【正文】 O)R8: if (E is NM) and (EC is NB) then (U is PB)R9: if (E is NM) and (EC is NM) then (U is PB)R10: if (E is NM) and (EC is NS) then (U is PB)R11: if (E is NM) and (EC is ZO) then (U is PB)R12: if (E is NM) and (EC is PS) then (U is PM)R13: if (E is NM) and (EC is PM) then (U is O)R14: if (E is NM) and (EC is PB) then (U is O)R15: if (E is NS) and (EC is NB) then (U is PM)R16: if (E is NS) and (EC is NM) then (U is PM)R17: if (E is NS) and (EC is NS) then (U is PM)R18: if (E is NS) and (EC is ZO) then (U is PM)R19: if (E is NS) and (EC is PS) then (U is O)R20: if (E is NS) and (EC is PM) then (U is NS)R21: if (E is NS) and (EC is PB) then (U is NS)R22: if (E is NO) and (EC is NB) then (U is PM)R23: if (E is NO) and (EC is NM) then (U is PM)R24: if (E is NO) and (EC is NS) then (U is PS)R25: if (E is NO) and (EC is ZO) then (U is O)R26: if (E is NO) and (EC is PS) then (U is NS)R27: if (E is NO) and (EC is PM) then (U is NM)R28: if (E is NO) and (EC is PB) then (U is NM)R29: if (E is PO) and (EC is NB) then (U is PM)R30: if (E is PO) and (EC is NM) then (U is PM)R31 if (E is PO) and (EC is NS) then (U is PS)R32: if (E is PO) and (EC is ZO) then (U is O)R33: if (E is PO) and (EC is PS) then (U is NS)R34: if (E is PO) and (EC is PM) then (U is NM)R35: if (E is PO) and (EC is PB) then (U is NM)R36: if (E is PS) and (EC is NB) then (U is PS)R37: if (E is PS) and (EC is NM) then (U is PS)R38: if (E is PS) and (EC is NS) then (U is O)R39: if (E is PS) and (EC is ZO) then (U is NM)R40: if (E is PS) and (EC is PS) then (U is NM)R41: if (E is PS) and (EC is PM) then (U is NM)R42: if (E is PS) and (EC is PB) then (U is NM)R43: if (E is PM) and (EC is NB) then (U is O)R44: if (E is PM) and (EC is NM) then (U is O)R45: if (E is PM) and (EC is NS) then (U is NM)R46: if (E is PM) and (EC is ZO) then (U is NB)R47: if (E is PM) and (EC is PS) then (U is NB)R48: if (E is PM) and (EC is PM) then (U is NB)R49: if (E is PM) and (EC is PB) then (U is NB)R50: if (E is PB) and (EC is NB) then (U is O)R51: if (E is PB) and (EC is NM) then (U is O)R52: if (E is PB) and (EC is NS) then (U is NM)R53: if (E is PB) and (EC is ZO) then (U is NB)R54: if (E is PB) and (EC is PS) then (U is NB)R55: if (E is PB) and (EC is PM) then (U is NB)R56: if (E is PB) and (EC is PB) then (U is NB)例如R56 if (E is PB) and (EC is PB) then (U is NB)表示如果偏差為正大，偏差變化為極大時(shí)，輸出為負(fù)大。