Tech Briefs Magazine - September 2022 - 34

Robotics & Automation
Advanced Humanoid Robotic Hand Technologies
The unique design of R2's hand enables the assembly to achieve the compact form factor of
a human hand while retaining the strength required to work with human tools.
Johnson Space Center, Houston, TX
N
ASA and General Motors developed
the Robonaut 2 (R2) a state-of-the-art,
dexterous, humanoid robot capable of
performing tasks in an automated fashion
(or via teleoperation). The R2 hand and
forearm assembly represents the cutting
edge of humanoid robotics technologies.
The highly modular design provides significant
improvements over prior humanoid
robotic hands, especially in the areas of
strength, speed, sensing, and ability to approximate
human grasps.
R2's hands are highly dexterous, enabling
the robot to perform ergonomically
challenging tasks. The robotic humanoid
lower arm design includes novel
robotic finger, thumb, and wrist assemblies.
A novel finger actuation system
comprises an actuator, tendon, conduit,
tension sensor, and terminator. The actuation
system is packaged in the wrist
and reduces the number of actuators,
providing significant space savings. Control
systems include methods for tensioning
and controlling torque of the
tendon-driven robotic fingers.
The R2 hand and forearm assembly is
designed in a modular fashion, enabling
rapid replacement of components and
sub-assemblies. The finger actuation control
system can operate using force- or
position-based control laws. R2's hands
feature an innovative tactile system that
grant the robot a sense of touch (e.g.,
measurement of external contact forces,
shear force, and slippage of objects held
in the hand) an important requirement
for robots designed to perform complex
tasks in an automated fashion. The tactile
system is enabled by novel six degree
of freedom (DoF) force torque sensors,
three of which are integrated into the fingers
(at the proximal, medial, and distal
phalanges) and two in the thumb (medial
and distal phalanges).
The dexterous hand plus forearm is a
completely self-contained unit with all
motors and avionics packaged inside the
forearm, reducing the number of conductors
required for power and commu34
Gear
Head
Ball Screw Assembly
Flexible Conduit
Motor
Tendon Terminator
Tension Sensor
The R2 hand and forearm assembly, including avionics. (Image: NASA)
nication. A calibration system ensures
the sensors maintain high accuracy
throughout operation. A novel grasp assist
device enables reliable, autonomous
interaction with a broad range of objects
(e.g., tools). A particle filter-based contact
state estimation performs object localization
and characterization.
R2's fingers have a top speed of more
than 200 mm/sec. The applications include
industrial manufacturing and
maintenance, space exploration, perwww.techbriefs.com
sonal
assistance and caregiving, emergency
services and operations in hazardous
environment, as well as repetitive
task automation.
NASA is actively seeking licensees to
commercialize this technology. Please
contact NASA's Licensing Concierge at
Agency-Patent-Licensing@mail.nasa.gov
or call at 202-358-7432 to initiate licensing
discussions. For more information, visit
https://technology.nasa.gov/patent/
MSC-TOPS-102.
Tech Briefs, September 2022
https://technology.nasa.gov/patent/MSC-TOPS-102 http://www.techbriefs.com
Tech Briefs Magazine - September 2022

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