ACT¶

ACT trains directly from a validated canonical LeRobot dataset. The maintained model representations are ee_local_relative and base_joint_relative.

Install¶

source ../IsaacLab/env_isaaclab/bin/activate
uv pip install -e source/am_isaac
uv pip install -e "source/am_isaac_il[act]"
uv pip install --no-deps "lerobot==0.4.4"
python -c "from importlib.metadata import version; print(version('lerobot'))"

The final command must print 0.4.4.

Validate the source dataset¶

python scripts/data/validate_lerobotdataset.py \
  --dataset_root <session-root> \
  --repo_id am_bench/press_button_ee_absolute \
  --target_hz 20

Use an absolute-action source dataset. ACT constructs relative trajectories at the logical policy rate without rewriting the source.

Train¶

python -m am_isaac_il.policies.act.train \
  --dataset.repo_id=am_bench/press_button_ee_absolute \
  --dataset.root=<session-root>/lerobot \
  --dataset.use_imagenet_stats=true \
  --policy.type=act \
  --policy.chunk_size=16 \
  --policy.n_action_steps=8 \
  --policy.device=cuda \
  --policy.push_to_hub=false \
  --output_dir=<checkpoint-root> \
  --job_name=press_button_act \
  --batch_size=8 \
  --steps=20000 \
  --num_workers=4 \
  --save_freq=5000 \
  --wandb.enable=false \
  --policy_target_hz=20 \
  --policy_action_representation=ee_local_relative

For BaseJoint data, use the corresponding dataset and set --policy_action_representation=base_joint_relative. A saved checkpoint contains pretrained_model plus the representation metadata required by evaluation.

Evaluate¶

python -m am_isaac_il.policies.act.eval \
  --task PressButton-Am-EE-Abs-PID-Direct-v0 \
  --checkpoint <checkpoint-root>/checkpoints/020000/pretrained_model \
  --num-rollouts 10 \
  --num-envs 1 \
  --n-action-steps 8 \
  --policy-target-hz 20 \
  --episode-length-s 20 \
  --save-video \
  --headless \
  --device cuda:0

Use a BaseJoint environment only with a BaseJoint checkpoint. ACT rejects temporal ensembling for relative representations because predictions anchored to different measured states cannot be averaged safely.

Evaluation output follows the common artifact contract.