[Proposal] add proper handling of gear ratio function for Actuator DCMotor

[guntgbtgv]

Proposal

In the DCMotor documentation, gear_ratio is supposed to be implemented. However, it seems that it is not implemented properly, and just assumed to be always 1:1 ratio.

Motivation

This is problematic for sim-to-real transfer, since it clips the torque AFTER the gear ratio, where in reality they should be clipped BEFORE the gear ratio.

Alternatives

Current implementation seems to 1) assume 1:1 gear ratio and 2) not applying the concept of gear ratio at all. The proper implementation should address gear_ratio properly, as described in the documentation for DCMotor

Build Info

Describe the versions where you are observing the missing feature in:

• Isaac Lab Version: 2.3.2
• Isaac Sim Version: 5.1

Checklist

• I have checked that there is no similar issue in the repo (required)

Acceptance Criteria

Add the criteria for which this task is considered done. If not known at issue creation time, you can add this once the issue is assigned.

• Criteria 1
• Criteria 2

[RandomOakForest]

Thank you for posting this proposal. Interesting catch. The team will review it.

[AntoineRichard]

@kellyguo11 let's make sure we enable this is 3.0. I think it should be the case with the new actuators, but I would have to check.