控制系統(tǒng)的介紹英文翻譯-免費閱讀
【正文】 （ 2） 產(chǎn)生一個方塊圖，獲取該系統(tǒng)的一種數(shù)學描述。 控制系統(tǒng)通常用高階線性微分方程來描述，用算子法來研究這些方程。例如，提高精度常常使瞬態(tài)響應(yīng)變差。后面第 7 章里，我們將闡述怎樣分析一個初步設(shè)計，然后修改，從而使其性能滿足系統(tǒng)的指標。在化工過程，運載器的導引和控制，國民經(jīng)濟，城市住增長模式，郵政服務(wù)以及很多其他的社會和城市問題中都有多變量系統(tǒng)的例子。各種各樣的子系統(tǒng)可能是電氣的，機械的，氣動的，生物的等等，因此為了完整地描述整個系統(tǒng)，需要了解很多不同學科中的基本關(guān)系。已經(jīng)作為一門學科建立起來的現(xiàn)代控制論，不僅用于傳統(tǒng)的控制系統(tǒng)，而且也用來解決許多新的問題，如城市發(fā)展分析，計量經(jīng)濟學，交通，生物醫(yī)學，能源分析及其他許多類似的，對現(xiàn)代人類有影響的問題。 蘇聯(lián)發(fā)射的人造地球衛(wèi)星開始了空間技術(shù)上的競爭以及政府在空間技術(shù)和軍事項目上的大量投 資。 20 世紀初，關(guān)于控制系統(tǒng)的大部分研究工作都和發(fā)電，化工等行業(yè)有關(guān)，而且關(guān)于飛機自動駕駛儀的設(shè)想也是在這一時期初形成的 。 however , many can be approximated within a useful though limited range as linear systems. Generally, this is an acceptable first approximation. A very important benefit to be derived by assuming linearity is that the superposition theorem applies. If we obtain the response due to two different inputs, then the response due to the bined input is equal to the sum of the individual response due to the bined input is equal to the individual responses. Another benefit is that operational mathematics can be used in the analysis of linear systems. The operational method allows us to transform ordinary differential equations which are much simpler to handle. Traditionally, control system were represented by higherorder linear differential equations and the techniques of operational mathematics were employed to study these equations. Such an approach is referred to as the classical method and is particularly useful for analyzing systems characterized by a single input and a single output. As systems began to bee more plex , it became increasingly necessary to use a digital Computer . The work on a puter can be advantageously carried out if the system under consideration is represented by a set of firstorder differential equations and the analysis is carried out via matrix theory. 8 This is in essence what is referred to as the state space or state variable approach . This method , although applicable to single inputoutput systems , finds important applications in the multivariable system . Another very attractive benefit is that it enables the control system engineer to study variables inside a system. Regardless of the approach used in the design and analysis of a control system , we must at least following steps: (1) Postulate a control system and the system specifications to be satisfied. (2) Generate a functional block diagram and obtain a mathematical representation of the system . (3) Analyze the system using any of the analytical or graphical methods applicable to the problem. (4) Check the performance (speed , accuracy, stab
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