Hi Manos and thank you for your notes.
However, I checked and as far as I can tell, the culprit is unlikely to be either of your suggestions.
My robot is moving really slow and there are no collisions, as it is merely a vertical robot arm moving its end effector around.
And the behavior in Gazebo vs. NRP seemed quite the same, though I did have some problems with the SDF file going a little crazy when launched in Gazebo standalone.. Now that I mention this for myself I guess it could be related
However, I would still like to know if there is a way to increase precision, also sub-sample precision, when simulating in NRP.
At least based on the Gazebo forum conversation, there may be situations where their solver does not manage to converge within the default iterations, which could cause similar jumpy motion.