improve serial_reading

src/lerobot/teleoperators/unitree_g1/exo_serial.py

@@ -38,6 +38,7 @@ def parse_raw16(line: bytes) -> list[int] | None:
 
 def read_raw_from_serial(ser) -> list[int] | None:
     """Read latest sample from serial; if buffer is backed up, keep only the newest."""
+    try:
         last = None
         while ser.in_waiting > 0:
             b = ser.readline()
@@ -51,6 +52,9 @@ def read_raw_from_serial(ser) -> list[int] | None:
             if b:
                 last = parse_raw16(b)
         return last
+    except (OSError, serial.SerialException) as e:
+        logger.warning(f"Serial read error: {e}")
+        return None
 
 
 @dataclass
@@ -104,13 +108,19 @@ class ExoskeletonArm:
             logger.warning(f"failed to load calibration: {e}")
 
     def read_raw(self) -> list[int] | None:
-        if not self._ser:
+        if not self._ser or not self._ser.is_open:
             return None
         return read_raw_from_serial(self._ser)
 
-    def get_angles(self) -> dict[str, float]:
+    def get_angles(self, raw: list[int] | None = None) -> dict[str, float]:
+        """Convert raw ADC values to joint angles.
+
+        Args:
+            raw: Optional raw ADC values. If None, reads from serial.
+        """
         if not self.calibration:
             raise RuntimeError("exoskeleton not calibrated")
+        if raw is None:
             raw = self.read_raw()
         return {} if raw is None else exo_raw_to_angles(raw, self.calibration)