1. Computer Engineering Group, Faculty of Technology; Bielefeld University; Universitätsstraße 25 Bielefeld 33615 Germany
2. Faculty of Engineering and Mathematics; Bielefeld University of Applied Sciences; Interaktion 1 Bielefeld 33619 Germany
3. DFKI GmbH; Robotics Innovation Center; Robert-Hooke-Straße 1 Bremen 28359 Germany