Set a LogPolicy suitable for real-time

Interface between libfranka and mc_rtc. It provides multi-robot support and connect mc_panda devices to their libfranka counterpart.

Setup

Nix

Building with Nix

To build the software, simply use

nix build .#mc-franka

Developping

To develop, use

nix develop .#mc-rtc-superbuild-mc-franka-devel

This will give you a shell with mc_rtc configured to use the mc_panda and mc_panda_lirmm robots, and mc_franka built from source. Follow the instructions in the terminal.

Running

You can use the mc-rtc-superbuild-mc-franka-devel environment where you compiled mc_franka yourself, or if you simply want to let Nix build and run the software:

• Step 1: create a suitable mc_franka configuration for your robot in an mc_rtc.yaml file (please refer to Usage section).

nix develop .#mc-rtc-superbuild-mc-franka # or -devel
# Run the gui in the background
(mc-rtc-magnum &)
# By default mc_rtc_ticker will use the configuration provided by `MC_RTC_CONTROLLER_CONFIG` env variable. This is set by the mc-rtc-superbuild derivation and devShell to contain all needed runtime depencencies and optionally a default controller's configuration
MCFrankaControl -f mc_rtc.yaml

From source

Dependencies

This package requires:

• mc_panda
• mc_rtc

You will also need the linux-libc-dev package on Ubuntu and Debian systems. To build and install the software:

1. Install this project's dependencies
2. Install this project (cmake/make/make install)

Usage

1. Make sure the system is setup properly to work with the robot
2. Make sure your user account has sufficient memory limits

For that last point, you want to edit /etc/security/limits.conf and add the following line:

USERNAME - memlock 1000000000

Then log-out and log-in, you can confirm the new limit is active by running:

ulimit -l

Your mc_rtc configuration file (typically ~/.config/mc_rtc/mc_rtc.yaml) should contain the following lines:

# General mc_rtc configuration to run a panda controller at 1kHz
MainRobot: PandaDefault # Or PandaHand/PandaFoot/PandaPump according to the end-effector installed on the robot
Enabled: YourController
Timestep: 0.001

# Set a LogPolicy suitable for real-time
LogPolicy: threaded

# Franka specific configuration
Franka:
  ControlMode: Position # Can be: Position/Velocity/Torque
  panda_default: # Name of the robot in the controller
    ip: 172.16.0.2 # IP of the robot
  panda_2: # Name of an extra panda in the controller
    ip: 172.16.1.2
  # Actuated robots that are not controlled via mc_franka
  ignored: [env/door, env/box]

Run the program:

MCFrankaControl

You can also provide an additional configuration file (to swap between different network configurations easily for example):

MCFrankaControl -f conf.yaml

Known issues

It may happen that some libraries are not found due to the high priviligies given for real-time scheduling. To overcome it, please consider running the following commands :

echo "$HOME/workspace/devel/catkin_data_ws/install/lib" | sudo tee -a /etc/ld.so.conf.d/mc_rtc_ros.conf
echo "$HOME/workspace/install/lib" | sudo tee -a /etc/ld.so.conf.d/mc_rtc.conf
echo "/opt/ros/${ROS_DISTRO}/lib" | sudo tee -a /etc/ld.so.conf.d/ros2.conf

Then run the following command :

sudo ldconfig

Video presentation

A video demonstrating panda motion generation and simultaneous pump actuation employing this implementation is available here:

Reference

Writing code takes time. If this implementation is useful for your research, please cite the related publication:

@INPROCEEDINGS{Dehio2021ICRA,
  title={Robot-Safe Impacts with Soft Contacts Based on Learned Deformations},
  author={Dehio, Niels and Kheddar, Abderrahmane},
  booktitle={IEEE Int. Conf. on Robotics and Automation},
  pages={1357-1363},
  year={2021},
  pdf = {https://hal.archives-ouvertes.fr/hal-02973947/document},
  url = {https://hal.archives-ouvertes.fr/hal-02973947}
}

This work was partially supported by the Research Project I.AM. through the European Union H2020 program under GA 871899.