arXiv Machine Learning

Koopman Dreamer: Spectrally Constrained Latent Dynamics for Stable World-Model Imagination

arXiv:2607. 19719v1 Announce Type: new Abstract: Latent world models improve sample efficiency in continuous control by optimizing policies over imagined latent trajectories, but common neural transitions offer limited direct control over modal persistence and error accumulation in long rollouts.

arXiv AI
4d ago

Beyond a single latent space: a dual-latent world model for long-horizon planning

The paper introduces the Dual-Latent World Model (Dual-WM), which separates local execution and long-range planning into distinct latent spaces and dynamics models. A new learning method, Long-Horizon Representation Learning with Weighted Rollout (LoRe), supervises predictions at both levels using exponential horizon weights. Experiments on five goal-conditioned visual control tasks show that Dual-WM improves success rates over strong baselines, especially at longer horizons.

By Delin Zhao, Zhengrong Yue, Shaobin Zhuang, Junlin He, Xiaoyu Chen, Zikang Wang, Yuxin Liu, Limin Wang, Yali Wang
arXiv Machine Learning
Aug 27

Temporally Centered SIGReg Improves LeWorldModel Representations for Robot Policy Learning

The paper investigates the LeWorldModel (LeWM) and its Sketched Isotropic Gaussian Regularizer (SIGReg), showing that the original Raw LeWM objective biases variance toward temporally persistent components, which suppresses residual variance and hampers robot state decodability. By applying SIGReg specifically to temporally centered residuals, the authors decouple persistent and residual variance allocation, improving representation quality. On the LIBERO benchmark, this adjustment boosts downstream policy success on the Goal suite by 1.66× and raises overall success rates from 63.6% to 83.8%, outperforming Diffusion Policy and pretrained OpenVLA without external pretraining.

By Chang Liu, Fei Suo, Yanzhou Jin, Zeyu Ping, Yusuke Iwasawa, Yutaka Matsuo, Yaonan Zhu
arXiv AI
6d ago

HaM-World: Soft-Hamiltonian World Models with Selective Memory for Planning

HaM-World introduces a structured world model that combines history-conditioned selective memory with a Soft‑Hamiltonian latent dynamics prior. The model decomposes the latent state into a canonical (q,p) subspace governed by an energy‑derived Hamiltonian vector field and a context subspace c capturing non‑conservative factors, while Mamba selective state‑space memory conditions the transition used for prediction, reward, value estimation, and planning. Across six DeepMind Control Suite tasks, HaM-World achieves top rankings on four tasks, improves average AUC, reduces imagined‑rollout error by 45% on short‑to‑medium horizons, and outperforms baselines under 12 out‑of‑distribution perturbations.

By Haoyun Tang, Haodong Cui, Keyao Xu, Zhandong Mei, Kun Wang
arXiv Machine Learning
Sep 14

Dynin-Robotics: Omnimodal Unified Diffusion Vision-Language-Action Model

Dynin‑Robotics introduces an omnimodal masked‑diffusion backbone, Dynin‑Omni, that jointly represents language, visual observations, goals, and actions as discrete tokens. By conditioning on different spans, the same model learns action prediction, next‑observation prediction, goal‑state prediction, and trajectory‑to‑instruction reconstruction, enabling test‑time scaling through goal prediction and action‑candidate evaluation. The system, pretrained on 1.33 million trajectories from 48 Open X‑Embodiment datasets, achieves competitive performance on LIBERO, zero‑shot LIBERO‑Plus, and a 78.4 % success rate on a Franka Research 3 robot, while a block‑parallel implementation speeds up action decoding by up to 29.2×.

By Hoeun Lee, Jaeik Kim, Jusang Oh, Jinhyeok Kim, Geon Choi, Hyeonggeun Kim, Jaeyoung Do