Add HIT policy

lerobot/__init__.py

@@ -188,6 +188,7 @@
 # lists all available policies from `lerobot/common/policies`
 available_policies = [
     "act",
+    "hit",
     "diffusion",
     "tdmpc",
     "vqbet",
@@ -216,7 +217,7 @@
 
 # keys and values refer to yaml files
 available_policies_per_env = {
-    "aloha": ["act"],
+    "aloha": ["act", "hit"],
     "pusht": ["diffusion", "vqbet"],
     "xarm": ["tdmpc"],
     "koch_real": ["act_koch_real"],

lerobot/common/policies/factory.py

@@ -61,6 +61,11 @@ def get_policy_and_config_classes(name: str) -> tuple[Policy, object]:
         from lerobot.common.policies.act.modeling_act import ACTPolicy
 
         return ACTPolicy, ACTConfig
+    elif name == "hit":
+        from lerobot.common.policies.hit.configuration_hit import HITConfig
+        from lerobot.common.policies.hit.modeling_hit import HITPolicy
+
+        return HITPolicy, HITConfig
     elif name == "vqbet":
         from lerobot.common.policies.vqbet.configuration_vqbet import VQBeTConfig
         from lerobot.common.policies.vqbet.modeling_vqbet import VQBeTPolicy

lerobot/common/policies/hit/configuration_hit.py

@@ -0,0 +1,155 @@
+#!/usr/bin/env python
+
+# Copyright 2024 Tony Z. Zhao and The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from dataclasses import dataclass, field
+
+
+@dataclass
+class HITConfig:
+    """Configuration class for the Humanoid Imitation Transformer policy.
+
+    Defaults are configured for training on bimanual Aloha tasks like "insertion" or "transfer".
+
+    The parameters you will most likely need to change are the ones which depend on the environment / sensors.
+    Those are: `input_shapes` and 'output_shapes`.
+
+    Notes on the inputs and outputs:
+        - Either:
+            - At least one key starting with "observation.image is required as an input.
+              AND/OR
+            - The key "observation.environment_state" is required as input.
+        - If there are multiple keys beginning with "observation.images." they are treated as multiple camera
+          views. Right now we only support all images having the same shape.
+        - May optionally work without an "observation.state" key for the proprioceptive robot state.
+        - "action" is required as an output key.
+
+    Args:
+        n_obs_steps: Number of environment steps worth of observations to pass to the policy (takes the
+            current step and additional steps going back).
+        chunk_size: The size of the action prediction "chunks" in units of environment steps.
+        n_action_steps: The number of action steps to run in the environment for one invocation of the policy.
+            This should be no greater than the chunk size. For example, if the chunk size size 100, you may
+            set this to 50. This would mean that the model predicts 100 steps worth of actions, runs 50 in the
+            environment, and throws the other 50 out.
+        input_shapes: A dictionary defining the shapes of the input data for the policy. The key represents
+            the input data name, and the value is a list indicating the dimensions of the corresponding data.
+            For example, "observation.image" refers to an input from a camera with dimensions [3, 96, 96],
+            indicating it has three color channels and 96x96 resolution. Importantly, `input_shapes` doesn't
+            include batch dimension or temporal dimension.
+        output_shapes: A dictionary defining the shapes of the output data for the policy. The key represents
+            the output data name, and the value is a list indicating the dimensions of the corresponding data.
+            For example, "action" refers to an output shape of [14], indicating 14-dimensional actions.
+            Importantly, `output_shapes` doesn't include batch dimension or temporal dimension.
+        input_normalization_modes: A dictionary with key representing the modality (e.g. "observation.state"),
+            and the value specifies the normalization mode to apply. The two available modes are "mean_std"
+            which subtracts the mean and divides by the standard deviation and "min_max" which rescale in a
+            [-1, 1] range.
+        output_normalization_modes: Similar dictionary as `normalize_input_modes`, but to unnormalize to the
