kaist_webots: webots_run | webots_joy_demo | webots_controllers

This is an example of a Webots Controller written in C++, running as a ROS Node. It demonstrates how to build a ROS package linked against the Webots CppLibrary, control a robot using ROS messages, and start the simulation from a single launch file. This package is based on webots_joystick, which uses the C API and a different launching method.

The 'joy' node from the 'joystick_drivers' stack receives input from a USB joystick and publishes the state of the buttons and axes on the '/joy' topic. This node uses that input to drive a simple simulated robot in Webots. Speed commands are sent to the differential drive model using the Webots C++ API.

Tested with Webots 6.4.4 and ROS Fuerte.

• Author: David Butterworth. Based on work by Andreas Breitenser and Olivier Michel.
• License: BSD

• Repository: kaist-ros-pkg

• Source: http://kaist-ros-pkg.googlecode.com/svn/trunk/kaist_webots/webots_joy_demo/

Installation

Follow these instructions to install the kaist_webots stack.

Usage

Plug-in your USB joystick. This joystick controller has been tested with the Microsoft Xbox-360 USB joystick.

You can test the joystick by running:

$ cat /dev/input/js0

(you should see strange characters when you press the buttons)

You can edit the joystick path in the launch file.

Run the demo:

$ roslaunch webots_joy_demo run.launch

The Webots simulator should load, as shown:

If the controller loads successfully, there should be no error messages in the Webots console:

You can control the simulated robot using the USB joystick.
For the Xbox-360 joystick, the controls are as follows:

Controlling your own Webots mobile robot

• Create a new Webots world with a differential drive robot

• Ceate a new ROS package e.g. myrobot_sim_webots. See Creating a ROS Package

• Add the Webots .wbt world file to your package, in the /world directory

• Copy the webots_joy_demo source to the /src directory

• Edit CMakeLists.txt, using this package as an example. Note how the destination of the compiled binary is in the controllers/binary_name directory to suit Webots requirements, not the default ROS directory /bin

• Edit your Webots world file and specify the name of the controller binary file

• Create a launch file in the /launch directory, using this package as an example. The Webots world file is specified as an argument to the webots_run node

• Build your package: rosmake myrobot_sim_webots

For an example of a joint position controller, see the webots_controllers package.