General Introduction on nuclear fusion (reading is strongly advised!)
Flexure pivots are monolithic devices that can undergo large rotations about one axis, while being very stiff with respect to all other degrees of freedom. Remote Centre of Motion flexure pivots, like the one shown in Figure 3, allow rotations about a virtual axis that is external to the volume occupied by the pivot itself. This is particularly useful in the case of ECRH launchers, because it allows to hide the pivot behind the steering mirror, thus protecting it from the microwave beam, while maintaining the rotation axis of the mirror on its surface, which is necessary for optical reasons. One of the drawbacks of flexure pivots is that they introduce an unwanted elastic resistance in the steering mechanism. Static balancing consists in introducing negative-stiffness elements to counteract and balance elastic resistance, thus producing a quasi-zero-stiffness mechanism. An example of a rectilinear static balancing system is shown in Figure 4. Such system could be used in conjunction with a transmission mechanism to balance the stiffness of the flexure pivots. However, a more elegant solution would introduce static balancing directly in the pivots, thus realizing a monolithic, statically balanced, remote centre of motion flexure pivot. The design of such component is the target of this activity.
Contacts: Daniele Busi
