ResearchResearch paperRobotics & Embodied AI1 source · Oct 16, 2026

MambaAct: Efficient Mamba Action Experts for Flow-Matching Vision-Language-Action Models

We introduce MambaAct, an efficient Mamba action expert for flow-matching VLA policies.

Key points

  • Vision-language-action (VLA) models have shown strong promise for generalist robotic manipulation, but their inference cost remains a major bottleneck for real-time control.
  • This limitation is especially pronounced in flow-matching VLAs such as $π{0.5}$, where the action expert is evaluated repeatedly during iterative denoising.
  • MambaAct retains the pretrained visual-language prefix encoder of $π{0.5}$, while replacing its transformer-based action expert with a compact Mamba-based action expert.
  • To preserve visual-language conditioning without repeated token-level cross-attention, MambaAct uses a lightweight Context Compressor to map Vision-language model (VLM) prefix tokens into a compact conditioning signal that gates and modulates each Mamba action block.

Sources (1)

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Before this

  1. Oct 15, 2026Granite Switch 4.1: Chat, Decisions, and Speech from One Endpoint
  2. Oct 15, 2026When Plans Change, Remember: Replanning-Guided Visual Memory for Vision-Language-Action Models
  3. Oct 15, 2026REKI: Registering Knowledge in VLAs
  4. Oct 15, 2026FastVLA: Task-Conditioned and Temporally Adaptive Visual Token Compression for Efficient Vision-Language-Action Models
  5. Oct 15, 2026Fast-VLA: You Only Think Once for Robot Manipulation
  6. Oct 15, 2026VLA-$Δ$: Learning Physical State Transition for Vision-Language-Action Models

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