metapod

This software provides robot dynamics algorithms. It uses a combination of a specific representation of robot models and C++ templates, such that each algorithm remains model-independant, yet is optimized for a particular robot at compile-time. It makes use of R. Featherstone's Spatial Algebra to describe forces, motions and inertias (cf. Rigid Body Dynamics Algorithms, Roy Featherstone).

Content

• include/metapod/spatial: header-only spatial algebra library.

• include/metapod: header-only library of robot dynamics algorithms. Algorithms consist of the combination of compile-time traversal algorithms and visitors. They can be applied to a robot model which is a class with a specific structure.

• robotbuilder: a library to help generating the source code of robot model classes.

• embedfile: an utility executable used to embed templates in the robotbuilder library.

• metapodfromurdf: an utility executable based on robotbuilder and liburdf which generates the the source code of robot model classes from an URDF description.

• binarytreemodel: an utility executable based on robotbuilder which generates the source code of robot model classes with a binary kinematic tree. Those models are named sample_[1-4]and are used for benckmarks.

• data: URDF definition of the simple_arm and simple_humanoid models which are used for examples, tests and benchmarks.

• tests: some tests for metapod and metapod::Spatial

• timer: a portable timer library used for the benchmarks.

• benchmark: some benchmarks

• doc: some doc.

Dependencies

The package depends on several packages which have to be available on your machine.

• System tools:
  • CMake (>=2.6)
  • pkg-config
  • usual compilation tools (GCC/G++, make, etc.)
• Libraries:
  • Eigen (>=3.0.0)
  • Boost (>=1.40.0) Boost Test is used in the test suite
  • optionally, liburdfdom or liburdf (as provided by ROS)

Setup

To compile this package, it is recommended to create a separate build directory:

mkdir _build
cd _build
cmake -DBUILD_METAPODFROMURDF=OFF ..
make install

Please note that CMake produces a CMakeCache.txt file which should be deleted to reconfigure a package from scratch.

In order to build the urdf converter, you'll need to install liburdfdom or liburdf. There are several options:

• Install urdfdom alone

  git clone git://github.com/ros/console_bridge.git && cd console_bridge
  git checkout 0.1.5
  mkdir build && cd build
  cmake ..
  make
  sudo make install
  
  git clone git://github.com/ros/urdfdom_headers && cd urdfdom_headers
  git checkout 0.2.2
  mkdir build && cd build
  cmake ..
  make
  sudo make install
  
  git clone git://github.com/ros/urdfdom && cd urdfdom
  git checkout 0.2.7
  mkdir build && cd build
  cmake ..
  make
  sudo make install
  

• Or install ROS groovy using the ubuntu packages and just do

  source /opt/ros/groovy/setup.bash
  

  before running cmake.

• Or install ROS fuerte using the ubuntu packages and just do

  source /opt/ros/fuerte/setup.bash
  

  before running cmake.

Documentation

Development branch documentation is available online.

Known Bugs

• Benchmark times different with different combination of outer and inner loop.

Martin Felis pointed out that an outer loop of one, with an inner loop of 100000 was not equivalent with the benchmarks, to an outer loop of 100 and an inner loop of 1000.

He also found out that it is related to a bug with timers in boost 1.40. Please use boot 1.48 to fix it.

• NP is mandatory

Benjamin Chretien pointed out that a dummy root link is necessary as a Galilean Frame for the urdf file parser of metapod.