layered_hardware_dynamixel

A ros2_control layer implementation for ROBOTIS Dynamixel actuators. See layered_hardware to understand the layered scheme.

Layer plugin: layered_hardware_dynamixel/DynamixelActuatorLayer

• sends commands to ROBOTIS Dynamixel actuators within write() function
• fetches actuators' states within read() function
• switches actuators' operating modes within perform_command_mode_swtich() function when controllers using associated interfaces activate

Hardware parameters

<layer_name> (yaml, required)

• map of parameter names and values for this layer

<layer_name>.serial_interface (string, default: '/dev/ttyUSB0')

• path to Usb2Dynamixel device

<layer_name>.baudrate (int, default: 115200)

• baudrate for Usb2Dynamixel device

<layer_name>.actuators (map<string, map>, required)

• map of parameters for each actuator

<layer_name>.actuators.<actuator_name>.id (int, required)

• id of the dynamixel actuator

<layer_name>.actuators.<actuator_name>.torque_constant (double, required)

• torque constant for conversion between current and torque in N*m/A
• ex. if the actuator's stall torque & current are 10.6 N*m & 4.4 A at the operating voltage, it would be 2.41 (= 10.6 / 4.4)

<layer_name>.actuators.<actuator_name>.operating_mode_map (map<string, string>, required)

• map to actuator's operating mode names from associated interface names (typically joint interfaces)
• possible operating mode names are 'clear_multi_turn', 'current_based_position', 'current', 'extended_position', 'reboot', 'torque_disable', & 'velocity'

Example of parameter description

<param name="example_dynamixel_actuator_layer">
    serial_interface: /dev/serial/by-id/...
    baudrate: 1000000
    actuators:
        example_dynamixel_1:
            id: 1
            torque_constant: 2.41
            operating_mode_map:
                example_joint_1/position: extended_position
                ...
        example_dynamixel_2:
            id: 2
            ...
</param>

Example

• single Dynamixel actuator

Tips

• if you feel slow communication speed with actuators, try adjusting the latency timer for your usb-serial device according to this comment