tf/tutorials demo problem ros-electric

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

asrinivasan31
51 ●3 ●4 ●6

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

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

Anand B
46 ●3 ●2

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