Single-handed pick task ("grab the bottle", RIGHT hand). Trained at the CloudWalk Robotics Lab (CW-RL), 2026-06, on 105 real-robot teleoperation episodes, for the UNITREE_G1_SONIC embodiment. Released as a reference fine-tune for teams building manipulation policies on the GR00T + SONIC + MuJoCo/G1 stack.
This is a behavior-cloning fine-tune of the full 3B model. Closed-loop evaluation on the real G1 is complete (4/12 grid, 2/5 at the fixed position) — see Evaluation.
AdamW, lr 1e-4 cosine, warmup_ratio 0.05, weight_decay 1e-5
Steps / batch
20,000 / global batch 48 (8 per GPU × 6 GPUs)
Augmentation
color jitter (brightness 0.3, contrast 0.4, saturation 0.5, hue 0.08)
Wall-clock
≈66 min (≈4.6 it/s)
Final train loss
≈0.0825 (from ≈1.2)
Repository contents
checkpoint-20000/ # final (20k steps, ~13.6 ep) — the only published checkpoint (one checkpoint per repo, lineage storage policy)
README.md # this file
Each checkpoint-NNNNN/ is a self-contained, deploy-ready snapshot:
DeepSpeed ZeRO partition states, optimizer, scheduler and RNG files are intentionally omitted — they are needed only to resume training and would add several GB per checkpoint.
Evaluation
Training signal. Train loss fell from ≈1.2 to ≈0.03 over 20,000 steps (final train_loss ≈ 0.0825). Full curves (loss, grad_norm, learning_rate, GPU util) are tracked in W&B (private run). There is no held-out split — the 105-episode dataset is small and validation defaults to the training data, so treat the loss as a fit probe, not as a generalization measure.
Closed-loop evaluation — completed (real G1).checkpoint-20000 was run closed-loop on the physical G1 + SONIC stack. As the uncurated baseline it sets the floor the rest of the family (v2/v4/v5/v6) is measured against. Low BC loss is a healthy prerequisite, not evidence of a good policy — this closed-loop result is the load-bearing signal.
Procedure. The bottle was placed at 12 fixed positions spanning one half-side of the table (the table is fixed relative to the robot). These are the same 12 positions used for data collection (see the source dataset card). One trial per position (12 trials) gives the grid result; then 5 consecutive trials were run at the fixed black-rectangle position. Legend: 🟥 red = knocked the bottle over · 🟧 orange = stuck in an "indecision" loop, never reaching the bottle · 🟩 green = successfully grasped the bottle. The policy was invoked with the task prompt "grab the bottle" — the same prompt used to collect the data.
⚠️ Single-trial methodology. Each of the 12 grid positions is tested once (1 trial/position); repeated placements at the same spot can succeed or fail differently — the fixed-position repeat test, where run, shows this per-position variance. Treat the grid score as a single-pass signal, not a repeated-trial mean.
Conclusion. The baseline. v1 is the family floor: lowest grid success (4/12, 33%), the highest non-convergence rate (5/12, 42%), and only 2/5 at the fixed position. Every curated variant (v2/v4/v5/v6) beats it on grid success, confirming that curation — not raw fitting — drove the gains. The gap is telling: v1's final train_loss (0.0825) is ~2.7× v2's (0.0303), yet its closed-loop success is 4/12 vs v2's 10/12 — training loss does not predict closed-loop competence.
Closed-loop control of the G1 (sim or real) is driven by the SONIC whole-body controller in GR00T-WholeBodyControl: the policy emits motion_token + hand-joint targets that the SONIC WBC decodes into whole-body joint commands. The server must be launched with the same UNITREE_G1_SONIC embodiment tag used in training. See the NVlabs VLA inference tutorial. This checkpoint is not plug-and-play on hardware — it requires the SONIC C++ deploy stack and the matching G1 setup.
Known caveats
Right-hand-only, single task. The dataset is one task ("grab the bottle") executed with the right hand. Left-hand and locomotion action dims reflect the (largely stationary) demonstrations; do not expect bimanual or locomotion behavior.
Single camera. Only the ego_view (head) camera was recorded — no wrist cameras. The policy has never seen wrist views.
