加熱爐燃燒模糊控制系統(tǒng)設(shè)計(jì)與應(yīng)用

1、加熱爐燃燒模糊控制系統(tǒng)的設(shè)計(jì)與應(yīng)用（電控學(xué)院 測(cè)控0902班 李園 0906070204）摘要：針對(duì)加熱爐煤氣，空氣流量計(jì)的不準(zhǔn)確，煤氣發(fā)熱值不真實(shí)等各種現(xiàn)狀，設(shè)計(jì)一種基于專家經(jīng)驗(yàn)的模糊控制程序，通過調(diào)節(jié)煤氣空氣調(diào)節(jié)閥，煙道閘板閥的開度來控制加熱溫度，并把加熱溫度穩(wěn)定在盡可能小的設(shè)定值+20之內(nèi)，達(dá)到均勻加熱，降低燃耗和氧化燒損、減少待溫時(shí)間和提高產(chǎn)能的目的。關(guān)鍵詞：加熱爐燃燒 模糊控制 The fuzzy control system design and application heating furnace burning(Electrical and control engineeri

2、ng Academy Measurement and control technology in class 0902LiYuan 0906070204)Abstract: According to the various kinds of present situation that is inaccuracy of the heating furnace and the air flow and gas calorific value is not real and so on, we design a kind of fuzzy control based on expert exper

3、ience program, which control the temperature of the heating and steadying the temperature of heating as small as possible in the setting value within + 20 through adjusting the gas air regulator and the flue damper valves opening to heat evenly, reduce fuel consumption lose oxygenation, spend less t

4、ime and increase temperature capacity. Keywords: the heating furnace burning; fuzzy control1 模糊控制的簡(jiǎn)介 1.1模糊控制原理 1.1.1模糊控制的產(chǎn)生在自動(dòng)控制技術(shù)產(chǎn)生之前，人們?cè)谏a(chǎn)過程中只能采用手動(dòng)控制方式。手動(dòng)控制過程分別是由人的眼-腦-手來完成的。后來，由于科學(xué)技術(shù)的進(jìn)步，人們逐漸采用各種測(cè)量裝置（如傳感器）代替人眼，完成對(duì)被控制量的觀測(cè)任務(wù)；利用各種控制器（如PID調(diào)節(jié)器）取代人腦的作用，實(shí)現(xiàn)比較、綜合被控制量與給定量之間的偏差，控制器所給出的輸出信號(hào)相當(dāng)于手動(dòng)控制過程中人腦的決策；使用各

5、種執(zhí)行機(jī)構(gòu)（如電動(dòng)機(jī)）對(duì)被控對(duì)象施加某種控制作用，這就起到了手動(dòng)控制中手的調(diào)整作用。 上述由測(cè)量裝置、控制器、被控對(duì)象及執(zhí)行機(jī)構(gòu)組成的自動(dòng)測(cè)控系統(tǒng)，就是人們所熟知的常規(guī)負(fù)反饋控制系統(tǒng)。常規(guī)控制首先要建立精確數(shù)學(xué)模型，但是對(duì)一些復(fù)雜的工業(yè)過程，建立精確的數(shù)學(xué)模型是非常困難的，或者是根本不可能的。于是常規(guī)控制技術(shù)在這里就遇到了不可逾越的障礙。但是，熟練的技術(shù)操作人員，通過感官系統(tǒng)進(jìn)行現(xiàn)場(chǎng)觀察，再根據(jù)自己的經(jīng)驗(yàn)就能很容易地實(shí)現(xiàn)這類控制過程，于是就產(chǎn)生了一個(gè)問題，能否把人的操作經(jīng)驗(yàn)總結(jié)為若干條控制規(guī)則，并設(shè)計(jì)一個(gè)裝置去執(zhí)行這些規(guī)則，從而對(duì)系統(tǒng)進(jìn)行有效的控制呢?答案是肯定的。這種裝置就是模糊控制器。與傳

