revision 1

lerobot/common/datasets/factory.py

@@ -86,10 +86,11 @@ def make_dataset(
             ]
         )
 
-    delta_timestamps = cfg.policy.delta_timestamps
-    for key in delta_timestamps:
-        if isinstance(delta_timestamps[key], str):
-            delta_timestamps[key] = eval(delta_timestamps[key])
+    delta_timestamps = cfg.policy.get("delta_timestamps")
+    if delta_timestamps is not None:
+        for key in delta_timestamps:
+            if isinstance(delta_timestamps[key], str):
+                delta_timestamps[key] = eval(delta_timestamps[key])
 
     dataset = clsfunc(
         dataset_id=cfg.dataset_id,

lerobot/common/policies/act/configuration_act.py

@@ -2,7 +2,7 @@ from dataclasses import dataclass, field
 
 
 @dataclass
-class ActConfig:
+class ActionChunkingTransformerConfig:
     """Configuration class for the Action Chunking Transformers policy.
 
     Defaults are configured for training on bimanual Aloha tasks like "insertion" or "transfer".

lerobot/common/policies/act/modeling_act.py

@@ -20,10 +20,10 @@ from torch import Tensor, nn
 from torchvision.models._utils import IntermediateLayerGetter
 from torchvision.ops.misc import FrozenBatchNorm2d
 
-from lerobot.common.policies.act.configuration_act import ActConfig
+from lerobot.common.policies.act.configuration_act import ActionChunkingTransformerConfig
 
 
-class ActPolicy(nn.Module):
+class ActionChunkingTransformerPolicy(nn.Module):
     """
     Action Chunking Transformer Policy as per Learning Fine-Grained Bimanual Manipulation with Low-Cost
     Hardware (paper: https://arxiv.org/abs/2304.13705, code: https://github.com/tonyzhaozh/act)
@@ -61,9 +61,11 @@ class ActPolicy(nn.Module):
     """
 
     name = "act"
-    _multiple_obs_steps_not_handled_msg = "ActPolicy does not handle multiple observation steps."
+    _multiple_obs_steps_not_handled_msg = (
+        "ActionChunkingTransformerPolicy does not handle multiple observation steps."
+    )
 
-    def __init__(self, cfg: ActConfig):
+    def __init__(self, cfg: ActionChunkingTransformerConfig):
         """
         TODO(alexander-soare): Add documentation for all parameters once we have model configs established.
         """
@@ -398,7 +400,7 @@ class ActPolicy(nn.Module):
 class _TransformerEncoder(nn.Module):
     """Convenience module for running multiple encoder layers, maybe followed by normalization."""
 
-    def __init__(self, cfg: ActConfig):
+    def __init__(self, cfg: ActionChunkingTransformerConfig):
         super().__init__()
         self.layers = nn.ModuleList([_TransformerEncoderLayer(cfg) for _ in range(cfg.n_encoder_layers)])
         self.norm = nn.LayerNorm(cfg.d_model) if cfg.pre_norm else nn.Identity()
@@ -411,7 +413,7 @@ class _TransformerEncoder(nn.Module):
 
 
 class _TransformerEncoderLayer(nn.Module):
-    def __init__(self, cfg: ActConfig):
+    def __init__(self, cfg: ActionChunkingTransformerConfig):
         super().__init__()
         self.self_attn = nn.MultiheadAttention(cfg.d_model, cfg.n_heads, dropout=cfg.dropout)
 
@@ -449,7 +451,7 @@ class _TransformerEncoderLayer(nn.Module):
 
 
 class _TransformerDecoder(nn.Module):
-    def __init__(self, cfg: ActConfig):
+    def __init__(self, cfg: ActionChunkingTransformerConfig):
         """Convenience module for running multiple decoder layers followed by normalization."""
         super().__init__()
         self.layers = nn.ModuleList([_TransformerDecoderLayer(cfg) for _ in range(cfg.n_decoder_layers)])
@@ -472,7 +474,7 @@ class _TransformerDecoder(nn.Module):
 
 
 class _TransformerDecoderLayer(nn.Module):
-    def __init__(self, cfg: ActConfig):
+    def __init__(self, cfg: ActionChunkingTransformerConfig):
         super().__init__()
         self.self_attn = nn.MultiheadAttention(cfg.d_model, cfg.n_heads, dropout=cfg.dropout)
         self.multihead_attn = nn.MultiheadAttention(cfg.d_model, cfg.n_heads, dropout=cfg.dropout)

lerobot/common/policies/factory.py

@@ -28,21 +28,21 @@ def make_policy(cfg):
             **cfg.policy,
         )
     elif cfg.policy.name == "act":
-        from lerobot.common.policies.act.configuration_act import ActConfig
-        from lerobot.common.policies.act.modeling_act import ActPolicy
+        from lerobot.common.policies.act.configuration_act import ActionChunkingTransformerConfig
+        from lerobot.common.policies.act.modeling_act import ActionChunkingTransformerPolicy
 
-        expected_kwargs = set(inspect.signature(ActConfig).parameters)
+        expected_kwargs = set(inspect.signature(ActionChunkingTransformerConfig).parameters)
         assert set(cfg.policy).issuperset(
             expected_kwargs
         ), f"Hydra config is missing arguments: {set(cfg.policy).difference(expected_kwargs)}"
-        policy_cfg = ActConfig(
+        policy_cfg = ActionChunkingTransformerConfig(
             **{
                 k: v
                 for k, v in OmegaConf.to_container(cfg.policy, resolve=True).items()
                 if k in expected_kwargs
             }
         )
-        policy = ActPolicy(policy_cfg)
+        policy = ActionChunkingTransformerPolicy(policy_cfg)
         policy.to(get_safe_torch_device(cfg.device))
     else:
         raise ValueError(cfg.policy.name)

lerobot/configs/policy/act.yaml

@@ -11,6 +11,7 @@ log_freq: 250
 n_obs_steps: 1
 # when temporal_agg=False, n_action_steps=horizon
 
+# See `configuration_act.py` for more details.
 policy:
   name: act
 

tests/test_available.py

@@ -18,14 +18,14 @@ from lerobot.common.datasets.xarm import XarmDataset
 from lerobot.common.datasets.aloha import AlohaDataset
 from lerobot.common.datasets.pusht import PushtDataset
 
-from lerobot.common.policies.act.modeling_act import ActPolicy
+from lerobot.common.policies.act.modeling_act import ActionChunkingTransformerPolicy
 from lerobot.common.policies.diffusion.policy import DiffusionPolicy
 from lerobot.common.policies.tdmpc.policy import TDMPCPolicy
 
 
 def test_available():
     policy_classes = [
-        ActPolicy,
+        ActionChunkingTransformerPolicy,
         DiffusionPolicy,
         TDMPCPolicy,
     ]