Intuitive Multimodal Interaction with Communication Robot Fritz

One of the most important motivations for many humanoid robot projects is that robots with a human-like body and human-like senses could in principle be capable of intuitive multimodal communication with people. The general idea is that by mimicking the way humans interact with each other, it will be possible to transfer the efficient and robust communication strategies that humans use in their interactions to the man-machine interface. This includes the use of multiple modalities, such as speech, facial expressions, gestures, body language, etc. If successful, this approach yields a user interface that leverages the evolution of human communication and that is intuitive to naive users, as they have practiced it since early childhood. We work towards intuitive multimodal communication in the domain of a museum guide robot. This application requires interacting with multiple unknown persons. The testing of communication robots in science museums and on science fairs is popular, because the robots encounter there many new interaction partners, which have a general interest in science and technology. Here, we present the humanoid communication robot Fritz that we developed as successor to the communication robot Alpha (Bennewitz et al., 2005). Fritz uses speech, facial expressions, eye-gaze, and gestures to interact with people. Depending on the audio-visual input, our robot shifts its attention between different persons in order to involve them into an interaction. He performs human-like arm gestures during the conversation and also uses pointing gestures generated with eyes, its head, and arms to direct the attention of its communication partners towards the explained exhibits. To express its emotional state, the robot generates facial expressions and adapts the speech synthesis. The remainder of the chapter is organized as follows. The next section reviews some of the related work. The mechanical and electrical design of Fritz is covered in Sec. 3. Sec. 4 details the perception of the human communication partners. Sec. 5 explains the robot's attentional system. The generation of arm gestures and of facial expressions is presented in Sec. 6 and 7, respectively. Finally, in the experimental section, we discuss experiences made during public demonstrations of our robot.