urdf_parser_py

Development Setup

You must manually run setup.py. For catkin development, you can install to $ws/../build/lib/pythonX.Y/dist-packages via

devel_prefix=$(cd $(catkin_find --first-only)/.. && pwd)
cd ../urdf_parser_py
python setup.py install --install-layout deb --prefix $devel_prefix

Authors

• Thomas Moulard - urdfpy implementation, integration
• David Lu - urdf_python implementation, integration
• Kelsey Hawkins - urdf_parser_python implementation, integration
• Antonio El Khoury - bugfixes
• Eric Cousineau - reflection update

Reflection

This an attempt to generalize the structure of the URDF via reflection to make it easier to extend. This concept is taken from Gazebo’s SDF structure, and was done with SDF in mind to a) make an SDF parser and b) make a simple converter between URDF and SDF.

Changes

• Features:
  • Transmission and basic Gazebo nodes.
  • General aggregate types, preserving order
  • Dumping to YAML, used for printing to string (dictionaries do not preserve attribute ordering)
• XML Parsing: minidom has been swapped out with lxml.etree, but it should not be hard to change that back. Maybe Sax could be used for event-driven parsing.
• API:
  • Loading methods rely primarily on instance methods rather than static methods, mirroring Gazebo’s SDF construct-then-load method
  • Renamed static parse_xml() to from_xml(), and renamed load_* methods to from_* if they are static

Todo

1. Support additional formats (SDF, drakeURDF, etc.)
   • Parse Gazebo’s SDF definition files at some point? For speed’s sake, parse it and have it generate code to use?
   • Consider auto-generating modules from schemas such as urdf.xsd. This can extend to SDF, drakeURDF.
2. Make a direct, two-way URDF <-> SDF converter.
   • Gazebo has the ability to load URDFs and save SDFs, but it lumps everything together
3. Consider a cleaner implementation for reflection.
   • Make the names a little clearer, especially the fact that from_xml and to_xml write to a node, but do not create a new one.
   • Abstraction layer is not clear. Should explicitly use abstract classes, and try to really clarify the dispatch order (xmlr.Element, xmlr.Param, xmlr.Object, etc.)
4. Figure out good policy for handling default methods. If saving to XML, write out default values, or leave them out for brevity (and to leave it open for change)? Might be best to add that as an option.
5. Find a lightweight package that can handle the reflection aspect more elegantly. Enthought traits? IPython’s spinoff of traits?

Changelog for package urdfdom_py

1.2.1 (2023-05-01)

• Switch to unittest.mock (#78)
• Add BSD LICENSE file (#77)
• Update Maintainers (#76)
• Contributors: Audrow Nash, Scott K Logan, Silvio Traversaro

1.2.0 (2022-03-30)

• Fix the binary install location. (#74)
• Get Iterable from collections.abc. (#73)
• Contributors: Chris Lalancette

1.1.0 (2021-03-15)

• Use a Python entry point for 'display_urdf' (#64)
• Move the 'display_urdf' script into the Python module (#64)
• Make 'file' argument to display_urdf required (#64)
• Make sure to add the version when creating a new URDF. (#62)
• Remove the from_parameter_server method from urdf.py for ROS 2. (#63)
• Silence pytest warnings when running locally. (#61)
• Contributors: Chris Lalancette, Scott K Logan

1.0.0 (2020-03-10)

• Add in support for the version tag. (#52) (#54)
• ROS 2 Port (reopened) (#53)
• Contributors: Chris Lalancette, Henning Kayser

0.4.1 (2019-10-22)

• Python 3 fixes (#38 #43 #48)
• Remove old example test (#37)
• Contributors: Chris Lalancette, Eric Cousineau, Markus Grimm, Timon Engelke

0.4.0 (2018-02-21)

• Add Link.visual and Link.collision properties (#28)
• Add tests for mutli-visual and multi-collision
• links and collisions load properly as aggregates
• Add XPath information when a parse error is encountered
• Remove travis support. (#22)
• Reformat python code to pep8 standard (#21)
• Update core.py to allow passing addHeader arg to to_xml_string function (#19)
• fixed defaults for xyz/rpy, fixed set_default for Param, added unit tests (#16)
• Make unit test run with [catkin_make run_tests]{.title-ref} (#15)
• Contributors: Chris Lalancette, Chris Paxton, Eric Cousineau, Shane Loretz, Will Baker, eugene-katsevman

0.3.3 (2017-02-10)

• Made Chris and Shane the maintainers
• Added python-lxml to the travis build.
• Reverted line break (ros/urdfdom#77) now that there is a more generic solution. (#5)
• Added line break to make errors easier to read. (#4)
• Contributors: Chris Lalancette, Isaac I.Y. Saito

0.3.1 (2016-02-22)

• Add travis
• Add package.xml for ROS release
• Tweak CMakeLists to reflect migration from urdfdom
• Contributors: Jackie Kay

0.3.0 (2016-02-16)

• [urdf_parser_py] Add missing newline
• color and texture in link material are optional
• fixed transmission parser to match specification

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