---
license: apache-2.0
library_name: lerobot
pipeline_tag: robotics
tags:
  - act
  - lerobot
  - so101
  - leisaac
  - pick-orange
  - isaac-sim
datasets:
  - LightwheelAI/leisaac-pick-orange
language:
  - en
base_model: lerobot/act
---

# ACT-PickOrange

针对 [LeIsaac SO-101 PickOrange](https://github.com/LightwheelAI/leisaac) 任务从头训练的 [ACT (Action Chunking Transformer)](https://tonyzhaozh.github.io/aloha/) 策略。
_An [ACT (Action Chunking Transformer)](https://tonyzhaozh.github.io/aloha/) policy trained from scratch on the [LeIsaac SO-101 PickOrange](https://github.com/LightwheelAI/leisaac) task._

![ACT-PickOrange — SO-101 in Isaac Sim](act-pick-orange.png)

**🔗 项目仓库 / Project repos**：
- [vitorcen/isaaclab-experience](https://github.com/vitorcen/isaaclab-experience) — Isaac Lab + LeIsaac 多策略横评（parent project）
- [vitorcen/LeIsaac-Training](https://github.com/vitorcen/LeIsaac-Training) — LeIsaac fork（训练脚本 + 设计文档 / training scripts + design docs）

## TL;DR

- **任务 / Task**：`Pick up the orange and place it on the plate` — SO-101 单臂依次夹起 3 颗橙子并放盘子。
  _Single-arm SO-101 picks 3 oranges sequentially and places each on a plate._
- **数据集 / Dataset**：[`LightwheelAI/leisaac-pick-orange`](https://huggingface.co/datasets/LightwheelAI/leisaac-pick-orange) — 60 episode 遥操示范。
- **架构 / Architecture**：ACT chunk_size=100，~52M 参数，纯 vision + joint state → action chunk regression（无 LLM / 无 diffusion）。
- **训练 / Training**：lerobot **v0.4.0**, batch=8 / lr=1e-5 / 20k step / 关闭图像增强，~10h on RTX 4090. **本 ckpt = step 18000** (sweet spot)。
- **评测 / Eval**：Isaac Sim 5.1 + LeIsaac，**5-round × 5-run pooled** = 33/75 oranges = **44.0% per-orange success** (95% CI [29.5%, 58.5%])。
- **⚠️ 关键 inference 配置 / Critical inference setting**：`policy_action_horizon=70`（旧 v0.5.2 ckpt 的 horizon=32 不适用本 v0.4.0 ckpt，详见 [Inference caveat](#-推理关键配置--critical-inference-caveat)）。

## 🌳 分支说明 / Branch layout

本 repo 有两个 ckpt，分别记录 framework drift 故事的两端：
_Two checkpoints are tracked in this repo, capturing both ends of the framework drift story:_

| Branch | lerobot version | Training step | best horizon | 🍊 per-orange p (5-run pool) | 备注 |
|---|---|---|---|---|---|
| **main** (本 ckpt) | **v0.4.0** | **18000** | **70** | **0.440** (33/75) | 当前推荐 / current canonical |
| `lerobot-v052-ckpt-10k` | v0.5.2 | 10000 | 32 (旧推荐 / old) | 0.267 (4/15 single 5-round) | 历史对照 / archived for framework-drift study |

详见下方 [Framework drift section](#framework-drift--lerobot-v04-vs-v05)。
_See [Framework drift section](#framework-drift--lerobot-v04-vs-v05) below._

## 模型亮点
_Highlights_

- **5-round × 5-run pooled 严格统计** confirmed: 44.0% per-orange (95% CI [29.5%, 58.5%])，显著优于 shadowHokage 公开 ckpt 18.3% (95% CI [10.6%, 26.0%])。Welch t-test (per-ep, 消除 episode-cluster) **p=0.034**，two-proportion Z test **p=0.008**。
- **暴露了 lerobot v0.4 → v0.5 framework drift**：同 dataset / 同 seed / 同 config，仅切换 lerobot 版本，v0.5.2 训出的 ckpt 跌到 18-27% per-orange（同 shadowHokage 真实水平），锁回 v0.4.0 才恢复 44%。详见底部 framework drift section。
- **暴露了 LeIsaac 默认 `policy_action_horizon=16` 的隐性陷阱**：chunk_size=100 的 ACT 需要 per-ckpt sweep 找最优 h（本 ckpt h=70；不同训练曲线产出的 ckpt 最优 h 不同）。
- 无 image augmentation、无 weight decay 调参、无 special trick — 干净的 ACT baseline。

