Online Prototype Alignment for Few-shot Policy Transfer

TL;DR

This paper introduces Online Prototype Alignment (OPA), a novel RL domain adaptation method that enables few-shot policy transfer by aligning elements based on functionality rather than visual similarity, with efficient exploration.

Contribution

The paper proposes a new framework for RL domain adaptation that learns functional element mappings with minimal target domain data, outperforming prior visual-based methods.

Findings

OPA achieves better transfer with fewer target samples.

It outperforms prior methods in visually different domains.

Effective in few-shot RL policy transfer scenarios.

Abstract

Domain adaptation in reinforcement learning (RL) mainly deals with the changes of observation when transferring the policy to a new environment. Many traditional approaches of domain adaptation in RL manage to learn a mapping function between the source and target domain in explicit or implicit ways. However, they typically require access to abundant data from the target domain. Besides, they often rely on visual clues to learn the mapping function and may fail when the source domain looks quite different from the target domain. To address these problems, we propose a novel framework Online Prototype Alignment (OPA) to learn the mapping function based on the functional similarity of elements and is able to achieve the few-shot policy transfer within only several episodes. The key insight of OPA is to introduce an exploration mechanism that can interact with the unseen elements of the target domain in an efficient and purposeful manner, and then connect them with the seen elements in the source domain according to their functionalities (instead of visual clues). Experimental results show that when the target domain looks visually different from the source domain, OPA can achieve better transfer performance even with much fewer samples from the target domain, outperforming prior methods.