International Journal of Social Robotics

, Volume 8, Issue 4, pp 513–521 | Cite as

Enhancing Emotional Facial Expressiveness on NAO

A Case Study Using Pluggable Eyebrows
  • Albert De BeirEmail author
  • Hoang-Long Cao
  • Pablo Gómez Esteban
  • Greet Van de Perre
  • Dirk Lefeber
  • Bram Vanderborght


Robots can express emotions for better human robot interaction. In this field, NAO robot is a platform widely used. This robot mainly expresses emotions by gestures and colored LED eyes, but, due to its white flat and inanimate face, the robot cannot express facial expressions. This work proposes a pluggable eyebrows device enabling NAO to express anger or sadness while performing other tasks. This device is plug-and-play and directly controllable by NAO’s development environments. Additionally, we developed a platform independent mapping of eyebrows angles with emotions. We first conducted an experiment that qualitatively attests the interest of this device. Three following experiments were conducted to: (1) confirm the relation between eyebrows angle and expressed emotion; (2) evaluate different shapes in order to select the most appropriate one; (3) prove that NAO is able to use the eyebrows to express emotions while performing non emotional tasks.


Facial expressions Emotions Nao robot Eyebrow Humanoid robot Eyes color 



The work leading to these results has received funding from the European Commission 7th Framework Program as a part of the project DREAM Grant No. 611391.


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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Robotics & Multibody Mechanics Research GroupVrije Universiteit BrusselBrusselsBelgium

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