its basic system skeleton’as diagnosis knowledge of abnormity, controland function. When the skeleton is used to developknowledge of sinter chemical composition, control .expert systems, it only requires loading the relevant knowledge of sintering energy expending, controldomain knowledge to the system according to the knowledge of sinter process state, and so on, andskeleton system' s requirement, and it need not rede- then choose expression method of knowledge andsign knowledge expression method and illation en-construct knowledge base.gine. It can lessen the development cost of expert(2) Choose illation engine, track the ilationsystem greatly and shorten the development period.process, and improve the knowledge base and illa-Therefore, researching and developing expert tion engine continuously.system skeleton for sintering process as a prototype(3) Assemble knowledge base and illation en-system of an expert system and a tool of secondary gine to build an archetypal system, simulate, anddevelopment has important theoretical and practicaltest the system by practical state that is present pos-meanings. It can also provide a powerful function sibly in locale.and convenient operation for developing sintering expert(4) Make use of the expert system class to de-system, and reduce cost and time of development.velop expert subsystems for sintering process, testthe function of every subsystem, and improve them.1 Construction of Skeleton System(5) Incorporate subsystems and test new sys-1.1 General structuretem by online application.Fig.1 shows a general structure of the expertsystem framework. The system actualized two func-1.2 Modules of skeleton systemtions: shell function and program function. TheBased on the structure characteristic, the skele-shell function is the classical expert system frame-on system is divided into four main modules:work including database and illation engine， The knowledge base, illation engine, expert systempattern of database and illation engine can be used toclass, and system application (Fig. 2).construct an expert archetypal system. The program 1. 2.1 Knowledge basefunction provides class of an expert system for theThe knowledge base is used to deposit knowl-developer. The developer can carry out secondary edge of sintering field, including fact, rule, and sodevelopment based on the prototype and then useon. The knowledge base module is made up of twothe expert system for online control of sintering functions. One is to construct new knowledge base.process. That can shorten developing period great- The system provides knowledge constructing plat-ly, with no necessity of program illation and expla- form for user according to the requirement. Thenation by the developer any more, and with only ne-other is to maintain knowledge base including adding,cessity of fixing attention on building a model, read- modifying, deleting, and inquiring knowledge.ing and analyzing online data, and designing the in-1. 2.2 Illation engineterface of software.According to the characteristics of sintering pro-The steps for developing an expert system for sinte-ring process using the skeleton system are as follows:Skeleton systemKnowledge[ Ilauion Expert systemSystem applicationhaseengineclass]Shell function.ArchetypalIllationsystemExpertImprove kmowledge basecontollingand ilation enginesinteringGlasses of expert systemProgram functionprocess中国煤化工YHCNMH GFig. 1 General structure of skeleton systemFig.2 Modules of skeleton system●8.Journal of Iron and Steel Research, InternationalVol.15cess, the ilation engine adopts two methods: for-ing knowledge base and setting ilation engine, thenward and backward ilations.start the engine to infer. If users want to know the(1) The forward ilation is called data drivingillation process, they can look over the interpretingtactic, which infers conclusions from the informa-function to get the middle steps. If matching ruletion of knowledge base according to certain tacticcannot be found from the knowledge base during thefrom original data. For example, if some informa-illation process, users can modify the knowledgetion is obtained from the expert system for control-base and add new rules, which is the learning func-ling chemical composition such as“R is high",“TFetion of the system.is in order" ,“CaO is high" , and“SiO2 is in order".2 Application of SystemExpert system has two rules as follows:Rule m: if R is high and TFe is in order, andOn the basis of the skeleton system, four ex-CaO is high and SiO2 is in order, then the flux ofpert systems have been developed for sinteringlimestone is on the high side;process: the control of chemical composition, theRule n: if the flux of limestone is on the highcontrol of sintering process state, the control of ex-side, then reduce the flux of limestone.pended energy, and the diagnosis of abnormity.When the information of“R is high”,“TFe isThen，they were applied in Baosteel Co Ltd andin order",“CaO is high", and“SiO2 is in order" is Panzhihua New Steel and Vanadium Co Ltd. All ofobtained, the route of forward ilation is: rule m- +them obtained good effects.rulen. (Fig. 3).(2) Backward ilation is the method of advan-3 Conclusionscing supposing (conclusion) at first and then getting(1) The expert system skeleton for sinteringthe proo[ to support the conclusion. It is opposite toprocess control has been designed and developed,forward ilation in logic.and the shell function and the program function with1.2.3Class of ex pert systemfour main modules including knowledge base, illa-In this module, it offers interface function andtion engine, system application, and class of expertprogram code of class for user, which actualizes thesystem have been actualized.language function of the skeleton system. The mod-(2) With the skeleton system, it can easily con-ule embodies the object oriented programming idea,struct knowledge base, actualize the forward or back-which abstracts the behavior of expert system to C+ + ward ilation method, and create prototype system.class and brings huge convenience for expert system(3) Using skeleton system, expert system fordevelopment in the futuref5-7]. Take a practical ex-sintering process has been developed, which consistspert system as an instance of the class, encapsulateof four branch systems including control of chemicalsome common functions such as ilation function,composition, control of sintering process state, con-and explain function that can be used directly introl of expended energy and diagnosis of abnormity.practice.References:1.2.4 Appliance module of systemThe function of this module is constructing a[1] FAN Xiao-bui, WANG Hai dong. Mathematical Model andAricial Itelligence of Sintering Process [M]. Changsha:simple expert system which can be regarded as pro-Central South University Press, 2002 (in Chinese).totype system of expert system for sintering. It only[2] Monika P W, Wolfgang N. Integrating Model Based and Heu-requires loading different knowledge bases to con-ristic Features in a Real Time Expert System [J]. IEEE Ex-struct expert system of different fields. After load-[3] Kard DS, RichardSH M. A Real Time Expert System Shellfor Quality Control [J]. IEEE Expert, 1992, (10): 36.Information“ R is high" ,“TFe is in order"[4] Lafley Thomas J. Real-Time Knowledge Based System CJ]. AI“CaO is high", and“SiOz is in order"Magazine, 1988, 9(1): 27.Middle[5] LI Zeng-zhi, WANG Yu, LI Gang. Analysis in Designing ObrprocessThe flux of limestone is on the high side中国煤化工Mini-Micro Systems,[6]CNMHGng[M].BeigTSigConchusionReduce the flux of limestoneC.nua University rress, 1999 (in Lninese).[7] WANG Yan. The Objeet Oriented Theory and c+ + PracticeFig. 3 Forward ilation[M]. 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