Learning Generalizable Skills from Offline Multi-Task Data for Multi-Agent Cooperation
Sicong Liu, Yang Shu, Chenjuan Guo, Bin Yang
TL;DR
This work addresses generalization in offline multi-task MARL by introducing HiSSD, a hierarchical framework that separates learning into common skills for cooperative temporal knowledge and task-specific skills for per-task action execution. The high-level planner learns transferable skills via KL-divergence trajectory matching and a forward state predictor, while the low-level controller leverages $eta$-VAE-based task embeddings and contrastive learning to tailor actions per task, all trained offline with an implicit Q-learning objective. Empirical results on SMAC and MAMuJoCo demonstrate robust unseen-task performance and meaningful skill visualizations, validating improved policy transfer and adaptive execution. Overall, HiSSD advances offline multi-task MARL by enabling robust generalization and task-aware action control without online interaction.
Abstract
Learning cooperative multi-agent policy from offline multi-task data that can generalize to unseen tasks with varying numbers of agents and targets is an attractive problem in many scenarios. Although aggregating general behavior patterns among multiple tasks as skills to improve policy transfer is a promising approach, two primary challenges hinder the further advancement of skill learning in offline multi-task MARL. Firstly, extracting general cooperative behaviors from various action sequences as common skills lacks bringing cooperative temporal knowledge into them. Secondly, existing works only involve common skills and can not adaptively choose independent knowledge as task-specific skills in each task for fine-grained action execution. To tackle these challenges, we propose Hierarchical and Separate Skill Discovery (HiSSD), a novel approach for generalizable offline multi-task MARL through skill learning. HiSSD leverages a hierarchical framework that jointly learns common and task-specific skills. The common skills learn cooperative temporal knowledge and enable in-sample exploitation for offline multi-task MARL. The task-specific skills represent the priors of each task and achieve a task-guided fine-grained action execution. To verify the advancement of our method, we conduct experiments on multi-agent MuJoCo and SMAC benchmarks. After training the policy using HiSSD on offline multi-task data, the empirical results show that HiSSD assigns effective cooperative behaviors and obtains superior performance in unseen tasks.
