[ros-users] Issues with rviz

Josh Faust jfaust at willowgarage.com
Fri May 21 18:59:11 UTC 2010


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> 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> 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>>
> >>> 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> 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>>> 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>>
> >>>    >>>> 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>
> >>> (650) 475-2827
> >>>
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> >
> >
> >
>
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