電大控制工程基礎(chǔ)試卷A答案

1、專業(yè)好文檔課程名稱： 控制工程基礎(chǔ) 學(xué)分： 2 試卷編號(hào)： a卷 考試方式： 閉卷 滿分分值： 100 考試時(shí)間： 120 分鐘一、 填空題(每空1分，共20分)1. 傳遞函數(shù)的定義是對(duì)于線性定常系統(tǒng),在初始條件為零的條件下，系統(tǒng)輸出量的拉氏變換與輸入量的拉氏變換之比。2. 瞬態(tài)響應(yīng)是系統(tǒng)受到外加作用激勵(lì)后，從初始狀態(tài)到最終或穩(wěn)定狀態(tài)的響應(yīng)過程。3. 判別系統(tǒng)穩(wěn)定性的出發(fā)點(diǎn)是系統(tǒng)特征方程的根必須為負(fù)實(shí)根或負(fù)實(shí)部的復(fù)數(shù)根，即系統(tǒng)的特征根必須全部在復(fù)平面的左半平面是系統(tǒng)穩(wěn)定的充要條件。4. i型系統(tǒng)在單位階躍輸入下，穩(wěn)態(tài)誤差為 0 ，在單位加速度輸入下，穩(wěn)態(tài)誤差為 。5. 頻率響應(yīng)是系統(tǒng)對(duì)正弦輸入

2、穩(wěn)態(tài)響應(yīng)，頻率特性包括幅頻和相頻兩種特性。6. 如果系統(tǒng)受擾動(dòng)后偏離了原工作狀態(tài)，擾動(dòng)消失后，系統(tǒng)能自動(dòng)恢復(fù)到原來的工作狀態(tài)，這樣的系統(tǒng)是(漸進(jìn))穩(wěn)定的系統(tǒng)。7. 傳遞函數(shù)的組成與輸入、輸出信號(hào)無關(guān)，僅僅決定于系統(tǒng)本身的結(jié)構(gòu)和參數(shù)，并且只適于零初始條件下的線性定常系統(tǒng)。8. 系統(tǒng)的穩(wěn)態(tài)誤差與輸入信號(hào)的形式及系統(tǒng)的結(jié)構(gòu)和參數(shù)或系統(tǒng)的開環(huán)傳遞函數(shù)有關(guān)。9. 如果在系統(tǒng)中只有離散信號(hào)而沒有連續(xù)信號(hào)，則稱此系統(tǒng)為離散(數(shù)字)控制系統(tǒng)，其輸入、輸出關(guān)系常用差分方程來描述。10. 反饋控制系統(tǒng)開環(huán)對(duì)數(shù)幅頻特性三頻段的劃分是以c（截止頻率）附近的區(qū)段為中頻段，該段著重反映系統(tǒng)階躍響應(yīng)的穩(wěn)定性和快速性；而低頻

3、段主要表明系統(tǒng)的穩(wěn)態(tài)性能。11. 對(duì)于一個(gè)自動(dòng)控制系統(tǒng)的性能要求可以概括為三個(gè)方面：穩(wěn)定性、快速 性和精確或準(zhǔn)確性。二設(shè)有一個(gè)系統(tǒng)如圖1所示，k1=1000n/m, k2=2000n/m, d=10n/(m/s)，當(dāng)系統(tǒng)受到輸入信號(hào) 的作用時(shí)，試求系統(tǒng)的穩(wěn)態(tài)輸出。(15分)解： 然后通過頻率特性求出 三一個(gè)未知傳遞函數(shù)的被控系統(tǒng)，構(gòu)成單位反饋閉環(huán)。經(jīng)過測(cè)試，得知閉環(huán)系統(tǒng)的單位階躍響應(yīng)如圖2所示。(10分)問：(1) 系統(tǒng)的開環(huán)低頻增益k是多少？(5分)(2) 如果用主導(dǎo)極點(diǎn)的概念用低階系統(tǒng)近似該系統(tǒng)，試寫出其近似閉環(huán)傳遞函數(shù)；(5分)解：（1），(2) 四已知開環(huán)最小相位系統(tǒng)的對(duì)數(shù)幅頻特性如圖

4、3所示。(10分)1. 寫出開環(huán)傳遞函數(shù)g(s)的表達(dá)式；(5分)2. 概略繪制系統(tǒng)的nyquist圖。(5分)1 2五已知系統(tǒng)結(jié)構(gòu)如圖4所示, 試求：(15分)1. 繪制系統(tǒng)的信號(hào)流圖。(5分)2. 求傳遞函數(shù)及。(10分)六系統(tǒng)如圖5所示，為單位階躍函數(shù)，試求：(10分)1. 系統(tǒng)的阻尼比和無阻尼自然頻率。(5分)2. 動(dòng)態(tài)性能指標(biāo)：超調(diào)量mp和調(diào)節(jié)時(shí)間。(5分)1 2 七如圖6所示系統(tǒng)，試確定使系統(tǒng)穩(wěn)定且在單位斜坡輸入下時(shí)，k的數(shù)值。(10分) 由勞斯判據(jù)： 第一列系數(shù)大于零，則系統(tǒng)穩(wěn)定得 又有：2.25 可得：k4 4k54八已知單位反饋系統(tǒng)的閉環(huán)傳遞函數(shù)，試求系統(tǒng)的相位裕量。(10分

5、)解：系統(tǒng)的開環(huán)傳遞函數(shù)為，解得if we dont do that it will go on and go on. we have to stop it; we need the courage to do it.his comments came hours after fifa vice-president jeffrey webb - also in london for the fas celebrations - said he wanted to meet ivory coast international toure to discuss his complaint.cska

6、 general director roman babaev says the matter has been exaggerated by the ivorian and the british media.blatter, 77, said: it has been decided by the fifa congress that it is a nonsense for racism to be dealt with with fines. you can always find money from somebody to pay them.it is a nonsense to h

7、ave matches played without spectators because it is against the spirit of football and against the visiting team. it is all nonsense.we can do something better to fight racism and discrimination.this is one of the villains we have today in our game. but it is only with harsh sanctions that racism an

8、d discrimination can be washed out of football.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to

9、 be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.mich

10、el platini, president of european footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian side added: we found no racist insults from fans of cska.baumgartner the di

11、sappointing news: mission aborted.the supersonic descent could happen as early as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with c

12、apsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometer

13、s) and into the stratosphere. as he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i would assume, he will slowly step out onto something resembling an olympic diving platform.below, the e

14、arth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. it will be like he is diving into the shallow end.skydiver preps for the big jumpwhen he jum

15、ps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to earth. but this will not be enough to stop him completely.if he goes too fast or spins out of control

16、, he has a stabilization parachute that can be deployed to slow him down. his team hopes its not needed. instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).in order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). he will have a reserve parachute that will open automatically if