【正文】 設(shè)計(jì)，更不同于課堂教學(xué)。否則系統(tǒng)無(wú)法正常工作，甚至可能導(dǎo)致設(shè)備毀壞，造成重大損失。即使是高階系統(tǒng)，在簡(jiǎn)化系統(tǒng)分析的情況下有許多也可以近似成二階系統(tǒng)來(lái)進(jìn)行分析。系統(tǒng)的校正性問(wèn)題，是一種原理性的局部設(shè)計(jì)。這種系統(tǒng)的響應(yīng)形狀只取決于輸入信號(hào)的形狀和系統(tǒng)的特性，與輸入信號(hào)施加的時(shí)刻無(wú)關(guān)。 在此次設(shè)計(jì)中，主要研究二階定常線(xiàn)性系統(tǒng)。第五節(jié) 系統(tǒng)基本指標(biāo)：在輸入為 r（t）＝ a＋ bt，（其中：a＝ 5 b＝ 1/ sec.）≤，要求動(dòng)態(tài)期望指標(biāo)： ； 第二章 系統(tǒng)建模第1節(jié) 各環(huán)節(jié)模型建立由于比較器產(chǎn)生偏差，從而構(gòu)成控制，他可以構(gòu)成一個(gè)環(huán)節(jié)或者起到連接作用。即：系統(tǒng)在右半s閉環(huán)極點(diǎn)個(gè)數(shù) Z = P – R = 0由于G(s)H(s)曲線(xiàn)的對(duì)稱(chēng)性，因此可以用系統(tǒng)的開(kāi)環(huán)頻率特性曲線(xiàn)G(jw)H(jw)對(duì)(1,j0)的包圍情況來(lái)判斷。系統(tǒng)的閉環(huán)特征方程為 作勞斯表： 根據(jù)勞斯判據(jù)系統(tǒng)穩(wěn)定性的要求是第一列的數(shù)據(jù)全部大于零，所以K0.由系統(tǒng)參數(shù)得知， 由于 （）；且所以，K第2節(jié) 穩(wěn)定（靜態(tài)）精度分析 單位階躍信號(hào)輸入時(shí)，由于0型系統(tǒng)的靜態(tài)位置誤差系數(shù)等于開(kāi)環(huán)增益的大小，所以0型系統(tǒng)在階躍信號(hào)輸入作用時(shí)的穩(wěn)態(tài)誤差也為常數(shù)。den=[ 1 75]?？紤] 到不敏感區(qū)或者允許誤差，有時(shí)取為從穩(wěn)態(tài)值的10%上升至90%時(shí)所需要的時(shí)間。（5）震蕩次數(shù)N（6）穩(wěn)態(tài)誤差穩(wěn)態(tài)誤差是當(dāng)時(shí)間t趨于無(wú)窮是，系統(tǒng)希望的輸出與實(shí)際的輸出之差，表示為。在頻域分析法中，以控制系統(tǒng)的頻率特性作為數(shù)學(xué)模型，以波德圖或者其他圖表作為分析工具，來(lái)研究，分析控制系統(tǒng)的動(dòng)態(tài)性能與穩(wěn)態(tài)性能。頻率特性G（jw)是輸入信號(hào)頻率w的復(fù)變函數(shù)，系統(tǒng)的頻率特性表示為極坐標(biāo)圖是當(dāng)頻率從連續(xù)變化時(shí)，G(jw)端點(diǎn)的極坐標(biāo)軌跡。G=75/(s*(*s+1)) Transfer function: 75 s^2 + s bode(G) 圖335 原系統(tǒng)的波德圖原系統(tǒng)波德圖分析：由圖知，該系統(tǒng)的相頻特性曲線(xiàn)一直都在線(xiàn)之上，所以穩(wěn)定裕度0,且幅頻特性曲線(xiàn)曲線(xiàn)，系統(tǒng)很顯然是穩(wěn)定的。系統(tǒng)對(duì)于給定的信號(hào)能夠跟蹤還是不能跟蹤，有差跟蹤還是無(wú)差跟蹤等，是有系統(tǒng)的無(wú)差度來(lái)決定的。在頻率法校正中，校正所依據(jù)的是給定的頻域性能指標(biāo)。滯后網(wǎng)絡(luò)將使系統(tǒng)帶寬降低，交界頻率左移，從而使系統(tǒng)的瞬態(tài)響應(yīng)變慢；滯后校正引入一個(gè)滯后的相位，故有降低系統(tǒng)穩(wěn)定性的趨向。)。本系統(tǒng)將采用物理仿真及其軟件MATLAB的使用對(duì)原系統(tǒng)進(jìn)行仿真。由于MATLAB提供了強(qiáng)大的矩陣處理和繪圖功能，很多專(zhuān)家因此在自己擅長(zhǎng)的領(lǐng)域用它編寫(xiě)了許多專(zhuān)門(mén)的MATLAB工具箱（Control Systems Toolbox),魯棒控制工具箱（Robust Control Toolbox),最優(yōu)化工具箱（Optimization Toolbox）等。一般情況下，矩陣類(lèi)計(jì)算可以達(dá)到10～15數(shù)量級(jí)的精度，符合一般科學(xué)與工程運(yùn)算的要求。MATLAB最重要的特征是它擁有解決特定應(yīng)用問(wèn)題的程序組，即TOOLBOX（工具箱），如信號(hào)處理工具箱，控制系統(tǒng)工具箱，神經(jīng)網(wǎng)絡(luò)工具箱，模糊邏輯工具箱，通信工具箱和數(shù)據(jù)采集工具箱等許多專(zhuān)業(yè)的工具箱。 原系統(tǒng)的Simulink系統(tǒng)模型；圖51 圖52 原系統(tǒng)在5+t作用下的響應(yīng)校正后系統(tǒng)的Simulink系統(tǒng)模型；圖53 圖54 校正后系統(tǒng)在5+t作用下的曲線(xiàn)校正前系統(tǒng)在輸入信號(hào)5+t作用下的響應(yīng)曲線(xiàn)：t=0::10。)。 plot(t,y,t,u,39。并且每當(dāng)我的論文遇到大的轉(zhuǎn)折點(diǎn)都會(huì)有他的指導(dǎo)，幫我拿捏好大的方向。€”must be credited to the 20th century. When human intelligence is disciplined by the analytical methods of modern science, and fortified by modern material resources and techniques, it can transform almost beyond recognition the most familiar aspects of the physical and social scene. There is surely a profound difference between a primitive recognition that some mechanisms are selfregulative while others are not, and the invention of an analytic theory which not only accounts for the gross facts but guides the construction of new types of systems. We now possess at least a first approximation to an adequate theory of automatic control, and we are at a point of history when the practical application of that theory begins to be conspicuous and widely felt. The future of automatic control, and the significance for human weal or woe