General classification of robots. Size criteria

Many papers discuss about robots (programming, control, arms, etc.). Because the “robot” subject became frequently used, it is useful to look inside, to components, where are they used, how, what is their size and so on. The first idea is to make a classification of robots. However, a generally classification is too difficult to be done. This paper proposes an overview about generally classification of robots and particularly analyzes the size criteria. Are the nanorobots, robots? Or no?