Accelerating Proximal Policy Optimization Learning Using Task Prediction for Solving Environments with Delayed Rewards

Fuente: arXiv
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Main Authors: Ahmad, Ahmad, Kermanshah, Mehdi, Leahy, Kevin, Serlin, Zachary, Siu, Ho Chit, Mann, Makai, Vasile, Cristian-Ioan, Tron, Roberto, Belta, Calin
Format: Preprint
Published: 2024
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author Ahmad, Ahmad
Kermanshah, Mehdi
Leahy, Kevin
Serlin, Zachary
Siu, Ho Chit
Mann, Makai
Vasile, Cristian-Ioan
Tron, Roberto
Belta, Calin
author_facet Ahmad, Ahmad
Kermanshah, Mehdi
Leahy, Kevin
Serlin, Zachary
Siu, Ho Chit
Mann, Makai
Vasile, Cristian-Ioan
Tron, Roberto
Belta, Calin
contents In this paper, we tackle the challenging problem of delayed rewards in reinforcement learning (RL). While Proximal Policy Optimization (PPO) has emerged as a leading Policy Gradient method, its performance can degrade under delayed rewards. We introduce two key enhancements to PPO: a hybrid policy architecture that combines an offline policy (trained on expert demonstrations) with an online PPO policy, and a reward shaping mechanism using Time Window Temporal Logic (TWTL). The hybrid architecture leverages offline data throughout training while maintaining PPO's theoretical guarantees. Building on the monotonic improvement framework of Trust Region Policy Optimization (TRPO), we prove that our approach ensures improvement over both the offline policy and previous iterations, with a bounded performance gap of $(2ςγα^2)/(1-γ)^2$, where $α$ is the mixing parameter, $γ$ is the discount factor, and $ς$ bounds the expected advantage. Additionally, we prove that our TWTL-based reward shaping preserves the optimal policy of the original problem. TWTL enables formal translation of temporal objectives into immediate feedback signals that guide learning. We demonstrate the effectiveness of our approach through extensive experiments on an inverted pendulum and a lunar lander environments, showing improvements in both learning speed and final performance compared to standard PPO and offline-only approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17861
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Accelerating Proximal Policy Optimization Learning Using Task Prediction for Solving Environments with Delayed Rewards
Ahmad, Ahmad
Kermanshah, Mehdi
Leahy, Kevin
Serlin, Zachary
Siu, Ho Chit
Mann, Makai
Vasile, Cristian-Ioan
Tron, Roberto
Belta, Calin
Machine Learning
Artificial Intelligence
In this paper, we tackle the challenging problem of delayed rewards in reinforcement learning (RL). While Proximal Policy Optimization (PPO) has emerged as a leading Policy Gradient method, its performance can degrade under delayed rewards. We introduce two key enhancements to PPO: a hybrid policy architecture that combines an offline policy (trained on expert demonstrations) with an online PPO policy, and a reward shaping mechanism using Time Window Temporal Logic (TWTL). The hybrid architecture leverages offline data throughout training while maintaining PPO's theoretical guarantees. Building on the monotonic improvement framework of Trust Region Policy Optimization (TRPO), we prove that our approach ensures improvement over both the offline policy and previous iterations, with a bounded performance gap of $(2ςγα^2)/(1-γ)^2$, where $α$ is the mixing parameter, $γ$ is the discount factor, and $ς$ bounds the expected advantage. Additionally, we prove that our TWTL-based reward shaping preserves the optimal policy of the original problem. TWTL enables formal translation of temporal objectives into immediate feedback signals that guide learning. We demonstrate the effectiveness of our approach through extensive experiments on an inverted pendulum and a lunar lander environments, showing improvements in both learning speed and final performance compared to standard PPO and offline-only approaches.
title Accelerating Proximal Policy Optimization Learning Using Task Prediction for Solving Environments with Delayed Rewards
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2411.17861