leggedrobotics/urdf2robcogen

A tool that translates a robot URDF description into the kindsl format that can be processed by RobCoGen.

URDF2ROBCOGEN {#mainpage}

Authors: Jan Carius ([email protected]) and Ruben Grandia ([email protected]), based on an earlier version by Diego Pardo ([email protected])

Maintainers: Jan Carius ([email protected]) and Ruben Grandia ([email protected])

What is this repository for?

This tool generates the RobCoGen description files (.kindsl & .dtdsl) from a URDF description format.

Building

Dependencies

• Eigen
• Boost
• ros::urdf
• kindr (a kinematics library for robotics)

Build the executable

We use catkin as a build system. To build the bare version use

catkin build urdf2robcogen

Build the documentation

We use rosdoc_lite with doxygen backend to build documentation for this catkin package.

rosdoc_lite /path/to/package

Usage

Two modes of operation are possible.

A) Run as standalone application (plain URDF file)

You must have a URDF description of your robot as a plaintext xml file. This should not contain xacro macros, i.e., you must invoke the xacro command beforehand to produce the URDF file.

To generate the robcogen description, execute

./urdf2robcogen_script RobotName /path/to/description.urdf

The generated files are written into the directory where the executable was executed (i.e., the output of pwd).

B) Using a launch file (xacro urdf file)

The urdf2robcogen.launch file converts a robot description on the parameter server.

roslaunch urdf2robcogen urdf2robcogen.launch robot_name:=myRobot description_name:=robot_description

See xacro_example.launch to see how to integrate this with generation of the robot description.

As a default, output files are placed in the /generated folder of this package.

Main differences between URDF and RobCoGen/Kindsl

• URDF:

  • Frame rotations are extrinsic (rotations about a fixed frame)
  • The axis of rotation of the joints is set with the vector property 'axis' of the joint element
  • There is no concept of Frame
  • Artificial links are used to define frames (a.k.a., link_frames), they may or may not have inertia
  • Artificial Joints (usually fixed) are used to connect link_frames to the real links
  • It is common to find URDF with 'virtual' links for compatibility with other tools
  • Virtual links might have incomplete information (i.e., inertial parameters)
  • The inertial parameters are expressed w.r.t a frame at the CoM of the link

• RobCoGen:

  • Frame rotations are intrinsic (rotations about the current frame)
  • Frame rotation order is x,y,z
  • The axis of rotation of the joint is always Z
  • Links always carry inertia and must have a parent joint that is moving (i.e., not fixed)
  • Additional frames can be defined at any link
  • Inertial parameters are expressed w.r.t. the link frame (i.e., the corresponding joint frame)
  • It includes a special feature to set a different frame for expressing the inertial parameters (ref_frame)

Caveats

• Double-check the ordering of the joints/links in the generated files. They may differ from what you expect.

urdf2robcogen's Issues

I can't get kindsl from example

hi Thanks your good job,but when I try to test,I get the error,could you help me?

roslaunch urdf2robcogen urdf2robcogen.launch robot_name:=test_robot description_name:=/home/robot203/boshirobot/urdf_gen/src/urdf2robcogen/examples/floating_base.urdf
... logging to /home/robot203/.ros/log/b1ba9dfe-b635-11eb-a2f9-b42e9984ee6d/roslaunch-robot203-3985.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://robot203:41143/

SUMMARY
========

PARAMETERS
 * /rosdistro: melodic
 * /rosversion: 1.14.10
 * /urdf2robcogen/description_name: /home/robot203/bo...
 * /urdf2robcogen/output_folder: /home/robot203/bo...
 * /urdf2robcogen/robot_name: test_robot
 * /urdf2robcogen/verbose: False

NODES
  /
    urdf2robcogen (urdf2robcogen/urdf2robcogen_node)

auto-starting new master
process[master]: started with pid [4004]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to b1ba9dfe-b635-11eb-a2f9-b42e9984ee6d
process[rosout-1]: started with pid [4015]
started core service [/rosout]
process[urdf2robcogen-2]: started with pid [4021]
terminate called after throwing an instance of 'ros::InvalidNameException'
  what():  Character [.] at element [75] is not valid in Graph Resource Name [/home/robot203/boshirobot/urdf_gen/src/urdf2robcogen/examples/floating_base.urdf].  Valid characters are a-z, A-Z, 0-9, / and _.
[urdf2robcogen-2] process has died [pid 4021, exit code -6, cmd /home/robot203/boshirobot/urdf_gen/devel/lib/urdf2robcogen/urdf2robcogen_node __name:=urdf2robcogen __log:=/home/robot203/.ros/log/b1ba9dfe-b635-11eb-a2f9-b42e9984ee6d/urdf2robcogen-2.log].
log file: /home/robot203/.ros/log/b1ba9dfe-b635-11eb-a2f9-b42e9984ee6d/urdf2robcogen-2*.log

Cool project ! But where do the generated files are saved?

I can't generate the kindsl file from my urdf file.

I use this tool to generate robcogen file but I get an error:

roslaunch urdf2robcogen cheetah2code.launch 
... logging to /home/zpl/.ros/log/0d0dd772-d0a7-11ea-987e-3413e89875f1/roslaunch-work-4531.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

xacro: in-order processing became default in ROS Melodic. You can drop the option.
started roslaunch server http://work:33891/

SUMMARY
========

PARAMETERS
 * /robot_description: <?xml version="1....
 * /rosdistro: melodic
 * /rosversion: 1.14.6
 * /urdf2robcogen/description_name: robot_description
 * /urdf2robcogen/output_folder: /home/zpl/local/s...
 * /urdf2robcogen/robot_name: cheetah
 * /urdf2robcogen/verbose: True

NODES
  /
    urdf2robcogen (urdf2robcogen/urdf2robcogen_node)

auto-starting new master
process[master]: started with pid [4544]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 0d0dd772-d0a7-11ea-987e-3413e89875f1
process[rosout-1]: started with pid [4555]
started core service [/rosout]
process[urdf2robcogen-2]: started with pid [4558]
[urdf2robcogen] Start generating files.
urdf2robcogen_node: /home/zpl/local/src/cheetah_catkin_ws/src/urdf2robcogen/src/Utils.cpp:63: Eigen::Matrix3d expressInertiaFromFrameAInComFrame(Eigen::Matrix3d, double, PoseInWorld, PoseInWorld): Assertion `isValidInertiaMatrix(C_I_C)' failed.
[urdf2robcogen-2] process has died [pid 4558, exit code -6, cmd /home/zpl/local/src/cheetah_catkin_ws/devel/lib/urdf2robcogen/urdf2robcogen_node __name:=urdf2robcogen __log:=/home/zpl/.ros/log/0d0dd772-d0a7-11ea-987e-3413e89875f1/urdf2robcogen-2.log].
log file: /home/zpl/.ros/log/0d0dd772-d0a7-11ea-987e-3413e89875f1/urdf2robcogen-2*.log

why this error urdf2robcogen_node: /home/zpl/local/src/cheetah_catkin_ws/src/urdf2robcogen/src/Utils.cpp:63: Eigen::Matrix3d expressInertiaFromFrameAInComFrame(Eigen::Matrix3d, double, PoseInWorld, PoseInWorld): Assertion isValidInertiaMatrix(C_I_C)' failed.` occur?
The urdf file is correct when I spawn it to gazebo.
How can I solve this?