Study on Intelligent Temperature Controller Based on Expert Controlling

Transcription

1 Sensors & Transducers 2014 by IFSA Publshng, S. L. hp:// Sudy on Inellgen Temperaure Conroller Based on Exper Conrollng Jan-Hu MA, Peng GUO, Ka MENG College of Mechancal Engneerng, Henan Insue of Engneerng, No.1 Xanghe Road, Longhu, Xnzheng Couny, Zhengzhou Cy n Henan Provnce, , Chna Tel.: E-mal: auomjh77@163.com Receved: 5 May 2014 /Acceped: 27 May 2014 /Publshed: 31 May 2014 Absrac: Ths paper summarzes and analyses he problems exsng n he obacco leaf curng process: lag and Low accuracy of emperaure conrol. The rerof desgn of he emperaure conrol sysem has been compleed accordng o he exper conrol prncple of he nellgen conrol. The desgn of he nellgen emperaure conroller has been done. Copyrgh 2014 IFSA Publshng, S. L. Keywords: Exper conrollng, Temperaure, Inellgen conrollng. 1. Inroducon Auomac conrol echnology has been wdely used n ndusral and agrculural producon n our counry. For example, n he process of obacco bakng, he auomac conrol of he emperaure and humdy n he barn solves he dffcul n radonal bakng process n whch he emperaure and humdy s no easy o conrol and he labor nensy s bg. For all hs, emperaure regulaon of Auomac conrol was lag. Hgh precson emperaure conrol n exsence usng a varey of mproved PID algorhm has he advanage of hgh accuracy, less overshoo. Bu he adjusmen me of whch s long and emperaure rsng s slowly. Tha sll faled o make he varous ndcaors of sysem reach he approvng level, whch s more used n he hermosa, only n waer or ol as medum [1]. Inellgen conrol s a new knd of conrol mehod developed n recen years. I s suable for unceran producon process whch conanng he complexy and ncompleeness and vagueness of he known algorhms. Tobacco bakng s an unceran, nonlnear, me-varyng dsrbued parameer sysem [2]. The exper conrol mehod n he nellgen conrol can acheve good resuls. Ths opc research he nellgen emperaure conroller based on exper conrol can make a real me adjusmen and conrol of obacco bakng emperaure based on obacco expers provde bakng process and he real-me deecon of curng barn. 2. Exper Conrol (EC) and Fuzzy Conrol (FC) The man mehods of nellgen conrol nclude Exper Conro1 and Fuzzy Conro1 and Neural Neworks Conro1 and HIC-Herarchcal Inellgen Conro1. Fuzzy Conro1 s common mehod of nellgen conrol. Bu Fuzzy conroller s based on fuzzy rules whch are seleced mperfecly because here has been no comprehensve o conrolled process [3]. So he Fuzzy conroller sll canno fully mee he requremens of flue-cured obacco process. The combnaon of exper sysem and radonal conrol heory led o he exper conrol mehod. Exper sysem s a knd of nellgen compuer 20 hp://

