Use SWIG to build a simple Python wrapper for the Kinova library. SWIG is used to generate a wrapper shared library _kinovapy.so and a wrapper python module kinovapy.py.

Building

Run make to build. The Makefile assumes you are using Python 2.7 and have the Kinova API libraries and header files installed in default locations. To use a different version of Python or alternate locations or Kinova library, you can override the Make variables PYTHON_INCLUDE (Python include directory path), KINOVA_INCLUDE_DIR (Kinova include directory path), KINOVA_LINK (Kinova linker flags).

You will need swig (tested with SWIG 1.3) and Python development packages installed (install python2.7-dev on Ubuntu/Debian).

The default Python include directory (PYTHON_INCLUDE) is /usr/include/python2.7 for Python 2.7. If you have a different version of Python installed, you can set PYTHON_INCLUDE to a different directory.

SWIG cannot parse some nested classes and the relatively new GCC "visibilty" attribute used by the standard Kinova header files, so you may want to use the header files from emulate-kinova-api even if using the real Kinova library, since the emulate-kinova-api headers have been modified to omit the "visibilty" attributes on functions if KINOVA_NOEXPORT is defined, which this SWIG wrapper does, and other minor changes.

To do so, first clonen the emulate-kinova-api repository from http://github.com/MobileRobots/emulate-kinova-api. Next, set a KINOVA_INCLUDE_DIR environment variable or set it on the make command line to use the header files from emulate-kinova-api.
You must choose the headers directory that matches the version of the real Kinova library you are going to link to. For example, for version 5.2.0:

make KINOVA_INCLUDE_DIR=../emulate-kinova-api/headers.50200

For 5.1.4 instead, use "headers.50104", and for 5.1.1, use "headers.50101". This will prevent mismatch between the contents of the headers and the actual symbols library.

You will also need to add the library directory to the LD_LIBRARY_PATH environment variable (e.g. for the example above, use export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:../emulate-kinova-api). Or copy the shared library to the same directory as the Python module.

You can also set KINOVA_LINK to choose which libraries to link to. For example, to use the emulate_kinova library instead of the real 5.2.0 Kinova libraries, build emulate-kinova-api first, then make this wrapper with:

make KINOVA_INCLUDE_DIR=../emulate-kinova-api/headers.50200 KINOVA_LINK="-L../emulate-kinova-api -l:emulate_kinova_50200.so"

We have to use the -l: link option instead of -l since the Kinova libraries and don't start with "lib". To use a different header file version, specify the alternate version in both thet headers directory and library name. For example, for 5.2.0:

Use

The Python module is named kinovapy:

import kinovapy

kinovapy.InitAPI()

Importing the kinovapy Python module will automatically load the _kinovapi.so wrapper library.

You will need to set PYTHONPATH and LD_LIBRARY_PATH environment variables to include this directory before running programs. `

Note: The Python wrapper links directly to the Kinova API shared library, it does not load it using dlopen as the Kinova C++ example programs do.

This has been tested with version 50104.

Only a few functions have been tested.

Some functions in the Kinova API take an int& argument via which the result/error code is passed back to the caller. In Python, values cannot be returned via argument references, instead a set (tuple) of values is returned by the function. For example, the GetDeviceCount function uses an int reference argument in C++:

int result;
int count = GetDeviceCount(result);

but in Python both the result and count are returned:

result,count = kinovapy.GetDeviceCount()

An extra function has been added to the wrapper that only returns the count, or -1 on error: GetNumDevices().

An extra function has also been added to the Python wrapper: SetActiveDeviceNum(i) takes an index instead of a KinovaDevice object.

The contents of the following objects can be printed/converted to strings for easier debugging and logging, similar to native Python objects and data structures:

• QuickStatus
• AngularPosition
• AngularInfo
• CartesianPosition
• CartesianInfo
• ForcesInfo

(i.e. they have str() methods defined)