+            original scale. Note that this is also used for normalizing the training targets.
+        vision_backbone: Name of the torchvision resnet backbone to use for encoding images.
+        pretrained_backbone_weights: Pretrained weights from torchvision to initalize the backbone.
+            `None` means no pretrained weights.
+        replace_final_stride_with_dilation: Whether to replace the ResNet's final 2x2 stride with a dilated
+            convolution.
+        pre_norm: Whether to use "pre-norm" in the transformer blocks.
+        dim_model: The transformer blocks' main hidden dimension.
+        n_heads: The number of heads to use in the transformer blocks' multi-head attention.
+        dim_feedforward: The dimension to expand the transformer's hidden dimension to in the feed-forward
+            layers.
+        feedforward_activation: The activation to use in the transformer block's feed-forward layers.
+        n_layers: The number of transformer layers to use for the transformer encoder.
+        temporal_ensemble_coeff: Coefficient for the exponential weighting scheme to apply for temporal
+            ensembling. Defaults to None which means temporal ensembling is not used. `n_action_steps` must be
+            1 when using this feature, as inference needs to happen at every step to form an ensemble. For
+            more information on how ensembling works, please see `ACTTemporalEnsembler`.
+        dropout: Dropout to use in the transformer layers (see code for details).
+        kl_weight: The weight to use for the KL-divergence component of the loss if the variational objective
+            is enabled. Loss is then calculated as: `reconstruction_loss + kl_weight * kld_loss`.
+    """
+
+    # Input / output structure.
+    n_obs_steps: int = 1
+    chunk_size: int = 50
+    n_action_steps: int = 50
+
+    input_shapes: dict[str, list[int]] = field(
+        default_factory=lambda: {
+            "observation.images.top": [3, 480, 640],
+            "observation.state": [14],
+        }
+    )
+    output_shapes: dict[str, list[int]] = field(
+        default_factory=lambda: {
+            "action": [14],
+        }
+    )
+
+    # Normalization / Unnormalization
+    input_normalization_modes: dict[str, str] = field(
+        default_factory=lambda: {
+            "observation.images.top": "mean_std",
+            "observation.state": "mean_std",
+        }
+    )
+    output_normalization_modes: dict[str, str] = field(
+        default_factory=lambda: {
+            "action": "mean_std",
+        }
+    )
+
+    # Architecture.
+    # Vision backbone.
+    vision_backbone: str = "resnet18"
+    pretrained_backbone_weights: str | None = "ResNet18_Weights.IMAGENET1K_V1"
+    replace_final_stride_with_dilation: int = False
+    # Transformer layers.
+    pre_norm: bool = False
+    dim_model: int = 512
+    n_heads: int = 8
+    dim_feedforward: int = 3200
+    feedforward_activation: str = "gelu"
+    n_layers: int = 4
+    # Future image feature predict loss
+    predict_horizon: int = 50
+    feature_loss_weight: float = 0.005
+
+    # Inference.
+    # Note: the original HIT didn't use temporal ensembling.
+    temporal_ensemble_coeff: float | None = None
+
+    # Training and loss computation.
+    dropout: float = 0.1
+    kl_weight: float = 10.0
+
+    def __post_init__(self):
+        """Input validation (not exhaustive)."""
+        if not self.vision_backbone.startswith("resnet"):
+            raise ValueError(
+                f"`vision_backbone` must be one of the ResNet variants. Got {self.vision_backbone}."
+            )
+        if self.n_action_steps > self.chunk_size:
+            raise ValueError(
+                f"The chunk size is the upper bound for the number of action steps per model invocation. Got "
+                f"{self.n_action_steps} for `n_action_steps` and {self.chunk_size} for `chunk_size`."
+            )
+        if self.n_obs_steps != 1:
+            raise ValueError(
+                f"Multiple observation steps not handled yet. Got `nobs_steps={self.n_obs_steps}`"
+            )
+        if (
+            not any(k.startswith("observation.image") for k in self.input_shapes)
+            and "observation.environment_state" not in self.input_shapes
+        ):
+            raise ValueError("You must provide at least one image or the environment state among the inputs.")