This review article provides an overview of papers that have studied body movement mirroring and synchrony within the field of human-robot interaction. The papers included in this review cover system studies, which focus on evaluating the technical aspects of mirroring and synchrony robotic systems, and user studies, which focus on measuring particular interaction outcomes or attitudes towards robots expressing mirroring and synchrony behaviors. We review the papers in terms of the employed robotic platforms and the focus on parts of the body, the techniques used to sense and react to human motion, the evaluation methods, the intended applications of the human-robot interaction systems and the scenarios utilized in user studies. Finally, challenges and possible future directions are considered and discussed.

This paper explores the effects of selected exaggerated nonverbal cues on the perception of the Pepper robot in a story-telling scenario. We conduct a video-based user study based on an online survey containing the Godspeed questionnaire and additional interviews. The results of the study indicate that using exaggeration as a method to design nonverbal cues can improve the perception of the robot in both robot-talking and robot-listening cases. We find that Pepper is perceived as animate and safe in both cases, and additionally as anthropomorphic for the case when the robot is talking.

In this paper, a human-humanoid imitation system is proposed, with a focus on the kinematic model used for translating end effector positions to joint angles. The overall system comprises the humanoid robot Pepper and a Kinect v2 camera for capturing human 3D joint positions. The presented kinematic model is based on analytical solutions of Pepper’s inverse kinematics and also uses the forward kinematics. The aim of the paper is to provide insights into deriving the kinematics of robotic chains for the purpose of pose matching imitation, as well as accuracy evaluation of the derived forward and inverse kinematic solutions. The solutions of the inverse kinematics provide results with a mean error of approximately 0.2°for the angle solutions of the head joints, 0.7°for the arm joints, and 4° for the torso (leg) joints. The evaluated speed lies within a range of 0.002 to 0.08 ms. These results indicate that the presented kinematic model is an effective method for translating end effector positions to joint angles for our pose imitation application in real-time or close to it. Finally, we show preliminary results of the proposed imitation system and discuss future work.