Animation engine for believable interactive user-interface robots

The iCat is an interactive and believable user-interface robot that performs the role of a "family companion" in home environments. To build this robot, we developed an animation engine that makes it possible to combine multiple interactive robot behaviors with believable robot animations. In order to do this, we build three special software components: 1) animation channels to control the execution of multiple robot behaviors and animations; 2) merging logic to combine individual device events; and 3) a transition filter for smooth blending. We illustrate the usage of the animation engine by describing an application of the iCat during which it speaks to a user while tracking the user\´s head, performing lip-syncing, doing eye-blinking and showing facial expressions.