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arXiv · 2605.02739

Latent Bridge: Feature Delta Prediction for Efficient Dual-System Vision-Language-Action Model Inference

Yudong Liu·Yuan Li·Zijia Tang·Yuxi Zheng·Yueqian Lin·Qinsi Wang·Yi Li·Shuangjun Liu·Shuai Zhang·Taotao Jing·Dashan Gao·Ning Bi·Jingwei Sun·Yiran Chen·Hai Li
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Abstract

Dual-system Vision-Language-Action (VLA) models achieve state-of-the-art robotic manipulation but are bottlenecked by the VLM backbone, which must execute at every control step while producing temporally redundant features. We propose Latent Bridge, a lightweight model that predicts VLM output deltas between timesteps, enabling the action head to operate on predicted outputs while the expensive VLM backbone is called only periodically. We instantiate Latent Bridge on two architecturally distinct VLAs: GR00T-N1.6 (feature-space bridge) and π0.5 (KV-cache bridge), demonstrating that the approach generalizes across VLA designs. Our task-agnostic DAgger training pipeline transfers across benchmarks without modification. Across four LIBERO suites, 24 RoboCasa kitchen tasks, and the ALOHA sim transfer-cube task, Latent Bridge achieves 95-100% performance retention while reducing VLM calls by 50-75%, yielding 1.65-1.73x net per-episode speedup.

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Yudong Liu, Yuan Li, Zijia Tang, Yuxi Zheng, Yueqian Lin, Qinsi Wang, Yi Li, Shuangjun Liu, Shuai Zhang, Taotao Jing, Dashan Gao, Ning Bi, Jingwei Sun, Yiran Chen, Hai Li. 2026-05-04. Latent Bridge: Feature Delta Prediction for Efficient Dual-System Vision-Language-Action Model Inference. https://arxiv.org/abs/2605.02739

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