Has anyone ever used KDL and kdl_parser?

edit

Easy approach for me was to use parameter server in a launch file

 <param name="robot_description" command="$(find xacro)/xacro.py $(find walking_excavator_urdf)/xacro_manzi/walking_excavator.urdf.xacro" />
 <node name="spawn_urdf" pkg="gazebo_ros" type="spawn_model" args="-param robot_description -urdf -x 0 -y 0 -z 1 -model robot" />

so from xacro/urdf you can directly load in ROS parameter, then use c++ code..

ros::NodeHandle node;
std::string robot_desc_string;
node.param("robot_description", robot_desc_string, std::string());
if (!kdl_parser::treeFromString(robot_desc_string, my_tree)){
  ROS_ERROR("Failed to construct kdl tree");
  return false;
}

This way you can get the tree, can verify with

   unsigned int nj = my_tree.getNrOfJoints();
   unsigned int js = my_tree.getNrOfSegments();
   ROS_INFO("NrOfJoints =%d   ||  NrOfSegments= %d \n", nj,js);

Hey Gabri89,

I used KDL a few years ago to solve some inverse calculations. But this only on the ROS side and I guess you want to do that also, referring that you are using the catkin_ws...? In that case I would recommend you to read the catkin tutorial to understand how to include dependencies.

For an approach what should be modified: Link to similar problem

But to answer your main question, the kdl_parser is meant to translate your robot model definition file (urdf) into a kdl tree. This enables kdl to see the robot model as an kinematic chain what is required.

Here is some sample where I used pykdlutils (python). Think in C++ it should look similar: Sample code

Hope it helps you.