A robot policy that notices it is drifting and replans, without retraining the backbone
AspireAI community · arXiv
Generative robot policies execute an action chunk open-loop to reduce policy-call frequency, which costs closed-loop reactivity - in contact-rich interaction, small perturbations compound inside the blind spot. VLA-Corrector adds a lightweight latent-space vision monitor that continuously compares predicted and actual visual feature evolution, and when deviation persists it truncates the chunk, discards the stale actions and calls corrective replanning through online gradient guidance. The monitor induces an event-triggered action horizon: long-horizon execution when the chunk is still reliable, short-horizon correction when it is not. It plugs into different VLA models without retraining the backbone and, per the authors, interrupts compounding errors while preserving much of the efficiency benefit of chunking and improving robustness on long-horizon contact-rich manipulation.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.