I recently used the Reflected Load Inertia plot for the first time on some 2D Delta robot arm models to determine the reflected inertia to the servo motors. I was surprised to see the Results show positive & negative values. How are negative inertia values possible?
i don't know much about that parameter but:
1. does everything move the way you expect it to
2. how many redundancies do you ahve in the model
3. have you setup a case with a known solution to check that the software is working?