Figure 33 - Pinch Grasp Torque
9.4
Optional Strain Gage Joint-Torque Sensor
The BarrettHand™ provides an optional Joint-Torque sensor for each finger. The Joint-Torque
sensor measures the torque about the outer joint on each finger, see Figure 34. The Joint-Torque
sensor is comprised of a flexible beam with four foil strain gages applied and wired in a
Wheatstone Bridge configuration. When a force is applied to the fingertip, Force A, the torque is
measured by the amount of deflection in the beam. The beam deflection is proportional to the
difference in cable tension, which translates to a force on the pulley attached to the flexible beam,
Force B. The flexing in the beam creates a measurable voltage change in the Wheatstone Bridge.
This difference in voltage is conditioned, amplified, converted and available to you in digital form.
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