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Main Authors: Chen, Xulin, Liu, Ruipeng, Gan, Zhenyu, Katz, Garrett E.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2404.13879
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author Chen, Xulin
Liu, Ruipeng
Gan, Zhenyu
Katz, Garrett E.
author_facet Chen, Xulin
Liu, Ruipeng
Gan, Zhenyu
Katz, Garrett E.
contents Uncertainties in transition dynamics pose a critical challenge in reinforcement learning (RL), often resulting in performance degradation of trained policies when deployed on hardware. Many robust RL approaches follow two strategies: enforcing smoothness in actor or actor-critic modules with Lipschitz regularization, or learning robust Bellman operators. However, the first strategy does not investigate the impact of critic-only Lipschitz regularization on policy robustness, while the second lacks comprehensive validation in real-world scenarios. Building on this gap and prior work, we propose PPO-PGDLC, an algorithm based on Proximal Policy Optimization (PPO) that integrates Projected Gradient Descent (PGD) with a Lipschitz-regularized critic (LC). The PGD component calculates the adversarial state within an uncertainty set to approximate the robust Bellman operator, and the Lipschitz-regularized critic further improves the smoothness of learned policies. Experimental results on two classic control tasks and one real-world robotic locomotion task demonstrates that, compared to several baseline algorithms, PPO-PGDLC achieves better performance and predicts smoother actions under environmental perturbations.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13879
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Lipschitz-Regularized Critics Lead to Policy Robustness Against Transition Dynamics Uncertainty
Chen, Xulin
Liu, Ruipeng
Gan, Zhenyu
Katz, Garrett E.
Machine Learning
Uncertainties in transition dynamics pose a critical challenge in reinforcement learning (RL), often resulting in performance degradation of trained policies when deployed on hardware. Many robust RL approaches follow two strategies: enforcing smoothness in actor or actor-critic modules with Lipschitz regularization, or learning robust Bellman operators. However, the first strategy does not investigate the impact of critic-only Lipschitz regularization on policy robustness, while the second lacks comprehensive validation in real-world scenarios. Building on this gap and prior work, we propose PPO-PGDLC, an algorithm based on Proximal Policy Optimization (PPO) that integrates Projected Gradient Descent (PGD) with a Lipschitz-regularized critic (LC). The PGD component calculates the adversarial state within an uncertainty set to approximate the robust Bellman operator, and the Lipschitz-regularized critic further improves the smoothness of learned policies. Experimental results on two classic control tasks and one real-world robotic locomotion task demonstrates that, compared to several baseline algorithms, PPO-PGDLC achieves better performance and predicts smoother actions under environmental perturbations.
title Lipschitz-Regularized Critics Lead to Policy Robustness Against Transition Dynamics Uncertainty
topic Machine Learning
url https://arxiv.org/abs/2404.13879