6、統(tǒng)的PID控制相比，模糊控制有其明顯的優(yōu)越性：1.由于模糊控制實(shí)質(zhì)上是用計(jì)算機(jī)去執(zhí)行操作人員的控制策略，因而可以避開復(fù)雜的數(shù)學(xué)模型。2.對(duì)于非線性，大滯后及帶有隨機(jī)干擾的復(fù)雜工業(yè)對(duì)象，由于數(shù)學(xué)模型難以建立，因而傳統(tǒng)的PID控制也就失效，而對(duì)這樣的系統(tǒng)，設(shè)計(jì)一個(gè)模糊控制器，卻沒有多大困難。實(shí)踐結(jié)果表明，在兩種系統(tǒng)均調(diào)到最佳狀態(tài)下，當(dāng)工作條件大幅度變化時(shí)，經(jīng)典的PID控制難以進(jìn)行調(diào)整，而模糊控制對(duì)過程參數(shù)改變不靈敏，在所有工作所有工作點(diǎn)上都能做到較穩(wěn)定的控制，這說明模糊控制本質(zhì)上是非線性的，并且對(duì)于對(duì)象的參數(shù)變化適應(yīng)性強(qiáng)，即所謂的“魯棒性”較好。1.1.2 模糊控制系統(tǒng)的組成模糊控制屬于計(jì)算機(jī)數(shù)字

7、控制的一種形式，通常由5個(gè)部分組成，其系統(tǒng)框圖如圖6-17所示。A/D模糊控制器D/A執(zhí)行機(jī)構(gòu)被控對(duì)象變送器+-r(t)e(t)u(k)e(k)u(t)g(t)y(t)1.1.3 模糊控制器的組成及各部分的工作原理模糊控制器主要包括輸入量模糊化接口、知識(shí)庫(kù)、推理機(jī)、輸出清晰化接口四個(gè)部分，如圖6-18所示。1）模糊化接口模糊控制器的輸入變量（通常為偏差和偏差的變化率）的實(shí)際變化范圍叫做這些變量的基本論域，顯然基本論域內(nèi)的量為精確量，當(dāng)計(jì)算機(jī)實(shí)現(xiàn)模糊控制算法進(jìn)行模糊控制時(shí)，每次采樣得到的被控制量需經(jīng)計(jì)算機(jī)計(jì)算，以便得到模糊控制器的輸入變量。為了進(jìn)行模糊化處理，必須將輸入變量從基本論域轉(zhuǎn)換到相應(yīng)的

8、模糊集論域。設(shè)輸入變量的基本論域?yàn)?x，x，輸入變量的模糊集論域?yàn)?n，-n+1，0，n-1，n，即可以給出精確量模糊化的量化因子 k = nx （6-43）把輸入變量乘以量化因子，就能實(shí)現(xiàn)輸入變量從基本論域到模糊集論域的轉(zhuǎn)換。通常，習(xí)慣上把輸入變量的模糊集論域設(shè)定為-6，-5，-4，-3，-2，-1，0，1，2，3，4，5，6，把在這區(qū)間的連續(xù)量模糊化為7檔：“正大”（PB）多數(shù)取+6附近；“正中”（PM）多數(shù)取+4附近；“正小”（PS）多數(shù)取+2附近；“零”（0）多數(shù)取0附近；“負(fù)小”（NS）多數(shù)取-2附近；“負(fù)中”（NM）多數(shù)取-4附近；“負(fù)大”（NB）多數(shù)取-6附近。這7檔對(duì)應(yīng)著7個(gè)模

9、糊子集 2）知識(shí)庫(kù) 數(shù)據(jù)庫(kù)：存放所有輸入輸出變量的全部模糊子集的隸屬度矢量值，若論域?yàn)檫B續(xù)域，則為隸屬度函數(shù)。對(duì)于以上例子，須將表6-7中內(nèi)容存放于數(shù)據(jù)庫(kù)，在規(guī)則推理的模糊關(guān)系方程求解過程中，向推理機(jī)提供數(shù)據(jù)。 規(guī)則庫(kù)：用來存放全部模糊控制規(guī)則，在推理時(shí)為“推理機(jī)”提供控制規(guī)則。模糊控制器的規(guī)則是基于專家知識(shí)或手動(dòng)操作熟練人員長(zhǎng)期積累的經(jīng)驗(yàn)，它是按人的直覺推理的一種語(yǔ)言表示形式。模糊規(guī)則通常由一系列的關(guān)系詞連接而成，如ifthen，else，also，end，or等，關(guān)系詞必須經(jīng)過“翻譯”才能將模糊規(guī)則數(shù)值化。3）推理機(jī)推理機(jī)在模糊控制器中的功能是：根據(jù)輸入的模糊量和知識(shí)庫(kù)（數(shù)據(jù)庫(kù)、規(guī)則庫(kù)）完

