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## note.0=[[visp_ros/Tutorials/How to build and install visp_ros|How to build and install visp_ros]]
## descriptive title for the tutorial
## title = How to do visual servoing with Parrot Bebop 2 drone using visp_ros
## multi-line description to be displayed in search
## description = This tutorial explains how to set up and use visp_ros package to do visual servoing with Parrot Bebop 2 drone.
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## next.0.link=[[https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-bebop2-vs.html|Detailed tutorial on Parrot Bebop 2 visual servoing using ViSP]]
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## level= BeginnerCategory
## keywords = visual servoing drone bebop2 parrot visp robot
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<<TableOfContents(4)>>

= Introduction =
 . {{attachment:img-bebop2.jpg||width="50%"}}

This tutorial explains how to use `visp_ros` package to do visual servoing with the Parrot Bebop 2 drone.

You can see the program in action in this video : <<Youtube(le07g-RRsJM)>>

= Prerequisites =
 * Parrot Bebop 2 drone
 * An April Tag from 36h11 family that will serve as target for the visual servoing (see [[https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-franka-pbvs.html#franka_prereq_target|this page]] to print one).
 * Modified version of ''bebop_autonomy'' package

In order to control the drone, the ROS wrapper ''[[https://github.com/AutonomyLab/bebop_autonomy|bebop_autonomy]]'' is required. However, this wrapper doesn't implement a way to send relative move commands to the drone.

We have added the necessary modifications in [[https://github.com/lagadic/bebop_autonomy|this  fork]].

You have to install `bebop_autonomy` from fork manually :

 . {{{
$ cd ~/catkin_ws/src
$ git clone https://github.com/lagadic/bebop_autonomy.git
$ cd bebop_autonomy/
$ git checkout inria-moveby
$ cd ~/catkin_ws
$ rosdep update
$ rosdep install --from-paths src -i
$ catkin_make
$ source ~/catkin_ws/devel/setup.bash
}}}

= Build visp_ros from source =

Note that `visp_ros` package has a dependency with `ros-<distro>-visp_bridge` and `ros-<distro>-visp` packages. Since `ros-<distro>-visp` package corresponds to ViSP 3.2.0 that is too old for `visp_ros` package, you need to install ViSP from source as well as `ros-<distro>-visp_bridge`.

To install ViSP from source, proceed as described in this [tutorial](file:///home/fspindle/visp_ws/visp/visp-build/doc/html/tutorial-install-ubuntu.html#install_ubuntu_quick).

Create first a workspace:
 . {{{
$ echo "export VISP_WS=$HOME/visp-ws" >> ~/.bashrc
$ source ~/.bashrc
$ mkdir -p $VISP_WS
}}}

Install a small number of recommended 3rd parties 
 . {{{
$ sudo apt-get install libopencv-dev libx11-dev liblapack-dev libeigen3-dev libdc1394-22-dev libv4l-dev libzbar-dev libpthread-stubs0-dev libjpeg-dev libpng-dev libdmtx-dev
}}}

Get ViSP source code 
 . {{{
$ cd $VISP_WS
$ git clone https://github.com/lagadic/visp.git
}}}

Create a build folder and build ViSP
 . {{{
$ mkdir -p $VISP_WS/visp-build
$ cd $VISP_WS/visp-build
$ cmake ../visp
$ make -j4
}}}
Set VISP_DIR environment variable
 . {{{
$ echo "export VISP_DIR=$VISP_WS/visp-build" >> ~/.bashrc
$ source ~/.bashrc
}}}

Now get `vision_visp` package:
```
$ cd ~/catkin_ws/src
$ git clone https://github.com/lagadic/vision_visp.git
```

To build `visp_ros` package from source run:

 . {{{
$ cd ~/catkin_ws/src
$ git clone https://github.com/lagadic/visp_ros.git
$ cd ~/catkin_ws
$ catkin_make -DVISP_DIR=${VISP_DIR}
$ source ~/catkin_ws/install/setup.bash
}}}


= Running the program =
`visp_ros` contains two launch files (`launch/bebop_servo_node.launch` and `launch/bebop_servo_nodelet.launch`) that allow to start the program. Both start two processes : the drone driver and the visual servoing program, with the necessary remappings. One uses regular nodes, and one uses nodelets (more efficient than nodes to transmit image data, see [[http://wiki.ros.org/nodelet|this page]] for more details on nodelets).

There are also some parameters you need to adapt to your current task :

 * The tag size (default : 0.14 meters)
 * The desired distance to the tag (default : 1.5 meter)
 * The orientation of the camera (default : -15 degrees for tilt and 0 degree for pan)

||<#cce0ff>'''Note:''' Before starting the program, the drone should be turned on and the computer connected to the drone Wifi network, as shown in the following pictures : ||


 . {{attachment:drone_connexion.png||width="40%"}}

||<#df6754>'''CAUTION''' : It's is strongly recommended to use this program outside or in a large room with non-uniform flooring, as the drone uses a downward-facing camera to estimate its motion from optical flow. If the surface under the drone is uniform, its movements will be inaccurate and dangerous. ||


----
Once everything is set up, you can launch the program :

 . {{{
$ roslaunch visp_ros bebop_servo_node.launch
}}}

or

 . {{{
$ roslaunch visp_ros bebop_servo_nodelet.launch
}}}

||<#df6754>'''CAUTION''' : If your Bebop2 has an other IP than the default which is `192.168.42.1` you may set `ip` parameter. ||
 . {{{
$ roslaunch visp_ros bebop_servo_nodelet.launch ip:=192.168.43.1
}}}


The drone driver will start, as well as the visual servoing program, that takes images from the drone camera as input, computes displacement commands, and sends them to the drone.

To make the drone take off and start the servoing, use (in another terminal) :

 . {{{
$ rostopic pub --once /bebop/takeoff std_msgs/Empty
}}}

To make the drone land, use :

 . {{{
$ rostopic pub --once /bebop/land std_msgs/Empty
}}}

= Understanding the program =
If you need more details on how the visual servoing program works, check the version in the open-source library ViSP : [[https://visp-doc.inria.fr/doxygen/visp-daily/tutorial-bebop2-vs.html#bebop2_ibvs|Tutorial: Visual-servoing with Parrot Bebop 2 drone]].

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