Patent ID: 6871548

Claim:
An apparatus for imposing or measuring a position or a force with at least four degrees of freedom, comprising a fixed base, a movable platform, articulated links connecting the movable platform in parallel to the base, and measuring means, said articulated links comprising at least four articulated kinematic units, each of which is mounted on the base and connected to a point of connection of the platform to move in conjunction with a movement of said point in a direction of translation corresponding to one of principal axes (X, Y, Z) of a spatial reference system, at least one pair of said kinematic units being connected to two of said points of connection spaced from one another and being arranged to move in conjunction with translations thereof in a same direction and thus in conjunction with a rotation of the platform when the amplitudes of the translations at said two points of connection are unequal, wherein each of the articulated kinematic units comprises a parallelogram which is elastically deformable in its own plane, an articulated transmission device connecting the parallelogram to the platform, and a linear displacement sensor providing an output signal to the measuring means, the parallelogram comprising a support element connected to the base, a translation element connected to the transmission device and two parallel arms connected to the translation element and to the support element by joints without play.