至此利用MATLAB建立的水箱水位模糊推理系統(tǒng)建立完畢，用菜單File——Export——To disk…將建立的系統(tǒng)以tank為名稱保存在磁盤中以防丟失，另外一定要用File——Export——To Work space…將其保存在工作空間中以便在下一節(jié)simulink仿真設(shè)計(jì)中調(diào)用。 對(duì)SIMULINK模型控制系統(tǒng)的構(gòu)建 MATLAB提供的圖形輸入與仿真工具有兩個(gè)顯著的功能：SIM（仿真）與LINK（連接），即可利用鼠標(biāo)在模糊窗口畫出所需的控制系統(tǒng)模型，然后利用SIMULINK提供的功能來對(duì)系統(tǒng)進(jìn)行仿真或線性化分析，使得復(fù)雜系統(tǒng)的輸入變得簡(jiǎn)單和直觀。在MATLAB命令窗口鍵入simulink回車，啟動(dòng)simulink，并打開控件工具箱，如圖45所示：圖 45 Simulink窗口及控件工具箱窗口利用控件工具箱窗口添加所需要的組件，其中Signal Generator（信號(hào)發(fā)生器）用來產(chǎn)生輸入信號(hào)，在此用它產(chǎn)生方波信號(hào)；Scope（示波器）元件用來觀察各環(huán)節(jié)輸出的輸出波形；Sum（求和模塊）用來計(jì)算給定輸入和輸出水位的誤差；Gain（增益模塊）用來設(shè)置量化因子或比例因子；Mux元件可以將多個(gè)輸入信號(hào)合成一個(gè)向量信號(hào)；Fuzzy Logic Controller為模糊邏輯控制器，選自Smulink的模糊模塊庫(kù)，用來調(diào)用上一節(jié)建好的FIS結(jié)構(gòu)文件，將FIS結(jié)構(gòu)與構(gòu)建的整個(gè)Simulink模型系統(tǒng)進(jìn)行連接；Constant元件用來產(chǎn)生一個(gè)常數(shù)值。 Matlab對(duì)水箱液位的仿真設(shè)計(jì) 常規(guī)PID對(duì)液位模型的仿真當(dāng)系統(tǒng)沒有延遲環(huán)節(jié)時(shí)常規(guī)PID控制系統(tǒng)的仿真模型，如圖46所示。 圖46 常規(guī)PID控制系統(tǒng)的仿真模型其仿真結(jié)果為下圖47所示： 圖47 常規(guī)PID控制系統(tǒng)的仿真結(jié)果 模糊控制對(duì)液位模型的仿真 常規(guī)PID控制系統(tǒng)與模糊控制系統(tǒng)對(duì)比的仿真模型如圖48所示： 圖48 常規(guī)PID控制與模糊控制系統(tǒng)對(duì)比的仿真模型仿真結(jié)果如圖49所示： 圖49 常規(guī)PID控制與模糊控制系統(tǒng)的仿真結(jié)果 混合式模糊控制對(duì)液位的仿真常規(guī)PID控制與混合模糊控制系統(tǒng)的仿真模型如圖410所示： 圖410 常規(guī)PID與混合模糊控制水箱液位的仿真模型仿真結(jié)果如圖411所示，添加積分環(huán)節(jié)減小超調(diào)量，使系統(tǒng)更加穩(wěn)定。 圖411 常規(guī)PID與混合模糊控制水箱液位的仿真結(jié)果 干擾后常規(guī)PID與模糊控制仿真對(duì)比當(dāng)受到振幅為3，頻率為1Hz的隨機(jī)干擾后，常規(guī)PID控制與模糊控制水箱液位的仿真模型如圖412所示：圖412 干擾后常規(guī)PID控制與模糊控制仿真模型其仿真結(jié)果如圖413所示圖413 干擾后常規(guī)PID控制與模糊控制仿真結(jié)果在仿真之前，還需要設(shè)置仿真參數(shù)，可以通過菜單Simulation——Simulation Parameters…，將會(huì)打開仿真參數(shù)設(shè)置對(duì)話框，如圖414： 圖 414 仿真參數(shù)設(shè)置對(duì)話框參數(shù)的設(shè)置如圖415：圖 415 仿真參數(shù)設(shè)計(jì)這里只用設(shè)置Solver選項(xiàng)卡，其余的選項(xiàng)卡用默認(rèn)設(shè)置即可。本節(jié)的任務(wù)主要是觀察在所給定的輸入信號(hào)下水箱水位隨時(shí)間的影響情況，并比較傳統(tǒng)PID控制器和模糊控制器的控制效果。選擇菜單Simulation——Start，系統(tǒng)便開始仿真。 