Torque measurement in Simscape?

Hi,

I've constructed a very basic model in Simscape in order to simulate two-mass model. I have one inertia that I'm driving with constant 90 Nm torque. This inertia is connected to a fixed transmission. Otherside of the transmission I have a inertia that represents the load.

The problem is that the torque applied in the motor side is not 90 Nm (according to the torque measurement). Does my torque sensor show wrong or do I apply the "ideal torque" wrong in my model? It looks like that the transmission works because I can see a doubled torque in the load side compared to the motor side. Thus it seems that my torque is not correctly applied to the system from the ideal torque source.

Any help is needed!

Answer 1

[Sebastian Castro]

If you think of the torque as a "current" that flows in a mechanical "circuit", notice that the torque has two possible paths to take:

1. Some of the torque goes into accelerating the motor inertia on the left
2. The rest of the torque goes into accelerating the load inertia on the right

I'm guessing the gear ratio is fairly large in that most of the torque goes towards accelerating the mass and a smaller amount makes it past the gear.

Also, in your particular system, there will always be torque going towards accelerating the inertias because there is no damping and therefore no steady-state speed. The system will continue accelerating forever.

- Sebastian

Answer 2

[fenix.d.0831]

maybe it is because of a large Inertia?