Torque Control

Overview

Use hand.torque for torque control. It supports setting target torque values and reading the current torque.

Torque values range from 0-100 (unitless, representing the relative torque percentage of the joint motors) for the 6 joint motors of the L6 dexterous hand:

Set Torque

# Using a list
hand.torque.set_torques([50.0, 30.0, 60.0, 60.0, 60.0, 60.0])

# Using an L6Torque object
from realhand.hand.l6 import L6Torque

target = L6Torque(
    thumb_flex=50.0, thumb_abd=30.0, index=60.0, middle=60.0, ring=60.0, pinky=60.0
)
hand.torque.set_torques(target)

Read Torque

Blocking Read

Send a request and wait for the response:

from realhand.exceptions import TimeoutError

try:
    data = hand.torque.get_blocking(timeout_ms=500)
    print(f"Thumb flexion: {data.torques.thumb_flex}")
    print(f"Index finger: {data.torques.index}")
except TimeoutError:
    print("Read timed out")

Cached Read

Get the most recent cached value without blocking:

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

Streaming Read

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

from realhand.hand.l6 import SensorSource, TorqueEvent

hand.start_polling({SensorSource.TORQUE: 0.05})

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

hand.stop_polling()
hand.stop_stream()

Examples

Full Control Flow

from realhand import L6
from realhand.hand.l6 import L6Torque

with L6(side="left", interface_name="can0") as hand:
    # Set torque
    hand.torque.set_torques([50.0, 30.0, 60.0, 60.0, 60.0, 60.0])

    # Blocking read of current torque
    data = hand.torque.get_blocking(timeout_ms=200)
    print(f"Current torque: {data.torques.to_list()}")

Real-Time Monitoring

from realhand import L6
from realhand.hand.l6 import SensorSource, TorqueEvent

with L6(side="left", interface_name="can0") as hand:
    hand.start_polling({SensorSource.TORQUE: 0.1})

    try:
        for event in hand.stream():
            match event:
                case TorqueEvent(data=data):
                    if data.torques.index > 80:
                        print("Index joint motor torque is too high")
                        break
    finally:
        hand.stop_polling()
        hand.stop_stream()