ELEGNT: Expressive and functional motion design for a non-anthropomorphic robot

Nonverbal behaviors such as posture, touch, and gaze are important in conveying internal states, consciously and unconsciously, in human interactions. For robots to interact naturally with humans, the design of robot movements must similarly incorporate expressive qualities—such as intent, attention, and emotion—as well as general operational considerations such as task accomplishment, spatial constraints, and time efficiency. In this paper, we present the design and prototyping of a lamp-like robot that explores the intersection between functional and expressive goals in motion design. Using a design research approach, we document the hardware design process, define motion primitives, and present a set of interactive status storyboards. We propose a framework that integrates both active and implicit resources during movement generation, and apply a sequence of robot behaviors to task- and community-oriented tasks. Through a user study comparing speech-driven motion versus performance across six task scenarios, our findings show that speech-driven motion significantly improves user interaction and perceived robot attributes. This effect is particularly evident in community-oriented activities.