When one approaches the control of electric motors, which it is currently referred to as variable speed, in the industrial field of the robotics or the public transport, the engineer is immediately confronted with many problems of different types: economic, technological, of robustness and of automatic control, accuracy, dynamics, equipment integrity, reliability, maintainability, availability, people safety and electromagnetic compatibility.
Solutions of the problems posed by these various practical requirements with objectives so essentially different, require various a fundamental knowledge of electronics, electro-mechanics, data processing, mathematics, control theory and mechanics.
An engineer is well prepared to use these various theoretical tools. Nevertheless, it is obvious that all main technical choices made upstream, fundamentally condition the downstream developed solutions. The aim of the development of technical applications is to make compatible various elements of the solution to be detailed downstream, with the constraining targets of the upstream development already specified.
All designers have, at one time or another, faced a difficult technical problem, even impossible to solve completely without modifying some choices made at an earlier stage of the project which did not seem to have, a priori, a constraining effect on the realization.
Another important cause of time-delay and of cost, is still the late discovery of consequences depending, in an indirect ...