libfranka Example Code: Unable to Set Realtime Scheduling – Operation Not Permitted

When running the following command:

./communication_test 172.16.0.2

You might encounter this error:

unable to set realtime scheduling: Operation not permitted Solution

To resolve this, simply add sudo before the command:

sudo ./communication_test 172.16.0.2

Error in ROS Launch Example

When running another example using ROS launch:

roslaunch franka_example_controllers move_to_start.launch robot_ip:=172.16.0.2

The same error appears:

unable to set realtime scheduling: Operation not permitted

Why Does This Happen?

The real-time kernel requires sudo privileges. However, when launching a ROS file using roslaunch, there is no direct way to add sudo to the internal commands.

Instead of adding sudo manually for each command, enter root mode and execute the launch file directly:

su

Enter your root password when prompted

roslaunch franka_example_controllers move_to_start.launch robot_ip:=172.16.0.2

Once in root mode, you no longer need sudo for the communication_test command. You can simply run:

./communication_test 172.16.0.2

This ensures the robotic arm functions correctly.

How to Enter Root Mode

To switch to root mode, use:

su

You’ll be prompted to enter the root password.

If You Haven’t Set a Root Password Before First, set a new root password with:

sudo passwd root

Then, enter root mode with:

su

Now, you should be able to run libfranka’s examples without issues.