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Positive-Only Drifting Policy Optimization

Machine Learning 2026-04-21 v1 Robotics

Abstract

In the field of online reinforcement learning (RL), traditional Gaussian policies and flow-based methods are often constrained by their unimodal expressiveness, complex gradient clipping, or stringent trust-region requirements. Moreover, they all rely on post-hoc penalization of negative samples to correct erroneous actions. This paper introduces Positive-Only Drifting Policy Optimization (PODPO), a likelihood-free and gradient-clipping-free generative approach for online RL. By leveraging the drifting model, PODPO performs policy updates via advantage-weighted local contrastive drifting. Relying solely on positive-advantage samples, it elegantly steers actions toward high-return regions while exploiting the inherent local smoothness of the generative model to enable proactive error prevention. In doing so, PODPO opens a promising new pathway for generative policy learning in online settings.

Keywords

Cite

@article{arxiv.2604.16519,
  title  = {Positive-Only Drifting Policy Optimization},
  author = {Qi Zhang},
  journal= {arXiv preprint arXiv:2604.16519},
  year   = {2026}
}

Comments

12 pages, 6 figures

R2 v1 2026-07-01T12:15:09.232Z