plateforme Stewart

CONT: La plateforme de Stewart [...] est un type de robot parallèle constitué de six actionneurs. Elle a six degrés de liberté : les trois coordonnées de translation ainsi que les angles de tangage, roulement et lacet (Angles d'Euler). Les six jambes sont actionnées pour changer de longueur et [faire] varier l'orientation de la plateforme [...]
OBS: Les plateformes de Stewart ont des applications dans la technologie des machine-outils et des grue, la recherche sous-marine, la simulation de vol, les antennes paraboliques, les télescopes et la chirurgie orthopédique.

CONT: The Stewart platform consists of two plates connected by six mobile and extensible legs. The lower or base plate is immobile. The upper or mobile plate has six degrees of freedom, three rotational and three translational. The platform is highly stable and easy to control. The platform's six legs each have two parts, an upper and a lower leg, with a piston-like cylindrical DoF between each pair of parts. The legs are connected to the base plate and the top plate by universal joints at each end of each leg. (These universals are not just sets of abstract DoFs. Each also contains a spider-like body, while also having two DoFs.) The upper part of each leg can slide into and out of the lower leg, allowing each leg to be varied in length. The position and orientation of the mobile platform (top plate) varies depending on the lengths to which the six legs are separately adjusted. Once the top is connected to the legs, the entire Stewart platform assembly has 36 DoFs. Only six DoFs are independent, the same as the top plate would have if it were disconnected. You can think of these independent DoFs as the six adjustable leg lengths or as equivalent to the six DoFs of the mobile plate.
OBS: Geodetic Technology trademarked ""hexapod"" for a Stewart platform in a machine tool context. However, apparently this has not stopped other machine tool manufacturers from using the term. A Free CNC software package, the Enhanced Machine Controller (EMC) [1] is capable of driving a stewart platform using standard G-codes such as used for milling machines, etc.