反應釜是化工生產(chan)過(guo)程中(zhong)的(de)重要設備,反應過(guo)程中(zhong)伴(ban)隨有(you)大量(liang)的(de)吸(xi)、放熱現象(xiang),具有(you)大滯后(hou)、時變(bian)、非線性、反應機(ji)理(li)(li)復雜等特點(dian)。傳(chuan)統的(de)PID控(kong)制是一種基于過(guo)程參(can)數(shu)(shu)(shu)的(de)控(kong)制方法,具有(you) 控(kong)制原(yuan)理(li)(li)簡單、穩定(ding)性好、可靠性高、參(can)數(shu)(shu)(shu)易調(diao)整(zheng)等優點(dian),但(dan)其設計依賴于被控(kong)對(dui)象(xiang)的(de)精(jing)確數(shu)(shu)(shu)學模(mo)型(xing),在(zai)(zai)線整(zheng)定(ding)參(can)數(shu)(shu)(shu)的(de)能力差(cha),而反應釜因(yin)為機(ji)理(li)(li)復雜、各個參(can)數(shu)(shu)(shu)在(zai)(zai) 系統反應過(guo)程中(zhong)時變(bian),不(bu)能建(jian)立(li)精(jing)確的(de)數(shu)(shu)(shu)學模(mo)型(xing),不(bu)能滿足系統在(zai)(zai)不(bu)同條件下(xia)對(dui)參(can)數(shu)(shu)(shu)自整(zheng)定(ding)的(de)要求,因(yin)而采用一般的(de)PID控(kong)制器無法實現對(dui)反應釜的(de)精(jing)確控(kong)制。
模(mo)糊(hu)控制(zhi)是(shi)(shi)一種基(ji)于規則的語(yu)言控制(zhi),在設計中不需要(yao)建立被控對(dui)象的精(jing)(jing)確數學模(mo)型,魯棒性強,干擾和(he)(he)參(can)數變化對(dui)控制(zhi)效果(guo)的影響被大(da)(da)大(da)(da)減弱,摔(shuai)制(zhi)效果(guo)好。但(dan)模(mo)糊(hu)控制(zhi)器是(shi)(shi)以誤差(cha)(cha)和(he)(he)誤差(cha)(cha)變化作為輸入變量,這種控制(zhi)器具有(you)模(mo)糊(hu)比例-微分控制(zhi)作用(yong),精(jing)(jing)度(du)不太(tai)高、穩態誤差(cha)(cha)較大(da)(da)、自適(shi)應能力有(you)限和(he)(he)易產生振蕩現象。
預(yu)測控(kong)(kong)(kong)(kong)制(zhi)(zhi)是(shi)一種優化(hua)控(kong)(kong)(kong)(kong)制(zhi)(zhi)算法,它是(shi)通過對某一性(xing)能指(zhi)標的(de)(de)(de)最優來確定未來的(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)(zhi)作用(yong)(yong)的(de)(de)(de),具有(you)對模(mo)型(xing)要(yao)求低(di)、魯棒性(xing)好(hao)、適用(yong)(yong)于數字(zi)計(ji)算機控(kong)(kong)(kong)(kong)制(zhi)(zhi)的(de)(de)(de)優點(dian)。由于計(ji)算機模(mo)型(xing)預(yu) 測控(kong)(kong)(kong)(kong)制(zhi)(zhi)具有(you)良好(hao)的(de)(de)(de)跟蹤(zong)性(xing)能,能有(you)效地(di)提高系(xi)統的(de)(de)(de)穩(wen)定性(xing)和消除誤差,對滯后(hou)過程有(you)明(ming)顯控(kong)(kong)(kong)(kong)制(zhi)(zhi)效果,更加符合工業溫(wen)(wen)度(du)控(kong)(kong)(kong)(kong)制(zhi)(zhi)的(de)(de)(de)實際要(yao)求,從而大(da)大(da)提高了(le)溫(wen)(wen)度(du)控(kong)(kong)(kong)(kong)制(zhi)(zhi)系(xi) 統的(de)(de)(de)性(xing)能。分析反(fan)應釜溫(wen)(wen)度(du)變化(hua)的(de)(de)(de)特(te)點(dian)以及(ji)控(kong)(kong)(kong)(kong)制(zhi)(zhi)難點(dian),總結(jie)當前溫(wen)(wen)度(du)控(kong)(kong)(kong)(kong)制(zhi)(zhi)系(xi)統精(jing)度(du)差的(de)(de)(de)根(gen)本(ben)原因,在此基礎上采用(yong)(yong)基于預(yu)測的(de)(de)(de)模(mo)糊自(zi)整(zheng)定PID集(ji)成控(kong)(kong)(kong)(kong)制(zhi)(zhi)技術(shu)實現反(fan)應釜溫(wen)(wen)度(du)控(kong)(kong)(kong)(kong)制(zhi)(zhi),其主要(yao)思想是(shi)利用(yong)(yong)系(xi)統模(mo)型(xing)的(de)(de)(de)預(yu)測輸(shu)出,結(jie)合常(chang)規PID的(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)(zhi)經驗,采用(yong)(yong)模(mo)糊推理方法,對控(kong)(kong)(kong)(kong)制(zhi)(zhi)器算法進(jin)(jin)行(xing)改進(jin)(jin)。
實驗結(jie)果表明,與通常的(de)(de)PID 控(kong)(kong)制(zhi)(zhi)方(fang)(fang)案相比,該(gai)方(fang)(fang)案提(ti)高了(le)系統的(de)(de)魯(lu)棒性(xing)(xing)(xing)和適應(ying)性(xing)(xing)(xing),較好(hao)的(de)(de)解(jie)決了(le)反應(ying)釜溫度控(kong)(kong)制(zhi)(zhi)的(de)(de)難題(ti)。完(wan)成了(le)反應(ying)釜溫度控(kong)(kong)制(zhi)(zhi)系統的(de)(de)硬件(jian)電路的(de)(de)設計、系統軟件(jian)的(de)(de)編譯與調 試,對(dui)基于預測的(de)(de)模糊自整定(ding)PID溫度控(kong)(kong)制(zhi)(zhi)系統進行了(le)仿真與實驗研究,與PIU控(kong)(kong)制(zhi)(zhi)方(fang)(fang)法相比,控(kong)(kong)制(zhi)(zhi)性(xing)(xing)(xing)能更(geng)加穩定(ding),可靠性(xing)(xing)(xing)更(geng)高,實時性(xing)(xing)(xing)、適應(ying)性(xing)(xing)(xing)、魯(lu)棒性(xing)(xing)(xing)都顯 著增強,控(kong)(kong)制(zhi)(zhi)效果較好(hao)。
