• To start relaxed_ik_ros2: refer to README.md in relaxed_ik_ros2. For detailed directions, see below.
• Note. When adding new nodes within the scripts folder, make sure to add filename under relaxed_ik_ros2 > CMakeLists.txt > install, or else when launch, the node file mentioned in the launch file will not be found and hence throw an error.

Running rviz and joint_states.py (or velocities.py) for simulation

First see the next 2 sections to set up relaxed_ik_ros2 and ros2 if needed. Then do the following. You need to open 2 terminals. Whenever the ros2 command does not work, that means that ros2 is not sourced so do source /opt/ros/${ROS_DISTRO}/setup.bash.

When input is raw angular velocity - velocities.py and demo.launch.py

# in one terminal, fire up the launch python wrapper file
cd src
ros2 launch relaxed_ik_ros2 demo.launch.py # rviz will pop up and the robot will be shown. There should be a blue light on for the RobotModel (meaning no errors)

# in another terminal, run the Python node (velocities.py)
. install/setup.bash
source /opt/ros/${ROS_DISTRO}/setup.bash
ros2 run relaxed_ik_ros2 velocities.py

Whenever changes are made to velocities.py or to relevant files in the relaxed_ik_ros2 package, the package must be built and compiled everytime (colcon build + . install/setup.bash).

If you need a reference on how velocities.py (should) operate, then you can run

ros2 run relaxed_ik_ros2 keyboard_input.py

and use keyboard keys to control the velocities/angles in rviz, in real-time.

When input is joint state (6 values for 6-dof robot) - joint_states.py and rviz_joint_states.py

Run similar commands but just replace the filenames to joint_states.py and rviz_joint_states.py for the script (ros run) and the launch file (ros launch), respectively.

Starting relaxed_ik_ros2

For the bulk of the instructions, follow the README in the relaxed_ik_ros2 folder. The UR description files are already in there, so you just have to install it. Installation: https://automaticaddison.com/how-to-create-a-urdf-file-of-the-ur3e-robotic-arm-ros-2/

# Intall python packages
pip3 install -r requirements.txt

# install the required packages
sudo apt-get update
sudo apt install python3-pykdl
sudo apt-get install ros-${ROS_DISTRO}-urdfdom-py
sudo apt-get install ros-${ROS_DISTRO}-ur-description

# verify installation via rviz (for example, UR3e)
source /opt/ros/${ROS_DISTRO}/setup.bash
ros2 launch ur_description view_ur.launch.py ur_type:=ur3e

Whenever you are building the relaxed_ik_ros2 package, use colcon build. Specifically, make sure you are in your workstation and not in src and run

colcon build --packages-select relaxed_ik_ros2 --symlink-install # will take about 3 ~ 8 seconds
. install/setup.bash

ROS2 Iron Installation

# Follow general instructions from [the official ROS2 website](https://docs.ros.org/en/iron/Installation/Ubuntu-Install-Debians.html)

## Setup locale
locale  # check for UTF-8

sudo apt update && sudo apt install locales
sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

locale  # verify settings

## Ensure that the Ubuntu Universal Repository is enabled
sudo apt install software-properties-common
sudo add-apt-repository universe
sudo apt update && sudo apt install curl -y

## Skip the ROS2 GPG key adding part in the instructions. Instead, refer to post [here](https://answers.ros.org/question/410123/ubuntu-2204-ros2-humble-installing-error-gpg-libc-bin/).
rm /etc/apt/sources.list.d/ros2.list # if exists
curl http://repo.ros2.org/repos.key | sudo apt-key add -
sudo apt-key list # find key name
sudo cp /etc/apt/trusted.gpg /usr/share/keyrings/ros-archive-keyring.gpg

## go back to general instructions
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu $(. /etc/os-release && echo $UBUNTU_CODENAME) main" | sudo tee /etc/apt/sources.list.d/ros2.list > /dev/null

sudo apt update && sudo apt install ros-dev-tools

sudo apt update

sudo apt upgrade

sudo apt install ros-iron-desktop

source /opt/ros/iron/setup.bash