# XR-1-Stage2

[[Project Page](https://github.com/Open-X-Humanoid/XR-1)] [[Paper](https://www.google.com/search?q=https://arxiv.org/abs/2411.02776v1)] [[GitHub](https://github.com/Open-X-Humanoid/XR-1)]

This repository contains the **Stage 2** weights for the **XR-1 (X Robotic Model 1)** project. This is the large-scale **Vision-Language-Action (VLA)** policy trained on top of the Unified Vision-Motion Codes (UVMC).

## 🤖 Model Description

**XR-1-Stage2** is a generative Transformer-based policy. While Stage 1 focused on tokenizing sensory and action data, Stage 2 performs the high-level reasoning required to map natural language instructions and visual observations into executable robotic actions.

### Key Features

* **VLA Architecture**: Integrates vision, language, and action into a unified Transformer framework.
* **Token-Based Policy**: Operates on the discrete latent space defined by the [XR-1-Stage1-UVMC](https://huggingface.co/X-Humanoid/XR-1-Stage1-UVMC) tokenizer.
* **End-to-End Control**: Predicts the next set of action tokens based on the current visual state and text prompt.

## 🧱 Model Hierarchy

1. **Stage 1 (UVMC)**: Encodes images and actions into discrete tokens.
2. **Stage 2 (VLA)**: **[This Model]** Predicts action tokens given instruction and image tokens.

## 🛠 Usage

To deploy this policy, you need both the Stage 1 tokenizer and these Stage 2 weights. Please refer to the [XR-1 GitHub Repository](https://github.com/Open-X-Humanoid/XR-1) for inference scripts and environment setup.


## 📝 Citation

If you use the XR-1 model in your research, please cite our work:

```bibtex
@article{fan2025xr,
  title={XR-1: Towards Versatile Vision-Language-Action Models via Learning Unified Vision-Motion Representations},
  author={Fan, Shichao and Wu, Kun and Che, Zhengping and Wang, Xinhua and Wu, Di and Liao, Fei and Liu, Ning and Zhang, Yixue and Zhao, Zhen and Xu, Zhiyuan and others},
  journal={arXiv preprint arXiv:2411.02776},
  year={2025}
}

```

## 📜 License

This project is licensed under the [MIT License](https://github.com/Open-X-Humanoid/XR-1/blob/main/LICENSE).

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**Contact**: For questions, please open an issue on our [GitHub](https://github.com/Open-X-Humanoid/XR-1) or contact us at opensource@x-humanoid.com.