机电技术专业英语徐起贺张庆良pataalessonTwenty-three课件教学.pptVIP

* 机电技术专业英语 Lesson Twenty-three Text Processes of mechanization have been developing and becoming more complex ever since the beginning of the Industrial Revolution at the end of the 18th century. The current developments of automatic processes are, however, different from the old ones. The “automation” of the 20th century is distinct from the mechanization of the 18th and 19th centuries in as much as mechanization was applied to individual operations, whereas “automation” is concerned with the operation and control of a complete producing unit1. And in many, though not all, instances the element of control is so great that whereas mechanization displaces muscle, “automation” displaces brain as well2. Mechanization and Automation Lesson Twenty-three The distinction between the mechanization of the past and what is happening now is, however, not a sharp one. At one extreme we have the electronic computer with its quite remarkable capacity for discrimination and control, while at the other end of the scale are “transfer machines”, as they are now called, which may be as simple as a convey or belt to another. An automatic mechanism is one which has a capacity for selfregulate; that is, it can regulate or control the system or process without the need for constant human attention or adjustment3. Now people often talk about “feedback” as being an essential factor of the new industrial techniques, upon which is based an automatic selfregulating system and by virtue of which any deviation in the system from desired conditions can be detected, measured, reported and corrected. When “feedback” is applied to the process by which a large digital computer runs at the immense speed through a long series of sums, constantly rejecting the answers until it finds one to fit a complex set of facts that Lesson Twenty-three have been put to it, it is perhaps different in degree from what we have previously been accustomed to machines. But “feedback”, as such, is a familiar m