Here we will explain how you can use the geometric relations semantics in your application, in particular using the Orocos Kinematics and Dynamics library as a geometry library, supplemented with the semantic support.

Preparing your own application using the ROS-build system

• Create a new ROS package (in this case with name myApplication), with a dependency on the geometric_semantics_kdl:

roscreate-pkg myApplication geometric_semantics_kdl

This will automatically create a directory with name myApplication and a basic build infrastructure (see the roscreate-pkg documentation)

• Add the newly created directory to your ROS_PACKAGE_PATH environment variable:

cd myApplication
export ROS_PACKAGE_PATH=$PWD:$ROS_PACKAGE_PATH

Writing your own application

• Go to the application directory:

roscd myApplication

• Create a main C++ file

touch myApplication.cpp

• Edit the C++ file with your favorite editor
  • Include the necessary headers. For instance:

#include <Pose/Pose.h>
#include <Pose/PoseCoordinatesKDL.h>

• • It can be convenient to use the geometric_semantics namespace and for instance the one of your geometry library (in this case KDL):

using namespace geometric_semantics;                                                                                                                                                                                                    using namespace KDL;

• • In your main you should create the necessary geometric relations. For instance for a pose, first create the KDL coordinates:

Rotation coordinatesRotB2_B1=Rotation::EulerZYX(M_PI,0,0);
Vector coordinatesPosB2_B1(2.2,0,0);
KDL::Frame coordinatesFrameB2_B1(coordinatesRotB2_B1,coordinatesPosB2_B1)

Then use this KDL coordinates to create a PoseCoordinates object:

PoseCoordinates<KDL::Frame> poseCoordB2_B1(coordinatesFrameB2_B1);

Then create a Pose object using both the semantic information and the PoseCoordinates:

Pose<KDL::Frame> poseB2_B1("b2","b2","B2","b1","b1","B1","b1",poseCoordB2_B1);

• • Now you are ready to do actual calculations using semantic checking. For instance to take the inverse:

Pose<KDL::Frame> poseB1_B2 = poseB2_B1.inverse()

Building your own application

• To build you application you should edit the CMakeLists.txt file created in you application directory. Add the your C++ main file to be build as an executable adding the following line:

rosbuild_add_executable(myApplication myApplication.cpp)

• Now you are ready to build, so type

rosmake myApplication

and the executable will be created in the bin directory.

• To run the executable do:

bin/myApplication

You will get the semantic output on your screen.