Implicit Projection: Improving Team Situation Awareness for Tacit Human-Robot Interaction via Virtual Shadows

Fluent teaming is characterized by tacit interaction without explicit communication. Such interaction requires team situation awareness (TSA) to facilitate. However, existing approaches often rely on explicit communication (such as visual projection) to support TSA, resulting in a paradox. In this paper, we consider implicit projection (IP) to improve TSA for tacit human-robot interaction. IP minimizes interruption and can thus reduce the cognitive demand to maintain TSA in teaming. We introduce a novel process for achieving IP via virtual shadows (referred to as IPS). We compare our method with two baselines that use explicit projection to maintain TSA. Results via human factors studies demonstrate that IPS supports better TSA and significantly improves unsolicited human responsiveness to robots, a key feature of fluent teaming. Participants acknowledged robots implementing IPS more favorable as a teammate. Simultaneously, our results also demonstrate that IPS is comparable to, and sometimes better than, the best-performing baselines on information accuracy.