Now state can handle systems with root joints as S03 or Euclidean groups
A proper solution needs to be developed in Pinocchio. For more details see the following issue: https://github.com/stack-of-tasks/pinocchio/issues/949
I have provided this temporary-fix, since it's limiting us to apply the StateMultibody
in fixed-base system with less than 6 DoF.
This issue was reported by @jmarti during the integration of double pendulum system.