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90 Human Inspired Dexterity in Robotic Manipulation

fingertip forces, or high degrees of freedom (DOFs), etc. However, they all
share the same design concept of mechanizing the biological counterparts.
Their design ideas can be traced back to the technology developed for indus-
trial assembly robots. Equipped with joint and tactile sensors, the motion of
such a human-like robotic hand can be seen as the coordination of five min-
iaturized high-precision industrial robots packed within a palm-sized space.
The development of the anatomically corrected testbed (ACT) hand [3] was
the first try toward replicating the human hand on an anatomical level.
However, its internal mechanisms are still based on hinges and gimbals.
We therefore categorize it as a special type of anthropomorphic robotic
hand. The inherent mismatch between mechanisms of these robotic hands
and biomechanics of the human hands essentially prevents us from using
natural hand motion to directly control them. Thus, none of them can
yet achieve human-level dexterity.
The development of prosthetic hands heavily relies on the lessons we
learned from building anthropomorphic robotic hands. State-of-the-art
prosthetic hands can now be controlled with two different methods: Using
nonintrusive methods such as electromyography (EMG) signals collected
from the residual limb or targeted muscle reinnervation regions [4]; or using
intrusive methods like directly implanting microelectrodes in the motor cor-
tex of the brain [5] or cuffing peripheral nerves with miniaturized electrodes
to collect control inputs [6]. As the control of prosthetic hands essentially
relies on the human brain, the same neuroprosthetic technology could be
more effective if the design of the prosthesis could be is similar to its biolog-
ical counterpart.
In contrast to these previous designs, we propose to use a highly biomi-
metic design to preserve the salient features of the human hand. Our design
aims to minimize the design mismatch between robot and human hands for a
more efficient control and a wider application.

6.2.2 Design Tools for Medicine and Biology Research

We envision our biomimetic hand to become a useful tool in medicine and
biology research. The transplanted hand is the only existing biological alter-
native for a lost human hand to date. Yet the long waiting list and slim
chance of finding the right donor keeps preventing the method to be reg-
ularly practiced at hospitals. And there are still ongoing debates about the
lifelong rejection side effects. In recent years, biologists started to investigate
the possibility of regrowing tissues and organs through biofabrication: