Sketching CuddleBits: Coupled Prototyping of Body and Behaviour for an Affective Robot Pet

Social robots that physically display emotion invite natural communication with their human interlocutors, enabling applications like robot-assisted therapy where a complex robot's breathing influences human emotional and physiological state. Using DIY fabrication and assembly, we explore how simple 1-DOF robots can express affect with economy and user customizability, leveraging open-source designs. We developed low-cost techniques for coupled iteration of a simple robot's body and behaviour, and evaluated its potential to display emotion. Through two user studies, we (1) validated these CuddleBits' ability to express emotions (N=20); (2) sourced a corpus of 72 robot emotion behaviours from participants (N=10); and (3) analyzed it to link underlying parameters to emotional perception (N=14). We found that CuddleBits can express arousal (activation), and to a lesser degree valence (pleasantness). We also show how a sketch-refine paradigm combined with DIY fabrication and novel input methods enable parametric design of physical emotion display, and discuss how mastering this parsimonious case can give insight into layering simple behaviours in more complex robots.