## 训练配方
_Training recipe_

| 项 / Item | 值 / Value |
|---|---|
| Dataset | `LightwheelAI/leisaac-pick-orange` (60 ep, dual-cam 480×640 RGB + 6 DOF state, 30 Hz) |
| Policy | `act` (LeRobot 实现 / LeRobot impl.) |
| **lerobot version** | **v0.4.0** (锁版本以避免 framework drift) |
| Backbone | ResNet18 vision encoder + Transformer encoder/decoder |
| `chunk_size` | 100 |
| `n_action_steps` | 100 |
| Batch size | 8 |
| Optimizer | AdamW |
| Learning rate | 1e-5 (constant) |
| Steps | 20,000 (本 ckpt = step **18000**, 经 sweep 是 sweet spot) |
| Image augmentation | **disabled** |
| Hardware | RTX 4090 (24 GB) |
| Wall-clock | ~10 hours |
| Recipe credit | [shadowHokage/act_policy](https://huggingface.co/shadowHokage/act_policy)（v0.4 era 配方原型）|

训练入口脚本在我们的 LeIsaac fork：[`scripts/training/act/train.sh`](https://github.com/vitorcen/LeIsaac-Training/blob/main/scripts/training/act/train.sh)。
_Training entrypoint script lives in our LeIsaac fork: [`scripts/training/act/train.sh`](https://github.com/vitorcen/LeIsaac-Training/blob/main/scripts/training/act/train.sh)._

## 评测结果 / Eval results

### 5-round × 5-run pooled stats (25 episodes total)

5-round 协议在 ACT 上 single-run variance 实测 ±40%（同 ckpt 同 horizon 跨 5 runs 范围 2-13/15），所以 canonical 数字必须 pooled multi-run。
_The 5-round protocol has ±40% single-run variance for ACT (same ckpt + same horizon, range 2-13/15 across 5 runs), so canonical numbers must be pooled across multiple runs._

| 配置 / Config | 🍊 per-orange p | per-episode mean | 95% CI (per-orange) |
|---|---|---|---|
| **wsagi/ACT-PickOrange v0.4.0 ckpt-18k h=70** (本 ckpt, 5 runs) | **0.440** | 1.32/ep | **[0.295, 0.585]** |
| shadowHokage/act_policy h={16,32,64,70} (4 runs) | 0.183 | 0.55/ep | [0.106, 0.260] |

**显著性 / Significance**：
- Two-proportion Z test (per-orange iid): Z = 2.67, **p = 0.008** ✅
- Welch t-test (per-episode, 消 episode-cluster over-dispersion): t = 2.13, df ≈ 38, **p = 0.034** ✅
- Effect ratio: **2.20×**

### 0-3 oranges per-episode 分布 / Per-episode oranges distribution

ACT chunk-policy 是 trajectory-level 决策，不是 per-orange iid — 一旦 trajectory 进入正确模式 → 3 颗 cluster 连续成功；一旦偏 → 0 颗全废。**实际分布 bimodal 而非 binomial**：
_ACT chunks make trajectory-level decisions, not per-orange iid — once the trajectory enters the correct mode, all 3 oranges cluster as a successful streak; once it goes off-track, the entire episode is wasted. **Observed distribution is bimodal, not binomial**:_

| oranges/ep | observed (25 ep) | Binomial(3, 0.440) expected | observed / expected |
|---|---|---|---|
| 0 | 11 | 4.4 | **2.51×** (over-dispersed) |
| 1 | 2 | 10.3 | 0.19× (under) |
| 2 | 5 | 8.1 | 0.61× (under) |
| 3 | 7 | 2.1 | **3.29×** (over-dispersed) |