10、成模糊推理，并求解模糊關(guān)系方程，從而獲得模糊控制量。例如，若已知偏差E和偏差的變化率EC的模糊集，則控制量的模糊集U可由模糊推理的合成算法獲得，即 式中， 模糊直積運(yùn)算； 模糊合成運(yùn)算； 模糊關(guān)系。 4）清晰化接口通過推理機(jī)進(jìn)行模糊決策所得到的輸出是模糊量，而被控對(duì)象只能接受一個(gè)控制量，因此要進(jìn)行控制必須經(jīng)過清晰化接口將模糊量轉(zhuǎn)換為精確量。將模糊量轉(zhuǎn)換為精確量通常采用以下三種方法： 最大隸屬度判決法：若對(duì)應(yīng)的模糊決策的模糊集中，元素u*U，且滿足則取u* （精確量）作為輸出控制量。u*就是該模糊子集中隸屬度最大的那個(gè)元素。如果這樣的隸屬度最大點(diǎn)u*不唯一，就取它們的平均值作為執(zhí)行量。 加權(quán)平均

11、判決法：該方法的輸出量u*的值由下式來決定取中位數(shù)法：在最大隸屬度判決法中，只考慮了最大隸屬數(shù)，而忽略了其它信息的影響。中位數(shù)判決法是將隸屬函數(shù)曲線與橫坐標(biāo)所圍成的面積平均分成兩部分，以分界點(diǎn)所對(duì)應(yīng)的論域元素作為判決輸出。2 加熱溫度模糊控制設(shè)計(jì)原理和過程2.1 基本原理: 總結(jié)專家技術(shù)人員及優(yōu)秀操作工人的現(xiàn)場(chǎng)經(jīng)驗(yàn); 參照模糊控制結(jié)構(gòu)選取誤差及誤差變化率作為輸入，這樣既可克服一維模糊控制動(dòng)態(tài)性能欠佳的不足，又能避免由于維數(shù)過高而使控制規(guī)則過于復(fù)雜，實(shí)現(xiàn)較困難的缺點(diǎn); 在上述基礎(chǔ)上將誤差、誤差變化率的模糊量經(jīng)合成算法，推得模糊規(guī)則表; 模糊控制規(guī)則自適應(yīng)修正。加熱溫度設(shè)三檔來控制，均熱段分別是1

12、250 10、1230 10、1210 10; 加熱段分別是1230 10、1190 10、1150 10，預(yù)熱段暫不作特定要求，檔位的選擇由毛軋主電機(jī)實(shí)際電流作為主要依據(jù)，若電流在額定電流范圍內(nèi)，則盡可能選擇較低溫度檔位，若因爐膛壓力過高而引起爐尾冒火，則也應(yīng)選擇低溫檔位。2.2 系統(tǒng)的模糊設(shè)計(jì)以均熱段為例: 冷風(fēng)閥和煤氣調(diào)節(jié)閥，err_T = pv sv，簡(jiǎn)寫為E ，誤差變化率表示為EC。溫度的控制精度目標(biāo)為 10。E模糊變量的集合范圍為 NB，NM，NS，ZO，PS，PM，PB ; EC 模糊變量的集合范圍為 NB，NS，ZO，PS，PB。據(jù)現(xiàn)場(chǎng)所采集的數(shù)據(jù)，發(fā)現(xiàn)三段的溫度變化曲線不完全

