基于二階參考模型隨動系統串聯校正畢業設計論文-資料下載頁

　　

【正文】 (or information) may be transmitted and relayed。 it must be familiar with the conditions under which selfexcitations and oscillations may occur, and it must devise mechanisms which will anticipate the probable course and sequence of events. Such a science will use and develop current theories of fundamental physicochemical processes. It is dependent upon the elaborate logicomathematical analyses of statistical aggregates, and upon an integration of specialized researches which until recently have seemed only remotely related. Our present theory of selfregulative systems has sprung from the soil of contemporary theoretical science. Its future is contingent upon the continued advance of basic research226。€”in mathematics, physics, chemistry, physiology and the sciences of human behavior.Automatic controls have been introduced into modern industry only in part because of the desire to offset rising labor costs. They are in fact not primarily an economy measure but a necessity, dictated by the nature of modern services and manufactured products and by the large demand for goods of uniformly high quality. Many articles in current use must be processed under conditions of speed, temperature, pressure and chemical exchange which make human control impossible, or at least impracticable, on an extensive scale. Moreover, modern machines and instruments themselves must often satisfy unprecedentedly high standards of quality, and beyond certain limits the discrimination and control of qualitative differences elude human capacity. The automatic control of both the manufacturing process and the quality of the product manufactured is therefore frequently indispensable. Once the pleasures of creating and contemplating the quasiorganic unity of selfregulative systems have been learned, it is only a short step to the extension of such controls to areas where they are not mandatory. Economic considerations undoubtedly play a role in this extension, but Messrs. Brown and Campbell are probably at least partly correct in their large claim that the modern development in automatic engineering is the consequence of a point of view which finds satisfaction in unified schemes for their own sake.HOW LIKELY is the total automatization of industry, and what are the broad implications for human welfare of present tendencies in that direction? Crystalgazing is a natural and valuable pastime, even if the visions beheld are only infrequently accurate. Some things, at any rate, are seen more clearly and certainly than others. If it is safe to project recent trends into the future, and if fundamental research in relevant areas continues to prosper, there is every reason to believe that the selfregulation of industrial production, and even of industrial management, will steadily increase. On the other hand, in some areas automatization will never be plete226。€”either because of the relatively high cost of conversion, or because we shall never be able to dispense with human ingenuity in coping with unforeseeable changes, or finally because of certain inherent limitations in the capacity of any machine which operates according to a closed system of rules. The dream of a productive system that entirely runs itself appears to be unrealizable.Some consequences of largescale automatic control in current technology are already evident, and are noted by several contributors to this series of articles. Industrial productivity has increased out of proportion to the increase in capital outlay. Many products are now of finer quality than they have ever been before. Working hours have been generally reduced, and much brutalizing drudgery has been eliminated. In addition, there are signs of a new type of professional man226。€”the automatic control system engineer. There has been considerable conversion and retraining of unskilled labor. A slow refashioning of educational facilities, in content as well as in organization, in engineering schools as well as in the research divisions of universities and industries, is in progress. In the main these developments contribute to human welfare.However, mentators on automatic control also see it as a potential source of social evil, and express fears226。€”not altogether illegitimate226。€”concerning its ultimate effect. There is first the fear that continued expansion in this direction will be acpanied by largescale technological unemployment, and in consequence by acute economic distress and social upheaval. As Mr. Leontief points out in his article, the possibility of disastrous technological unemployment cannot be ruled out on purely theoretical grounds。 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 excelle