ANRO summer school

h1. Lab 5: Inverse kinematics

h2. Scope:

This laboratory consists of two parts:

* A short introduction.

* Writing your own ROS package.

h2. The task:

* Develop the system from the previous laboratory by either copying the package or modifying it.

* Create ROS node IKIN that calculates inverse kinematics (IK) of the manipulator.

* Create an analytical algorithm for IK without use of KDL.

* Ignore orientation of the end effector. In this task, only position (translation) is relevant.

* The node should use the same ROS parameters as previously implemented node DKIN.

* Commands for IKIN should be read from the node that interpolates trajectory in operational space.

* The calculated joint position should be sent to robot_state_publisher.

  * If IK cannot be solved, the node IKIN does not publish new position and it sends error information to ROS log.

* Compare two positions in RVIZ:

  * The one calculated by the node that interpolates trajectory in operational space.

  * Position calculated by robot_state_publisher.

  !lab5-scheme-a.png!

* Send a number of commands to operational space interpolation node and check if they are executed properly.

  * In particular, the node ocmd commands motion of the end effector that follows rectangle and ellipse shape. Each motion should be executed periodically. The trajectory should be visualized as a streak in RVIZ.

    * Set such physical parameters of the manipulator (e.g. lengths of links) that the desired example motion is possible.

* Each example motion should be executed successfully for any initial configuration of the robot.

  * You can set the initial position using the method from the previous laboratory (i.e. interpolation in joint space).

  * Chose such solution for IK that the robot does not make any discontinuous motions.

    * Do not add any limits in joint space.

* Additionally:

  * Take into account limits of IK for the workspace of the robot.

    * If IK cannot be solved, the node should not publish new position and it should send error information 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.

  * On all graphs of structure of the system topics and services should be shown differently.

  * The plots generated with rqt_plot should prove compatibility of poses of end effector calculated in different streams with the position calculated by interpolator (with and without IK).

* 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.