本章小結(jié)通過對(duì)基于模糊規(guī)則的PID控制器的設(shè)計(jì)和SIMULINK仿真，得出結(jié)論如下：模糊控制器的設(shè)計(jì)過程。在參數(shù)調(diào)整中，規(guī)則變化對(duì)控制性能的影響較大，其次是隸屬函數(shù)，量化因子只是一種微調(diào)。從調(diào)試步驟看，則往往先看量化因子，對(duì)于簡(jiǎn)單的系統(tǒng)，通常只要改變量化因子即可達(dá)到基本的控制要求。但是較復(fù)雜的控制系統(tǒng)，既要調(diào)節(jié)量化因子還要調(diào)節(jié)比例因子，達(dá)到共同控制系統(tǒng)的目的。根據(jù)上一節(jié)仿真結(jié)果的比較，我們能看出模糊控制較傳統(tǒng)的PID控制來講具有響應(yīng)速度快、適應(yīng)性較強(qiáng)，即魯棒性好、超調(diào)量小穩(wěn)定時(shí)間較長(zhǎng)等優(yōu)點(diǎn)，顯示出預(yù)期良好的穩(wěn)態(tài)性能。加入積分環(huán)節(jié)環(huán)節(jié)能夠更好的克服超調(diào)，增強(qiáng)系統(tǒng)的穩(wěn)定性和抗干擾能力。結(jié) 論模糊控制器是模糊控制系統(tǒng)和其它控制系統(tǒng)區(qū)別最大的環(huán)節(jié)，實(shí)質(zhì)上模糊控制器是一種非線性的比例微分(PD)控制關(guān)系。實(shí)際上Matlab模糊控制工具箱為模糊控制器的設(shè)計(jì)提供了一種非常簡(jiǎn)便的途徑，通過它我們不需要進(jìn)行復(fù)雜的模糊化、模糊推理及反模糊化運(yùn)算，只需要設(shè)定相應(yīng)參數(shù)，就可以很快得到我們想要的控制器，而且修改也很方便。具體包括以下幾步：（1）確定模糊控制器的結(jié)構(gòu):；（2）輸入輸出的模糊化；（3）模糊推理決策算法設(shè)計(jì)。模糊控制器的設(shè)計(jì)過程的參數(shù)調(diào)整中，規(guī)則變化對(duì)控制性能的影響較大，其次是隸屬函數(shù)，量化因子只是一種微調(diào)。本次設(shè)計(jì)分別用常規(guī)PID控制系統(tǒng)和模糊控制系統(tǒng)對(duì)雙容水箱的液位用MATLAB進(jìn)行仿真運(yùn)行。結(jié)果表明模糊控制較傳統(tǒng)的PID控制來講具有響應(yīng)速度快、適應(yīng)性較強(qiáng)，即魯棒性好、超調(diào)量小穩(wěn)定時(shí)間較長(zhǎng)等優(yōu)點(diǎn)，顯示出預(yù)期良好的穩(wěn)態(tài)性能。最后通過驗(yàn)證系統(tǒng)的抗干擾性，表明模糊控制系統(tǒng)具有較強(qiáng)的抗干擾能力。普通的模糊控制器中缺少積分功能，從而導(dǎo)致系統(tǒng)的精度受到一定限制，為了克服模糊控制器的控制靜態(tài)誤差，故把積分功能引入模糊控制器中組成混合模糊控制器。通過仿真對(duì)比可得加入積分環(huán)節(jié)可以減少超調(diào)，消除系統(tǒng)的余差且抗干擾性能加強(qiáng)。參考文獻(xiàn)[1] 胡壽松．自動(dòng)控制原理（第五版）[M].科學(xué)出版社，.[2] 王孝武. 現(xiàn)代控制理論基礎(chǔ)[M]．機(jī)械工業(yè)出版社，.[3] 李士勇等．模糊控制和智能控制理論與應(yīng)用[M]．哈爾濱工業(yè)大學(xué)出版社,.[4] 韓俊峰，李玉惠．模糊控制技術(shù)[M]．重慶：重慶大學(xué)出版社，.[5] 王正林，王勝開，[M].電子工業(yè)出版社，.[6] 王偉，張晶濤，[J].自動(dòng)化學(xué)報(bào)，2000,11(6):1117.[7] 湯兵勇、路林吉，王文杰．模糊控制理論與應(yīng)用技術(shù)[M]．北京：清華大學(xué)出版社，.[8] 劉曙光、魏俊民，竺志超．模糊控制技術(shù)[M]．北京：中國(guó)紡織出版社，.[9] L. A. Sets[M]. Information and Control,.[10] [D].蘭州理工大學(xué)碩士學(xué)位論文，.[11] 李友善、李軍．模糊控制理論及其在過程控制中的應(yīng)用[M]．北京：國(guó)防工業(yè)出版社，.[12] 李士勇．模糊控制和智能控制理論與應(yīng)用[M]．哈爾濱：哈爾濱工業(yè)大學(xué)出版社，.[13] Wang H O, Tanaka K, Griffin M F. An approach to fuzzy control of nonlinear system: stability and design issues[J].Fuzzy Systems, IEEE Tra