Option 2: Install from source

The following guide is based on Franka Control Interface documentation. (link).

This you want build the packages from source, uninstall first the existing installation of libfranka and franka_ros to avoid conflicts:

   sudo apt remove "*libfranka*"

Building libfranka

Install first the following dependencies packages from Ubuntu:

sudo apt install build-essential cmake git libpoco-dev libeigen3-dev

Then, download the source code of libfrankafrom Github:

cd ~
git clone --recursive https://github.com/frankaemika/libfranka
cd libfranka

In the source directory, create a build directory and run CMake:

mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
cmake --build .

You now need to add the path of this library to you system path so that libfranka can be found at runtime. To do this, when in the build/ directory:

pwd

We then add this path to the end of our ~/.bashrc file, such an example is:

nano ~/.bashrc

# add the following line to the end of the file
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/home/<username>/libfranka/build"
# now save and exit the file

source ~/.bashrc

Building the ROS package

Create a catkin workspace for your ros projetc.

cd ~
mkdir -p catkin_ws/src
cd catkin_ws
source /opt/ros/kinetic/setup.sh
catkin_init_workspace src

Then clone the franka_ros from Github:

git clone --recursive https://github.com/frankaemika/franka_ros src/franka_ros

Install any missing dependencies and build the packages:

rosdep install --from-paths src --ignore-src --rosdistro melodic -y --skip-keys libfranka
catkin_make -DCMAKE_BUILD_TYPE=Release -DFranka_DIR:PATH=~/libfranka/build
source devel/setup.sh

Useful Package for MPC_ros project

qpOASES is required for solving quadratic optimization problem. A ros-wrapper version is preferred here to use directly is ROS.

Setting up the real-time Kernel

In order to control your robot using libfranka, the controller program on the workstation PC must run with real-time priority under a PREEMPT_RT kernel . This section describes the procedure of patching a kernel to support PREEMPT_RT and creating an installation package.

note

NVIDIA binary drivers are not supported on PREEMPT_RT kernels.

  • First, install the necessary dependencies:

    apt-get install build-essential bc curl ca-certificates fakeroot gnupg2 libssl-dev lsb-release libelf-dev bison flex

  • Download the version of the real-time kernel and associated patch, the version of the real- time kernel and the patch must be the same. Here, for ubuntu 18, i choose version 5.4.10

    wget https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/linux-5.4.19.tar.xz
wget https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/5.4/patch-5.4.19-rt11.patch.xz

  • Unzip

    xz -cd linux-5.4.19.tar.xz | tar xvf -
cd linux-5.4.19
xzcat ../patch-5.4.19-rt11.patch.xz | patch -p1

  • Configure your real-time kernel:

    cp /boot/config-5.3.0-40-generic .config
make oldconfig
Preemption Model

1. No Forced Preemption (Server) (PREEMPT_NONE)

2. Voluntary Kernel Preemption (Desktop) (PREEMPT_VOLUNTARY)

3. Preemptible Kernel (Low-Latency Desktop) (PREEMPT__LL) (NEW)

4. Preemptible Kernel (Basic RT) (PREEMPT_RTB) (NEW)

> 5. Fully Preemptible Kernel (RT) (PREEMPT_RT_FULL) (NEW)

If preemptinble not found, try it in General Setting

  • Compile:

   make -j20
   sudo make modules_install -j20
   sudo make install -j20

  • Verifying the new kernel Restart your system. The Grub boot menu should now allow you to choose your newly installed kernel. To see which one is currently being used, see the output of the uname -a command. It should contain the string PREEMPT RT and the version number you chose.

  • Allow a user to set real-time permissions for its processes After the PREEMPT_RT kernel is installed and running, add a group named realtime and add the user controlling your robot to this group:

sudo addgroup realtime
sudo usermod -a -G realtime $(whoami)

tips

Links for real-time kernel installation: