A robot policy predicted future scenes in latent space instead of pixels and cut wall-clock latency up to 24 times
AspireAI community · arXiv (Jialei Chen, Kai Wang, Kang Chen)
Vision-language-action models follow instructions well but rarely look ahead, and world-action models that do condition on predicted futures usually pay for it with expensive pixel-level video generation. LaWAM exposes predictive dynamics to the policy through compact latent visual subgoals instead of reconstructed future video, training a latent action model in the latent space of a pretrained vision foundation model and repurposing its forward decoder to predict future observation features. It reaches state-of-the-art or competitive success rates across LIBERO at 98.6 percent and RoboTwin at 91.22 percent plus real-world manipulation, runs at 187 ms per action-chunk prediction, and achieves up to 24 times lower wall-clock latency than pixel-space world-action models.
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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.