INTRODUCTION

In this paper we introduce Feelix (Figure 1), a 70cm-tall humanoid-looking LEGO robot that displays different facial emotional expressions in response to tactile stimulation.

Figure 1: Feelix.

1#1

Feelix is a descendant of Elektra [8], a mobile, also ``humanoid'' LEGO robot first exhibited at the FIRA Robot World Cup in Paris in 1998. People, in particular children, found it very natural to interpret the happy and angry expressions of Elektra's smiley-like face; however, the interaction humans could have with it to elicit these expressions was not so natural, as it consisted in inserting color LEGO parts into its chest. Our motivation for building Feelix--Elektra's body with a new head and feet--was twofold. First, we aimed at a more plausible interaction with the robot. We wanted to focus on the interaction itself, and therefore we did not want it to be influenced by the robot performing a particular task. For this, we decided to exploit the potential that robots, unlike computer simulations, offer for physical manipulation, as this plays an important role in children development and in human interaction in general. Interaction with Feelix is therefore through tactile stimulation rather than through other sensory modalities that do not require physical contact, such as vision. Occasionally, we have observed as a side-effect humans mirroring the emotion they want to elicit in Feelix in their own faces and in the nature of the presses they apply on the feet. Our second motivation was to achieve a richer interaction so that a wider range of interaction patterns giving rise to a wider range of emotional responses (both in the robot and, by empathy, in the human) was possible. However these emotional responses must be clearly recognizable, and therefore we limited ourselves to implementing the ones known in the emotion literature as ``basic emotions''. People were not only able to recognize the expressions quite successfully (see Section 4), but in many cases the even mimicked Feelix' expression with vocal inflection while commenting on the expression (``ooh, poor you!'', ``look, now it's happy!''). People thus seem to empathize with the robot rather naturally.

Our models of emotional interaction and expression are inspired by psychological theories about emotions in humans. This makes Feelix not only a robot very suitable for entertainment purposes, but also a proof-of-concept that these theories can be used with a synthetic approach that nicely complements the analytic perspective for which they were conceived.