ProcVLM-2B

ProcVLM-2B is a procedure-grounded vision-language model for estimating progress rewards from robot manipulation observations. Given a task description and a recent window of video frames, the model reasons about the remaining atomic actions and predicts the current task completion percentage.

Model Details

• Model name: ce-amtic/ProcVLM-2B
• Model type: Vision-language model for robot progress reward inference
• Architecture: Qwen3-VL-style multimodal causal language model
• Input: One or more RGB images sampled from a robot trajectory, plus a natural-language task description
• Output: Textual reasoning and a completion estimate formatted as <progress>XX%</progress>
• Primary use case: Frame-wise progress reward prediction for robotic manipulation videos

Intended Use

ProcVLM-2B is designed for research on robot learning, progress reward modeling, embodied evaluation, and procedure-aware video understanding. Typical use cases include:

• estimating task completion progress from robot videos;
• producing dense progress rewards from sparse demonstrations;
• adapting progress prediction to a new environment with one-shot LoRA fine-tuning.

This model is not intended to be used as a safety-critical controller without downstream validation.

Quick Start

Clone the ProcVLM repository and install the environment:

git clone https://github.com/ProcVLM/ProcVLM.git
cd ProcVLM

uv sync --python 3.10
source .venv/bin/activate
uv pip install flash-attn --no-build-isolation

Run progress reward inference on a video:

python evqa/inference.py \
    --model_path ce-amtic/ProcVLM-2B \
    --video_path path/to/your/video.mp4 \
    --output_path path/to/progress_predictions.jsonl \
    --task "fold the red T-shirt" \
    --window_size 8

Each JSONL row contains a sampled frame_index and its corresponding progress prediction.

You can also visualize predictions as a video:

python evqa/eval/visualize_progress_video.py \
    --model_path ce-amtic/ProcVLM-2B \
    --video_path path/to/your/video.mp4 \
    --output_path path/to/progress_visualization.mp4 \
    --task "fold the red T-shirt" \
    --window_size 8

Python API

The same inference workflow is available through infer_progress_from_video():

from evqa.inference import infer_progress_from_video

records = infer_progress_from_video(
    model_path="ce-amtic/ProcVLM-2B",
    video_path="path/to/your/video.mp4",
    task="fold the red T-shirt",
    window_size=8,
)

for item in records:
    print(item["frame_index"], item["progress"])

The returned records include:

• frame_index: source video frame index;
• timestamp_sec: source video timestamp;
• window_frame_indices: frame indices used as the model input window;
• progress: parsed progress value in [0, 100];
• reasoning: model reasoning with the progress tag removed;
• model_output: raw model output.

Prompt Format

ProcVLM uses a procedural progress prompt. The default template is:

Given the recent observation and the task "{task}", first infer the remaining atomic actions required to complete the task. Then estimate the current completion percentage and output it as a float wrapped by <progress> tags.

The model should answer with reasoning and a final progress tag, for example:

To complete the task: Tower the blocks, the following steps are required:
1. Grasp the green block.
2. Place the green block onto the red block.
Therefore, the estimated progress percentage is <progress>84.13%</progress>.

Or if the task is finished:

The task requires: Tower the blocks. Images show no block outside the tower, no further steps required. 
Therefore, the estimated progress percentage is <progress>100.00%</progress>.

vLLM Batch Inference

For high-throughput multi-image inference, the ProcVLM repository provides evqa.model.batch_chat_with_vllm():

from evqa.model import batch_chat_with_vllm

outputs = batch_chat_with_vllm(
    batch_items=[
        {
            "image": [
                "frames/frame_000000.jpg",
                "frames/frame_000010.jpg",
                "frames/frame_000020.jpg",
            ],
            "conversations": [
                {
                    "from": "human",
                    "value": 'Given the recent observation and the task "fold the red T-shirt", first infer the remaining atomic actions required to complete the task. Then estimate the current completion percentage and output it as a float wrapped by <progress> tags.',
                }
            ],
        }
    ],
    model_path="ce-amtic/ProcVLM-2B",
    max_new_tokens=1024,
    temperature=0.0,
    tp=1,
)

One-Shot LoRA Adaptation

ProcVLM can be adapted to a new environment with one successful task demonstration, plus optional additional successful or unsuccessful demonstrations. See the one-shot adaptation guide for:

• annotating coarse sub-task stages with the visual UI;
• generating a LoRA fine-tuning dataset;
• running evqa/one-shot/lora_oneshot.sh;
• using the saved LoRA checkpoint with evqa/inference.py --use_lora.

Limitations

• The model estimates progress from visual observations and task text; it may be unreliable under strong domain shift, severe occlusion, unusual camera viewpoints, or ambiguous task descriptions.
• The progress output is a learned estimate, not a calibrated physical measurement.
• For long-horizon videos, inference quality depends on the sampled frame window and the task description.
• The model should be validated in the target robot environment before being used as a reward signal for training or deployment.

Citation

If you use ProcVLM, please cite the paper:

@misc{feng2026procvlmlearningproceduregroundedprogress,
      title={ProcVLM: Learning Procedure-Grounded Progress Rewards for Robotic Manipulation}, 
      author={Youhe Feng and Hansen Shi and Haoyang Li and Xinlei Guo and Yang Wang and Chengyang Zhang and Jinkai Zhang and Xiaohan Zhang and Jie Tang and Jing Zhang},
      year={2026},
      eprint={2605.08774},
      archivePrefix={arXiv},
      primaryClass={cs.RO},
      url={https://arxiv.org/abs/2605.08774}, 
}

License

Please refer to the license information on this model repository and the upstream base model license before using the weights.