of its extension to fresh areas of modern life, are still obscure. But if the future is not to take us pletely by surprise, we need to survey, as this issue of Scientific American does, the principal content of automatic control theory, the problems that still face it and the role that automatic control is likely to play in our society.THE CENTRAL ideas of the theory of selfregulative systems are simple and are explained with exemplary clarity in Mr. Tustin’s essay which follows. Every operating system, from a pump to a primate, exhibits a characteristic pattern of behavior, and requires a supply of energy and a favorable environment for its continued operation. A system will cease to function when variations in its intake of energy or changes in its external and internal environment bee too large. What distinguishes an automatically controlled system is that it possesses working ponents which maintain at least some of its typical processes despite such excessive variations. As need arises, these ponents employ a small part of the energy supplied to the system to augment or diminish the total volume of that energy, or in other ways to pensate for environmental changes. Even these elementary notions provide fruitful clues for understanding not only inanimate automatically controlled systems, but also organic bodies and their interrelations. There is no longer any sector of nature in which the occurrence of selfregulating systems can be regarded as a theme for oracular mysterymongering. However, some systems permit a greater degree of automatic control than others. A system’s susceptibility to control depends on the plexity of its behavior pattern and on the range of variations under which it can maintain that pattern. Moreover, responses of automatic controls to changes affecting the operation of a system are in practice rarely instantaneous, and never absolutely accurate. An adequate science of automatic control must therefore develop prehensive ways of discriminating and measuring variations in quality。 special circumstances will determine whether or not it occurs. But, as he also notes, the brief history of automatic control in the U. S. suggests that serious unemployment is not its inevitable conitant, at least in this country. The U. S. appears to be capable of adjusting itself to a major industrial reorganization without uprooting its basic patterns of living. Largescale technological unemployment may be a more acute danger in other countries, but the problem is not insurmountable, and measures to circumvent or to mitigate it can be taken.There is next the fear that an automatic technology will impoverish the quality of human life, robbing it of opportunities for individual creation, for pride of workmanship and for sensitive qualitative discrimination. This fear is often associated with a condemnation of “materialism” and with a demand for a return to the “spiritual” values of earlier civilizations. All the available evidence shows, however, that great cultural achievements are attained only by societies in which at least part of the population possesses considerable worldly substance. There is a good empirical basis for the belief that automatic control, by increasing the material wellbeing of a greater fraction of mankind, will release fresh energies for the cultivation and flowering of human exce