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LaserScan is shifting and dancing as the robot moves

asked 2021-06-25 10:55:24 -0500

jmyazbeck gravatar image

updated 2021-06-25 10:57:00 -0500

My laser scan is shifting / dancing as the robot moves. I don't know what might be causing this... It stabilizes sometimes but most of the time the behavior is similar to this .

What should I look at to fix it?

I dont hve amcl running with my navigation stack, could that be it? I didnt judge that I would need it since the localization is happening in a different framework and I don't seem to have any problem with that.

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  1. Please explain what "localization is happening in a different framework" means.
  2. What code module are you using to calculate a robot pose from the scan data?
  3. What frames are in your transform tree from map->base_scan?
Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-06-26 14:29:17 -0500 )edit
  1. Basically what I am trying to accomplish is use ROS's navigation stack for my Isaac SDK application. So what happens is that I am sending raw scan data from Isaac, odom data from Isaac, the start pose and the goal pose from there and I am letting ROS plan out and move the robot around. ROS sends cmd_vel commands to my Isaac app which converts it accordingly to move the robot. In isaac, there is a particle filter localizer that takes the raw scan, adds some noise to it and works like any particle filter localizer would (I assume). And I can say it works fine since with Isaac applications no problems were seen at this level.

  2. On ROS side, nothing... as I said, everything is being sent from Isaac for the navigation stack to do its job. I thought amcl would help the nav stack on ros side ...

jmyazbeck gravatar image jmyazbeck  ( 2021-06-26 16:02:03 -0500 )edit

Are you merging the 2 scans before going into a single particle filter, or do you run a particle filter for each scan frame? Have you verified that only 1 source is generating the robot pose?

Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-06-27 07:53:16 -0500 )edit

Both scans are being merged inside the particle filter component. The component by itself works fine in all apps I worked with

On a side note, would you be able to give me some input on this issue as well? I would appreciate it a lot!

jmyazbeck gravatar image jmyazbeck  ( 2021-06-27 09:00:25 -0500 )edit

So does the output from the particle filter jump around, as @janindu speculated?

Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-06-27 10:47:03 -0500 )edit

Did you figure out what the problem is? If so, please post an answer to help others in the future.

Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-07-01 07:02:18 -0500 )edit

I did not yet! I am planning on trying soon... For now I am stuck with this problem if you don't mind taking a look at it. I will definitely post an answer as soon as I manage to get my hands on that

jmyazbeck gravatar image jmyazbeck  ( 2021-07-01 07:16:26 -0500 )edit

It seemed that it was a computational power problem. I am not sure of it, but I ran my simulation on a more powerful computer and this problem occurred less often. I unfortunately didn't manage to try implementing amcl to see if it would fix the problem.

jmyazbeck gravatar image jmyazbeck  ( 2021-07-16 12:20:03 -0500 )edit

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answered 2021-06-26 00:28:49 -0500

janindu gravatar image

It looks like the localizer that you are using is providing jumpy pose estimates. That causes your laser scan projections to be jumpy as well.

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Okay, I will try using amcl to localize the robot and see if this fixes it

jmyazbeck gravatar image jmyazbeck  ( 2021-06-26 06:40:04 -0500 )edit

Let me know how it goes.

janindu gravatar image janindu  ( 2021-06-26 07:13:29 -0500 )edit

Making a broken system more complex is not a good debug strategy. My advice is to not add amcl.

Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-06-26 14:31:55 -0500 )edit

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Asked: 2021-06-25 10:55:24 -0500

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Last updated: Jun 26