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Gazebo real and simulation time

asked 2012-06-05 02:30:32 -0500

Erwan R. gravatar image

Hello,

As running gazebo, I noticed the lower toolbar with RMS Error, xReal Time, Real time, etc. I'm wondering how exactly are computed all this times and why, when I'm roslaunching lots of nodes, xReal Time is decreasing (as the simulator is slower and the computer also) ?

If I missed some doc about that, please link.

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answered 2012-06-05 04:08:14 -0500

DimitriProsser gravatar image

In your .world file, you can specify the desired update rate for Gazebo using the <updateRate> tag.

<physics:ode>
   ...
   <stepTime>STEP_TIME</stepTime>
   <updateRate>UPDATE_RATE</updateRate>
   ...
</physics:ode>

The value of <updateRate> has three configurations:

  1. UPDATE_RATE < 0: Gazebo will attempt to run the simulation in real time

  2. UPDATE_RATE = 0: Gazebo will attempt to run the simulation as fast as possible

  3. UPDATE_RATE > 0: This number will represent the desired physics update frequency. In this case, Gazebo will run STEP_TIME*UPDATE_RATE times reality.

If Gazebo is not able to update at your desired rate, it will update as fast as it can. It's based on the system's computing power, so more nodes = less CPU time for Gazebo.

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Thanks for answering. Is there a default value if the tag isn't defined (if real time is 1.0, I think the default value is negative) ?

Erwan R. gravatar imageErwan R. ( 2012-06-05 04:52:58 -0500 )edit

I don't know what the default value is. Gazebo always runs at sub-real-time for me (about 0.75 real-time).

DimitriProsser gravatar imageDimitriProsser ( 2012-06-05 06:12:14 -0500 )edit

Okey, I'm gonna experience some values to check that. Thanks for help ! :)

Erwan R. gravatar imageErwan R. ( 2012-06-05 21:39:45 -0500 )edit

Has this been tested to work in Fuerte? I am setting the parameter as you suggest but with no luck (the simulation in my case is running too fast, I would like real time)

phil0stine gravatar imagephil0stine ( 2012-06-25 10:46:15 -0500 )edit

This is for the Electric version of Gazebo. Fuerte migrated to Gazebo 1.0. I don't know how to do this in that version

DimitriProsser gravatar imageDimitriProsser ( 2012-06-25 11:06:01 -0500 )edit

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Asked: 2012-06-05 02:30:32 -0500

Seen: 5,038 times

Last updated: Jun 05 '12