Add code to communicate with Hiwonder motors

lerobot/common/robot_devices/motors/hiwonder.py

@@ -0,0 +1,217 @@
+import traceback
+
+import numpy as np
+import serial
+
+from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
+
+BAUDRATE = 115_200
+TIMEOUT_S = 1
+COMMAND_HEADER = [0x55, 0x55]  # Header for all commands sent to Hiwonder motors
+BYTE_MASK = 0xFF
+
+# https://drive.google.com/file/d/1DQGBBng8UFziv5hg15qmyvakItG3w6Ss/view?usp=sharing
+
+# data_name: (command, length)
+HIWONDER_CONTROL_TABLE = {
+    "SERVO_MOVE_TIME_WRITE": (0x01, 0x07),
+    "SERVO_MOVE_TIME_READ": (0x02, 0x03),
+    "SERVO_MOVE_TIME_WAIT_WRITE": (0x07, 0x07),
+    "SERVO_MOVE_TIME_WAIT_READ": (0x08, 0x03),
+    "SERVO_MOVE_START": (0x0B, 0x03),
+    "SERVO_MOVE_STOP": (0x0C, 0x03),
+    "SERVO_ID_WRITE": (0x0D, 0x04),
+    "SERVO_ID_READ": (0x0E, 0x03),
+    "SERVO_ANGLE_OFFSET_ADJUST": (0x11, 0x04),
+    "SERVO_ANGLE_OFFSET_WRITE": (0x12, 0x03),
+    "SERVO_ANGLE_OFFSET_READ": (0x13, 0x03),
+    "SERVO_ANGLE_LIMIT_WRITE": (0x14, 0x07),
+    "SERVO_ANGLE_LIMIT_READ": (0x15, 0x03),
+    "SERVO_VIN_LIMIT_WRITE": (0x16, 0x07),
+    "SERVO_VIN_LIMIT_READ": (0x17, 0x03),
+    "SERVO_TEMP_MAX_LIMIT_WRITE": (0x18, 0x04),
+    "SERVO_TEMP_MAX_LIMIT_READ": (0x19, 0x03),
+    "SERVO_TEMP_READ": (0x1A, 0x03),
+    "SERVO_VIN_READ": (0x1B, 0x03),
+    "SERVO_POS_READ": (0x1C, 0x03),
+    "SERVO_OR_MOTOR_MODE_WRITE": (0x1D, 0x07),
+    "SERVO_OR_MOTOR_MODE_READ": (0x1E, 0x03),
+    "SERVO_LOAD_OR_UNLOAD_WRITE": (0x1F, 0x04),
+    "SERVO_LOAD_OR_UNLOAD_READ": (0x20, 0x03),
+    "SERVO_LED_CTRL_WRITE": (0x21, 0x04),
+    "SERVO_LED_CTRL_READ": (0x22, 0x03),
+    "SERVO_LED_ERROR_WRITE": (0x23, 0x04),
+    "SERVO_LED_ERROR_READ": (0x24, 0x03),
+}
+
+
+def calculate_checksum(data):
+    """Calculate the checksum for the given data."""
+    checksum = ~(sum(data)) & BYTE_MASK
+    return checksum
+
+
+def low_byte(value):
+    """Extract the low byte of a 16-bit integer."""
+    return value & BYTE_MASK
+
+
+def high_byte(value):
+    """Extract the high byte of a 16-bit integer."""
+    return (value >> 8) & BYTE_MASK
+
+
+class HiwonderMotorsBus:
+    """
+    The HiwonderMotorBus class allows to efficiently read and write to the attached motors. It relies on
+    the [Hiwonder Bus Communication Protoco](https://drive.google.com/file/d/1JKyt_OUg9V6cIBC-SiX6IIAACsvz86aB/view?usp=sharing).
+
+    A HiwonderMotorBus instance requires a port (e.g. `HiwonderMotorBus(port="/dev/tty.usbmodem575E0031751"`)).
+
+    Example of usage for 1 motor connected to the bus:
+    ```python
+    motor_name = "gripper"
+    motor_index = 6
+    motor_model = "lx-16a"
+
+    motors_bus = HiwonderMotorBus(
+        port="/dev/tty.usbmodem575E0031751",
+        motors={motor_name: (motor_index, motor_model)},
+    )
+    motors_bus.connect()
+
+    position = motors_bus.read()
+
+    # move from a few motor steps as an example
+    few_steps = 30
+    motors_bus.write(position + few_steps)
+
+    # when done, consider disconnecting
+    motors_bus.disconnect()
+    ```
+    """
+
+    def __init__(self, port: str, motors: dict[str, tuple[int, str]]):
+        self.port = port
+        self.serial = None
+        self.is_connected = False
+        self.motors = motors
+
+    def connect(self):
+        """Open the serial port and establish a connection."""
