We report work on a LEGO robot capable of displaying several emo- tional expressions in response to physical contact. Our motivation has been to explore believable emotional exchanges to achieve plausible interaction with a simple robot. We have worked toward this goal in two ways. First, acknowledging the importance of physical manipulation in children's inter- actions, interaction with the robot is through tactile stimulation; the various kinds of stimulation that can elicit the robot's emotions are grounded in a model of emotion activation based on different stimulation patterns. Sec- ond, emotional states need to be clearly conveyed. We have drawn inspira- tion from theories of human basic emotions with associated universal facial expressions, which we have implemented in a caricaturized face. We have conducted experiments on both children and adults to assess the recogniz- ability of these expressions.
Transactions on Systems, Man, and Cybernetics, Part a, 2001, Vol 31, Issue 5, p. 454-459