tleyden's profile - activity

I would like to communicate with ROS via Erlang, and there seems to be two possible approaches:

A) Erlang library that knows how to talk to ROS via TCPROS (eg, pure Erlang approach)

or

B) Call ROS C library from Erlang (eg, something akin to JNI)

I see for Java, it started out with a JNI approach and then it was switched to a pure Java approach, which tells me a pure Erlang approach might be the best approach.

Just curious, how often does the TCPROS protocol change? Does it change every major release or is it relatively stable?

On the turtlebot wiki page for groovy, it says that turtlebot_simulator is coming soon.

However, I see the following Ubuntu 12.04 package available: ros-groovy-turtlebot-simulator

Has anyone gotten turtlebot working in groovy?

I updated the wiki page to make it a bit clearer.

That worked! Thanks.

In the Using urdf with robot_state_publisher tutorial, it says:

Run rviz, choosing odom as your fixed frame. Add a Robot Model and TF.

and I got stuck there. I ran:

rosrun rviz rviz

but not sure how to do any of the other steps mentioned above. Anyone know how to make this work?

Thanks! That helps clears things up a bit.

In the stage SimulatingOneRobot tutorial, it mentions to install teleop_base. I couldn't find that package, does it still exist?

I managed to control the erratic robot via:

$ roslaunch turtlebot_teleop keyboard_teleop.launch

So it looks like the stage SimulatingOneRobot tutorial should be updated to use this command, or whatever the most appropriate command for controlling the erratic robot.

I'm trying to follow the Stage SimulatingOneRobot tutorial and when I try to start rviz via:

rosrun rviz rviz -d `rospack find stage`/rviz/stage.vcg

I get the following errors on the rviz console:

[ERROR] [1359742184.993057147, 96.500000000]: The plugin for class 'Grid' failed to load. Error: According to the loaded plugin descriptions the class Grid with base class type rviz::Display does not exist. Declared types are rviz/Axes rviz/Camera rviz/Grid rviz/GridCells rviz/Image rviz/InteractiveMarker rviz/LaserScan rviz/Map rviz/Marker rviz/MarkerArray rviz/Odometry rviz/Path rviz/PointCloud rviz/PointCloud2 rviz/Polygon rviz/Pose rviz/PoseArray rviz/Range rviz/RobotModel rviz/TF rviz_plugin_tutorials/Imu and in the rviz UI, I see this error:

1. Laser Scan (Laser Scan) This config file uses an old format with 'Type=Laser Scan'. The new format uses the C++ class name, for example 'ClassName=rviz::GridDisplay' for a Grid display.

I think I managed to fix it by changing the stage.vcg that ships with stage (stage/rviz). After I made these changes, the errors went away and I could see output from the laser scan in rviz.

Here is a snippet from the new stage.vcg file:

[Display0]
ClassName=rviz::GridDisplay
Name=Grid
[Display1]
ClassName=rviz::TFDisplay
Name=Transforms
[Display2]

What is the best way to get this fix pushed upstream?

I want to create two simulated robots which will engage in predator/prey behavior. I don't actually care what kind of robots they are, the simpler the better. But I do need a way to detect when the predator collides with the prey in order to remove the prey from the simulation (due to being eaten).

I've managed to get a few turtles running in the turtlesim, but how would I go about doing collision detection? Would I have to roll my own node or is there something existing I can use?

If I switched from turtlesim to either stage or gazebo, would this be easier to leverage pre-built tools do the collision detection?