2 program ha conans knowledge and reasonng, whch conans a ceran level of doman expers knowledge and experence, has he ably o solve specfc problems. Exper Conrol also called he Exper nellgen Conrol s he combnaon of heory and echnology of Exper sysem wh Conrol heory, mehod and echnology. I can realze he conrol of he sysem mang he Exper's experence n unknown envronmens. Exper conrol s ryng o "jon" an experenced engneer on he bass of he radonal conrol o realze he funcon of conrol. Is man body s made of knowledge base and reasonng mechansm. Is reasonng oupu s based on he approprae rules Accordng o a ceran sraegy and acquson and organzaon o doman knowledge (Pror experence, dynamc nformaon, arge, ec) [4]. Inellgen conroller s made of he daabase, knowledge base, reasonng machne, learnng lnk, he fxed lnk and he board, s srucure dagram s shown n Fg. 1. Y () + E + U + Y() Fg. 1. The srucure dagram of nellgen conroller. Daabase sores all he momens of samplng values, devaon, conrol measure and s conrol rules, weghng coeffcen of each of he conrol rules ec. Knowledge base s used o sore he experse provded by expers of doman. I s a collecon or warehouse used o sorage orderly ΔU knowledge. Reasonng mechansm s desgned o complee funcons of reasonng and decson-makng of sysem. The blackboard descrbes he nermedae sae of solvng process of he problem and ac as an nformaon ransmer of every ac knowledge. Self learnng and correcon lnk s responsble for supplemen or modfy he conen of knowledge base accordng o he nformaon onlne. 3. The Applcaons of Inellgen Conroller Based on Exper Conrol Applcaon of nellgen conrol o obacco bakng machnery "jon" a conrol of an experenced engneer on he bass of he radonal conrol. 3.1 The Hardware Desgn of Sysem Curng barn s chose of brck and le cvl curng barn ha s now wdely used also known as naural venlaon and ar downward curng barn (herenafer referred o as ar downward curng barn). Addng a hea exchanger and ho ar crculaon devce bul he forced venlaon and ho ar crculaon sysem. The conrol objecve s bakng process provded by he exper. Sysem consss of nellgen conroller, emperaure and humdy sensor, ho ar crculaon fan, combuson-supporng blower, he ho wnd unnel venlaon fan; skylgh we fan, ec. The C8051F310 MCU s as he core of he sysem (Fg.2). The DS1820 emperaure sensors made by DALLAS Company complee he ask for emperaure daa collecon and converson (Fg. 3). A he same me, he DMB12864B-01 n/w ype nellgen LCD dsplay s chose o make a real me monorng of emperaure change n curng barn. Accordng o he bes emperaure conrol curve n he process of obacco bakng, usng exper conrol mehod o conrol coal and ar supply. Fg. 2. The dagram sysem overall desgn. 21

3 modfy he each perod accordng o he LCD dsplay on he promp modfcaon emperaure and me value. Then sar runnng key, he mer T0 and T1 and seral communcaon. T0 s manly used for sngle chp mcrocompuer, he mng of T1 s manly used o conrol he samplng frequency. T1 daa overflow began o adjus emperaure measuremen subroune, compare emperaure afer send dsplay subrounes and call conrol calculae way program, he oupu conrol amoun. Curng barn s a nonlnear, me-varyng dsrbued parameer sysem. I apparenly s very dffcul sad s characerscs wh accurae mahemacal analycal formula. So has lmaons o ry o use quanave mahemacal mehod o conrol hs sysem, Conrol calculae way program should consder he combnaon of qualave and quanave mehods. Inellgen conrol s jus o use qualave experence, learnng he mers of logcal reasonng ably and memory. I fully learned mah and auomac conrol heory, combnng qualave and quanave knowledge, n order o mee he conrol requremens [4]. A barn emperaure closed loop conrol srucure s shown n Fg.5. y () + e u() Fg. 3. Temperaure measuremen crcu connecons. Temperaure sensor and humdy sensor connec he sysem hrough he mcroconroller I/O por drecly and send he measured emperaure o he MCU. MCU send he measured emperaure o he keyboard and dsplay un hrough daa sorage. Conras he daa wh prese emperaure. Sound and lgh alarm wll be drven by MCU when he emperaure beyond he upper and lower lm. And hen he conrol coal or exhaus moor swch wll be drven and ac. Core crcu of nellgen conroller nclude he sngle chp mcrocompuer communcaon module, perpheral emperaure deecon module, LCD dsplay and keyboard module and moor drve module, ec. Fg. 5. A barn emperaure closed loop conrol srucure. Here y () s he desgned value of emperaure; s he adjusmen amoun; () u s he conrolled quany; e () s he devaon rae of change defned by he followng formula: e y y y y, () = () (); [ (), u(), () e (), e ()] are he saes of he observable space. Transon curve of was shown as he Fg. 6, whch was obaned when enered y () no he sysem a he sep pon The Sofware Desgn of Sysem The sofware desgn of nellgen emperaure conroller can be dvded no he monorng of he man program, emperaure measuremen subroune and dsplay subroune, conrol calculae way program, ec. The workng process of he sysem s he followng. Open afer he power supply, SCM has formed a hree-sep bakng process curve, f need o modfy he nex seps can be performed; If need o y () y () 1 A B D E F C G Fg. 6. Transon curve. 22

