Physics Rigid Bodies wrong linear and angular velocities measurements


I’m having a problem with the readings of linear and angular velocities of rigid bodies on Isaac Sim. For example, if we create an scene and add the anymal_base.usd provided as a sample asset, the linear and angular velocities will be very noisy getting to high values. This brings a lot of problems if we add an IMUsensor to its base, as it will read as the robot is moving when it is not (thus also in all the applications using imu measurements).
This error comes up using many of the sample models that come with isaac.

  • If I change the “kind” property of the collision meshes to “subcomponent” (there may be other possibilities) this error goes away (I don’t have an explanation for this behavior).
  • Using the model anymal_c.usd this error doesn’t appear until we delete the cylinder mesh of the legs (I can’t neither explain this).
  • It may be also coming from waking-up articulations to control them.

I’m having this error on my own robot, and I’m trying to determine the reason so I can fix it in my model.

PD: This may be causing also problems in the torque measurements of the joints.