Getting Started...

[charlescva]

Hello. I am completely new to ROS and the concept of using it with the AR Drone. Unfortunately I have spent most of my career using java/php and other heavy footprint languages for big data applications, so although the concepts are comfortable with networking, UDP, functions, etc... the syntax and terminology has me lost.

Anyway, I love learning new things and picked up the AR Drone 2.0 last friday. I have enjoyed what it can do, but would like to have better control using event triggered input keys, or predefined inputs, etc.

I am new to the catkin framework, but not new to linux and compiling source and dealing with dependencies. After doing some reading on packages and nodes, I have found that it sounds similar to java 'storm topologies' in which I use graphs of nodes to determine real time data flow in distributed environments, ensuring that no input is ever dropped.

Currently I am able to connect to my drone with wifi, and start the ardrone_driver node in the ardrone_autonomy package. I can see all kinds of parameters and their values, (such as battery life), but I'm not sure where to go from there. Looking through the catkin tutorials, it seems like i should see the node running in 'roscore', but i don't. I understand the concept of sending a command by publishing an empty ROS message to the "ardrone/takeoff and ardrone/land topics" But not sure how to actually send a message to those topics.

http://wiki.ros.org/Topics#Topic_Tools this implies i should be able to use rostopic, but there are a lot of parameters in the launch which define outdoor mode = 1, and maximum_altitude to 3000, but I'm not sure about the unit of measure and I am indoors, perhaps 3000 = 3 meters?

Anyway, I was hoping someone could fill me in a little bit, as I would like to get involved and learn more without destroying my new AR Drone.

Thanks for reading.

Charles

[charlescva]

Okay update.

I got the drone to take off and land.

Modified the launch file (.../src/ardrone_autonomy-hydro-devel/launch/ardrone.launch) and set outdoor mode = 0, which I assume is the same as turning on indoor mode? Then recompiled.

First the ros core daemon has to be running, # roscore (New Terminal) next, started the driver # rosrun ardrone_autonomy ardrone_driver (2nd Terminal)

I wasn't sure what the readme meant by publishing an empty message, so I adopted this from the ROS wiki: (Inside a 3rd Terminal) rostopic pub /topic_name std_msgs/String hello and changed it to: rostopic pub /ardrone/takeoff std_msgs/Empty -1

So, I added the following aliases to my ~/.bashrc source ~/catkin_ws/install/setup.bash alias droneUp="rosrun ardrone_autonomy ardrone_driver" alias takeOff="rostopic pub /ardrone/takeoff std_msgs/Empty -1" alias land="rostopic pub /ardrone/land std_msgs/Empty -1"

Next step, keyboard mapping.

Another question, what is aggressive launch? Sounds suspicious.

[mani-monaj]

@charlescva This might be a very good starting point:

http://robohub.org/up-and-flying-with-the-ar-drone-and-ros-getting-started/

The article is a little outdated, but the ROS API of the driver is the same, so it should work fine. I hope that will help.

[charlescva]

@mani-monaj Thanks for the direction. I am looking into this now.

[kbogert]

If you have a spare PS3 controller lying around I'd definitely recommend that rather than trying to control the drone with a keyboard. You can use my project here: https://github.com/kbogert/ps3_ardrone and the instructions for connecting the controller to ROS: http://wiki.ros.org/ps3joy/Tutorials/PairingJoystickAndBluetoothDongle

IMNSHO controlling the drone with an actual controller is light years better than anything else I've tried.

[charlescva]

I do have a PS3 controller. I was planning to move towards using a gamepad after getting some basic keyboard inputs working. I also have a joystick I purchased to use with flight simulator/ace combat. I figured that would be the ultimate solution for precision control. Thanks for the feedback, I will definitely be going through your projects once I get through setting up the dev environment. Still have a lot to learn about using ROS in general.

[charlescva]

@kbogert So I have a few of the different packages working. First, I am able to run the tutorials package from Mike Hamer, and I can successfully control the AR Drone with the keyboard. However, like you said, it does not feel natural.

So the first thing I did was follow the information here: http://wiki.ros.org/ps3joy/Tutorials/PairingJoystickAndBluetoothDongle I am able to open a 2nd terminal session, run sudo jstest /dev/input/js0 and hit the connect button my PS3 controller and see the outputs. So that seems to be working okay.

Next, I downloaded the ZIP from the ps3_ardrone project, extracted the ps3_ardrone-master folder into my ~/catkin-ws/src folder, and from the catkin workspace ran 'catkin_make install'. This ran without errors, so i then followed the run.txt instructions:

charles@:~/catkin_ws$ sudo bash [sudo] password for charles: root@:~/catkin_ws# rosrun ps3joy ps3joy.py No inactivity timeout was set. (Run with --help for details.) Waiting for connection. Disconnect your PS3 joystick from USB and press the pairing button. Connection activated

Now, at this point I tried to roslaunch the ps3_ardrone launch file: charles@:~$ roslaunch ps3_ardrone ps3_ardrone.launch [ps3_ardrone.launch] is neither a launch file in package [ps3_ardrone] nor is [ps3_ardrone] a launch file name

however, I get the error above. using catkin_find_pkg, i see the package.

charles@:~$ catkin_find_pkg ps3_ardrone Multiple packages found with the same name "ardrone_tutorials":

• catkin_ws/src/ardrone_tutorials-master
• catkin_ws/install/share/ardrone_tutorials Multiple packages found with the same name "ps3_ardrone":
• catkin_ws/src/ps3_ardrone-master
• catkin_ws/install/share/ps3_ardrone Multiple packages found with the same name "ardrone_autonomy":
• catkin_ws/src/ardrone_autonomy-hydro-devel
• catkin_ws/install/share/ardrone_autonomy

I guess I'm missing something?

[kbogert]

Hmm, try: source ~/catkin_ws/install/setup.bash

and see if it still can't find it.

[kbogert]

Oh wait, the name of the folder has to be ps3_ardrone, not ps3_ardrone-master. Same with ardrone_autonomy and ardrone_tutorials. The folder name has to match the package name for roslaunch to find it.

[charlescva]

Hmm. Tried renaming the folder as well as sourcing the setup.bash file. Same error. I'll try cleaning out the workspace and building again. Thanks.