控制系統(tǒng)的介紹英文翻譯-wenkub.com
2024-11-01 13:35 本頁(yè)面
【正文】 （ 4） 檢查其性能（速度、精度、穩(wěn)定性，及其他 準(zhǔn)則）是否滿足指標(biāo)。這種方法的另一個(gè)誘人之處是它使控制系統(tǒng)工程師可以研究系統(tǒng)內(nèi)部的變量。當(dāng)系統(tǒng)變的越來(lái)越復(fù)雜時(shí)，使用數(shù)字計(jì)算機(jī)就顯得非常必要了。另一個(gè)好處是在線性系統(tǒng)分析中可以應(yīng)用算子法。 別忘了，所有實(shí)際系統(tǒng)中都有非線性，但是許多系統(tǒng)在有限而適 用的范圍內(nèi)都可以近似為一個(gè)線性系統(tǒng)，這是很重要的。 1 度就可以令使用者滿意；但某種低溫系統(tǒng)中的溫度控制則要求把溫度控制在幾分之一度之內(nèi)。我們特別關(guān)心響應(yīng) 的速度即瞬態(tài)響應(yīng)，響應(yīng)的精度即穩(wěn)態(tài)響應(yīng)以及穩(wěn)定性等等。一般來(lái)說(shuō)，當(dāng)我們開(kāi)始設(shè)計(jì)一個(gè)控制系統(tǒng)時(shí)，所做的只是初步構(gòu)思，然后產(chǎn)生一個(gè)用于分析數(shù)學(xué)模型。它們都有輸入，控制，輸出和干擾對(duì)象；它們都可以描述成一個(gè)控制器加上一個(gè)被控對(duì)象；它們都有某種類型的比較器。用這種方法有利于把一個(gè)大系統(tǒng)分解成若干個(gè)子系統(tǒng)，所以我們一次可以只研究一個(gè)子系統(tǒng)。 作為控制系統(tǒng)的一個(gè)實(shí)例，考慮簡(jiǎn)化的空間飛行器的姿態(tài)角控制。 3. 系統(tǒng)描述 由于我們生活中經(jīng)常碰到控制系統(tǒng)，因此對(duì)它們的研究相當(dāng)重要。其中激勵(lì)或輸入為 x（ t），響應(yīng)或輸出為 y（ t）。 今天，雖然生產(chǎn)工藝仍然起著 重要作用，但控制系統(tǒng)已成為一門科學(xué)?，F(xiàn)在我們已經(jīng)可以設(shè)計(jì)飛行用的小型計(jì)算機(jī)，使人類降落在月球上。到了 50 年代中期，數(shù)字計(jì)算機(jī)的發(fā)展為工程 9 師們提供了一個(gè)新的工具，這就大大地加強(qiáng)了他們從事大型和復(fù)雜系統(tǒng)的研究能力。這也得 益于奈魁斯特關(guān)于穩(wěn)定性理論方面的研究工作，這一理論到現(xiàn)在也還是經(jīng)典性上午。盡管歷史上出現(xiàn)過(guò)許多控制系統(tǒng)的實(shí)例，但是直到 18 世紀(jì)中葉才出現(xiàn)一些蒸汽驅(qū)動(dòng)的控制裝置。 4 Introduction to Control System 1. 1 HISTORICAL PERSPECTIVE The desire to control the forces of nature has been with man since early civilizations. Although many examples of control systems existed in early times, it was not until the mideighteenth century that several steam engine, and perhaps the most noteworthy invention was the speed control flyball governor invented by James Watt. The period biginnign about twentyfive years before World War Two saw rapid advances in electronics and especially in circuit theory, aided by the now classical work of Nyquist in the area of stability theory, The requirements of sophisticated weapon systems, submarines, aircraft and the like gave new impetus to the work in control systems before and after the war The advent of the analog puter coupled with advances in electronics saw the beginning of the establishment of control systems as a science. By The midfifties, the progress in digital puters had given the engineers a new tool that greatly enhanced their capability to study large and plex systems. The availability of puters also opened the era of datalogging, puter control, and the state space of modern method of analysis. The sputnik began the space race and large governmental expenditures in the space as well as military effort. During this time. circuits became miniaturized and large sophisticated systems could be put together very pactly thereby allowing a putational and control advantage coupled with systems of small physical dimensions. We were now capable of designing and flying miniputers and landing men on the moon. The post sputnik age saw much effort in system optimization and adaptive systems. Finally, the refinement of the chip and related puter development has created an explosion
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