Non-verbal behaviors such as posture, gestures and gaze are essential to convey internal states, both consciously and unconsciously, in human interaction. For robots to interact more naturally with humans, robot motion design must also integrate expressive qualities, such as intention, attention, and emotions, into traditional functional considerations such as task completion, constraints space and time efficiency. In this article, we present the design and prototyping of a lamp-like robot that explores the interplay between functional and expressive goals in motion design. Using a research design methodology, we document the hardware design process, define expressive motion primitives, and describe a set of interaction scenario storyboards. We propose a framework that incorporates functional and expressive utilities during motion generation and implement the behavioral sequences of robots in different function-oriented and social tasks. Through a user study comparing expression-driven movements versus function-driven movements in six task scenarios, our findings indicate that expression-driven movements significantly improve user engagement and perceived robot qualities. This effect is especially pronounced in socially oriented tasks.
ELEGNT: expressive and functional movement design for non-anthropomorphic robot
