Inside the Inspire RH56DFQ Robotic Hand | Complete Teardown

In this talk

1. 0:31

   Six degrees of movement

   The hand has six actuators for four fingers, a thumb, and a moving wrist. Its linked fingers curl together as linear push rods press against them, while springs return them. The thumb has two actuators, and the hand is rated for half-Newton resolution.

2. 2:03

   Force sensing and control

   There are no sensors or motors in the fingers. Each actuator has position and force sensing, so the hand can target a position or a force; pressure at a fingertip is transmitted mechanically to a sensor at the actuator base. A microprocessor in the palm coordinates the six actuators, with a small controller circuit in each one.

3. 7:00

   Compact linear actuators

   Each actuator combines a small motor, gearbox, and lead screw to turn rotation into linear force. The wrist actuator places its motor beside the gearbox to fit the available space. A machined aluminum frame gives the actuators a rigid structure to push against.

4. 8:56

   Motor and gear mechanism

   The actuators use coreless brushed DC motors, whose lightweight rotors can respond quickly and avoid cogging torque. Two planetary gear sets provide about a 4.8-to-1 ratio before the lead screw converts rotation into a push. The mechanism can produce up to 70 newtons, while the version in this hand is limited to about 30 newtons to keep movement reasonably quick.

5. 17:30

   Design trade-offs for robotic hands

   The RH56DFQ prioritizes affordability and useful grasping over independent movement of every finger. Its linked fingers and actuator-based sensing limit what it can do, while other designs can use tendons, cables, or motors near the fingers. Kason and Turnbull describe humanoid hands as an area where companies are still exploring different approaches.