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Problem with Gmapping

asked 2012-08-28 23:53:08 -0600

camilla gravatar image

updated 2012-08-28 23:57:29 -0600

I'm trying to use gmapping to create a map of my lab.
I'm using a NXT withLejos firmware, I checked that all the topic /tf, /odom and /scan are working well, but I get this error:

[ WARN] [1346231329.853649941]: MessageFilter [target=/odom ]: Dropped 100.00% of messages so far. Please turn the [ros.gmapping.message_notifier] rosconsole logger to DEBUG for more information.

The command I used to launch gmapping is:

rosrun gmapping slam_gmapping scan:=scan (/scan is the topic on which are published the message of type sensor_msgs::LaserScan)

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Do this: Please turn the [ros.gmapping.message_notifier] rosconsole logger to DEBUG for more information.

dornhege gravatar image dornhege  ( 2012-08-29 00:57:32 -0600 )edit

The problem was that I called my frame /world and not /odom, now that i adopted the ROS Naming Convenction the warning message doesn't appear anymore

camilla gravatar image camilla  ( 2012-08-29 04:38:24 -0600 )edit

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answered 2012-08-29 00:54:43 -0600

Lorenz gravatar image

If you are sure that the odom and the scan topic are published correctly and gmapping connects to them (verify with rosnode info gmapping), this probably happens because of bad time stamps.

gmapping requires to have correct time stamps in the odometry message and the laser scan as well as in the tf transforms between the robot's base frame and your laser. If you are using several machines, make sure that their clocks are synchronized.

For more information on what exactly is the problem, start up rxconsole and enable debug for ros.gmapping.message_notifier as the warning message states.

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Maybe one remark: AFAIK gmapping does not use odometry from the odom topic, but uses the /odom frame from tf.

dornhege gravatar image dornhege  ( 2012-08-29 01:15:22 -0600 )edit

True. It only uses tf.

Lorenz gravatar image Lorenz  ( 2012-08-29 01:17:00 -0600 )edit

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Asked: 2012-08-28 23:53:08 -0600

Seen: 3,121 times

Last updated: Aug 29 '12