README.md

---
license: apache-2.0
tags:
- robotics
- vla
- vision-language-action
- libero
- model-compression
pipeline_tag: robotics
---

# VLADrop-pi05-LIBERO-drop16-language-keep0-17

Checkpoint for [Drop-Then-Recovery: How Redundant Are Vision-Language-Action Models?](https://arxiv.org/abs/2606.27755).

DTR (Drop-Then-Recovery) removes transformer blocks from a pretrained VLA model and
recovery-fine-tunes the smaller dense model. Code: https://github.com/s1ghhh/VLADrop

## This checkpoint

| | |
|---|---|
| Paper row | Table 1 'Keep 2 Language' (16/18 dropped, first & last kept) |
| Dropped blocks | LLM (PaliGemma) blocks [1..16] (keep blocks 0 and 17) |
| Recovery training | batch size 64, 59796 steps (FLOPs-matched to baseline), lr 5e-5 |
| LIBERO success rate | Spatial 94.6 / Object 96.0 / Goal 90.6 / Long 82.6 / Avg 91.0 |

## Usage

This is an [openpi](https://github.com/Physical-Intelligence/openpi)-format pi0.5 checkpoint
(PyTorch). Use with the VLADrop fork: https://github.com/s1ghhh/VLADrop

```bash
python scripts/serve_policy_batch_drop.py \
    --config pi05_libero_dropped \
    --dir <this_repo_local_path> \
    --port 8000
```

**Important:** the drop lists are NOT stored inside the checkpoint. Pass the exact
`llm_drop_attn_list` / `llm_drop_mlp_list` shown above (via config or CLI) when serving,
otherwise layers will be mismatched. `assets/` contains the LIBERO norm stats.
The optimizer state (`train_state/`) is not included.

## Citation

```bibtex
@article{sun2026vladrop,
  title={Drop-Then-Recovery: How Redundant Are Vision-Language-Action Models?},
  author={Sun, Guoheng and Feng, Kaixi and He, Shwai and Gong, Xiaochuan and He, Yexiao and Wang, Ziyao and Shen, Zheyu and Ye, Wanghao and Kompella, Ramana Rao and Liu, Gaowen and Li, Ang},
  journal={arXiv preprint arXiv:2606.27755},
  year={2026}
}
```