Force units for angular and linear drive

Omniverse Isaac Sim
1

Hello,

I am trying to figure out the units of force applied in an angular and linear drive for a joint.

I have made a 1m lever arm with a 100g weight at the end to simulate a 1Nm force, I am looking for the minimum force capable of lifting the system.
I did this in 2 of my files and I get different values for each of them

All my files have the same following parameters:
-units in cm (0.01 meter per unit in the root layer)
-magnitude = 981

  • the damping and stiffness of my joint are the same.

In my first file which was an empty file, it takes an angular force of 160 to lift the lever arm.
In the second file, which is my project file, I need an angular force of 10000

For the linear drive i got 1N = 16 (force set to 16 to lift 100g) in both files

What could be the cause and what parameters does the force depend on?
Thanks

2

How are you applying the force? Through an offset in drive target?

Note that you should disable any damping/friction to get accurate forces for such a measurement. In particular, joint friction for articulations, and rigid-body linear and angular damping.

Then the forces should be torque or force in the units system that you setup, e.g. 0.01 meter per unit and should match.

Are you accounting for the weight of the link that holds the 100g weight?