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TF frames order, which should be fixed and which should be the parent and child?

asked 2018-11-20 19:53:19 -0500

karimemara17 gravatar image

updated 2018-11-20 19:55:06 -0500

Mobile robot moving around static known map. Map was built with hector SLAM.

Is that the right order for the frame tree?

Do I need the base_footprint?

Fixed fram Odom Tree --> odom --> base_link --> laser --> map

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answered 2018-11-21 01:26:43 -0500

Delb gravatar image

You should have a look at the different REP related to frames : REP 103, REP 105 and REP 120.

The standard tf tree in your case looks like : map -> odom -> base_link -> laser. Map should be at the top of the tf tree since it's the world frame.

It's not required to have the base_footprint, it's just the base_link frame with z=0, you are free to create it or not.

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And in RVIZ the map should be the fixed frame? So when I estimate the pose and give it the goal it be on the map right?

I will take a look at the different REP and will update the question. Thank you for help!

karimemara17 gravatar imagekarimemara17 ( 2018-11-21 09:51:04 -0500 )edit

The fixed frame is mostly for visualization purpose you could even set it on a wheel (eventhough it's stupid). Do you talk about 2D pose estimate and 2D nav goal in rviz ? If so then it will be according to the fixed frame of rviz, that's why it's better to set map as the fixed frame.

Delb gravatar imageDelb ( 2018-11-21 10:10:18 -0500 )edit

If not then it's up to you to define the reference frame_id when giving a goal (which sould be map).

Delb gravatar imageDelb ( 2018-11-21 10:10:46 -0500 )edit

Yes it I was talking about the 2D pose estimate and 2D nav goal in rviz. I did all that and set the frames in the order you suggested and it still doesn't want to move. It does this when estimating the 2D pose ( https://drive.google.com/file/d/1AKht...

karimemara17 gravatar imagekarimemara17 ( 2018-11-21 10:23:30 -0500 )edit

Also I should mention that I'm running rviz and navigation stake on a pc while the lidar and the base are on Raspberry Pi over network.

I also tried roswtf and I gave me an error something like ERROR The following nodes should be connected but aren't GlobalCostmapFootprint --> localCM footprint

karimemara17 gravatar imagekarimemara17 ( 2018-11-21 10:28:11 -0500 )edit

The behavior in your video is very strange, I would suggest you to create a new question for this describing everything you do that result to this (the move_base config, the launch files and the commands you run for example).

Delb gravatar imageDelb ( 2018-11-22 00:59:53 -0500 )edit

Thank you again, and yes I just posted the question: https://answers.ros.org/question/3091...

karimemara17 gravatar imagekarimemara17 ( 2018-11-22 12:00:55 -0500 )edit

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Asked: 2018-11-20 19:53:19 -0500

Seen: 61 times

Last updated: Nov 21 '18