Voodle: Vocal Doodling to Sketch Affective Robot Motion

Social robots must be believable to be effective; but creating believable, affectively expressive robot behaviours requires time and skill. Inspired by the directness with which performers use their voices to craft characters, we introduce Voodle (vocal doodling), which uses the form of utterances -- e.g., tone and rhythm -- to puppet and eventually control robot motion. Voodle offers an improvisational platform capable of conveying hard-to-express ideas like emotion. We created a working Voodle system by collecting a set of vocal features and associated robot motions, then incorporating them into a prototype for sketching robot behaviour. We explored and refined Voodle's expressive capacity by engaging expert performers in an iterative design process. We found that users develop a personal language with Voodle; that a vocalization's meaning changed with narrative context; and that voodling imparts a sense of life to the robot, inviting designers to suspend disbelief and engage in a playful, conversational style of design.