urdf_parser_py Exception with new transmission specification

[v4hn]

urdf_parser_py fails when processing a URDF containing a element
which adheres to the current specification given in
http://wiki.ros.org/urdf/XML/Transmission .
Because the old specification expected a "type" attribute,
which the new spec includes as a sub-element, the python parser throws "type"-is-missing Exceptions.
Also, the actuator definition became more complex and now includes the mechanicalReduction parameter.

As a temporary fix it's enough to comment the following in urdf.py over here:

xmlr.reflect(Transmission, tag = 'transmission', params = [
        name_attribute,
#       xmlr.Attribute('type', str),
#       xmlr.Element('joint', 'element_name'),
#       xmlr.Element('actuator', 'element_name'),
#       xmlr.Element('mechanicalReduction', float)
        ])

This works over here, because we never access the transmission definitions via urdfdom, but obviously it's just a hot fix, nothing more..

Because it's not possible to quickly overlay this ros-code in a uniform local workspace
(you just recently removed catkin support...),
it's pretty important to me to see this fixed in the official ros (ubuntu) packages soon

• one way or the other.

[eacousineau]

Good find! I'll add a check when it's parsing the transmission object specifically. I will spend an hour on it tomorrow.
Can you post the URDF you're parsing so I have it to work off of?

And for a manual overlay, maybe you can run CMake such that it installs to your local site packages, something like:

cd urdfdom
mkdir build
cd build
cmake .. -DCMAKE_INSTALL_PREFIX=~/.local
# Install all of urdfdom to local usr setup
make install

It looks like it might install it to dist-packages, though, so I can't speak to it working like that.

[v4hn]

Thanks in advance!

We work with calvin[0].
I uploaded the fully generated urdf to [1].

---

[0] - http://wiki.ros.org/calvin_robot
[1] - http://files.v4hn.de/calvin_description.urdf

[eacousineau]

Started work on it.
You can piggy back off of the devel or install-space for overlaying the install of the package, even though it does not use catkin:

cd urdfdom
mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$(dirname $(catkin_find --first-only))
make install

(This assumes that catkin_find --first-only will return a directory in your devel-space)

Tested it out with the following command:

python -c 'import urdf_parser_py; print urdf_parser_py.__file__'

Should print out to the directory you specified.

[eacousineau]

I've implemented the code, but it is not yet ready. I need to be test and debug it tomorrow: https://github.com/eacousineau/urdfdom/compare/feature;issue-22?expand=1
For the URDF you've posted, it looks like a straight dump from rosparam. Could you regenerate with the following comand?

python -c 'import rospy; open("/tmp/calvin.urdf", "w").write(rospy.get_param("robot_description"))'

Thanks!

[eacousineau]

I apologize, I was unable to work on it today. I will address it either tomorrow or Tuesday.

[v4hn]

I'm sorry for not answering in time.

At the moment I'm experiencing technical difficulties
much more severe than a failing python module (failing workstation).

I hope to get back to you soon!

[v4hn]

I just uploaded the properly formatted patch to [0].
Thanks for your time.

---

[0] - http://v4hn.de/files/calvin_description.urdf

[eacousineau]

Thank you! I finished up the tests and submitted the pull requests.

You can see the diff patch when it parses calvin and then spits it back out to a string: gen.patch

[isucan]

merged #23