emg2tendon — pretrained models
Seq2seq regression from surface EMG to musculoskeletal tendon controls:
16-channel sEMG @ 2 kHz → 39-channel MyoHand tendon control ∈ [0, 1], over
2-second windows (T = 4000). Trained on the full emg2pose dataset
(25,253 recordings, 193 subjects, ~370 h), with tendon targets produced by a
QForce inverse-dynamics pipeline through the MyoSuite MyoHand model.
Reference implementation + eval code:
https://github.com/sagarverma/emg2tendon
Project page:
https://emg2tendon.github.io
Paper:
emg2tendon: From sEMG Signals to Tendon Control in Musculoskeletal Hands, Sagar Verma, RSS 2025.
Files
| File | Model | Params | val tendon RMSE | open-loop pose (deg) |
|---|
tds.ckpt | TDS (time-depth-separable conv) | 0.10 M | 0.310 | 15.1–16.2 |
sensingdynamics.ckpt | SensingDynamics | 0.56 M | 0.308 | 15.1–16.2 |
neuropose.ckpt | NeuroPose | 7.15 M | 0.308 | 15.1–16.2 |
cldm.ckpt | Conditional Latent Diffusion (self-contained: both VAEs + U-Net) | 7.01 M | 0.440 | 16.8–17.6 |
emg_stats.npz | per-channel EMG mean/std — required for inference | — | — | — |
Checkpoints are PyTorch-Lightning .ckpt files (state_dict +
hyper_parameters), loaded by the wrappers in the GitHub repo
(RegressionModule for the three baselines, CLDMModule for CLDM).
ablations/ — improvement-campaign checkpoints
Trained on an 8,000-recording subset for speed, to ablate a modernized
training recipe (window-sampling fix, velocity + smoothness loss, EMG
augmentation, pose-sensitivity-weighted tendon loss, temporal architectures):
| File | Description | Params | val tendon RMSE | Δ vs reference |
|---|
tds_old.ckpt | TDS, original recipe (reference) | 0.10 M | 0.3105 | — |
tds_new.ckpt | TDS, new recipe + sensitivity weighting | 0.10 M | 0.3090 | −0.5% |
tds_new_nosens.ckpt | TDS, new recipe, no sensitivity weighting | 0.10 M | 0.3089 | −0.5% |
tcn_new.ckpt | TCN (~2 s receptive field) | 1.57 M | 0.3057 | −1.5% |
gru_new.ckpt | GRU velocity-decode (best) | 1.17 M | 0.3049 | −1.8% |
Use ablations/emg_stats.npz with these — the normalization statistics
were computed over the 8k subset and differ from the full-25k statistics at
the root.
Usage
1git clone https://github.com/sagarverma/emg2tendon && cd emg2tendon
2pip install torch pytorch-lightning hydra-core diffusers "numpy==1.26.4"
3
4python - <<'PY'
5from huggingface_hub import snapshot_download
6print(snapshot_download("Micropilot/emg2tendon"))
7PY
Then run the shipped eval / render entrypoints:
1# pose-space evaluation (per-step + open-loop rollout through MyoHand)
2python scripts/evaluate_pose.py --model tds --checkpoint tds.ckpt \
3 --index index.json --stats_cache emg_stats.npz
4
5# side-by-side MuJoCo video (reference vs achieved pose)
6MUJOCO_GL=egl python scripts/render_model.py --model tds --checkpoint tds.ckpt \
7 --emg emg/<base>.npy --pose pose/<base>.npy --index index.json \
8 --stats_cache emg_stats.npz --out out.mp4
Inference contract: EMG is per-channel standardized with the shipped
mean/std ((emg - mean) / std, guarding std < 1e-8); tendon output stays
in native [0, 1] space and is never normalized. Tensors are channel-first
([N, C, T]) at the module boundary — see CONTRACT.md in the code repo.
Evaluation
Protocol: the three held-out emg2pose generalization conditions (unseen user,
unseen stage, user+stage), 200 recordings per condition. Predicted
tendon controls are forward-simulated through MyoHand and the achieved pose is
compared to the emg2pose ground truth, both per-step and in a 0.5 s
open-loop rollout.
| Model | per-step (deg) | open-loop 0.5 s (deg) |
|---|
| ground-truth tendon (ID ceiling) | 0.11 | ~14.0 |
| TDS / SensingDynamics / NeuroPose | ~0.09 | 15.1–16.2 |
| CLDM | ~0.11 | 16.8–17.6 |
The inverse-dynamics step itself is near-exact (0.109° MAE per-step over all
25,253 recordings), so per-step numbers sit at the ID ceiling for every model.
Limitations
- The open-loop ceiling is ~14°: even perfect tendon controls drift under
MyoHand muscle dynamics. The baselines are already within ~1–2° of it, so
there is little headroom for a better EMG→tendon model to improve open-loop
pose — these baselines are near-optimal for this metric, not the bottleneck.
cldm.ckpt is undertrained (diffusion stage cut short for compute
budget) and underperforms the regression baselines here — the opposite of the
paper's ranking. Treat it as a starting point, not a faithful CLDM result.
- Trained only on emg2pose (wrist-worn 16-ch sEMG band, right/left hand, seated
desk-scale gestures). No claims outside that distribution.
- Ablation checkpoints use an 8k subset and are not directly comparable to the
root full-25k checkpoints.
License
cc-by-nc-4.0, inherited from the emg2pose dataset these models are trained
on (Meta, CC BY-NC 4.0). Non-commercial use only.
Citation
1@inproceedings{verma2025emg2tendon,
2 title = {{emg2tendon: From sEMG Signals to Tendon Control in Musculoskeletal Hands}},
3 author = {{Sagar Verma}},
4 year = 2025,
5 booktitle = {Robotics: Science and Systems}
6}