Roboception Dynamics API

The rc_dynamics_api provides an API for easy handling of the dynamic-state data streams provided by Roboception’s rc_visard stereo camera with self-localization.

Dynamic-state estimates of the rc_visard relate to its self-localization and ego-motion estimation. These states refer to rc_visard’s current pose, velocity, or acceleration and are published on demand via several data streams. For a complete list and descriptions of these dynamics states and the respective data streams please refer to rc_visard’s user manual.

Compiling and Installing

This package is based on some open source projects that are listed below. All dependencies are provided as submodules that are optionally used if the packages cannot be found on the system:

• C++ Requests (version 1.3.0): Requesting and deleting data streams is done via rc_visard’s REST-API. This library provides an easy-to-use interface for doing REST-API calls.

• Google Protocol Buffers: The data sent via rc_visard’s data streams is serialized via Google protocol message definitions (/roboception/msgs). After receiving the data, the rc_dynamics_api needs these definitions in order to de-serialized it. This project requires both the protobuf-compiler for compiling the protocol buffer definition files and the libprotobuf C++ library.

After cloning the git repository, the packages described above are cloned as submodules by:

git submodule update --init --recursive

Additionally this packages uses the single header file of

• JSON for Modern C++ (version 3.7.3): A simple and modern C++ JSON parsing library.

Linux

Building follows the standard cmake build flow.

cd <main-directory>
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=<install-directory> ..
make
make install

Windows and Visual Studio

Building is based on cmake. Therefore, cmake must be downloaded and installed according to the operating system from https://cmake.org/download/ After starting the cmake-gui, the path to the main directory as well as the build directory must be specified. It is common to choose a sub-directory of the main directory and name it ‘build’ for the the temporary files that are created during the build process. After setting both paths, the ‘Configure’ button must be pressed. In the up-coming dialog, it can be chosen for which version of Visual Studio and which platform (e.g. Win64) the project files should be generated. The dialog is closed by pressing ‘Finish’.

After configuration, the value of the key with the name ‘CMAKE_INSTALL_PREFIX’ may be changed to an install directory. By default, the install directory is set to a path like ‘C:/Program Files/…’. The ‘Generate’ button leads to creating the project file. Visual Studio can be opened with this project by pressing the ‘Open Project’ button.

By default, a ‘Debug’ version will be compiled. This can be changed to ‘Release’ for compiling an optimized version. The package can then be created, e.g. by pressing ‘F7’. For installing the compiled package, the ‘INSTALL’ target can be created in the project explorer.

After installation, the install directory will contain three sub-directories. The ‘bin’ directory contains the tools and DLLs. The ‘include’ sub-directory contains the sub-directories ‘rc_dynamics_api’ and ‘roboception’. The former contains the main headers of the library to build own applications. The latter contains the protobuf headers of the rc_dynamics interface. There may be other include directories that may be created by the submodules. They can be ignored or deleted. Finally, the ‘lib’ sub-directories contains the rc_dynamics_api link library that is required for building own applications. Other link libraries may be installed by the submodules. They can be ignored or deleted.

Tools

Currently, the rc_dynamics_api comes with the following tool which is also meant as an example on how to use this API:

• rcdynamics_stream

  Connect with an rc_visard device and request a specific data stream. The received data messages containing aspects of rc_visard’s dynamic state can be simply printed to std::out or saved as .csv-file.

  Simplest example:

  Connect to rc_visard with specified IP address and request the ‘imu’ stream. A certain amount of messages are received and simply print to std::out

    ./tools/rcdynamics_stream -v 10.0.2.99 -s imu
  

  Different use case with more command line parameters:

  Connect to rc_visard with specified IP address and request the ‘pose_rt’ stream for 10 seconds. The client host’s network interface to be used to receive the data is specified as ‘eth0’. Messages are stored in the specified file as .csv-lines.

    ./tools/rcdynamics_stream -v 10.0.2.99 -s pose_rt -i eth0 -a -t10 -o poses.csv
  

Links

• http://www.roboception.com