Comparing the available robot platforms against the requirements, it became apparent that there is a gap for affordable as well as flexible and modular humanoids with rich sensorimotor capabilities for multimodal human-robot interaction.
NICO was developed on the basis of the first version of NimbRo-OP and likewise, features a humanoid anatomy resembling a child. The NimbRo-OP robot from the AIS group of the University of Bonn was designed as an open robot for the RoboCup TeenSize league. Thus, many features useful for human-robot interaction (HRI) research are left out in its design, such as arms and hands with high numbers of DoF. The open design of the robot, however, allows the development and integration of extensions for HRI research. A major limitation of NimbRo-OP was its software framework optimized for robot soccer which, to our knowledge, has not been used outside the original group. Nevertheless, the hardware provided an ideal base to add the functionality we needed for our research.
A similar platform, the Poppy robot, features a well documented and by now widely used software framework in Python. This general purpose library (PyPot library 4 ) to control Robotis Dynamixel servo motors, facilitates the development of any project including such motors. But Like NimbRo-OP, Poppy has non-actuated hands and the amount, as well as the type of available sensors in the current design, were not sufficient for multimodal interaction research. We decided to bring both developments together and to extend the Nimbro-OP with the needed sensing capabilities and a newly designed torso with more flexible arms and hands and to extend the PyPot library towards a NICO API to make use of the new functionality.
Thus, NICO was born!