UR20 Teleoperation

This package launches the UR20 teleoperation stack with one ROS 2 launch file.

Prerequisites

Source the ROS 2 Humble environment and make sure the workspace dependencies are installed:

source /opt/ros/humble/setup.bash
cd /home/glahr/ros/teleop_ws
rosdep install --from-paths src --ignore-src -r -y

The workspace must contain these packages:

• ur20_teleop - this package
• ros2_robotiqgripper - the Robotiq gripper server
• joy - the joystick driver

A joystick must be connected for joy_node to publish joystick messages. The gripper server also requires a Robotiq gripper reachable at 192.168.1.102.

Build

Build the package from the workspace root:

cd /home/glahr/ros/teleop_ws
source /opt/ros/humble/setup.bash
colcon build --packages-select ur20_teleop
source install/setup.bash

If the ros2_robotiqgripper package is part of this workspace and has changed, rebuild the workspace or build that package as well.

Run the launch file

cd /home/glahr/ros/teleop_ws
source /opt/ros/humble/setup.bash
source install/setup.bash
ros2 launch ur20_teleop teleop.launch.py

The launch file is installed by the ur20_teleop package, so the launch command uses ur20_teleop as its package name.

What the launch file runs

Launch entry	ROS 2 package	Executable	Purpose
robotiq_gripper_server	ros2_robotiqgripper	server.py	Starts the Robotiq gripper service server and sets its IPAddress parameter to 192.168.1.102.
joy_node	joy	joy_node	Reads the connected joystick and publishes sensor_msgs/msg/Joy messages on /joy.
ur20_teleop	ur20_teleop	ur20_teleop	Runs the C++ UR20 teleoperation node. It reads joystick and joint-state data, receives /robot_description, calculates joint velocities, publishes commands, and calls the gripper service.

The C++ executable is called ur20_teleop. The node created by that executable is named ur20_cpp_teleop; these are different names.

Important interfaces

The C++ teleoperation node:

• subscribes to /joy
• subscribes to /joint_states
• subscribes to /robot_description
• publishes joint velocity commands on /forward_velocity_controller/commands
• calls the Robotiq_Gripper service provided by ros2_robotiqgripper

A running robot driver or simulation must provide /joint_states, /robot_description, and the controller that consumes /forward_velocity_controller/commands.

Troubleshooting

Gripper server exits while processing a request

If the gripper server reports an error while parsing GET FLT, check that:

1. The gripper is powered and connected.
2. 192.168.1.102 is the correct IP address.
3. The gripper accepts the expected socket protocol at its configured port.
4. The gripper server can be run independently and communicate with the hardware.

The launch file only passes the IP address parameter; it does not configure the gripper hardware or the robot driver.

Check the installed launch file

ros2 pkg prefix ur20_teleop
ros2 pkg executables ur20_teleop

The package should list the ur20_teleop executable after a successful build, and the launch file should be under the package's installed share/ur20_teleop/launch directory.

Stop

Press Ctrl+C in the terminal running the launch file. This shuts down all three nodes started by the launch description.