rosserial_qt

Client implementation for rosserial using the multi-platform Qt library. For the moment it only supports TCP/IP, but it could be easily adapted for UDP (using QUdpSocket) or serial port (using QSerialPort) communications.

Usage

1. Generate the source files by running rosrun rosserial_qt make_library.py <output_path>
2. Compile your client application using the library. You should add the roslib library to you include path, and add the .cpp files to your source files.

Remarks:

• C++11 support is required
• Unlike other client implementations of rosserial, the NodeHandle uses a dynamically sized buffer.
• There is no need to call spinOnce() manually : the NodeHandle will call spinOnce() periodically and on reception of new data, using the Qt event loop
• Unlike rosserial_arduino using C-style arrays, the message generation script will convert arrays to std::vector and std::array

Examples

Some simple examples of applications using the library are in the test directory To use the examples you should first generate the ros_lib directory, for example like this :

roscd rosserial_qt
rosrun rosserial_qt make_library.py .

Performance

CPU usage seems to be quite close to native roscpp nodes. (TODO : add some data)

Supported platforms

This library should work on all platforms supported by Qt (Linux, Windows, Android, ios...) I have succesfully tested this library on :

• Linux
• Windows

Server-side configuration

The current implementation needs the message length to be coded on 4 bytes (rosserial's default is 2 bytes). This has been implemented in rosserial-server (modified version available here : https://github.com/1r0b1n0/rosserial ), but has to be configured with the msg_length_bytes parameter. You should also configure the receive buffer size depending of your application. The rosserial-python server implementation will not work, as it doesn't support 4 bytes coding of the message length.

Example launch file :

<launch>
  <node pkg="rosserial_server" type="socket_node" name="rosserial_server_socket_node">
    <param name="msg_length_bytes" value="4"/>
    <param name="buffer_size" value="1000000"/>
    <param name="tcp_nodelay" value="true"/>
  </node>
  <node pkg="rosserial_python" type="message_info_service.py" name="rosserial_message_info" />
</launch>