AI-assisted flexible electronics in humanoid robot heads for natural and authentic facial expressions

The realization of natural and authentic facial expressions in humanoid robots poses a challenging and prominent research domain, encompassing interdisciplinary facets including mechanical design, sensing and actuation control, psychology, cognitive science, flexible electronics, artificial intelligence (AI), etc. We have traced the recent developments of humanoid robot heads for facial expressions, discussed major challenges in embodied AI and flexible electronics for facial expression recognition and generation, and highlighted future trends in this field. Developing humanoid robot heads with natural and authentic facial expressions demands collaboration in interdisciplinary fields such as multi-modal sensing, emotional computing, and human-robot interactions (HRIs) to advance the emotional anthropomorphism of humanoid robots, bridging the gap between humanoid robots and human beings and enabling seamless HRIs.