Torque Control

Use hand.torque to control and read the torque of the 16 joint motors on the L20 dexterous hand.

• Torque range: 0-100
• Unit: Unitless percentage

Set Torque

from realhand import L20
from realhand.hand.l20 import L20Torque

# Using a list (16 joints)
hand.torque.set_torques([50.0] * 16)

# Using an L20Torque object
torques = L20Torque(
    thumb_abd=50.0,  # Thumb abduction
    thumb_yaw=30.0,  # Thumb rotation
    thumb_root1=60.0,  # Thumb root
    thumb_tip=40.0,  # Thumb tip
    index_abd=50.0,  # Index abduction
    index_root1=60.0,  # Index root
    index_tip=40.0,  # Index tip
    middle_abd=50.0,  # Middle abduction
    middle_root1=60.0,  # Middle root
    middle_tip=40.0,  # Middle tip
    ring_abd=50.0,  # Ring abduction
    ring_root1=60.0,  # Ring root
    ring_tip=40.0,  # Ring tip
    pinky_abd=50.0,  # Pinky abduction
    pinky_root1=60.0,  # Pinky root
    pinky_tip=40.0,  # Pinky tip
)
hand.torque.set_torques(torques)

Read Torque

Blocking Read

from realhand.exceptions import TimeoutError

try:
    data = hand.torque.get_blocking(timeout_ms=500)
    print(f"Thumb abduction: {data.torques.thumb_abd}")
    print(f"All torque values: {data.torques.to_list()}")
except TimeoutError:
    print("Read timed out")

Cached Read

data = hand.torque.get_snapshot()
if data:
    print(f"Torque: {data.torques.to_list()}")
    print(f"Timestamp: {data.timestamp}")

Streaming Read

Receive all sensor events through the top-level hand.stream() interface:

from realhand.hand.l20 import SensorSource, TorqueEvent

hand.start_polling({SensorSource.TORQUE: 0.1})

try:
    for event in hand.stream():
        match event:
            case TorqueEvent(data=data):
                print(f"Torque: {data.torques.to_list()}")
finally:
    hand.stop_polling()
    hand.stop_stream()

Complete Example

from realhand import L20

with L20(side="left", interface_name="can0") as hand:
    # Set torque
    hand.torque.set_torques([50.0] * 16)

    # Read current torque
    data = hand.torque.get_blocking(timeout_ms=500)
    print(f"Current torque: {data.torques.to_list()}")

    # Set different torque values for each finger
    hand.torque.set_torques(
        [
            80.0,
            80.0,
            80.0,
            80.0,  # Thumb
            60.0,
            60.0,
            60.0,  # Index
            60.0,
            60.0,
            60.0,  # Middle
            60.0,
            60.0,
            60.0,  # Ring
            60.0,
            60.0,
            60.0,  # Pinky
        ]
    )