An Expressive System for Endowing Robots or Animated Characters with Affective Facial Displays

The expressive system presented in this chapter is designed to link a model of emotion (or other underlying internal states) with socially appropriate expressive behaviors in an intelligent agent or robot. The system was initially developed to provide an affective interface to Joshua Blue, a computer simulation of an embodied mind that includes emotion and is designed to learn from its environment and interact effectively in social contexts. While many of the components of this system are not new, their combination in an expressive system is innovative. The advantages of this implementation include the ability to accommodate different emotion models (or models of other internal states), to easily specify dynamic sequences of expressive behavior, and to directly inspect, continuously monitor, and intervene to change the underlying states in a system as they occur. The system currently uses a real-time 3D facial avatar with a simplified anatomical model, but may be readily modified to direct the expressive behaviors of more complex animated characters or robots.