4 Wh he help of people emprcal knowledge of emperaure conrol, adjusmen process of s as follows. Grealy reduce he conrol volume u() when s greaer han he y () ; Grealy ncrease he conrol volume u() when s far less han y () ; Deermne he sze of he conrol volume accordng o he varaon endency of he u f ; Increase he conrol volume () < y () and change of () y s sable; Increase, manan or decrease conrol by consderng devaon and he devaon change rae when change of has a endency o decrease he devaon (BC curve) f < y () ; Grealy reduce he conrol volume u() when change of has a endency o ncrease he devaon (CD curve) f > y () ; Reduce he conrol volume u() when change of s sable (DE curve) f () () y > y ; Increase, manan or decrease conrol by consderng devaon and he devaon change rae when change of has a endency o decrease he devaon (EF curve) f > y () ; Grealy ncrease he conrol volume u() when has a endency o ncrease he devaon (FG curve) f < y (). () e, he greaer he correspondng conrol volume; On he conrary, conrol volume s small; he value change of e () and correspondng conrol volume follow he same rule. The revsed oal oupu conrol amoun s defned as followng formula [4]: ( ) β ( ) ( 1 β) ( ) = + Δ, (1) * u k u k u k In he formula: β = 0.8 ~ 0.9 Usng above formula can comple subroune of conrol algorhm [4] (Fg. 7): p( k) 0 p( k ) = 0 e e () [ () u () ] ( = 1, 2,, m) In concluson, people s experence of consan emperaure value conrol man bass on devaon and he devaon change rae. So dvde observable sae space no some suaons named as ( = 1, 2,, m) n hs knd of knowledge expresson of conrol process. Every suaon s sgnfed by a rple as: e e () [ () u () ] ( = 1, 2,, m) In fac, every rple sgnfy a se of producon conrol rules of sysem as: e e () [ () ] u () ( = 1, 2,, m) Ths se of producon conrol rules can be amended by self-learnng. Accordng people's experence of people s experence of consan emperaure value conrol, he bgger he value of Fg. 7. Conrol algorhm flow char. 4. The Conras of he Inellgen Conroller and he Tradonal Conrol Through esng and analyss he hardware of he sysem s superor. The daa acquson and processng s real-me and mos funcons are mplemened by sofware. Inellgen conroller has smple and compac srucure, and does no requre an exernal clock rese crcu; Use 3.3 V power supply, he sysem power consumpon s small; PCS are conneced o he mcroconroller hrough he adaper, whch can be acheved onlne debuggng and smulaon whou he emulaor head. In order o ensure he changes n he envronmen n he real-me deecon of curng barn, daa 23

5 acquson and processng mus mee ceran me lm, so as o make real-me processng, agans he happenng of he accden. Because of he perpheral crcu s smple, he sofware can be modfed a any me, so he sysem has srong adapably. In addon, he sysem adops modular srucure desgn; n he case s easy o add new modules and easy o exend he funcons of he sysem whou changng he srucure. References [2]. P. G. Harrald, M. Kamsra, Evolvng arfcal neural neworks o combne fnancal forecass, IEEE Transacon on Evoluon Compuers, Vol. 1, Issue 1, 1997, pp [3]. LIN Yan, XUE Yu-Zh, The realzaon of hgh precson emperaure conrol sysem, Conrol Engneerng of Chna, Vol. 12, Issue 3, 2005, pp [4]. Wang Shunhuang, Shu Dqan, Inellgen conrol sysem and s applcaon, Chna Machne Press, Bejng, [1]. L. X. Wang, Adapve fuzzy sysems and conrol: desgn and sably analyss, Prence Hall, NJ, Copyrgh, Inernaonal Frequency Sensor Assocaon (IFSA) Publshng, S. L. All rghs reserved. (hp:// 24