Why Does the Effort Output Become Zero in Isaac Sim Even Though I’m Continuously Sending an Effort Command?

Omniverse Isaac Sim
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1

I’m using Isaac Sim to apply force to an object with a robot. Specifically, I’m using Effort control by sending an Effort command via a ROS topic, and I’m receiving the Effort output through the ROS Joint State. However, the Effort input to the robot arm and the Effort output do not match. Even when the robot is gripping an object and I continue to send an Effort command, the output Effort becomes zero. Why does this happen?

I’ve attached a graph showing, from top to bottom:

  1. The Effort command (input)
  2. The Position (Joint State output)
  3. The Velocity (Joint State output)
  4. The Effort (Joint State output)

image
image755×694 50.1 KB

Position and Velocity appear correct, but I can’t figure out why the Effort output is zero even though I’m continuously sending an Effort command. The Drive type is set to “force,” and both Damping and Stiffness are set to zero.

Isaac Sim Version

4.5.0

Operating System

Ubuntu 22.04

GPU Information

  • Model: RTX4080
1 Like
3

Hi there, thank you for your question. Would you be able to provide any scripts to replicate this behavior? It would help me look into this issue faster. If there are multiple files you can upload them into a zip.