13、相同，所以分別定義E，EC的取值范圍。分析發(fā)現(xiàn)均熱段的溫度曲線較其它兩段平穩(wěn)，采樣控制周期暫定為10s。根據(jù)溫度的控制精度目標(biāo)為 10，均熱段E 模糊變量各變量的取值為:E7.5NB;7.5E5NM;5E2.5NS;2.5 E2.5ZO;2.5E5PS;5E7.5PM;7.5EPB。根據(jù)現(xiàn)場(chǎng)所收集的均熱段數(shù)據(jù)ECmin =0.49 /s,ECmax=0.79/s.均熱段EC模糊變量各變量的取值為:EC0.28NB;0.28EC0.06NS; 0.06EC0.36ZO;0.36EC0.58PS; 0.58ECPB。煤氣閥門控制U 模糊變量的集合范圍為 NB，NM，NS，ZO，PS，PM，PB ，

14、對(duì)應(yīng)的閥門變化開度為3%,2%,1%,0%,1%,2%,3% 。溫度模糊控制規(guī)則如表一所示表一 溫度模糊控制表EC UENBNSZ0PSPBNBPBPBPBPMPSNMPBPBPMPSZ0NSPBPMPSZ0NSZ0PMPSZ0NSNMPSPSZ0NSNMNBPMZ0NSNMNBNBPBNSNMNBNBNB設(shè)計(jì)一個(gè)模糊器，滿足如下條件:輸入誤差E：-7.5-7.5范圍內(nèi)分為7個(gè)論域：NB NM NS Z0 PS PM PB;隸屬度函數(shù)滿足高斯分布；輸入誤差變化率Ec：-0.28-0.58范圍內(nèi)分為5個(gè)論域：NB NS Z0 PS PB; 隸屬度函數(shù)滿足高斯分布；模糊推理過程：output=(輸

15、入隸屬度函數(shù)值+輸入誤差的隸屬度函數(shù)值)/2*輸出論域的中心值?？刂埔?guī)則：% %if error input is NB and error input rate is NB, then output is PB;% % if error input is NB and error input rate is NS, then output is PB;% % if error input is NB and error input rate is Z0, then output is PB;% % if error input is NB and error input rate is PS

16、, then output is PM;% % if error input is NB and error input rate is PB, then output is PS; % % if error input is NM and error input rate is NB, then output is PB;% % if error input is NM and error input rate is NS, then output is PB;% % if error input is NM and error input rate is Z0, then output i

17、s PM;% % if error input is NM and error input rate is PS, then output is PS;% % if error input is NM and error input rate is PB, then output is Z0; % % if error input is NS and error input rate is NB, then output is PB;% % if error input is NS and error input rate is NS, then output is PM;% % if err

18、or input is NS and error input rate is Z0, then output is PS;% % if error input is NS and error input rate is PS, then output is Z0;% % if error input is NS and error input rate is PB, then output is NS; % % if error input is Z0 and error input rate is NB, then output is PM;% % if error input is Z0

19、and error input rate is NS, then output is PS;% % if error input is Z0 and error input rate is Z0, then output is Z0;% % if error input is Z0 and error input rate is PS, then output is NS;% % if error input is Z0 and error input rate is PB, then output is NM; % % if error input is PS and error input

20、 rate is NB, then output is PS;% % if error input is PS and error input rate is NS, then output is Z0;% % if error input is PS and error input rate is Z0, then output is NS;% % if error input is PS and error input rate is PS, then output is NM;% % if error input is PS and error input rate is PB, the

21、n output is NB; % % if error input is PM and error input rate is NB, then output is Z0;% % if error input is PM and error input rate is NS, then output is NS;% % if error input is PM and error input rate is Z0, then output is NM;% % if error input is PM and error input rate is PS, then output is NB;

22、% % if error input is PM and error input rate is PB, then output is NB;% % if error input is PB and error input rate is NB, then output is NS;% % if error input is PB and error input rate is NS, then output is NM;% % if error input is PB and error input rate is Z0, then output is NB;% % if error inp

23、ut is PB and error input rate is PS, then output is NB;% % if error input is PB and error input rate is PB, then output is NB;1. 輸入誤差為：程序?yàn)椋簒1 = (-7.5:0.1:7.5);y0 = gaussmf(x1, 1 -7.5);y1 = gaussmf(x1, 1 -5);y2 = gaussmf(x1, 1 -2.5);y3 = gaussmf(x1, 1 0);y4 = gaussmf(x1, 1 2.5);y5 = gaussmf(x1, 1 5);

