#
Damiao Motors and CAN Bus

This guide covers setup and usage of Damiao motors with LeRobot via CAN bus communication.

Currently, only Linux is supported, as the OpenArms CAN adapter only has drivers for Linux.

##
Linux CAN Setup

Before using Damiao motors, you need to set up the CAN interface on your Linux system.

###
Install CAN Utilities

    sudo apt-get install can-utils

###
Configure CAN Interface (Manual)

For standard CAN FD (recommended for OpenArms):

    sudo ip link set can0 down
    sudo ip link set can0 type can bitrate 1000000 dbitrate 5000000 fd on
    sudo ip link set can0 up

For standard CAN (without FD):

    sudo ip link set can0 down
    sudo ip link set can0 type can bitrate 1000000
    sudo ip link set can0 up

###
Configure CAN Interface (Using LeRobot)

LeRobot provides a utility script to setup and test CAN interfaces:

    # Setup multiple interfaces (e.g., OpenArms Followers with 2 CAN buses)
    lerobot-setup-can --mode=setup --interfaces=can0,can1

##
Debugging CAN Communication

Use the built-in debug tools to test motor communication:

    # Test motors on all interfaces
    lerobot-setup-can --mode=test --interfaces=can0,can1

    # Run speed/latency test
    lerobot-setup-can --mode=speed --interfaces=can0

The test mode will scan for motors (IDs 0x01-0x08) and report which ones respond. Example output:

    can0: UP (CAN FD)
      Motor 0x01 (joint_1): ✓ FOUND
        → Response 0x11 [FD]: 00112233...
      Motor 0x02 (joint_2): ✓ FOUND
      Motor 0x03 (joint_3): ✗ No response
      ...
      Summary: 2/8 motors found

##
Usage

###
Basic Setup

    from lerobot.motors import Motor
    from lerobot.motors.damiao import DamiaoMotorsBus

    # Define your motors with send/receive CAN IDs
    motors = {
        "joint_1": Motor(id=0x01, motor_type_str="dm8009", recv_id=0x11),
        "joint_2": Motor(id=0x02, motor_type_str="dm4340", recv_id=0x12),
        "joint_3": Motor(id=0x03, motor_type_str="dm4310", recv_id=0x13),
    }

    # Create the bus
    bus = DamiaoMotorsBus(
        port="can0",  # Linux socketcan interface
        motors=motors,
    )

    # Connect
    bus.connect()

###
Reading Motor States

    # Read single motor position (degrees)
    position = bus.read("Present_Position", "joint_1")

    # Read from multiple motors
    positions = bus.sync_read("Present_Position")  # All motors
    positions = bus.sync_read("Present_Position", ["joint_1", "joint_2"])

    # Read all states at once (position, velocity, torque)
    states = bus.sync_read_all_states()
    # Returns: {'joint_1': {'position': 45.2, 'velocity': 1.3, 'torque': 0.5}, ...}

###
Writing Motor Commands

    # Enable torque
    bus.enable_torque()

    # Set goal position (degrees)
    bus.write("Goal_Position", "joint_1", 45.0)

    # Set positions for multiple motors
    bus.sync_write("Goal_Position", {
        "joint_1": 45.0,
        "joint_2": -30.0,
        "joint_3": 90.0,
    })

    # Disable torque
    bus.disable_torque()

##
Configuration Options

Parameter | Default | Description
--- | --- | ---
`port` | - | CAN interface (`can0`) or serial port (`/dev/cu.usbmodem*`)
`use_can_fd` | `True` | Enable CAN FD for higher data rates
`bitrate` | `1000000` | Nominal bitrate (1 Mbps)
`data_bitrate` | `5000000` | CAN FD data bitrate (5 Mbps)

##
Motor Configuration

Each motor requires:

- `id`: CAN ID for sending commands
- `motor_type`: One of the supported motor types (e.g., `"dm8009"`, `"dm4340"`)
- `recv_id`: CAN ID for receiving responses

OpenArms default IDs follow the pattern: send ID `0x0N`, receive ID `0x1N` where N is the joint number.

##
Troubleshooting

###
No Response from Motors

1. Check power
2. Verify CAN wiring: Check CAN-H, CAN-L, and GND connections
3. Check motor IDs: Use Damiao Debugging Tools to verify/configure IDs
4. Test CAN interface: Run `candump can0` to see if messages are being received
5. Run diagnostics: `lerobot-setup-can --mode=test --interfaces=can0`

###
Motor Timeout Parameter

If motors were configured with timeout=0, they won’t respond to commands. Use Damiao Debugging Tools to set a non-zero timeout value.

###
Verify CAN FD Status

    ip -d link show can0 | grep fd

Update on GitHub