Continuum Kinematics

h1. What does this library do?

{{>toc}}

This library computes and visualizes the "continuum" kinematics of robots such as the "Bionic Handling Assistant" (BHA), for which you can see a use case on "youtube":http://www.youtube.com/watch?v=kk3w2VchgWA.

The kinematics are computed based on the _constant curvature_ assumption, i.e. that the physical bending occurs homogeneously within each robot segment.

Yet, an arbitrary number of segments can be stacked. This technique, some computational tricks therein, and its usefulness on the BHA are described in this "paper":http://www.cor-lab.de/bib/constant-curvature-continuum-kinematics-fast-approximate-model-bionic-handling-assistant that appeared at the IROS 2012 conference.

More information can be found in this "blog article":http://planet-robotics.net/articles/2012-04-16-simulating-festo-bionic-handling-assistant.html.

h1. Using the example binaries

h3. Example 1: The ContinuumSegmentDemo (3D visualization)

!/attachments/download/188/segmentdemo.jpg!

This didactic example shows the geometric model underlying the simulated continuum kinematics, i.e. that each segment of a continuum robot behaves

like a torus segment. The example shows an animated movement of such a segment. Press @Alt-T@(orus), @Alt-G@(eometry) to toggle various visualization modes.

The code shows how to use the basic class @ContinuumSegmentDrawable@, which takes take of the 3D rendering.

h3. Example 2: The ContinuumRobotDemo (3D visualization)

!/attachments/download/189/trunkdemo.jpg!

h3. Example 3: The BhaTrajectoryPrediction 

!/attachments/download/190/predictiondemo.jpg!

Predict and visualize the end-effector trajectory for the "Bionic Handling Assistant" morphology given a posture-trajectory.

In the 3D visualization, press @N@ to generate a new trajectory.

h2. Windows binaries

In order to execute the examples, you need some "Microsoft Visual C++" libaries:

* The easiest way to get them is installing the "Microsoft Visual C++ 2010 Redistributable Package" from http://www.microsoft.com/download/en/details.aspx?id=5555

* Having the "Microsoft Visual C++ 2010" development environment installed does the same job, of course.

h2. Linux Debian packages

There are debian-packages for "Ubuntu Linux Oneiric". Get them by adding the line

<pre>

deb http://packages.cor-lab.de/ubuntu/ oneiric testing

</pre>

to your @/etc/apt/sources.list@ file. Then type

<pre>

sudo apt-get install continuumkinematics-bin

</pre>

The example binaries will be installed to @/usr/bin/examples@.

*ToDo*: Make Public key public https://support.cor-lab.org/projects/ciserver/wiki/RepositoryUsage

h2. Troubleshooting

h1. Install and use from source

h2. Dependencies

* Required: "NemoMath":https://code.cor-lab.org/projects/nemomath/wiki/Wiki

** Which requires: "Eigen 2":http://eigen.tuxfamily.org/index.php?title=Main_Page

** Which requires: "Boost":http://www.boost.org/ (header-only parts)

* Required: "CMake":http://www.cmake.org/

* Optional: "libqglviewer-qt4-dev":http://www.libqglviewer.com/, in case you want to use the visualization. The pure kinematics part can be built and deployed without this dependency.

** Which requires: "Qt 4":http://qt.nokia.com/

h2. Building from source

* Get the source from https://code.cor-lab.org/svn/continuumkinematics, e.g.

  <pre>

svn co https://code.cor-lab.org/svn/continuumkinematics</pre>

* Build it under *Linux* or *MacOS*

<pre>

cd continuumkinematics/build

cmake -DCMAKE_INSTALL_PREFIX=${PREFIX} ..

make install</pre>

* Build it under *Windows/MSVC*

<pre>

cd continuumkinematics

call project\build_vs.bat</pre>

h2. Troubleshooting

* During configuration, cmake says *@Qt qmake not found!@*. Simply check out where the qmake binary is located in your filesystem and put this in your cmake call:

   <pre>

-DQT_QMAKE_EXECUTABLE="${PATH_TO_QMAKE}/qmake" </pre>

* If you get linking errors like *@undefined reference to `QGLViewer::***'@*, you are probably linking against @libqglviewer-qt3@ instead of @qt4@

** If you don't have the right version of @qglviewer@ around, install it.

** If cmake still does not configure the correct library, you can manually chose the correct path by setting the variables "@QGLVIEWER_*@":

   <pre>

cmake -DCMAKE_INSTALL_PREFIX=${PREFIX} -DQGLVIEWER_INCLUDE_DIR=${QGL_QT4_DIR}/include -DQGLVIEWER_LIBRARIES=${QGL_QT4_DIR}/lib/${library_name} ..

make install</pre>

* When running the example binaries, you get the error message *@QWidget: Must construct a QApplication before a QPaintDevice@*

** An annoying problem that is currently only observed under Windows/MSVC: It seems to happen when QGLViewer is built in *@release@* mode, but you build the @continuumkinematics@ code in *@debug@* mode, or vice versa.

** Solution: find out how QGLViewer was built (most likely as @release@) and set the build-configuration accordingly in the cmake call:

   <pre>-DCMAKE_BUILD_TYPE=[release/debug]</pre>

h2. Platform/Compiler support

Currently, the following combinations are explicitly supported and known to work:

* *Ubuntu Linux/GCC* with Ubuntu version from @10.04 LTS (Lucid Lynx)@ and newer, and @GCC>=4.3@, 32bit as well as 64bit

* *MacOS/CLang3.0*

* *Windows 7/MSVC2010*, 32bit

The following platforms are known _not_ to work:

* GCC 4.2 or older

* MSVC 2008 or older