24、y6 = gaussmf(x1, 1 7.5);plot(x1,y0 y1 y2 y3 y4 y5 y6);2. 輸入誤差的變化率為：程序?yàn)椋篨2 = (-0.28:0.1:0.58);y0 = gaussmf(x2, 0.5 -0.28);y1 = gaussmf(x2, 0.5 -0.06);y2 = gaussmf(x2, 0.5 0.15);y3 = gaussmf(x2, 0.5 0.36);y4 = gaussmf(x2, 0.5 0.58);plot(x2,y0 y1 y2 y3 y4);3. 程序?yàn)椋簒1=-7.5;x2=-0.28; % define input type i

25、n fuzzy zoney0 = gaussmf(x1, 1 -7.5);y1 = gaussmf(x1, 1 -5);y2 = gaussmf(x1, 1 -2.5);y3 = gaussmf(x1, 1 0);y4 = gaussmf(x1, 1 2.5);y5 = gaussmf(x1, 1 5);y6 = gaussmf(x1, 1 7.5);a=y0 y1 y2 y3 y4 y5 y6;b=max(a);% caculate input in fuzzy zone,get input_type and input_authorityvalueif x1=-7.5 if b=a(1)

26、type=NB; authorityvalue=y0; elseif b=a(2) type=NM; authorityvalue=y1;elseif b=a(3) type=NS; authorityvalue=y2;elseif b=a(4) type=Z0; authorityvalue=y3;elseif b=a(5) type=PS; authorityvalue=y4;elseif b=a(6) type=PM; authorityvalue=y5;elseif b=a(7) type=PB; authorityvalue=y6; endelseif x17.5 type=PB;

27、authorityvalue=1; elseif x1-7.5 type=NB; authorityvalue=1;endend type authorityvalue%error calculate.ey0 = gaussmf(x2, 0.5 -0.28);ey1 = gaussmf(x2, 0.5 -0.06);ey2 = gaussmf(x2, 0.5 0.15);ey3 = gaussmf(x2, 0.5 0.36);ey4 = gaussmf(x2, 0.5 0.58);a=ey0 ey1 ey2 ey3 ey4;b=max(a);% caculate input in fuzzy

28、zone,get input_type and input_authorityvalueif x2=-0.28 if b=a(1) etype=NB; eauthorityvalue=y0; elseif b=a(2) etype=NS; eauthorityvalue=y1; elseif b=a(3) etype=Z0; eauthorityvalue=y2; elseif b=a(4) etype=PS; eauthorityvalue=y3; elseif b=a(5) etype=PB; eauthorityvalue=y4; endelse if x20.58 etype=PB;

29、eauthorityvalue=1; elseif x2-0.28 etype=NB; eauthorityvalue=1; endend etype eauthorityvalue % caculate output by if type=NB& etype=NB out=(authorityvalue+eauthorityvalue)/2*(0.03); % if input is NB and errorinput is NB, then output is PB; elseif type=NB& etype=NS out=(authorityvalue+eauthorityvalue)

30、/2*(0.03); % if input is NB and errorinput is NS, then output is PB; elseif type=NB& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*(0.03); % if input is NB and errorinput is Z0, then output is PB; elseif type=NB& etype=PS out=(authorityvalue+eauthorityvalue)/2*0.02; % if input is NB and errorinput

31、 is PS, then output is PM; elseif type=NB& etype=PB out=(authorityvalue+eauthorityvalue)/2*0.01; % if input is NB and errorinput is PB, then output is PS; elseif type=NM& etype=NB out=(authorityvalue+eauthorityvalue)/2*0.03; % if input is NM and errorinput is NB, then output is PB;elseif type=NM& et

32、ype=NS out=(authorityvalue+eauthorityvalue)/2*0.03; % if input is NM and errorinput is NS, then output is PB;elseif type=NM& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*0.02; % if input is NM and errorinput is Z0, then output is PM;elseif type=NM& etype=PS out=(authorityvalue+eauthorityvalue)/2*

