The first main important assumption is that we will only consider what is called as the bending vibration of the link. That means the link is allowed to bend but it is not allowed to stretch. Longitudinal deformation is negligible.
The second major assumption that we make is that we will assume that the deformations are small. We can use the linear elasticity theory. And a consequence of this is that planar cross-sections remain plane and undistorted.
Based on these assumptions we can model two typical links in a robot, a flexible robot.
