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robotics-diffusion-transformer/RDT2-VQ

sourceHugging Faceapache-2.0updated 8mo agoView on Hugging Face
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RDT2-VQ: Vision-Language-Action with Residual VQ Action Tokens

RDT2-VQ is an autoregressive Vision-Language-Action (VLA) model adapted from [Qwen2.5-VL-7B-Instruct](https://huggingface.co/Qwen/Qwen2.5-VL-7B-Instruct) and trained on large-scale UMI bimanual manipulation data. It predicts a short-horizon relative action chunk (24 steps, 20 dims/step) from binocular wrist-camera RGB and a natural-language instruction. Actions are discretized with a lightweight Residual VQ (RVQ) tokenizer, enabling robust zero-shot transfer across unseen embodiments for simple, open-vocabulary skills (e.g., pick, place, shake, wipe).

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Table of contents


Highlights

  • Zero-shot cross-embodiment: Demonstrated on Bimanual UR5e and Franka Research 3 setups; designed to generalize further with correct hardware calibration.
  • UMI scale: Trained on 10k+ hours from 100+ indoor scenes of human manipulation with the UMI gripper.
  • Residual VQ action tokenizer: Compact, stable action codes; open-vocabulary instruction following via Qwen2.5-VL-7B backbone.

Model details

Architecture

  • Backbone: Qwen2.5-VL-7B-Instruct (vision-language).
  • Observation: Two wrist-camera RGB images (right/left), 384×384, JPEG-like statistics.
  • Instruction: Short imperative text, recommended format “Verb + Object.” (e.g., “Pick up the apple.”).

Action representation (UMI bimanual, per 24-step chunk)

  • 20-D per step = right (10) + left (10):
  • pos (x,y,z): 3
  • rot (6D rotation): 6
  • gripper width: 1
  • Output tensor shape: (T=24, D=20), relative deltas, float32.
  • The RVQ tokenizer yields a fixed-length token sequence; see tokenizer card for exact code lengths.

Tokenizer

  • Tokenizer repo: `robotics-diffusion-transformer/RVQActionTokenizer`
  • Use float32 for the VQ model.
  • Provide a [LinearNormalizer](http://ml.cs.tsinghua.edu.cn/~lingxuan/rdt2/umi_normalizer_wo_downsample_indentity_rot.pt) for action scaling (UMI convention).

Hardware & software requirements

Approximate single-GPU requirements (Qwen2.5-VL-7B-Instruct scale):

ModeRAMVRAMExample GPU
Inference≥ 32 GB≥ 16 GBRTX 4090
LoRA FT≥ 32 GBA100 40GB
Full FT≥ 80 GBA100 80GB / H100 / B200
For deployment on real robots, follow your platform’s end-effector + camera choices and perform hardware setup & calibration (camera stand/pose, flange, etc.) before running closed-loop policies.

Tested OS: Ubuntu 24.04.


Quickstart (inference)

python
# Run under repository: https://github.com/thu-ml/RDT2

import torch
from transformers import AutoProcessor, Qwen2_5_VLForConditionalGeneration

from vqvae import MultiVQVAE
from models.normalizer import LinearNormalizer
from utils import batch_predict_action

# assuming using gpu 0
device = "cuda:0"


processor = AutoProcessor.from_pretrained("Qwen/Qwen2.5-VL-7B-Instruct")
model = Qwen2_5_VLForConditionalGeneration.from_pretrained(
    "robotics-diffusion-transformer/RDT2-VQ"
    torch_dtype=torch.bfloat16,
    attn_implementation="flash_attention_2",
    device_map=device
).eval()
vae = MultiVQVAE.from_pretrained("robotics-diffusion-transformer/RVQActionTokenizer").eval()
vae = vae.to(device=device, dtype=torch.float32)