33、0.01; % if input is NM and errorinput is PS, then output is PS;elseif type=NM& etype=PB out=(authorityvalue+eauthorityvalue)/2*0.000001; % if input is NM and errorinput is PB, then output is Z0;elseif type=NS& etype=NB out=(authorityvalue+eauthorityvalue)/2*0.03; % if input is NS and errorinput is N

34、B, then output is PB;elseif type=NS& etype=NS out=(authorityvalue+eauthorityvalue)/2*0.02; % if input is NS and errorinput is NS, then output is PM;elseif type=NS& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*0.01; % if input is NS and errorinput is Z0, then output is PS;elseif type=NS& etype=PS

35、out=(authorityvalue+eauthorityvalue)/2*0.000001; % if input is NS and errorinput is PS, then output is Z0;elseif type=NS& etype=PB out=(authorityvalue+eauthorityvalue)/2*(-0.01); % if input is NS and errorinput is PB, then output is NS;elseif type=Z0& etype=NB out=(authorityvalue+eauthorityvalue)/2*

36、0.02; % if input is Z0 and errorinput is NB, then output is PM;elseif type=Z0& etype=NS out=(authorityvalue+eauthorityvalue)/2*0.01; % if input is Z0 and errorinput is NS, then output is PS;elseif type=Z0& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*0.000001; % if input is Z0 and errorinput is Z

37、0, then output is Z0;elseif type=Z0& etype=PS out=(authorityvalue+eauthorityvalue)/2*(-0.01); % if input is Z0 and errorinput is PS, then output is NS;elseif type=Z0& etype=PB out=(authorityvalue+eauthorityvalue)/2*(-0.02); % if input is Z0 and errorinput is PB, then output is NM;elseif type=PS& ety

38、pe=NB out=(authorityvalue+eauthorityvalue)/2*0.01; % if input is PS and errorinput is NB, then output is PS;elseif type=PS& etype=NS out=(authorityvalue+eauthorityvalue)/2*0.000001; % if input is PS and errorinput is NS, then output is Z0;elseif type=PS& etype=Z0 out=(authorityvalue+eauthorityvalue)

39、/2*(-0.01);% if input is PS and errorinput is Z0, then output is NS;elseif type=PS& etype=PS out=(authorityvalue+eauthorityvalue)/2*(-0.02); % if input is PS and errorinput is PS, then output is NM;elseif type=PS& etype=PB out=(authorityvalue+eauthorityvalue)/2*(-0.03); % if input is PS and errorinp

40、ut is PB, then output is NB;elseif type=PM& etype=NB out=(authorityvalue+eauthorityvalue)/2*0.000001; % if input is PM and errorinput is NB, then output is Z0; elseif type=PM& etype=NS out=(authorityvalue+eauthorityvalue)/2*(-0.01); % if input is PM and errorinput is NS, then output is NS;elseif typ

41、e=PM& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*(-0.02); % if input is PM and errorinput is Z0, then output is NM;elseif type=PM& etype=PS out=(authorityvalue+eauthorityvalue)/2*(-0.03); % if input is PM and errorinput is PS, then output is NB;elseif type=PM& etype=PB out=(authorityvalue+eauth

42、orityvalue)/2*(-0.03); % if input is PM and errorinput is PB, then output is NB;elseif type=PB& etype=NB out=(authorityvalue+eauthorityvalue)/2*(-0.01); % if input is PB and errorinput is NB, then output is NS;elseif type=PB& etype=NS out=(authorityvalue+eauthorityvalue)/2*(-0.02); % if input is PB

43、and errorinput is NS, then output is NM;elseif type=PB& etype=Z0 out=(authorityvalue+eauthorityvalue)/2*(-0.03); % if input is PB and errorinput is Z0, then output is NB;elseif type=PB& etype=PS out=(authorityvalue+eauthorityvalue)/2*(-0.03); % if input is PB and errorinput is PS, then output is NB;elseif type=PB& etype=PB out=(authorityvalue+eauthorityvalue)/2*(-0.03); % if input is PB and errorinput is PB, then output is NB; end outx1-7.5-7.5-7.5-7.5-7.5x2-0.28-0.060.150.360.58typeNBNBNBNBNBauthorityvalue11111etypeNBNSZ0PSPBeauthorityvalue10.04393.7267e-66.1019e-131.9287e-22out0.030