TMRL: Diffusion Timestep-Modulated Pretraining Enables Exploration for Efficient Policy Finetuning
On the map: Offline RL and imitation learning from data → Diffusion and flow policies for offline RL
Abstract (arXiv)
Fine-tuning pre-trained robot policies with reinforcement learning (RL) often inherits the bottlenecks introduced by pre-training with behavioral cloning (BC), which produces narrow action distributions that lack the coverage necessary for downstream exploration. We present a unified framework that enables the exploration necessary to enable efficient robot policy finetuning by bridging BC pre-training and RL fine-tuning. Our pre-training method, Context-Smoothed Pre-training (CSP), injects forward-diffusion noise into policy inputs, creating a continuum between precise imitation and broad action coverage. We then fine-tune pre-trained policies via Timestep-Modulated Reinforcement Learning (TMRL), which trains the agent to dynamically adjust this conditioning during fine-tuning by modulating the diffusion timestep, granting explicit control over exploration. Integrating seamlessly with arbitrary policy inputs, e.g., states, 3D point clouds, or image-based VLA policies, we show that TMRL improves RL fine-tuning sample efficiency. Notably, TMRL enables successful real-world fine-tuning on complex manipulation tasks in under one hour. Videos and code available at https://weirdlabuw.github.io/tmrl/.
Key facts. Cited by 3 papers in the map (data through 13 Oct 2026). Placed in Diffusion and flow policies for offline RL, one of 13 directions in Offline RL and imitation learning from data. Builds on 59 of its 68 references that are in the map. First posted on arXiv 12 May 2026.
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Citing papers per year: 2026: 3.
3 papers.
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- 2026Imperfection for Precision: Upcycling Imperfect Data for High-Precision Robotic Manipulation22 Sep 2026
- 2026Support-Constrained RL Enables Real-World Policy Improvement without Real-World Experience25 Jun 2026
- 2026Ambient Diffusion Policy: Imitation Learning from Suboptimal Data in Robotics10 Jun 2026
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