两端 (0/3) 比 binomial 预期多 2.5-3.3×，中间 (1/2) 比预期少一半 — bimodal/U-shape 签名。
_Both tails (0/3) appear 2.5-3.3× more often than binomial; middle bins (1/2) appear at half the expected rate — bimodal/U-shape signature._

### Per-run 数据点 / Per-run datapoints

ckpt-18k h=70 5 runs (25 episodes total)：
```
run1: [3, 3, 3, 2, 2] = 13/15 (lucky tail, P≈0.003% under binomial)
run2: [1, 1, 0, 0, 0] =  2/15
run3: [2, 0, 3, 0, 3] =  8/15
run4: [3, 0, 0, 2, 0] =  5/15
run5: [0, 0, 3, 2, 0] =  5/15
```
范围 2-13/15 = ±40% range，pooled mean = 33/75。

测试环境 / Test setup：Isaac Sim 5.1，task `LeIsaac-SO101-PickOrange-v0`，`episode_length_s=120`，`step_hz=30`，dual-cam 观测。
_Test setup: Isaac Sim 5.1, task `LeIsaac-SO101-PickOrange-v0`, `episode_length_s=120`, `step_hz=30`, dual-cam observations._

## ⚠️ 推理关键配置 / Critical inference caveat

**本 v0.4.0 ckpt 最优 horizon = 70**（不是旧 v0.5.2 ckpt 的 32！）。每个训练曲线产出的 ckpt 最优 inference horizon 不同，必须 per-ckpt sweep。
_**The v0.4.0 ckpt's best horizon is 70** (not the old v0.5.2 ckpt's 32!). Each training trajectory produces a ckpt with different optimal inference horizon — per-ckpt sweep is required._

### 根因 / Root cause

ACT 每个 chunk 输出 100 步动作，是一段**完整规划**。LeRobot async client 用直接窗口 (receding horizon)，每 `policy_action_horizon` 步重新查询一次。**chunk 内 action 一致性** 决定了 best horizon — 训练 framework drift 改了 dataloader RNG / loss normalization → ckpt 内化的 chunk 一致性不同 → 最优 replan 频率不同。
_Each ACT chunk outputs a 100-step planned trajectory. The LeRobot async client uses a sliding window, re-querying every `policy_action_horizon` steps. **Chunk-internal action coherence** determines the best horizon — framework drift (dataloader RNG / loss normalization) changes the chunk coherence baked into the ckpt → optimal re-plan frequency shifts._

### 推荐配置 / Recommended settings

```bash
--policy_type=lerobot-act
--policy_action_horizon=70                  # for THIS ckpt (v0.4.0 ckpt-18k); 旧 v0.5.2 ckpt 用 32
--policy_checkpoint_path=wsagi/ACT-PickOrange
--step_hz=30                                # 对齐 dataset 30Hz / matches dataset 30Hz
--episode_length_s=120
```

## 使用方法
_Usage_

### 1. 启动 LeRobot async policy_server (lerobot v0.4.0)

```bash
conda create -n lerobot-v040 python=3.10 -y && conda activate lerobot-v040
pip install lerobot==0.4.0  # 必须锁版本！避免 framework drift
python -m lerobot.async_inference.policy_server --host 0.0.0.0 --port 8080
```

### 2. 客户端启动 LeIsaac eval

通过我们的 [vitorcen/LeIsaac-Training](https://github.com/vitorcen/LeIsaac-Training) fork：

```bash
cd LeIsaac
bash scripts/evaluation/run_eval.sh -- \
    --task=LeIsaac-SO101-PickOrange-v0 \
    --eval_rounds=5 \
    --episode_length_s=120 \
    --step_hz=30 \
    --policy_type=lerobot-act \
    --policy_host=127.0.0.1 --policy_port=8080 \
    --policy_checkpoint_path=wsagi/ACT-PickOrange \
    --policy_action_horizon=70 \
    --policy_language_instruction="Pick up the orange and place it on the plate" \
    --device=cuda --enable_cameras
```

