Preliminaries
Cuspidal robots: theory and applications

Two main categories of robots are studied in this article. The first is serial robots, in which the end device (a tool or gripper) is connected to a fixed base via a single articulated kinematic chain (figure 1 , left). The second category, parallel robots [S 7 768], move a platform carrying the end unit via several articulated kinematic chains mounted in parallel (figure 1 , right). Most of the article (sections