Decentralized Model-Based ACKTR for Large-Scale Multi-Agent Path Planning Under Partial Observability
Multi-agent path planning (MAPP) under partial observability requires agents to coordinate their movements and complete tasks efficiently without access to global information. The planning space and coordination complexity grow rapidly with increasing numbers of agents, targets, and obstacles. We formulate large-scale MAPP as a partially observable networked Markov decision process. Based on this formulation, we propose a decentralized model-based Actor-Critic using the Kronecker-factored trust region (DM-ACKTR) algorithm. The algorithm integrates local model learning with ACKTR-based policy optimization in an independent learning architecture. Each agent learns a local model to predict the next observation and reward. These predictions are used to construct additional transitions for Actor and Critic updates. A neighborhood-based communication mechanism incorporates information from nearby agents into value estimation. Region partitioning reduces each agent’s effective planning space. These improvements enable DM-ACKTR to continue outperforming the baseline algorithms as the scale of the MAPP problem increases. Experiments across three training and five evaluation scenarios show that DM-ACKTR achieves the best overall performance. Among the five evaluated algorithms, it consistently obtains the highest TCR and lowest CR, improving TCR by 2.06–4.35% and reducing CR by 11.26–25.95% relative to the respective best baselines.