Perceptive and torque-control NMPC wiki¶

I - Software Overview¶

I.1. Openrobots¶

Collections of all the open-source software used at LAAS. You can find more details in Openrobots Wiki-Homepage

I-2. Robotpkg¶

Robotpkg is a packaging system for installing robotics software developed by the robotic community.
We will use robotpkg to install the required modules for the simulations (state estimation, gazebo interface...) as well as third-party dependencies (qpOases).

I-3. GenoM¶

The Generator of Modules, aka GenoM, generator of modules, designed to be middleware independant, i.e. the same module can be compiled for, e.g., ROS or Pocolibs, without any modification.
This allows a great code re-usability and to abstract the user from any specific choice of a middleware.
Originally GenoM has been developed tightly with Pocolibs, then from version 3, aka GenoM3, ROS templates has been provided.

Another specificity of GenoM is the interaction with and between components.
Each component is started independantly like a linux executable (within a roscore, for ROS, or a h2 intance, for Pocolibs), then the connection between ports (or topics) is made using a supervisor, Genomix, either with it Matlab or TCL.

I-4. Pocolibs¶

Pocolibs is a middleware, like ROS.
It aims at being more performant and faster than ROS, when running on a single machine, thanks to the exploitation of shared memory. ROS, on the other hand, uses a network layer for sending messages between nodes, this leads to greater delays and loss of performances.

I-5. TeleKyb¶

The TeleKyb software platform provides the aerial-robotic oriented softwares developped at LAAS-CNRS.
In particular, we will use:

• mrsim a Multi-Robot SIMulator. It is design to be a transparent interface w.r.t. the real aerial vehicles used in LAAS-CNRS. It makes the transition between simulation and experiment transparent, from the software point of view.
• pom a UKF-based state estimator merging state feedback for different sources (e.g. mocap + IMU)
• optitrack export the motion capture data to the genom software stack
• rotorcraft low-level interface, with either the simulated or real platform
• nhfc near-hovering flight controller, used for unmodeled take-off and post-failure recovery
• maneuver a global trajectory planner, providing position and attitude (as quaternions) as well as first and second derivatives. It implement take-off and waypoint-to-waypoint motions. A joystick-based velocity control is implemented, but not used in this project.

I-6. Gazebo¶

To simulate the platform, we use the Gazebo simulator. To interface it with the genom software stack, we use two dedicated components:

• mrsim-gazebo a plugin to interface the simulated multi-rotor with the genom components (in place of mrsim)
• optitrack-gazebo emulates the optitrack network interface to publish the model poses

II - Installation procedure¶

This section is a tutorial on how to install the software architecture to run the simulations.
Note that everything has been tested on Ubuntu 18.04 since it is the OS used by the LAAS-CNRS robotic platform. It should work seamlessly on other OS, but there is no guarantee.

II-0. Clone the Perceptive and torque-control NMPC repository¶

Clone the repo associated to this project. Its root will act as the devel folder for the following.

git clone git://redmine.laas.fr/laas/perceptive-torque-nmpc.git
cd ./perceptive-torque-nmpc/

II-1. Setup robotpkg¶

(Steps taken from http://robotpkg.openrobots.org/install.html)

1. Clone the robotpkg lastest release:¶

git clone git://git.openrobots.org/robots/robotpkg

2. Create an install folder called openrobots/, and update the environement variables accordingly, to ease the future steps:¶

mkdir openrobots
export ROBOTPKG_BASE=`pwd`/openrobots
export PATH=$PATH:$ROBOTPKG_BASE/bin:$ROBOTPKG_BASE/sbin

3. Install robotpkg¶

cd robotpkg/bootstrap
./bootstrap --prefix=$ROBOTPKG_BASE

4. Install the required components and there dependencies¶

The installation can be done 'manually' by navigating to the desired folder in ./robotpkg/ and install with make update; but we will simplify the process using a set.
To do so, we need to edit the config file: $ROBOTPKG_BASE/etc/robotpkg.conf. Add the following at the end of the file:

PKG_OPTIONS.%-genom3 = \
        codels \
        pocolibs-server \
        pocolibs-client-c

PKGSET.mpcset = \
    sysutils/arduio-genom3 \
    architecture/genom3 \
    architecture/genom3-pocolibs \
    robots/rotorcraft-genom3 \
    localization/pom-genom3 \
    localization/optitrack-genom3 \
    motion/nhfc-genom3 \
    optimization/qpoases \
    net/genomix \
    supervision/matlab-genomix \
    supervision/tcl-genomix \
    shell/eltclsh \
    simulation/mrsim-genom3 \
    simulation/mrsim-gazebo \
    simulation/libmrsim \
    simulation/optitrack-gazebo

PREFER.lapack = robotpkg
PREFIX.matlab = <path/to/Matlab>

The last line need to point to the Matlab root folder in the system (e.g. /opt/Matlab).
It is recommanded to use Matlab for the proposed simulations since the syntax is more intuitive and comprehensible for the user to modify them. However, we also provide all the launch files in tcl, as well as the environment to run them (shell/eltclsh in the above list is a custom tcl script shell).
Also, all the above is meant for using Pocolibs, not ROS. Futur version of this tutorial might come to use the ROS install.

Now return to the robotpkg folder and install all the set:

cd ..
make update-mpcset

During the installation, some required dependencies need to be install with the usual package manager (e.g. apt on Ubuntu). When the install stops, install the required packages and rerun the above command.

5. Matlab configuration¶

The last step is to update Matlab path to use the custom libraries, if relevant.
Add the following paths in the Matlab path window:

</path/to/openrobots>/lib/matlab
</path/to/openrobots>/lib/matlab/simulink
</path/to/openrobots>/lib/matlab/simulink/genomix

(change </path/to/openrobots> to the content of $ROBOTPKG_BASE)