posco_act_square_260822_left_c20

posco_act_square_260822_left_c20

ACT (action-chunking transformer) policy trained with LeRobot 0.4.3 on the POSCO left-arm pick-and-place dataset.

Configuration

Right-arm dimensions were dropped before training: in these recordings they are effectively constant (action std down to 0.0), so under normalization they contribute unit-variance sensor noise the policy cannot learn.

Usage

from lerobot.policies.act.modeling_act import ACTPolicy
from lerobot.policies.factory import make_pre_post_processors

repo = "learner1119/posco_act_square_260822_left_c20"
policy = ACTPolicy.from_pretrained(repo).eval()
pre, post = make_pre_post_processors(policy.config, pretrained_path=repo)

processed = pre(observation)                       # normalizes + tokenizes
chunk = policy.predict_action_chunk(processed)     # (B, 20, 8), normalized
actions = post(chunk[:, 0])                        # -> real action space

On lerobot >= 0.4 normalization lives in these processor pipelines, not inside the policy. Calling predict_action_chunk on raw observations silently returns wrong actions -- always go through pre / post.

Caveat

Trained on all available episodes with no held-out split, so it has no honest offline validation number attached. Treat reported training loss as fit quality, not generalization.