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A robot controller's final layer was the only part worth replacing: a Gaussian readout trained on 0.02 percent of states matched the flow policy at up to twice the inference speed

AspireAI community · arXiv (Gaussian distillation of flow policies)
Flow policies are among the strongest robot controllers and naturally model multimodal action distributions, but they need many denoising steps per action, and this paper finds the fix does not require touching the policy itself. The authors show that the continuous-action distributions of the flow policies they study are well approximated by Gaussians, so the Gaussian Action Readout simply replaces the final layer with a Gaussian readout trained on just 0.02 percent of eligible states while the rest of the network stays frozen. That readout samples with a single action-network pass and gives closed-form likelihoods, reaching near-teacher task success at up to twice the inference speed. The limitation is that the analysis covers the flow policies the authors selected, and the headline speedup comes with a Gaussian approximation of a genuinely multimodal action distribution, so the approach may not transfer to policies whose action modes sit far apart.
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