---
license: mit
task_categories:
  - robotics
tags:
  - lerobot
  - robotics
  - bimanual
  - manipulation
  - robotwin
  - simulation
  - cup-nesting
size_categories:
  - n<1K
---

# RoboTwin Cup-Nesting (Bimanual, Dual-Aloha)

500 successful expert demonstrations of **bimanual cup nesting** — a dual-arm
robot nests three cups into one another — collected in the [RoboTwin
2.0](https://github.com/RoboTwin-Platform/RoboTwin) simulator with strong domain
randomization. Format: **LeRobot v2.1**.

## What's in it

| | |
|---|---|
| Episodes | 500 (all success-filtered) |
| Frames | 287,571 @ 30 fps |
| Embodiment | dual-arm Aloha (`aloha-agilex`), 14-DoF |
| Action / state | 14-dim absolute joint positions |
| Cameras | head + left-wrist + right-wrist RGB, 240×320, h264 |
| Domain randomization | background, cluttered table, lighting, table height |

### Instructions (a note on honesty)

Two instruction styles are present, **both on cup-nesting episodes**:

- **50 color-conditioned** episodes: `"stack the other cups into the {green|blue|red} cup"` (17 / 17 / 16).
- **450 generic** episodes: `"stack the three cups by nesting them into one another"`.

The 450 generic episodes were originally captioned with a stale *"stack the three
bowls…"* instruction inherited when this task was adapted from RoboTwin's built-in
`stack_bowls_three`. **The objects are cups in every episode** (verified visually);
only the captions were generic. They have been relabeled to the generic cup
instruction above. If you need clean color-conditioning signal, use the 50
color-conditioned episodes; the other 450 are color-agnostic nesting demos.

## Collection

Trajectories were generated by RoboTwin's motion-planning expert (curobo + mplib),
success-gated (only episodes passing the nesting success check are kept), on a
custom `stack_cups_three` task (our adaptation of RoboTwin's `stack_bowls_three`).

## Known consumer gotcha: `is_success`

`is_success` is declared with shape `(1,)`, so LeRobot stores each cell as
`list<bool>` (`[True]`/`[False]`). In Python, `bool([False])` is **`True`** —
a non-empty list is truthy. Unwrap the scalar before use:
`bool(cell[0])`, not `bool(cell)`.

## Loading

```python
from lerobot.common.datasets.lerobot_dataset import LeRobotDataset
ds = LeRobotDataset("buzinguyen/robotwin-cups-nesting")
```

## Attribution & Licensing

- This dataset (trajectories + renders) is released under the **MIT License**.
- Generated with **RoboTwin 2.0**; 3D assets (`021_cup`) and the `aloha-agilex`
  embodiment are from RoboTwin's repositories (MIT). The bowls task template is
  RoboTwin's `stack_bowls_three`; the cup task and all trajectories are ours.
- Full third-party notice: see `THIRD_PARTY_LICENSES.md`.

If you use this dataset, please cite RoboTwin 2.0:

```bibtex
@article{chen2025robotwin,
  title={RoboTwin 2.0: A Scalable Data Generator and Benchmark with Strong Domain
         Randomization for Robust Bimanual Robotic Manipulation},
  author={Chen, Tianxing and others},
  journal={arXiv preprint arXiv:2506.18088},
  year={2025}
}
```