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Glossary · EXPLAINER

What is a VLA (vision-language-action) model?

A VLA model is a robot foundation model that takes camera images and a language instruction and outputs robot actions directly.

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Definition

A vision-language-action (VLA) model maps what the robot sees and what it is told to what it should do. Most start from a pretrained vision-language model and add an action head trained on robot data.

How it works

  1. Encode images (and often robot state) plus the text instruction.
  2. Predict future actions such as end-effector poses and gripper commands.
  3. Execute some actions, observe again, and re-plan.

Why it matters

VLAs are the main approach behind "generalist" robot policies that work across tasks and robot types. See embodied AI.

Frequently asked questions

How does a VLA differ from a vision-language model (VLM)?

A VLM answers in text. A VLA adds an action output, typically a short sequence of future motor commands, so it can control a robot.

What is an action chunk?

A fixed-length sequence of future actions predicted at once. Research such as Vela explores continuous trajectories instead.

What are the limitations of VLAs?

Many rely mostly on the current camera frame, lack touch and memory, and struggle with long, contact-rich tasks. Models like NEURA's Neuron AI add more senses and memory.

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