valid_action_id_length = (
    vae.pos_id_len + vae.rot_id_len + vae.grip_id_len
)
# TODO: modify to your own downloaded normalizer path
# download from http://ml.cs.tsinghua.edu.cn/~lingxuan/rdt2/umi_normalizer_wo_downsample_indentity_rot.pt
normalizer = LinearNormalizer.from_pretrained("umi_normalizer_wo_downsample_indentity_rot.pt")  # 

result = batch_predict_action(
    model,
    processor,
    vae,
    normalizer,
    examples=[
        {
            "obs": {
                # NOTE: following the setting of UMI, camera0_rgb for right arm, camera1_rgb for left arm
                "camera0_rgb": ..., # RGB image in np.ndarray of shape (1, 384, 384, 3) with dtype=np.uint8
                "camera1_rgb": ..., # RGB image in np.ndarray of shape (1, 384, 384, 3) with dtype=np.uint8
            },
            "meta": {
                "num_camera": 2
            }
        },
        ...,    # we support batch inference, so you can pass a list of examples
    ],
    valid_action_id_length=valid_action_id_length,
    apply_jpeg_compression=True,
    # Since model is trained with mostly jpeg images, we suggest toggle this on for better formance
    instruction="Pick up the apple."
    # We suggest using Instruction in format "verb + object" with Capitalized First Letter and trailing period 
)

# get the predict action from example 0
action_chunk = result["action_pred"][0] # torch.FloatTensor of shape (24, 20) with dtype=torch.float32
# action_chunk (T, D) with T=24, D=20
#   T=24: our action_chunk predicts the future 0.8s in fps=30, i.e. 24 frames
#   D=20: following the setting of UMI, we predict the action for both arms from right to left
#   - [0-2]: RIGHT ARM end effector position in x, y, z (unit: m)
#   - [3-8]: RIGHT ARM end effector rotation in 6D rotation representation
#   - [9]: RIGHT ARM gripper width (unit: m)
#   - [10-12]: LEFT ARM end effector position in x, y, z (unit: m)
#   - [13-18]: LEFT ARM end effector rotation in 6D rotation representation
#   - [19]: LEFT ARM gripper width (unit: m)

# rescale gripper width from [0, 0.088] to [0, 0.1]
for robot_idx in range(2):
    action_chunk[:, robot_idx * 10 + 9] = action_chunk[:, robot_idx * 10 + 9] / 0.088 * 0.1
For installation and fine-tuning instructions, please refer to the official GitHub repository.

Intended uses & limitations

Intended uses

  • Research in robot manipulation and VLA modeling.
  • Zero-shot or few-shot deployment on bimanual systems following the repo’s [hardware calibration](https://github.com/thu-ml/RDT2/tree/main?tab=readme-ov-file#1-important-hard-ware-set-up-and-calibration) steps.

Limitations

  • Open-world robustness depends on calibration quality, camera placement, and gripper specifics.
  • Requires correct normalization and RVQ code compatibility.
  • Safety-critical deployment requires supervision, interlocks, and conservative velocity/force limits.

Safety & responsible use

  • Always test in simulation or with hardware limits engaged (reduced speed, gravity compensation, E-stop within reach).

Troubleshooting

SymptomLikely causeSuggested fix
Drifting / unstable gripper widthsScale mismatchApply LinearNormalizer; rescale widths (\[0,0.088] → \[0,0.1]).
Poor instruction followingPrompt formatUse “Verb + Object.” with capitalization + period.
No improvement after FTOOD actionsCheck RVQ bounds & reconstruction error; verify normalization.
Vision brittlenessJPEG gapEnable --image_corruption; ensure 384×384 inputs.

Changelog

  • 2025-09: Initial release of RDT2-VQ on Hugging Face.

Citation

bibtex
@article{liu2026rdt2,
  title={RDT2: Exploring the Scaling Limit of UMI Data Towards Zero-Shot Cross-Embodiment Generalization},
  author={Liu, Songming and Li, Bangguo and Ma, Kai and Wu, Lingxuan and Tan, Hengkai and Ouyang, Xiao and Su, Hang and Zhu, Jun},
  journal={arXiv preprint arXiv:2602.03310},
  year={2026}
}

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