[ros-users] Issues with rviz
Jan Elseberg
j.elseberg at jacobs-university.de
Tue May 25 08:45:20 UTC 2010
Hi,
I uploaded a short bag.file of the robot. You can get it under
http://plum.eecs.jacobs-university.de/exchange/volksbot.bag . There's also
http://plum.eecs.jacobs-university.de/exchange/only_laser.bag where only
the laser topic (/volksbotRT/LMS) and /tf is recorded. If you need
anything else, please let me know.
Jan.
Josh Faust wrote:
> Can you post a bag file with /tf and the laser scan topic somewhere?
>
> Josh
>
> On Fri, May 21, 2010 at 5:21 AM, Jan Elseberg
> <j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>> wrote:
>
> Wim,
>
> I have played around with the timestamps of the laser scan message.
> Neither increasing nor decreasing
> the timestamp changes the behaviour, except that for large enough
> offsets either of the following errors
> is produced:
>
> For frame [/front_laser]: No transform to fixed frame
> [/base_link]. TF
> error: [You requested a transform that
> is 2.637 miliseconds in the past, but the most recent transform in the
> tf buffer is 8.092 miliseconds old.]
>
> For frame [/front_laser]: No transform to fixed frame
> [/base_link]. TF
> error: [You requested a transform that
> is 3.212 seconds in the past, but the tf buffer only has a history of
> 3.138 seconds.]
>
> I have also changed the publishing frequency of the laser scan
> messages
> to 5 Hz. Unfortunately, this also had
> no effect on the error.
>
> Jan
>
>
> Wim Meeussen wrote:
> > Jan,
> >
> > When rviz receives laser scan messages, it only keeps the 10 most
> > recent messages in a buffer. So, if you send laserscans at 50 Hz (it
> > looks like that's the rate you use), that means rviz only stores 0.2
> > seconds worth of laser scans. So when your laser scans are more than
> > 0.2 seconds ahead of your tf transforms, rviz would be unable to
> > transform any laser scans. To find out if this is the problem
> you hare
> > seeing, you should modify the timestamps of your laser scan
> messages,
> > by deducting something like 1 second from each timestamp before
> > sending out the message from the laser scanner driver. Or you could
> > create a node that takes in laser scanner messages, modifies the
> > timestamp, and send out the modified laser scans.
> >
> > Wim
> >
> >
> > On Thu, May 20, 2010 at 9:33 AM, Jan Elseberg
> > <j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>> wrote:
> >
> >> Hi,
> >>
> >> the issue occurs when using rviz on a seperate computer
> (synchronized to the
> >> robot with ntp) as well as when used only on the robot. The
> tf-tree of rviz
> >> is attached, it is the same as before.
> >>
> >> Jan
> >>
> >> Tully Foote wrote:
> >>
> >>> Jan, Are you running rviz on a seperate machine? If so make
> sure that the
> >>> clocks are synced using ntp or similar between the multiple
> machines.
> >>> To see the tf tree that rviz is using try running "view_frames
> >>> --node=rviz_******" where ******* is the UUID of the anonymous
> rviz process
> >>> which you can get from rosnode list.
> >>> Tully
> >>>
> >>> On Thu, May 20, 2010 at 9:19 AM, Jan Elseberg
> >>> <j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>
> <mailto:j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>>>
> >>> wrote:
> >>>
> >>> 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 <http://ros.org/wiki/tf>
> >>> <http://ros.org/wiki/tf>
> >>> >>> <http://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"
> >>> <j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>
> >>> <mailto:j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>>
> >>> >>>> <mailto:j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>
> >>> <mailto:j.elseberg at jacobs-university.de
> <mailto:j.elseberg at jacobs-university.de>>>> 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
> >>> >>>> <Fixed_Frame> 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 at code.ros.org <mailto:ros-users at code.ros.org>
> <mailto:ros-users at code.ros.org <mailto:ros-users at code.ros.org>>
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> <mailto:ros-users at code.ros.org> <mailto:ros-users at code.ros.org
> <mailto:ros-users at code.ros.org>>>
> >>> >>>> https://code.ros.org/mailman/listinfo/ros-users
> >>> >>>>
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> >>> >
> >>> >
> >>> >
> >>>
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> >>>
> >>>
> >>>
> >>> --
> >>> Tully Foote
> >>> Systems Engineer
> >>> Willow Garage, Inc.
> >>> tfoote at willowgarage.com <mailto:tfoote at willowgarage.com>
> <mailto:tfoote at willowgarage.com <mailto:tfoote at willowgarage.com>>
> >>> (650) 475-2827
> >>>
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