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Main Authors: Aghabozorgi, Mehran, Moazeni, Alireza, Zhang, Yanshu, Li, Ke
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.14351
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author Aghabozorgi, Mehran
Moazeni, Alireza
Zhang, Yanshu
Li, Ke
author_facet Aghabozorgi, Mehran
Moazeni, Alireza
Zhang, Yanshu
Li, Ke
contents Model-based reinforcement learning promises strong sample efficiency but often underperforms in practice due to compounding model error, unimodal world models that average over multi-modal dynamics, and overconfident predictions that bias learning. We introduce WIMLE, a model-based method that extends Implicit Maximum Likelihood Estimation (IMLE) to the model-based RL framework to learn stochastic, multi-modal world models without iterative sampling and to estimate predictive uncertainty via ensembles and latent sampling. During training, WIMLE weights each synthetic transition by its predicted confidence, preserving useful model rollouts while attenuating bias from uncertain predictions and enabling stable learning. Across $40$ continuous-control tasks spanning DeepMind Control, MyoSuite, and HumanoidBench, WIMLE achieves superior sample efficiency and competitive or better asymptotic performance than strong model-free and model-based baselines. Notably, on the challenging Humanoid-run task, WIMLE improves sample efficiency by over $50$\% relative to the strongest competitor, and on HumanoidBench it solves $8$ of $14$ tasks (versus $4$ for BRO and $5$ for SimbaV2). These results highlight the value of IMLE-based multi-modality and uncertainty-aware weighting for stable model-based RL.
format Preprint
id arxiv_https___arxiv_org_abs_2602_14351
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle WIMLE: Uncertainty-Aware World Models with IMLE for Sample-Efficient Continuous Control
Aghabozorgi, Mehran
Moazeni, Alireza
Zhang, Yanshu
Li, Ke
Machine Learning
Artificial Intelligence
Model-based reinforcement learning promises strong sample efficiency but often underperforms in practice due to compounding model error, unimodal world models that average over multi-modal dynamics, and overconfident predictions that bias learning. We introduce WIMLE, a model-based method that extends Implicit Maximum Likelihood Estimation (IMLE) to the model-based RL framework to learn stochastic, multi-modal world models without iterative sampling and to estimate predictive uncertainty via ensembles and latent sampling. During training, WIMLE weights each synthetic transition by its predicted confidence, preserving useful model rollouts while attenuating bias from uncertain predictions and enabling stable learning. Across $40$ continuous-control tasks spanning DeepMind Control, MyoSuite, and HumanoidBench, WIMLE achieves superior sample efficiency and competitive or better asymptotic performance than strong model-free and model-based baselines. Notably, on the challenging Humanoid-run task, WIMLE improves sample efficiency by over $50$\% relative to the strongest competitor, and on HumanoidBench it solves $8$ of $14$ tasks (versus $4$ for BRO and $5$ for SimbaV2). These results highlight the value of IMLE-based multi-modality and uncertainty-aware weighting for stable model-based RL.
title WIMLE: Uncertainty-Aware World Models with IMLE for Sample-Efficient Continuous Control
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.14351