Render Rate and Logic Rate

Omniverse Isaac Sim
1

Hi,

I create a robot and an action graph to publish joint_states and subscriber joint_command to the robot. But The rate of topic is as same as render rate ~30`50 Hz when I run simulation.

How do I setup these topic publish with 100Hz or 200Hz but render still be 30-40 Hz?

2

I recommend checking out the official Isaac Sim documentation on ROS2 Setting Publish Rates — Isaac Sim Documentation. This tutorial explains how to decouple the simulation (logic) rate from the render rate and configure your ROS2 publishers to operate at your desired frequency.

3

Hi VickNV,

I read the documents. But my case is:

  • ROS2 topic will publish and subscribe with external topic with 500Hz.
    So I want the speed is stable. And render in Isaac sim can be 30Hz~40Hz for visualization.

  • When I set physics_rate = 500, it works but if my robot moved, the rate is down a lot, it’s about 30 Hz.
    How to improve it because it is not ideal to tune robot

5

Could you verify whether the desired ROS topic rate can be achieved in headless mode (without a GUI or rendering)?

6

@VickNV

I checked, the problem is rendering. If the app does not render, the publish rate is stable. But if the app render, the ROS2 topic will stop and wait until finishing the render.

I read the document and the solution is asynchronous udpate type.

But Asynchronous does not work well with ROS2 now. So I have another post to discuss the problem.

1 Like
8

May I know which document you were referring to?

9

@VickNV

Yes, of course.

I read here: Physics Simulation Fundamentals — Isaac Sim Documentation

10

For adjusting the rendering rate, I recommend reviewing the Subscribers and Events at Custom FPS example.

For the “Asynchronous” update type, could you share which documentation you learned about setting it via the UI?

11

I read here: Physics Simulation Fundamentals — Isaac Sim Documentation

It said about physics time step and render time step

12

I hope the example helps—feel free to let me know if you need more information.

1 Like
13

Hello!

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