Communication of intent in assistive free flyers

Assistive free-flyers (AFFs) are an emerging robotic platform with unparalleled flight capabilities that appear uniquely suited to exploration, surveillance, inspection, and telepresence tasks. However, unconstrained aerial movements may make it difficult for colocated operators, collaborators, and observers to understand AFF intentions, potentially leading to difficulties understanding whether operator instructions are being executed properly or to safety concerns if future AFF motions are unknown or difficult to predict. To increase AFF usability when working in close proximity to users, we explore the design of natural and intuitive flight motions that may improve AFF abilities to communicate intent while simultaneously accomplishing task goals. We propose a formalism for representing AFF flight paths as a series of motion primitives and present two studies examining the effects of modifying the trajectories and velocities of these flight primitives based on natural motion principles. Our first study found that modified flight motions might allow AFFs to more effectively communicate intent and, in our second study, participants preferred interacting with an AFF that used a manipulated flight path, rated modified flight motions as more natural, and felt safer around an AFF with modified motion. Our proposed formalism and findings highlight the importance of robot motion in achieving effective human-robot interactions.