Basic Synchros and Servomechanisms - Part II
Cód:
491_9781443773089
PREFACE IS the purpose of these two Manuals on BASIC SYNCHROS AND SERVOMECHANISMS to describe and illustrate, in the simplest possible way, the fundamental characteristics of two groups of devices which are not only used in many types of military equipment, but which are also essential components in what will assuredly be one of the most revolutionary industrial techniques of the second half of the 20th century. Automatic process control-automation, to use its more popular name-is an outgrowth of the technical advances made in military equipment during the Second World War. It is far more than the mere regrouping of existing machines, which is what many people believe it to be. It is a radically new concept. The idea of mechanization implies a set of mechanical devices carrying out a series of motions-pre-determined, accurate, and continuous as long as power is supplied-but lacking any ability to modify their own behaviour if conditions begin to vary. Automation, on the other hand, implies a built-in brain-systemn-however rudimentary-in a robot-like plant capable not only of performing mechanical operations, but also of adapting the initial instructions it has been given in the light of changes which it observes to be occurring in the conditions of its own operation. The control devices of an automated system have four main functions to fulfil. They must detect changes in conditions as they occur they must report these changes to the brain they must decide what corrections are needed to carry out, in the changed conditions, the basic instructions they have been given and they must command that the necessary action be taken by the muscles, or operating elements of the system. All these decisions and actions must be taken and performed within a minutely short space of time-much faster than any human intelligence could possibly achieve. It is with the electrical and electronic devices which detect and report changes in operating conditions as they occur, and which deci
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