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1、課程名稱:《系統(tǒng)辨識理論與實踐》(TheoryandPracticeofSystemIdentification)PartII辨識方法第6章多變量系統(tǒng)辨識方法6.1傳遞函數(shù)矩陣模型參數(shù)辨識方法6.2Markov參數(shù)辨識方法6.3輸入輸出差分模型參數(shù)辨識方法6.4AUDIAlgorithmforMultivariableSystems6.4.1AugmentedUDIdentificationStructure6.4.2ParameterandLossFunctionMatrices6.4.3Recurs
2、iveAUDIAlgorithm6.4.4SimulationExample1PartII辨識方法第6章多變量系統(tǒng)模型參數(shù)辨識方法基于輸入輸出數(shù)據(jù)的多變量系統(tǒng)模型參數(shù)辨識包括:①傳遞函數(shù)矩陣模型參數(shù)辨識方法;②Markov參數(shù)辨識方法;③輸入輸出差分模型參數(shù)辨識方法。6.1傳遞函數(shù)矩陣模型參數(shù)辨識方法考慮如下傳遞函數(shù)矩陣?1?1?1??Bz()Bz()Bz()11121r???1?1?11Bz()B(z)B(z)Gz(?1)=??21222r?1??Az()???1?1?1????Bm12(z)Bm(z
3、)Bmr(z)其中?1?1?2?n?Az()=1+(1)az+(2)az++()anz??1?1?2?n?Bzij()=(1)bijz+(2)bijz++()bnzij??i??12,,,m;j12,,,r則以傳遞函數(shù)矩陣模型表達的多變量系統(tǒng)可描述成??11Az()()=(zkBz)()+()ukwk????1?1?1Bz()Bz()Bz()11121r????1?1?1Bz()B(z)B(z)?B(z?1)=??21222r???????1?1?1式中,?????Bm1(z)Bm2(z)Bmr1(z)
4、?T?z()=k?zkzk12(),(),,()zkm??T?u()=k?ukuk12(),(),,()ukr??T??w()=k?wkwk12(),(),,wkm()?2且有?E?w()k??0??2?Cov?wI()k???w?2??E?w()()ijw????wijI這種多變量系統(tǒng)的描述框圖如圖6.1所示。圖6.1多變量系統(tǒng)圖第i個子系統(tǒng)可表示為r??11Az()()=zki?Bzij()()+()ukjekij?1?1ek()=(Az)()wkii令3TT??????T,?T???T,bbT,T
5、,,bT??i?i??i12iir??T?=?a(1),(2),a,()an???Tb=??b(1),(2),b,()bn?ij??ijijij?TTT??ii()=k????zu(),k()k?T???TTTT=z(),ku(),ku(),k,u()k???ir12?T?zi()=k??zki(?1),?zki(?2),,?zki(?n)??Tu()=k??uk(?1),(uk??2),,(ukn)?j??jjj??i??12,,,m;j12,,,r則可將多變量系統(tǒng)寫成最小二乘格式Tzk()=??()
6、k?ek()iiii式中,zk(),??()k,和ek()分別是第i子系統(tǒng)的輸出變量、數(shù)據(jù)向量、模型iiii參數(shù)向量、噪聲變量。當噪聲變量ek()可視作白噪聲時,利用最小二乘辨識原i理,可得第i子系統(tǒng)的模型參數(shù)遞推辨識算法為??()=k??(-1)k+K()k??zk()????T()(k?k1)iii??iii?1TK()k?P(k?1)()1?k????()(kPk?1)()?kiii??iiiTP()k???I?K()k?()kP(k?1)i??iii這種把多變量系統(tǒng)分解為m個獨立子系統(tǒng),分別估計
7、各子系統(tǒng)的模型參數(shù)的算法,是以各子系統(tǒng)的損失函數(shù)達到最小為目標的,即L2J()=????zk()???T()k?minii???iiik?1??i但這并不一定能使mJ()=???J()???miniii?1為使4mJ()=???J()???miniii?1置T??????T,?T,?T,,?T?im??12????TTTTTTTTTTT?,bb,,,bbb,,,,b,,b,b,,b???11121r21222rm1m2mr?T??=?a(1),(2),a,()an??T?bij=????bij(1),(
8、2),bij,()bnij?TT???zu1()kk()00???TTzu()kk0()0?H()=k??2??????TT?????zum()kk0()???T?h()k1???T???h2()k???????T?????hm()k?T?z()=k?zkzk12(),(),,()zkm??T?e()=k?ekek12(),(),,ekm()??TTTT?u()=k????u12(),ku(),k,ur()k?T?zi()=k?zki(?1