Wim, the timestamps of the laser scans are concurrent to the ones I'm getting with "rostopic echo /tf". I was under the impression that tf would give me an error of some kind in this scenario ? Also, if the issue lies with my tf-tree, shouldn't there be similar problems in my node that transforms the laser scans into the /map frame using the tf::TransformListener ? Regards, Jan Wim Meeussen wrote: > Jan, > > Your tf tree looks fine, but it is possible that the timestamps of > your laser scans are wrong. Your tf buffer keeps a 10-seconds window > of transformations. When the timestamp of your laser scan does not fit > in that 10 seconds window, tf won't be able to transform it. From the > data you sent, it looks like your tf buffer is nicely synchronized > with the current time in your system, so I would suspect that your > laser scans have timestamps that are either more than 10 seconds in > the past, or some number of seconds in the future. > > You can check the timestamp of your laser scans using "rostopic echo > laser_scan/header/stamp". > > Wim > > > > >> I've attached the results of view_frames. I have also tried the other stuff >> on the troubleshooting guide. Transformations between the laser frame and >> every other frame work fine. Across the longest tf-chain (/front_laser to >> /map) the average delay is approx 25ms and the maximal delay is approx. >> 55ms. From this it appears to me that the tf-tree is correctly set up, but >> maybe there is something else I can check? >> >> Regards, >> >> Jan Elseberg >> Eitan Marder-Eppstein wrote: >> >>> Jan, >>> >>> It sounds like something may be wrong with your transform tree. Can you >>> try running "rosrun tf view_frames"? This will generate a PDF of the current >>> transform tree structure. You may also want to check the troubleshooting >>> link on the sidebar of this page: http://www .ros.org/wiki/tf >>> for more information on useful tf debugging >>> strategies. >>> >>> Hope this helps, >>> >>> Eitan >>> >>> >>>> On May 20, 2010 3:38 AM, "Jan Elseberg" >>> > wrote: >>>> >>>> Hi everyone, >>>> >>>> I am trying to get our robot to work with the navigation stack of ros. >>>> I've been following the tutorial on >>>> http://www.ros.org/wiki/navigation/Tutorials/RobotSetup . After setting >>>> up the robot with a tf-tree and sensor nodes , I have noticed a problem >>>> with rviz. I am unable to display the laserscan messages in any frame >>>> other than the laser coordinate system itself, i.e., whenever I select a >>>> other than /front_laser the status of the laser scan >>>> display shows the error: >>>> >>>> "Unknown reason for transform failure". >>>> >>>> Also, this warning appears in the bash: >>>> >>>> [WARN] 1274341043.701801000: MessageFilter [target=/base_link ]: Dropped >>>> 99.03% of messages so far. Please turn the [ros.rviz.message_notifier] >>>> rosconsole logger to DEBUG for more information. >>>> >>>> Doing so gives me these repeating debug messages: >>>> >>>> MessageFilter [target=/base_link ]: Added message in frame /front_laser >>>> at time 1274341252.994, count now 10 >>>> MessageFilter [target=/base_link ]: Removed oldest message because >>>> buffer is full, count now 10 (frame_id=/front_laser, >>>> stamp=1274341252.813649). >>>> >>>> This suggests a problem with the tf-tree to me. However, when using the >>>> "transformPoint(...)" function of tf::TransformListener in my own nodes >>>> to transform the laser scan into the global frame everything works as >>>> intended with no errors/warnings. >>>> >>>> Does someone have an idea what I am doing wrong? >>>> >>>> Thank you for any help! >>>> >>>> >>>> Jan Elseberg >>>> >>>> _______________________________________________ >>>> ros-users mailing list >>>> ros-users@code.ros.org >>>> https://code.ros.org/mailman/listinfo/ros-users >>>> >> _______________________________________________ >> ros-users mailing list >> ros-users@code.ros.org >> https://code.ros.org/mailman/listinfo/ros-users >> >> >> > > > >