Pre-Requisites

Module 1 : Learn to Visualise the Robot.

The last module was focussed on visualising robots.

Before we delve more deeper into various physical hardware, it is necessary that we pick-up the very first basics of ROS . Review the given playlist below to clear some core concepts of ROS .

ROS Tutorials - ROS Noetic For Beginners

Objective :-

• [ ] Create visualization environment for both RViz and Gazebo for the robot given in the picture above - The OWL Robot.

• [ ] Review the Kinematics and Dynamics Library (KDL):

  • Task: Familiarize yourself with the Kinematics and Dynamics Library (KDL) as it will be extensively used in future assignments.

  • Steps:

    1. Visit the KDL ROS Wiki page.

    kdl - ROS Wiki

    1. Understand the basic functionalities provided by KDL, such as forward and inverse kinematics.

    2. Explore examples on how to compute the pose of a robot’s end effector using KDL.

    3. Install the necessary KDL packages on your system.

• [ ] Write a ROS Node for End Effector Position:

  • Task: Create a ROS node that takes the current joint state of the OWL Robot from either Gazebo or RViz and prints the end effector position on the terminal.
  • Steps:
    1. Create the Node:
       • Initialize a new ROS package (if you don’t have one already) for this assignment.
       • Write a Python or C++ script that subscribes to the /joint_states topic to get the current joint positions of the robot.
    2. Use KDL for Calculations:
       • Use KDL to compute the forward kinematics and find the end effector position based on the joint states.
    3. Print End Effector Position:
       • The node should output the (x, y, z) coordinates of the end effector in the terminal.
    4. Test and Validate:
       • Run your node while the robot is in motion in Gazebo or RViz, and ensure that the end effector position updates correctly.
       • Compare the results with the expected position based on the robot's configuration.