【正文】 any of these 39。 answer ed Cr awl ey,39。clock tr ain t o London, 39。I suppose i t would, but I never catch a later tr ain.39。cl ock tr ai n, but t hat you caught the which would st il l get you to work on tim e. You see, on the mor ning of the m urder, t he 8. 0 o39。 So do I, 39。My key, 39。倒立擺系統(tǒng)是一個(gè)典型的自不穩(wěn)定系統(tǒng)，其中擺作為一個(gè)典型的振動(dòng)和運(yùn)動(dòng)問題，可以抽象為許多問題來研究。s Radi cal Progr essive Part y. Af t er t he elect ions, Crawl ey went t o the f orm er Pr im e Mi nister39。f r e r i des39。 asked the i nspector. 39。 39。 lesson90 f or supper ？ 晚餐吃什么？ Though Br azi l is one of the r ichest count ri es in t he worl d, much of i t has not yet been devel oped. It was mai nl y f or t his r eason that the Br azil an gover nment decided to have a new ci ty bui lt 600 mi les nort h west of Ri o de Janeir o. Desi gned by t he great ar chitect Cost a, t he new cit y, Br asi li a, r eplaced Ri o de Janei ro as t he capi tal of i n 1960. Br asi li a has been careful ly pl anned f or moder n li ving. It s wide r oads, which can t ake f ourt en l anes of tr af ic, have been kept away f rom li ving areas. Chi ldr en do not have to cr oss busy st r eet s to go t o school . Housewives can vi sit shoppi ng on foot, f or in t hese speci al ly designed li ving areas, cars ar e unnecesary. At f ir st , t he gover nment had gr eat dif fi cul ty i n pers uadi ng peopl e to l eave Ri o and t o set tl e in Br asi li a. Si nce 1960, however, t he popul at ion has been gr owing al l the ti me. Bras il ia has quickly establi shed i tself as the capital of the countr y. The i dea t o have the capital moved so far i nl and wil l have a gr e at ef fect on the f ut ure of Br azi l. Leson91 Three men i n a basket 三人同籃 A pil ot not iced a bal loon whi ch seemed t o be making f or a Royal Ai r Force Stat ion nearby. He inf ormed t he stati on at once, but no one there was abl e to explai n the m yst er y. The of fi cer i n t he contr ol tower was ver y angry when he heard the news, because baloons can be a great danger to ai rcraf t. He said t hat someone might by spyi ng on the st at ion and t he pi lot was order ed to keep tr ack of t he st range object. The pil ot m anaged to ci rcl e the bal oon for som e ti me. He coul d make out thr e men in a basket under i t and one of t hem was holding fi el dglasses. When t he bal loon was over t he st ati on, t he pi lot saw one of the m en t aki ng phot ogr aphs. Soon aft er wards, the bal oon began to descend and i t landed near an ai rf iel d. The poli ce were cal ed in, but they coul d not ar rest anyone, f or the basket cont ai ned two Members of Parl iament and the Comm anding Of f icer of t he stati on! As the Comm anding Of icer expl ai ned later , one half of t he st at ion di d not know what t he other hal f was! Leson92 Aski ng for t rouble 自找麻 煩 It m ust have been about t wo i n the m or ning when I r eturned home. I tr ied t o wake up my wif e by r inging t he door bel , but she was fast asleep, so I got a l adder fr om t he shed i n the gar den, put i t agai nst the wal l, and began cli mbi ng towards t he bedr oom wi ndow. I was alm ost t her e when a sar cast ic voice below sai d, 39。s busy wor king, but woul d you mind i ng wi th me to t he Wel l , I 39。 (2)不確定性主要是指建立系統(tǒng)數(shù)學(xué)模型時(shí)的參數(shù)誤差、量測噪聲以及機(jī)械傳動(dòng)過程中的減速齒輪間隙等非線性因素所導(dǎo)致的難以量化的部分。 (6)約束限制由于實(shí)際機(jī)構(gòu)的限制，如運(yùn)動(dòng)模塊行程限制，電機(jī)力矩限制等。目前，直線型倒立擺作為一種實(shí)驗(yàn)儀器以其結(jié)構(gòu)相對簡單、形象直觀、構(gòu)件參數(shù)易于改變和價(jià)格低廉等優(yōu)點(diǎn)，已經(jīng)廣泛運(yùn)用Her e and t here: they had just di scovered t hat a pr isoner had escaped. At t hat mom ent , a large bl ack car wit h f our of fi cer s inside i t, stopped at t he camp gat es. The off icers got out and t he pri soner st ood to at tenti on and salut ed as t hey passed. When t hey had gone, the dri ver of t he car came t owar ds him. The man obviously want ed to t alk. He was r at her el der ly wi t h grey hair and clear blue eyes. The pri soner felt sorr y f or hi m, but t her e was nothi ng el se he coul d do. As the man came near, the pr isoner knocked hi m t o t he gr ound wit h a shar p bl ow. Then, jumpi ng into the car, he drove of f as quickly as he could. ？ Fishermen and sail or s som etim es cl ai m to have sen m onster s in t he sea. Though people have oft en laughed at stor ies tol d by s eamen, it i s now known that many of these 39。擺桿的級數(shù)越多，控制難度越大，而擺桿的長度也可能是變化的。 (5)開環(huán)不穩(wěn)定性倒立擺系統(tǒng)有兩個(gè)平衡狀態(tài)：垂直向下和垂直向上。 I shout ed. 39。 answered t he pol iceman in the same tone. 39。clock t rain di d not run at al . I t broke down at stati on and was taken of f the l ine.39。 39。 said the man. 39。 but I l ove to hear you say i t39。monst ers39。近些年來，國內(nèi)外不少專家、學(xué)者一直將它視為典型的研究對象，提出了很多控制方案，對倒立擺系統(tǒng)的穩(wěn)定性和鎮(zhèn)定問題進(jìn)行了大量研究，都在試圖尋找不同的控制方法實(shí)現(xiàn)對倒立擺的控制，以便檢查或說明該方法的嚴(yán)重非線性和絕對不穩(wěn)定系統(tǒng)的控制能力，其控制方法在軍工、航天、機(jī)械人領(lǐng)域和一般工業(yè)過程中都有著廣泛的用途，如精密儀器的加工、機(jī)器人行走過程中的平衡控制、火箭發(fā)射中的垂直度控制、導(dǎo)彈攔截控制、航空對接控制、衛(wèi)星飛行中的 姿態(tài)控制等方面均涉及到倒置問題。You see, I 39。 I l ooked down and near ly fel of f the ladder when I saw a pol iceman. I imm edi at ely r egr et ed answeri ng in the way I did, but I sai d, 39。 said the i nspect or, 39。 I m ust be at work at o39。s hom e. We shal al l r emember Page f or hi s patience and under st andi ng and f or the ki ndl y encouragement he gave us when we went so unwil li ngl y to school. A gr eat m any f orm er pupil s wi l be atending a farewel l di nner i n his next Thur sday. It i s a cur ious coincidence t hat t he day bef ore hi s reti rement , Page wi l have been t eaching f or a total of for ty years. Af ter he has r eti red, he wil l devote hi msel f to gar deni ng. For him, t his wi l be an enti rely new hobby. But this does not m at ter , for, as he has oft en remarked, one i s never t oo ol d t o learn. Leson86 Out of contr ol 失控 As the m an tr ied t o swi ng t he speed boat r ound, the st er ingwheel came away i n hi s hands. He waved desper ately t o his panion, who had been wat er ski ing f or t he last fi ft en m inutes. Bot h m en had hardl y had ti me t o reali ze what was happeni ng when t