+        if self.is_connected:
+            raise RobotDeviceAlreadyConnectedError(
+                f"HiwonderMotorsBus({self.port}) is already connected. Do not call `motors_bus.connect()` twice."
+            )
+        try:
+            self.serial = serial.Serial(self.port, baudrate=BAUDRATE, timeout=TIMEOUT_S)
+            self.is_connected = True
+            print("Connection established")
+        except Exception:
+            traceback.print_exc()
+            print("\nCould not open port.\n")
+            raise
+
+    def disconnect(self):
+        """Close the serial port connection."""
+        if self.serial:
+            self.serial.close()
+            self.is_connected = False
+            print("Connection closed")
+
+    @property
+    def motor_names(self) -> list[str]:
+        return list(self.motors.keys())
+
+    def write(self, values: int | float | np.ndarray, motor_names: str | list[str] | None = None):
+        if not self.is_connected:
+            raise RobotDeviceAlreadyConnectedError(f"HiwonderMotorsBus({self.port}) is not connected.")
+
+        if motor_names is None:
+            motor_names = self.motor_names
+
+        if isinstance(motor_names, str):
+            motor_names = [motor_names]
+
+        if isinstance(values, (int, float)):
+            values = [values] * len(
+                motor_names
+            )  # Replicate value for each motor if a single value is provided
+
+        motor_commands = zip(motor_names, values, strict=False)
+
+        for motor_name, value in motor_commands:
+            motor_id, _ = self.motors[motor_name]  # Using only the ID for the command
+            duration = 0  # Get to the next position as soon as possible
+
+            # Command structure: 55 55 ID LEN CMD P1 P2 P3 P4 CHK
+            # Retrieve command and length from the control table
+            cmd, length = HIWONDER_CONTROL_TABLE["SERVO_MOVE_TIME_WRITE"]
+            # Prepare the packet
+            data = [
+                motor_id,
+                length,
+                cmd,
+                low_byte(value),
+                high_byte(value),
+                low_byte(duration),
+                high_byte(duration),
+            ]
+            checksum = calculate_checksum(data)
+            command = COMMAND_HEADER + data + [checksum]
+
+            self.serial.write(bytearray(command))
+
+    def read(self, motor_names: str | list[str] | None = None):
+        """Send a command to read the current position of the motors."""
+        if not self.is_connected:
+            raise RobotDeviceNotConnectedError(
+                f"HiwonderMotorsBus({self.port}) is not connected. You need to run `motors_bus.connect()`."
+            )
+
+        if motor_names is None:
+            motor_names = self.motor_names
+
+        if isinstance(motor_names, str):
+            motor_names = [motor_names]
+
+        motor_ids = [self.motors[name][0] for name in motor_names]  # Extract motor IDs based on names
+
+        positions = {}
+        for motor_name, motor_id in zip(motor_names, motor_ids, strict=False):
+            # Command structure for reading position: 55 55 ID LEN CMD CHK
+            # Retrieve command and length from the control table
+            cmd, length = HIWONDER_CONTROL_TABLE["SERVO_POS_READ"]
+
+            # Prepare the command packet
+            data = [motor_id, length, cmd]
+            checksum = calculate_checksum(data)
+            command = COMMAND_HEADER + data + [checksum]
+
+            # Send the command
+            self.serial.write(bytearray(command))
+
+            # Wait for response and handle it
+            try:
+                response = self.serial.read(8)  # Adjust size based on expected response
+                if len(response) == 8:
+                    header1, header2, resp_id, resp_len, resp_cmd, param1, param2, resp_chk = response
+                    # Calculate expected checksum and compare
+                    expected_checksum = calculate_checksum(response[2:-1])
+                    if resp_chk == expected_checksum:
+                        # Combine param1 and param2 to form the actual position
+                        position = param1 + (param2 << 8)
+                        positions[motor_name] = position  # Store position with motor ID as the key
+                    else:
+                        print(f"Checksum mismatch for motor {motor_id}.")
+                else:
+                    print(f"No response or invalid response for motor {motor_id}.")
+            except Exception as e:
+                print(f"Failed to read position for motor {motor_id}: {str(e)}")
+
+        return positions
+
+
+# Example usage
+if __name__ == "__main__":
+    pass