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AMCL Time-based updating

asked 2019-03-08 15:31:08 -0600


I am using an Rover Robotics OpenRover to run AMCL on a robot and I see that AMCL updates once it has moved a certain distance. When the robot is not moving it doesn't update. I want to configure it to update while not moving. Is it possible to set a time based update interval instead of distance, that way the robot tries to improve is position while not moving?

Higher-level question, why don't I see people doing this in any tutorial. It seems like an obvious thing to do.

Regards, Nick Fragale

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answered 2019-03-13 20:38:07 -0600

billy gravatar image

AMCL has a service for updating on command.

request_nomotion_update (std_srvs/Empty)

Service to manually perform update and publish updated particles.

So setup a timer and request the service periodically.

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That's not what services are meant for and a pretty heavy operation to build and tear down the XMLRPC at any rate > 1hz

stevemacenski gravatar image stevemacenski  ( 2019-03-14 12:30:37 -0600 )edit

Easy way to call the service every second:

watch -n 1 rosservice call /request_nomotion_update
chadi gravatar image chadi  ( 2021-05-07 04:12:41 -0600 )edit

answered 2019-03-08 20:18:08 -0600

Not out of the box, but if you read the AMCL code, I think you'll find it pretty simple to change those criteria.

Why _not_ do it? Imagine your robot is just hanging out for a few hours, scan matcher and the lasers aren't perfect, you'll end up drifiting in place while staying still I imagine. Also, if you're running a robot at let's say conservatively 0.5m/s, you're probably going to trigger your AMCL config once a second typically (more or less, I'm just looking at defaults). Do you really want to run this more than once a second?

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Asked: 2019-03-08 15:31:08 -0600

Seen: 436 times

Last updated: Mar 13 '19