Standby-Based Deadlock Avoidance Method for Multi-Agent Pickup and Delivery Tasks

Abstract

**Read paper on the following link:** https://ifaamas.org/Proceedings/aamas2022/pdfs/p1427.pdf **Abstract:** The multi-agent pickup and delivery (MAPD) problem, in which multiple agents iteratively carry materials without collisions, has received attention, but the conventional MAPD algorithms usually assume grid-like environments that are specifically designed such as automated warehouses. In these environments, many pickup/delivery locations are deployed where agents can stay for a long time, and the detours to avoid collision are plentiful because of freedom of movement. In contrast, a maze-like environment such as a rescue or a construction site generally has fewer pickup/delivery locations and the numbers may be unbalanced, resulting in many agents concentrating on these locations and inefficient operations. Moreover, the agents easily get stuck to avoid other agents and are deadlocked. Therefore, we propose a deadlock avoidance method, standby-based deadlock avoidance (SBDA), to improve transportation efficiency even in a maze-like environment. The SBDA is an algorithm using standby nodes, which is determined in real-time using the articulation-point-finding algorithm, and in which the agent is guaranteed to wait for any finite time. We demonstrated that our proposed method outperforms the conventional methods in maze-like restricted environments. Then, we analyze how the parameter for selecting standby nodes affects the performance.