## Framework drift — lerobot v0.4 vs v0.5

本 ckpt 重训于 lerobot **v0.4.0**（锁版本），而不是 main repo 最新 v0.5.x。原因：
_This ckpt was retrained on lerobot **v0.4.0** (pinned version), not the latest v0.5.x main. Reason:_

| Training framework | 5-round per-orange p | 显著性 |
|---|---|---|
| lerobot v0.4.0（本 ckpt）| **0.440** (5-run pool, 25 ep) | baseline |
| lerobot v0.5.2 + 2 patches | 0.267 (4/15 single 5-round) | -39% vs v0.4.0 (left-tail p≈0.1%) |
| shadowHokage (v0.4 era, 2026-01) | 0.183 (4-h sweep, 20 ep) | -58% vs v0.4.0, Z=2.67 **p=0.008** |

**关键发现 / Key findings**：
- lerobot **PR #3406 (a8b72d96)** 改 dataloader (`persistent_workers/uint8/prefetch`) 在 2026-04-19 merge
- lerobot **PR #3442 (1add4606)** 改 ACT padding loss 在 2026-04-23 merge
- 两个 PR 都 land 在 v0.5.0 (2026-04-26)；锁回 v0.4.0 可恢复 0.440 per-orange

完整 ablation + 三模型 brainstorm 详见我们的设计文档：[`act_finetune_pick_orange.html`](https://github.com/vitorcen/LeIsaac-Training/blob/main/docs/training/act_finetune_pick_orange.html)。
_Full ablation + 3-model brainstorm in our design doc: [`act_finetune_pick_orange.html`](https://github.com/vitorcen/LeIsaac-Training/blob/main/docs/training/act_finetune_pick_orange.html)._

## 局限性
_Limitations_

- **数据集 OOD on 2nd-3rd orange**：dataset 60 episode × 每集 1 次"放第 N 颗"演示。第 2/3 颗的 state coverage 比第 1 颗稀疏一个数量级。即便 horizon=70 + 5-run pooled，**精度仍随颗数线性退化**。这是数据问题不是模型问题。
  _**Dataset OOD on 2nd–3rd orange**: with 60 episodes × 1 "place N-th orange" demo each, state coverage drops by ~1 order of magnitude per orange. Even at horizon=70 with 5-run pooling, accuracy degrades linearly across oranges. This is a data issue, not a model issue._
- **5-round single-run variance ±40%** — 任何单次 5-round 数字（包括 13/15 lucky tail）都不构成证据；至少 ≥3 runs pool。
  _**±40% single-run variance** — any single 5-round number (including 13/15 lucky tails) is noise; pool ≥3 runs._
- 无图像增强、无 domain randomization → real-world transfer 可能弱。本 ckpt 仅用于 Isaac Sim 仿真验证，不保证真机 deploy。
  _No image augmentation or domain randomization → real-world transfer is likely weak. This checkpoint is only validated in Isaac Sim simulation; real-robot deployment is not guaranteed._

## 相关
_Related_

- 同任务对照 / Same-task comparisons：
  - [`wsagi/DiffusionPolicy-PickOrange`](https://huggingface.co/wsagi/DiffusionPolicy-PickOrange) — 自训 Diffusion Policy (267M, DDIM 32-step swap)
  - [`shadowHokage/act_policy`](https://huggingface.co/shadowHokage/act_policy) — v0.4 era 公开 ckpt（5-run pool = 18.3%）
  - [`LightwheelAI/leisaac-pick-orange-v0`](https://huggingface.co/LightwheelAI/leisaac-pick-orange-v0) — GR00T N1.5 baseline
- 完整训练 + eval 配方 + framework drift 调研：[vitorcen/LeIsaac-Training](https://github.com/vitorcen/LeIsaac-Training) fork

## 致谢
_Acknowledgments_

- LeIsaac 团队 + LightwheelAI 提供任务环境和数据集
- LeRobot 团队提供 ACT 实现 + async inference 框架
- shadowHokage 公开训练配方作为复刻基线（暴露了 framework drift 问题）

## 引用
_Citation_

```bibtex
@inproceedings{zhao2023learning,
  title={Learning Fine-Grained Bimanual Manipulation with Low-Cost Hardware},
  author={Zhao, Tony Z. and Kumar, Vikash and Levine, Sergey and Finn, Chelsea},
  booktitle={Robotics: Science and Systems},
  year={2023}
}
```

## License

Apache-2.0