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66 episodes · 10 fps · 2 cameras · 256×256 av1

DAgger aggregated dataset: MolmoAct2 teacher on LIBERO-10 task 6

Training data used to distill MolmoAct2 (5B) into SmolVLA (0.45B) on a single LIBERO task, assembled with DAgger (Ross et al., 2011).

  • Task: libero_10 task 6, "put the white mug on the plate and put the chocolate pudding to the right of the plate" (long-horizon, two objects in sequence)
  • 66 episodes / 19,691 frames, 10 fps, 256x256, two cameras

What is in it

Two parts, aggregated as the DAgger paper prescribes (D <- D u D_i).

Part Episodes Collected by Actions labelled by
Teacher trajectories 36 MolmoAct2 driving the robot MolmoAct2
Student-visited states 30 (12 failures) the distilled SmolVLA student MolmoAct2 (relabelled)

The second part is the point of DAgger. Teacher success trajectories never contain the states where the student actually goes wrong, so a student trained only on them never learns to recover. Here the student was run in the environment, every episode it visited was kept including failures, and the teacher then answered "what would I do here?" for each of those states.

Teacher rollouts were filtered to successes only (36 saved out of 38 attempts, 94.7 %).

Features

Key Type Shape
observation.images.image video 256 x 256 x 3 (agentview)
observation.images.image2 video 256 x 256 x 3 (wrist)
observation.state float32 (8,)
action float32 (7,)

action is the teacher's action after the environment post-processor, i.e. the 7-D command actually sent to the simulator.

What was measured with it

lerobot-eval, same task, seed 1000, 50 episodes, n_action_steps=10.

Model Trained on Success
SmolVLA baseline human demos, all 40 LIBERO tasks 48.0 %
SmolVLA distilled teacher part only (8,409 frames) 56.0 %
SmolVLA DAgger this dataset (19,691 frames) 58.0 %
SmolVLA full-VLM this dataset, VLM unfrozen 58.0 %
MolmoAct2 (teacher) 100 %

Aggregating 2.3x more data, aimed exactly at the student's failure modes, moved 56 % to 58 %. Unfreezing the VLM on top of that moved it by 0 pp. An off-the-shelf X-VLA (0.9B) scores 92 % on this task without any of this.

Published so the negative result is reproducible, not because the resulting policies are good.

Usage

from lerobot.datasets.lerobot_dataset import LeRobotDataset

ds = LeRobotDataset("AmberHyunKIM/dagger_libero10_task6", video_backend="pyav")
print(ds.meta.total_episodes, len(ds))

video_backend="pyav" matters on machines without FFmpeg shared libraries, where torchcodec fails to load.

Caveats

  • Single task, one seed range. Collection used seeds 2000+, evaluation seed 1000, so train and eval initial states do not overlap, but this is still one task.
  • Only the teacher's final 7-D action is recorded. No output distribution, no intermediate features. Anyone wanting deeper distillation signal must regenerate.
  • Actions come from MolmoAct2 running in bf16 + AMP.
  • Episode boundaries between the two parts are not tagged in the dataset itself. The first 36 episodes are teacher trajectories, the remaining 30 are relabelled student states.
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