2. Different types of compensators

A distinction is made between 2 families, depending on whether or not the compensator takes up the background effect.

Any movement in space is entirely defined by 3 translations and 3 rotations along the 3 axes of an orthonormal system. For each of the types listed below, we give the degree of freedom allowed by the compensator along the 3 main axes of its own system. The degree of freedom gives the component (translation and rotation), along each axis, of the relative displacement acceptable between the ends of the compensator. In this reference system and among the 6 degrees of freedom, there is torsion along the longitudinal axis.

A compensator has no torsional degrees of freedom. A compensator without external structures therefore has 5 degrees of freedom. It can, however, accept a torsional moment due to its operation with the deformation...