AMCL false localization adjustments

asked 2014-02-06 03:25:02 -0500

Hansg91
1889 ●51 ●65 ●87

Hey everyone,

I am testing out some navigation software I developed and I am using AMCL for the localization and wheel odometry for its input.

While I am testing I didn't want AMCL to adjust the robots position in the map, so I am publishing empty laserscans. The environment is just a large fabricated square map with no obstacles. From what I can tell, AMCL has no reason to adjust the robots position then, yet still it does. It will frequently jump around a little, from one spot over to the other.

As I mentioned, there are no objects or walls nearby and the laserscans are empty, what could then be causing this jump?

Best regards, Hans

answered 2014-02-06 19:54:08 -0500

fergs

13902 ●59 ●157 ●196 http://www.robotandchisel.com

Even with empty laserscans, AMCL is still receiving odometry data from your robot, and therefore the particle filter will continue to update. The "jumps" are probably just that the particle cloud is spreading out. You can visualize the actual particle poses with RVIZ using the particlecloud topic, which should show exactly what is going on.

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Thank you for your reply, it is indeed the particle filter spreading out and causing these jumps. I limited the particles to 1 and it barely occurs now. What would be the correct way to limit the localization to just use odometry? I didn't want to include lasescans yet.

Hansg91 ( 2014-02-07 07:05:59 -0500 )edit

I think what you probably want to use is http://wiki.ros.org/fake_localization this has the same API as AMCL, it can be given an initial pose via RVIZ/parameters, but it just forwards the odometry.