refactor(processor): clarify action types, distinguish PolicyAction, RobotAction, and EnvAction (#1908)

* refactor(processor): split action from policy, robots and environment

- Updated function names to robot_action_to_transition and robot_transition_to_action across multiple files to better reflect their purpose in processing robot actions.
- Adjusted references in the RobotProcessorPipeline and related components to ensure compatibility with the new naming convention.
- Enhanced type annotations for action parameters to improve code readability and maintainability.

* refactor(converters): rename robot_transition_to_action to transition_to_robot_action

- Updated function names across multiple files to improve clarity and consistency in processing robot actions.
- Adjusted references in RobotProcessorPipeline and related components to align with the new naming convention.
- Simplified action handling in the AddBatchDimensionProcessorStep by removing unnecessary checks for action presence.

* refactor(converters): update references to transition_to_robot_action

- Renamed all instances of robot_transition_to_action to transition_to_robot_action across multiple files for consistency and clarity in the processing of robot actions.
- Adjusted the RobotProcessorPipeline configurations to reflect the new naming convention, enhancing code readability.

* refactor(processor): update Torch2NumpyActionProcessorStep to extend ActionProcessorStep

- Changed the base class of Torch2NumpyActionProcessorStep from PolicyActionProcessorStep to ActionProcessorStep, aligning it with the current architecture of action processing.
- This modification enhances the clarity of the class's role in the processing pipeline.

* fix(processor): main action processor can take also EnvAction

---------

Co-authored-by: Steven Palma <steven.palma@huggingface.co>

examples/phone_to_so100/evaluate.py

@@ -25,7 +25,7 @@ from lerobot.processor import RobotProcessorPipeline
 from lerobot.processor.converters import (
     identity_transition,
     observation_to_transition,
-    transition_to_action,
+    transition_to_robot_action,
 )
 from lerobot.record import record_loop
 from lerobot.robots.so100_follower.config_so100_follower import SO100FollowerConfig
@@ -76,7 +76,7 @@ robot_ee_to_joints_processor = RobotProcessorPipeline(
         ),
     ],
     to_transition=identity_transition,
-    to_output=transition_to_action,
+    to_output=transition_to_robot_action,
 )
 
 # Build pipeline to convert joint observation to ee pose observation

examples/phone_to_so100/record.py

@@ -22,10 +22,10 @@ from lerobot.datasets.utils import combine_feature_dicts
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import RobotProcessorPipeline
 from lerobot.processor.converters import (
-    action_to_transition,
     identity_transition,
     observation_to_transition,
-    transition_to_action,
+    robot_action_to_transition,
+    transition_to_robot_action,
 )
 from lerobot.record import record_loop
 from lerobot.robots.so100_follower.config_so100_follower import SO100FollowerConfig
@@ -89,7 +89,7 @@ phone_to_robot_ee_pose_processor = RobotProcessorPipeline(
             max_ee_twist_step_rad=0.50,
         ),
     ],
-    to_transition=action_to_transition,
+    to_transition=robot_action_to_transition,
     to_output=identity_transition,
 )
 
@@ -107,7 +107,7 @@ robot_ee_to_joints_processor = RobotProcessorPipeline(
         ),
     ],
     to_transition=identity_transition,
-    to_output=transition_to_action,
+    to_output=transition_to_robot_action,
 )
 
 # Build pipeline to convert joint observation to ee pose observation

examples/phone_to_so100/replay.py

@@ -20,7 +20,7 @@ import time
 from lerobot.datasets.lerobot_dataset import LeRobotDataset
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import RobotProcessorPipeline
-from lerobot.processor.converters import action_to_transition, transition_to_action
+from lerobot.processor.converters import robot_action_to_transition, transition_to_robot_action
 from lerobot.robots.so100_follower.config_so100_follower import SO100FollowerConfig
 from lerobot.robots.so100_follower.robot_kinematic_processor import (
     AddRobotObservationAsComplimentaryData,
@@ -59,8 +59,8 @@ robot_ee_to_joints_processor = RobotProcessorPipeline(
             initial_guess_current_joints=False,  # Because replay is open loop
         ),
     ],
-    to_transition=action_to_transition,
-    to_output=transition_to_action,
+    to_transition=robot_action_to_transition,
+    to_output=transition_to_robot_action,
 )
 
 robot_ee_to_joints_processor.reset()

examples/phone_to_so100/teleoperate.py

@@ -17,7 +17,7 @@ import time
 
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import RobotProcessorPipeline
-from lerobot.processor.converters import action_to_transition, transition_to_action
+from lerobot.processor.converters import robot_action_to_transition, transition_to_robot_action
 from lerobot.robots.so100_follower.config_so100_follower import SO100FollowerConfig
 from lerobot.robots.so100_follower.robot_kinematic_processor import (
     AddRobotObservationAsComplimentaryData,
@@ -72,8 +72,8 @@ phone_to_robot_joints_processor = RobotProcessorPipeline(
             speed_factor=20.0,
         ),
     ],
-    to_transition=action_to_transition,
-    to_output=transition_to_action,
+    to_transition=robot_action_to_transition,
+    to_output=transition_to_robot_action,
 )
 
 robot.connect()