refactor(unitree_g1): move lowstate_to_obs out of g1_utils into unitree_g1

Keep g1_utils close to main: the lowstate -> obs mapping lives in unitree_g1
(where get_observation builds it, left unchanged from main) and the SONIC
controller imports it from there.

src/lerobot/robots/unitree_g1/controllers/sonic_whole_body.py

@@ -44,8 +44,8 @@ from ..g1_utils import (
     G1_29_JointIndex,
     compute_pd_gains,
     get_gravity_orientation,
-    lowstate_to_obs,
 )
+from ..unitree_g1 import lowstate_to_obs
 
 logger = logging.getLogger(__name__)
 

src/lerobot/robots/unitree_g1/g1_utils.py

@@ -163,47 +163,6 @@ class G1_29_JointArmIndex(IntEnum):
     kRightWristYaw = 28
 
 
-def lowstate_to_obs(lowstate) -> dict:
-    """Build a robot observation dict from a Unitree lowstate.
-
-    Shared by ``UnitreeG1.get_observation`` and the SONIC pipeline so the
-    lowstate -> obs mapping lives in exactly one place. Keys match the
-    ``<joint>.q``/``imu.*`` schema consumed across the controllers.
-    """
-    obs: dict = {}
-
-    for motor in G1_29_JointIndex:
-        idx = motor.value
-        obs[f"{motor.name}.q"] = lowstate.motor_state[idx].q
-        obs[f"{motor.name}.dq"] = lowstate.motor_state[idx].dq
-        obs[f"{motor.name}.tau"] = lowstate.motor_state[idx].tau_est
-
-    imu = lowstate.imu_state
-    if imu.gyroscope:
-        obs["imu.gyro.x"] = imu.gyroscope[0]
-        obs["imu.gyro.y"] = imu.gyroscope[1]
-        obs["imu.gyro.z"] = imu.gyroscope[2]
-    if imu.accelerometer:
-        obs["imu.accel.x"] = imu.accelerometer[0]
-        obs["imu.accel.y"] = imu.accelerometer[1]
-        obs["imu.accel.z"] = imu.accelerometer[2]
-    if imu.quaternion:
-        obs["imu.quat.w"] = imu.quaternion[0]
-        obs["imu.quat.x"] = imu.quaternion[1]
-        obs["imu.quat.y"] = imu.quaternion[2]
-        obs["imu.quat.z"] = imu.quaternion[3]
-    if imu.rpy:
-        obs["imu.rpy.roll"] = imu.rpy[0]
-        obs["imu.rpy.pitch"] = imu.rpy[1]
-        obs["imu.rpy.yaw"] = imu.rpy[2]
-
-    wr = getattr(lowstate, "wireless_remote", None)
-    if wr:
-        obs["wireless_remote"] = bytes(wr) if not isinstance(wr, (bytes, bytearray)) else wr
-
-    return obs
-
-
 def make_locomotion_controller(name: str | None):
     """Instantiate a locomotion controller by class name. Returns None if name is None."""
     if name is None:

src/lerobot/robots/unitree_g1/unitree_g1.py

@@ -105,6 +105,47 @@ class G1_29_LowState:  # noqa: N801
     mode_machine: int = 0  # Robot mode
 
 
+def lowstate_to_obs(lowstate) -> dict:
+    """Build a robot observation dict from a Unitree lowstate.
+
+    Shared by ``UnitreeG1.get_observation`` and the SONIC pipeline so the
+    lowstate -> obs mapping lives in exactly one place. Keys match the
+    ``<joint>.q``/``imu.*`` schema consumed across the controllers.
+    """
+    obs: dict = {}
+
+    for motor in G1_29_JointIndex:
+        idx = motor.value
+        obs[f"{motor.name}.q"] = lowstate.motor_state[idx].q
+        obs[f"{motor.name}.dq"] = lowstate.motor_state[idx].dq
+        obs[f"{motor.name}.tau"] = lowstate.motor_state[idx].tau_est
+
+    imu = lowstate.imu_state
+    if imu.gyroscope:
+        obs["imu.gyro.x"] = imu.gyroscope[0]
+        obs["imu.gyro.y"] = imu.gyroscope[1]
+        obs["imu.gyro.z"] = imu.gyroscope[2]
+    if imu.accelerometer:
+        obs["imu.accel.x"] = imu.accelerometer[0]
+        obs["imu.accel.y"] = imu.accelerometer[1]
+        obs["imu.accel.z"] = imu.accelerometer[2]
+    if imu.quaternion:
+        obs["imu.quat.w"] = imu.quaternion[0]
+        obs["imu.quat.x"] = imu.quaternion[1]
+        obs["imu.quat.y"] = imu.quaternion[2]
+        obs["imu.quat.z"] = imu.quaternion[3]
+    if imu.rpy:
+        obs["imu.rpy.roll"] = imu.rpy[0]
+        obs["imu.rpy.pitch"] = imu.rpy[1]
+        obs["imu.rpy.yaw"] = imu.rpy[2]
+
+    wr = getattr(lowstate, "wireless_remote", None)
+    if wr:
+        obs["wireless_remote"] = bytes(wr) if not isinstance(wr, (bytes, bytearray)) else wr
+
+    return obs
+
+
 class UnitreeG1(Robot):
     config_class = UnitreeG1Config
     name = "unitree_g1"