Lab 3: Forward kinematics¶

Scope:¶

This laboratory consist of two parts:

• A short introduction.
• Writing your own ROS package.

The task:¶

• Develop the system from the previous laboratory by either copying the package or modifying it.
• Using C++ or Python create a ROS node NONKDL_DKIN that calculates forward kinematics of manipulator using analytical method (without KDL).
  • The node gets current position of joints from joint_state_publisher node.
  • The result (i.e. position of end effector of type geometry_msgs/PoseStamped) should be published on ROS topic and visualized in RVIZ.
  • Do not interpolate movement.
  • Please refer to RVIZ documentation http://wiki.ros.org/rviz/Tutorials
  • Read parameters (e.g. lengths of links) from ROS parameter server.
    
• Create a second node KDL_DKIN that uses KDL, with the same functionality as NONKDL_DKIN.
  • Connect it to existing nodes in place of NONKDL_DKIN.
    
• Test the results in RVIZ. Compare nodes NONKDL_DKIN and KDL_DKIN with data from robot_state_publisher.
  • Check if the calculated pose is the same as the pose calculated by robot_state_publisher. Compare the poses in RVIZ.
  • All three nodes that calculate forward kinematics should publish to different topics.
  • Reference frames of the end effector should coincide. Set different visualization parameters (e.g. width, length of arrows) to see them all.
  • The documentation of tests should be supplemented with plots of end effector position calculated using different methods and plots of configuration space position.
    
• Joint limits should be taken into account.
  • If joint position is outside limits, the pose of end effector should not be published and error should be published to ROS log.
• Add wiki page to your repository (the documentation). The page should contain description of source files, instruction for launching and description of tests.
• Use separate roslaunch files for:
  • roscore and RVIZ (it should be running until URDF file is modified).
  • The rest of the system.
• Test the system and show it to the tutor.