Universal Robots Forum

Moment of Inertia matrix

Hi.

I found the information of Moment of Inertia.

[Moment of Inertia for Newton-Euler Dynamic]
(Moment of Inertia for Newton-Euler Dynamic - #2 by Ebbe):

But there are wrong data which i think in urcontrol.conf.UR3 and urcontrol.conf.UR5 file.

In urcontrol.conf.UR5

inertia_matrix = [ [0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0.000144] ]

In urcontrol.conf.UR16

inertia_matrix = [ [0.03351, 0.00002, -0.00001, 0.00002, 0.03374, 0.00374, -0.00001, 0.00374, 0.02100],
[0.02796, -0.00010, -0.00720, -0.00010, 0.47558, 0.00003, -0.00720, -0.00001, 0.47635],
[0.01091, 0.00006, 0.01012, 0.00006, 0.12060, 0.00001, 0.01012, 0.00001, 0.11714],
[0.00609, -0.00001, -0.00000, -0.00001, 0.00245, 0.00083, 0.00000, 0.00083, 0.00579],
[0.00389, -0.00001, 0.00000, -0.00001, 0.00219, -0.00045, 0.00000, -0.00045, 0.00363],
[0.00117, 0.00000, 0.00000, 0.00000, 0.00118, 0.00000, 0.00000, 0.00000, 0.00084] ]

The inertia data of UR5 and UR16 are very different.
Is that correct data ?

And i find Moment of Inertia of e-series cobot.

thank you

Hi

It is correct that the models would be more accurate if the inertias of UR3e and UR10e were estimated, and not just zeros.

The effective difference is however not very big, so the benefit of adding it would be minimal. And if we changed it, the new values would alter how the robot moved a bit, meaning that suddenly the cycle times of applications would change a tiny bit, which could be problematic for some applications.