https://github.com/leggedrobotics/urdf2robcogen
A tool that translates a robot URDF description into the kindsl format that can be processed by RobCoGen.
https://github.com/leggedrobotics/urdf2robcogen
kindsl rigid-body-dynamics robcogen ros urdf
Last synced: 5 months ago
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A tool that translates a robot URDF description into the kindsl format that can be processed by RobCoGen.
- Host: GitHub
- URL: https://github.com/leggedrobotics/urdf2robcogen
- Owner: leggedrobotics
- License: bsd-3-clause
- Created: 2018-11-30T16:21:38.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2020-10-01T14:03:35.000Z (about 5 years ago)
- Last Synced: 2025-04-06T20:46:28.887Z (6 months ago)
- Topics: kindsl, rigid-body-dynamics, robcogen, ros, urdf
- Language: C++
- Size: 33.2 KB
- Stars: 32
- Watchers: 7
- Forks: 10
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# URDF2ROBCOGEN {#mainpage}
**Authors**: Jan Carius (jcarius@ethz.ch) and Ruben Grandia (rgrandia@ethz.ch), based on an earlier version by Diego Pardo (depardo@ethz.ch)
**Maintainers**: Jan Carius (jcarius@ethz.ch) and Ruben Grandia (rgrandia@ethz.ch)
## What is this repository for?
This tool generates the [RobCoGen](https://robcogenteam.bitbucket.io/) description files (.kindsl & .dtdsl) from a [URDF](http://wiki.ros.org/urdf) description format.
## Building
[](https://ci.leggedrobotics.com/job/github_leggedrobotics/job/urdf2robcogen/job/master/)
**Dependencies**
* [Eigen](http://eigen.tuxfamily.org)
* [Boost](https://www.boost.org/)
* [ros::urdf](http://wiki.ros.org/urdf)
* [kindr](https://github.com/ethz-asl/kindr) (a kinematics library for robotics)
**Build the executable**
We use [catkin](http://wiki.ros.org/catkin) as a build system.
To build the bare version use
```bash
catkin build urdf2robcogen
```
**Build the documentation**
We use `rosdoc_lite` with doxygen backend to build documentation for this catkin package.
```base
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](http://wiki.ros.org/xacro) macros, i.e., you must invoke the xacro command beforehand to produce the URDF file.
To generate the robcogen description, execute
```bash
./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.
```bash
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.