OPIRL: Sample Efficient Off-Policy Inverse Reinforcement Learning via Distribution Matching

TL;DR

OPIRL introduces a sample-efficient off-policy IRL method that reduces environment interactions, learns transferable reward functions, and generalizes well across different environments and tasks.

Contribution

The paper proposes OPIRL, a novel off-policy IRL algorithm that improves sample efficiency and reward generalization compared to prior on-policy methods.

Findings

Significantly fewer environment interactions needed

Achieves comparable or better policy performance

Reward functions generalize across tasks and dynamics

Abstract

Inverse Reinforcement Learning (IRL) is attractive in scenarios where reward engineering can be tedious. However, prior IRL algorithms use on-policy transitions, which require intensive sampling from the current policy for stable and optimal performance. This limits IRL applications in the real world, where environment interactions can become highly expensive. To tackle this problem, we present Off-Policy Inverse Reinforcement Learning (OPIRL), which (1) adopts off-policy data distribution instead of on-policy and enables significant reduction of the number of interactions with the environment, (2) learns a stationary reward function that is transferable with high generalization capabilities on changing dynamics, and (3) leverages mode-covering behavior for faster convergence. We demonstrate that our method is considerably more sample efficient and generalizes to novel environments through the experiments. Our method achieves better or comparable results on policy performance baselines with significantly fewer interactions. Furthermore, we empirically show that the recovered reward function generalizes to different tasks where prior arts are prone to fail.