Deployment needs the SONIC stack. The checkpoint outputs motion_token + hand joints for UNITREE_G1_SONIC; it only produces robot motion through the SONIC WBC + ZMQ deploy pipeline. It is not directly executable on a bare G1.
Train loss is not held-out. No episode split; the loss is a smoothed train-fit probe, not a generalization metric.
Possible overfit. Loss reached ≈0.03 over ≈13.6 epochs on 105 episodes. Only checkpoint-20000 is published (one checkpoint per repo, lineage storage policy); no intermediate rung is retained.
Closed-loop evaluated. 4/12 grid success (33%) + 2/5 at the fixed position — the family floor; every curated variant (v2/v4/v5/v6) beats it. See Evaluation.
Grip anticipation (family-wide). Observed in closed-loop eval: the policy performs the full grasp motion — approaching and closing the hand — even when no bottle is on the table, and even with the table removed entirely, as if the bottle were present. This grip-anticipation artifact is shared across the whole grab-bottle family (the same training demonstrations). Worth gating on bottle detection for downstream deployment.
Prompt conditioning — untested. All training data was collected with the task prompt "grab the bottle", and the same prompt is used to invoke the policy at inference — a constant across every episode and every model in this family. We have not tested whether conditioning the prompt on the bottle's presence (e.g. "grab the bottle if there is one in the image") would gate the grasp and reduce the grip-anticipation artifact noted above (the robot closing its hand even with no bottle present). It is a plausible mitigation, but unverified: the model may have learned the grasp as an unconditional reflex from the demonstrations, independent of prompt phrasing.
Training environment. Trained on 6× B200 GPUs with NCCL_IB_DISABLE=1 NCCL_P2P_LEVEL=NVL (InfiniBand off, P2P over NVLink) and W&B in offline mode (synced post-run). These affect only the training run, not the weights.
DP speedup resampling (wrist-Cartesian, 3 mm/frame, max_K=40) of the merged set; no segment removal — reference baseline. ≈16 ep @20k lands on v2's sweet spot.
Developed by cloudwalk-research in the CloudWalk Robotics Lab (CW-RL). Fine-tuned from nvidia/GR00T-N1.7-3B using Isaac-GR00T; targets the Unitree G1 with the SONIC whole-body controller.
Citation
If you build on this checkpoint, cite both upstream GR00T/SONIC and this fine-tune:
bibtex
1@misc{cwrl_gr00t_grab_bottle_v1_2026,
2 title = {GR00T N1.7 Fine-Tune v1 --- Unitree G1 "grab the bottle" (right hand, SONIC WBC)},
3 author = {{CloudWalk Robotics Lab}},
4 year = {2026},
5 howpublished = {Hugging Face model repository},
6 url = {https://huggingface.co/cloudwalk-research/gr00t-n17-g1-grab-bottle-rh-105ep-v1-finetune}
7}
89@article{gr00t_n1_2025,
10 title = {GR00T N1: An Open Foundation Model for Generalist Humanoid Robots},
11 author = {{NVIDIA}},
12 year = {2025},
13 eprint = {2503.14734},
14 archivePrefix = {arXiv},
15 url = {https://arxiv.org/abs/2503.14734}
16}
1718@article{sonic_2025,
19 title = {SONIC: Supersizing Motion Tracking for Natural Humanoid Whole-Body Control},
20 author = {Luo, Zhengyi and others},
21 year = {2025},
22 eprint = {2511.07820},
23 archivePrefix = {arXiv},
24 url = {https://arxiv.org/abs/2511.07820}
25}
2627@software{isaac_gr00t,
28 title = {{Isaac-GR00T}: NVIDIA's open foundation model stack for generalist humanoid robots},
29 author = {{NVIDIA}},
30 url = {https://github.com/NVIDIA/Isaac-GR00T},
31 year = {2025}
32}
License
Inherits the NVIDIA Open Model License Agreement of the base model nvidia/GR00T-N1.7-3B — see the license terms. This is a research preview: not intended for safety-critical use; closed-loop deployment on a physical humanoid requires human oversight.
