ardrone_autonomy : A ROS Driver for ARDrone 1.0 & 2.0

Introduction

"ardrone_autonomy" is a ROS driver for Parrot AR-Drone quadrocopter. This driver is based on official AR-Drone SDK version 2.0 and supports both AR-Drone 1.0 and 2.0. "ardrone_autonomy" is a fork of AR-Drone Brown driver and being developed in Autonomy Lab of Simon Fraser University by Mani Monajjemi.

Installation

Pre-requirements

Installation Steps

The installation follows the same steps needed usually to compile a ROS driver.

• Get the code: Clone (or download and unpack) the driver to your personal ROS stacks folder (e.g. ~/ros/stacks) and cd to it.

cd ~/ros/stacks
git clone TBA
rosstack profile && rospack profile
roscd ardrone_autonomy

• Compile the AR-Drone SDK: The driver contains a slightly patched version of AR-Drone 2.0 SDK which is located in ARDroneLib directory. To compile it, execute the ./build_sdk.sh. Any system-wide dependencies will be managed by the SDK's build script. You may be asked to install some packages during the installation procedure. You can verify the success of the SDK's build by checking the lib folder.

./build_sdk 
[After a couple of minutes]
ls ./lib
TBA

• Compile the driver: You can easily compile the driver by using rosmake ardrone_autonomy command.

How to Run

The driver's executable node is ardrone_driver. You can either use rosrun ardrone_autonomy ardrone_driver or put it in your launch file.

Reading from AR-Drone

Navigation Data

All the drone information will be published to the ardrone/navdata topic. The message type is ardrone_autonomy::Navdata and contains the following information:

• header: ROS message header
• batteryPercent: The remaining charge of the Drone (%)
• state: The Drone's current state: ** 0: Unknown ** 1: Inited ** 2: Landed ** 3,7: Flying ** 4: Hovering ** 5: Test (?) ** 6: Taking off ** 8: Landing ** 9: Looping (?)
• rotx: left/right tilt in degrees (rotation about the X axis)
• roty: forward/backward tilt in degrees (rotation about the Y axis)
• rotz: orientation in degrees (rotation about the Z axis)
• altd: estimated altitude (cm)
• vx, vy, vz: Linear velocity (mm / s) [TBA: Convention]
• ax, ay, az: Linear acceleration (g) [TBA: Convention]
• tm: Timestamp of the data returned by the Drone

Tag Detection

The Navdata message also returns the special tags that are detected by the Drone's on-board vision processing system. To learn more about the system and the way it works please consult AR-Drone SDK 2.0's developers guide. These tags are being detected on both drone's video cameras on-board at 30fps. To configure (or disable) this feature look at the "Parameters" section below.

[TBA]

Cameras

Both AR-Drones are equipped with two cameras. One frontal camera pointing forward and one vertical camera pointing downward. This driver will create three topics for each drone: ardrone/image_raw, ardrone/front/image_raw and ardrone/bottom/image_raw. Each of these three are standard ROS camera interface and publish image transport compatible ROS video streams.

• The /ardrone/* will always contain the selected camera's video stream and information.

• The way that the other two streams work depend on the type of Drone.

** Drone 1

Drone 1 supports four modes of video streams: Front Camera only, Bottom Camera only, Front Camera with bottom camera picture in picture and Bottom camera with front camera picture in picture. According to active configuration mode, the driver decomposes the PIP streams and publishes pure front/bottom streams to corresponding topics. The camera_info topic will include the correct image size.

** Drone 2

Drone 2 does not support PIP feature anymore, therefore only one of ardrone/front or ardrone/bottom topics will be updated based on which is selected at the time.

Sending Commands to AR-Drone

The drone will takeoff, land or emergency stop/reset by Publishing an Empty ros messages to the following topics: ardrone/takeoff, ardrone/land and ardrone/reset.

In order to fly the drone after takeoff, you can publish a message of type geometry_msgs::Twist to the ardrone/cmd_vel topic.

[TBA]

The range for each component should be between -1.0 and 1.0. The maximum range can be configured using ROS parameters below. Publishing 0 values for all components will make the drone keep hovering.

Services

Calling ardrone/togglecam service with no parameters will change the active video camera stream.

Parameters

The parameters listed below are named according to AR-Drone's SDK 2.0 configuration. Unless you set the parameters using rosparam or in your lauch file, the default values will be used. These values are applied during driver's phase. Please refer to AR-Drone's SDK 2.0 developer's guide for information about the valid values.

• bitrate_ctrl_mode - default: DISABLED
• max_bitrate - (AR-Drone 2.0 only) Default: 4000 Kbps
• bitrate - Default: 4000 Kbps
• outdoor - Default: 0
• flight_without_shell - Default: 1
• altitude_max: - Default: 3000 mm
• altitude_min: - Default: 100 mm

License

TODO List

• Enrich Navdata with magneto meter and baro meter information
• Add separate topic for drone's debug stream (navdata_demo)
• Add the currently selected camera name to Navdata
• Make the togglecame service accept parameter

FAQ

• How can I report a bug?
• Why the ARDroneLib has been patched?