Research Interests

My research sits at the intersection of reinforcement learning, large language models, and robot learning. Below is a more detailed account of the specific directions I am pursuing and the questions that drive my work.

RL Post-Training for Language Models

A central theme of my research is understanding how reinforcement learning can be used after supervised pre-training to unlock new capabilities in large language models. Recent work has shown that RL-based post-training—such as RLHF [1] and RLVR [2]—can substantially improve reasoning, instruction following, and alignment. I am particularly interested in:

  • Self-distillation and self-play: can models improve by training on their own outputs, bootstrapping capability without new human data? This connects to ideas from expert iteration [3] and self-play in games [4].
  • Reward modeling and reward hacking: how do we design reward signals that remain faithful proxies for human intent as models become more capable? The problem of reward hacking [5] is a key bottleneck.
  • Continual RL post-training: rather than a single RL fine-tuning phase, can we develop curricula that iteratively refine models over time, akin to continual learning [6]?

Robot Learning and Visuomotor Policies

The second pillar of my work concerns learning sensorimotor policies for robotic manipulation. Foundation models pre-trained on internet-scale data provide rich representations, but bridging the gap to physical action remains an open challenge. I am exploring:

  • Vision-language-action models (VLAs): architectures that map visual observations and language instructions directly to robot actions [7], and how to fine-tune them efficiently for new tasks.
  • On-policy RL for robotics: methods like PPO [8] and GRPO [2] applied in simulation and on real hardware, with a focus on sample efficiency and sim-to-real transfer.
  • World models and planning: learning predictive models of environment dynamics [9] that enable model-based planning and reduce the need for costly real-world interaction.

Unifying Theme

RL is the connective tissue across these interests. Whether the “backbone” is a language model or a visuomotor policy, the core algorithmic questions are shared: how to define good reward signals, how to explore efficiently, and how to leverage pre-trained representations for downstream adaptation. I believe progress on these fronts will be mutually reinforcing—advances in RL post-training for LLMs will inform robot learning, and vice versa.

References

[1]
L. Ouyang et al., “Training language models to follow instructions with human feedback,” Advances in Neural Information Processing Systems, vol. 35, pp. 27730–27744, 2022.
[2]
Z. Shao et al., “DeepSeekMath: Pushing the limits of mathematical reasoning in open language models,” arXiv preprint arXiv:2402.03300, 2024.
[3]
T. Anthony, Z. Tian, and D. Barber, “Thinking fast and slow with deep learning and tree search,” in Advances in neural information processing systems, 2017.
[4]
D. Silver et al., “Mastering the game of Go without human knowledge,” Nature, vol. 550, no. 7676, pp. 354–359, 2017.
[5]
J. Skalse, N. Howe, D. Krasheninnikov, and D. Krueger, “Defining and characterizing reward hacking,” Advances in Neural Information Processing Systems, vol. 35, pp. 20460–20471, 2022.
[6]
J. Kirkpatrick et al., “Overcoming catastrophic forgetting in neural networks,” Proceedings of the National Academy of Sciences, vol. 114, no. 13, pp. 3521–3526, 2017.
[7]
A. Brohan et al., “RT-2: Vision-language-action models transfer web knowledge to robotic control,” arXiv preprint arXiv:2307.15818, 2023.
[8]
J. Schulman, F. Wolski, P. Dhariwal, A. Radford, and O. Klimov, “Proximal policy optimization algorithms,” arXiv preprint arXiv:1707.06347, 2017.
[9]
D. Hafner, J. Pasukonis, J. Ba, and T. Lillicrap, “Mastering diverse domains through world models,” arXiv preprint arXiv:2301.04104, 2023.