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tf/tutorials demo problem ros-electric

asked 2011-11-19 06:29:22 -0500

asrinivasan31 gravatar image

Hi All:

I can't get the turtle_tf demo to work based on the following link: tf/Tutorials

This is the error I get when I do roslaunch turtle_tf turtle_tf_demo.launch:

Use arrow keys to move the turtle.
process[turtle2_tf_broadcaster-5]: started with pid [9096]
process[turtle_pointer-6]: started with pid [9101]
Traceback (most recent call last):
File "/opt/ros/electric/stacks/geometry_tutorials/turtle_tf/node/turtle_tf_listener.py", line 57, in <module>
(trans,rot) = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time())
tf.ExtrapolationException: Lookup would require extrapolation at time 1321729575.578088045, but only time 1321729575.578494072 is in the buffer, when looking up transform from frame [/turtle1] to frame [/turtle2]
[turtle_pointer-6] process has died [pid 9101, exit code 1].
log files: /home/adith/.ros/log/8cffc6c6-12e1-11e1-81b9-0026829e5a54/turtle_pointer-6*.log

Another post mentions this same problem but they were using diamondback. How do I resolve this on electric?

Thanks in advance.

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3 Answers

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answered 2012-03-02 08:15:02 -0500

Anand B gravatar image

Add tf.ExtrapolationException to the list of exceptions to be discarded when making the call to tf.lookupTransform. New code will look like this,

    try:
        (trans,rot) = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time())
    except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
        continue
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Hi, I found we still need this Patch for hydro

Kawamura Masaya gravatar imageKawamura Masaya ( 2014-12-02 21:15:50 -0500 )edit
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Kawamura Masaya gravatar imageKawamura Masaya ( 2014-12-02 21:19:05 -0500 )edit
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answered 2012-02-10 04:19:31 -0500

this post is marked as community wiki

This post is a wiki. Anyone with karma >75 is welcome to improve it.

this is actually a warning when you request a frame with timestamp which is in future with respect to the latest frame available.

The warning text is probably changed in electric. The corresponding warning in diamondback is given in the following tutorial.

http://www.ros.org/wiki/tf/Tutorials/tf%20and%20Time%20%28C%2B%2B%29

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answered 2011-11-19 09:33:52 -0500

asrinivasan31 gravatar image

Update: I was able to do the rest of the tutorial and duplicate what the demo was trying to achieve, so I guess it doesn't matter any more.

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Hi, I have the same error message. Could you let me know how you resolved the problem? I am using Ubuntu 11.04, Electric ROS.

maruchi gravatar imagemaruchi ( 2012-03-29 06:20:39 -0500 )edit

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Asked: 2011-11-19 06:29:22 -0500

Seen: 902 times

Last updated: Mar 02 '12