Indiana University Bloomington

Luddy School of Informatics, Computing, and Engineering

Technical Report TR745:
Meta Proximal Policy Optimization for Cooperative Multi-Agent Continuous Control

Boli Fang
(May 2022), 35 pages
[2. Additional Notes: Master Thesis; paper has been accepted at IJCNN 2022.]
In this thesis we propose Multi-Agent Proxy Proximal Policy Optimization (MA3PO), a novel multi-agent deep reinforcement learning algorithm that tackles the challenge of cooperative continuous multi-agent control. Our method is driven by the observation that most existing multi-agent reinforcement learning algorithms mainly focus on discrete state/action spaces and are thus computationally infeasible when extended to environments with continuous state/action spaces.

To address the issue of computational complexity and to better model intra-agent collaboration, we make use of the recently successful Proximal Policy Optimization algorithm that effectively explores of continuous action spaces, and incorporate the notion of emph{intrinsic motivation} via emph{meta-gradient methods} so as to stimulate the behavior of individual agents in cooperative multi-agent settings. Towards these ends, we design proxy rewards to quantify the effect of individual agent-level intrinsic motivation onto the team-level reward, and apply meta-gradient methods to leverage such an addition with a learning-to-learning optimization paradigm so that our algorithm can learn the team-level cumulative reward effectively.

Furthermore, we have also conducted experiments on various open multi-agent reinforcement learning benchmark environments with continuous action spaces. Our results demonstrate that our meta proximal policy optimization algorithm is not only comparable with other existing state-of-the-art algorithmic benchmarks in terms of performances, but also significantly reduces training time complexity as compared to existing techniques.

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