RL24_HW_2

Ferdinando Dionisio, Vittorio Lisi, Giovanni Gabriele Imbimbo, Emanuele Cifelli

Overview

This homework involves developing a ROS package to dynamically control a 7-degrees-of-freedom robotic manipulator in the Gazebo simulation environment.

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Instructions

1. Clone the repository from GitHub:

   cd src
   git clone -b REV_3 https://github.com/ferd-bot/RL_24_Homework_2_Robotics.git .

   Warning:
   The above git clone command (with the dot) works only if the target directory is empty.

   • If not, you can remove extra files using:

     rm -rf *

   • Alternatively, download the repository normally (without the dot) and manually move the files out of the RL_24_Homework_2_Robotics folder while remaining inside the src directory.

2. Configure and build all packages in the workspace:

   cd ~/ros2_ws
   rm -rf build/ install/ log/
   colcon build
   source install/setup.bash

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Launching the Manipulator

1. Control Modes

The new code supports controlling the manipulator in three modes:

• Position Mode:
  Launch the iiwa_arm_controller (with RViz):

  ros2 launch iiwa_bringup iiwa.launch.py command_interface:="position" robot_controller:="iiwa_arm_controller"

• Velocity Mode:
  Launch the velocity_controller (with RViz):

  ros2 launch iiwa_bringup iiwa.launch.py command_interface:="velocity" robot_controller:="velocity_controller"

• Effort Mode:
  Launch the effort_controller (with Gazebo simulation):

  ros2 launch iiwa_bringup iiwa.launch.py command_interface:="effort" robot_controller:="effort_controller" use_sim:="true"

2. Launching Trajectories

To execute trajectories, open a new terminal and run the following commands depending on the desired control mode:

• Position Mode:

  ros2 run ros2_kdl_package ros2_kdl_node 0 --ros-args -p cmd_interface:=position

• Velocity Mode:

  ros2 run ros2_kdl_package ros2_kdl_node 0 --ros-args -p cmd_interface:=velocity

• Effort Mode with Operational Space:

  ros2 run ros2_kdl_package ros2_kdl_node 0 --ros-args -p cmd_interface:=effort -p control_space:=operational_space

• Effort Mode with Joint Space:

  ros2 run ros2_kdl_package ros2_kdl_node 0 --ros-args -p cmd_interface:=effort -p control_space:=joint_space

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Available Trajectories

The following trajectories are supported, all with effort-based control in Operational Space.
Trajectories are numbered from 0 to 3:

1. Linear with Trapezoidal Velocity Profile:

   ros2 run ros2_kdl_package ros2_kdl_node 0 --ros-args -p cmd_interface:=effort -p control_space:=operational_space

2. Linear with Cubic Velocity Profile:

   ros2 run ros2_kdl_package ros2_kdl_node 1 --ros-args -p cmd_interface:=effort -p control_space:=operational_space

3. Circular with Trapezoidal Velocity Profile:

   ros2 run ros2_kdl_package ros2_kdl_node 2 --ros-args -p cmd_interface:=effort -p control_space:=operational_space

4. Circular with Cubic Velocity Profile:

   ros2 run ros2_kdl_package ros2_kdl_node 3 --ros-args -p cmd_interface:=effort -p control_space:=operational_space

To execute trajectories in Joint Space, simply set control_space:=joint_space.
For Position or Velocity Control, modify the cmd_interface parameter as explained above.

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Notes

A new topic called /torque_plot has been defined in the code.
This topic allows you to visualize the torques sent to the manipulator's joints.

You can monitor this topic in the terminal:

ros2 topic echo /torque_plot

Alternatively, use rqt_plot for graphical visualization:

rqt

Within rqt, set up the plugin for plotting and insert the data corresponding to the joints:

/torque_plot/data[0]
/torque_plot/data[1]
/torque_plot/data[2]
/torque_plot/data[3]
/torque_plot/data[4]
/torque_plot/data[5]
/torque_plot/data[6]

Note:
The /torque_plot topic is activated within the ros2_kdl node.
To visualize it, you must run the KDL node in Effort Mode at least once.

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Videos

For simplicity, only videos demonstrating Effort-Based Control in Operational Space with Gazebo are attached:

• Operational Space
• Joint Space
• Velocity Controller: Trajectory Linear Trapezoidal