Social Triangles and Aggressive Lines: Multi-Robot Formations Impact Navigation and Approach

Spatial formations can give many social cues, such as illustrating a group of people are having a conversation (social affiliation), or that they are trying to move swiftly through a space (functional goal). This work explored how people perceive varied robots formations while navigating through a space and approaching people. Evaluation occurred across four different geometric formations: wedge, v-shape, vertical line, and horizontal line (Fig 3). Two studies were conducted: the first being an exploratory study of three robots navigating through a public space, and the second being a controlled user study of the same robots approaching humans in different formations. Results showed that triangle shapes were generally received more positively than lines, with wedge being the viewed as harmless, polite, welcoming, and encouraging the human to join the robot group, whereas horizontal line was seen as threatening and unwelcoming. From a path planning perspective, v-shape and wedge were also more robust to controller variance. Results from this work show that formation impacts how people perceive robots, and as a result may impact task success. Future researchers can use these results to inform their behavior design for multi-robot groups to increase task success and desired communication effects.