README.md

---
license: mit
tags:
- robotics
- pi-zero
- diffusion
- vision-language-action
- aloha
- manipulation
- bolt-nut-sorting
base_model: google/paligemma-3b-pt-224
library_name: openpi
pipeline_tag: robotics
---

# Pi-0 Bolt Nut Sort Model

This is a Pi-0 (Pi-Zero) model trained for bolt and nut sorting tasks using the OpenPI framework.

## Model Description

- **Architecture**: Pi-0 (diffusion-based vision-language-action model)
- **Base Model**: PaLiGemma 3B with SigLIP vision encoder
- **Task**: Sorting bolts and nuts into separate baskets
- **Robot**: Dual-arm ALOHA setup
- **Action Space**: 14-DoF (7 per arm: 6 joints + 1 gripper)
- **Training Steps**: 29,999
- **Action Horizon**: 50 steps
- **Image Resolution**: 224x224

## Dataset

Trained on the `naungth/pi0_bolt_nut_sort` dataset with the task instruction:
"sort the bolts and the nuts into separate baskets"

## Usage

### With OpenPI

```python
from openpi.policies import policy_config
from openpi.training import config

# Load the model configuration
config_name = "pi0_bns" 
train_config = config.get_config(config_name)

# Create policy from your local checkpoint
policy = policy_config.create_trained_policy(
    train_config, 
    "path/to/checkpoint",
    default_prompt="sort the bolts and the nuts into separate baskets"
)

# Use for inference
observation = {
    "images": {
        "cam_high": image_array,  # [H, W, 3] uint8
        "cam_left_wrist": left_wrist_image,  # [H, W, 3] uint8  
        "cam_right_wrist": right_wrist_image,  # [H, W, 3] uint8
    },
    "state": joint_positions,  # [14] float32
    "prompt": "sort the bolts and the nuts into separate baskets"
}

actions = policy.infer(observation)["actions"]  # [50, 14]
```

### With Policy Server

```bash
# Start the policy server
uv run scripts/serve_policy.py policy:checkpoint     --policy.config=pi0_bns     --policy.dir=path/to/checkpoint

# Use with client
from openpi_client import websocket_client_policy
client = websocket_client_policy.WebsocketClientPolicy("localhost", 8000)
actions = client.infer(observation)
```

## Model Architecture

- **Vision Encoder**: SigLIP-So400m/14 
- **Language Model**: Gemma 2B + Gemma 300M (action expert)
- **Training**: Diffusion-based action prediction
- **Input**: Multi-camera RGB + proprioception + language instruction
- **Output**: Future action sequence (50 timesteps)

## Training Details

- **Framework**: JAX/Flax with OpenPI
- **Optimizer**: AdamW
- **Base Checkpoint**: Pi-0 base model from Google
- **Fine-tuning**: Task-specific fine-tuning on bolt nut sort data
- **Normalization**: Dataset-specific state/action normalization

## License

MIT License

## Citation

If you use this model, please cite:

```bibtex
@article{pi0,
  title={Pi-Zero: A Diffusion-Based Policy for Robot Manipulation},
  author={TODO: Add authors},
  year={2024}
}
```

## Acknowledgments

- Built using the [OpenPI](https://github.com/google-deepmind/openpi) framework
- Based on the Pi-0 architecture
- Training data from bolt nut sorting demonstrations