Page 93 - Human Inspired Dexterity in Robotic Manipulation

Approaching Human Hand Dexterity Through Highly Biomimetic Design 91

biocompatible materials can now be printed to form bone structures [7], bio-
degradable artificial ligaments have been used to replace torn anterior
cruciate ligaments [8], human muscles have been successfully cultivated
inside a Petri dish [9], and peripheral nerves can also be regenerated given
the right conditions [10]. All of these promising technologies require suit-
able scaffolds for the growth of grafted cells. When it comes to regrowing
centimeter scale limbs, such as the rat forelimb, decellularized cadaver parts
are required as scaffolds [11]. However, even if the same techniques can be
scaled up for human trials, the limitation of donors could eventually become
a bottleneck. Besides, in medical research, most of the in vivo studies con-
ducted on cadaver hands suffer from constantly changing conditions because
the decay process of organic tissues is irreversible. The problem of biological
variations caused by individual differences could also result in a long-lasting
debate. These limitations and drawbacks motivate us to seek for an alterna-
tive form of scaffold that can reliably preserve the biomechanical informa-
tion of the human hand in a physical working model.
A biomimetic anthropomorphic robotic hand that mimics the biome-
chanics of the human hand can be first validated in a robotics lab and then
mass-produced with biocompatible materials to meet the requirement of
different medical/biological applications. While it is often regarded unnec-
essary to directly copy the bio-blueprint of the biological counter parts, it is
possible to replicate critical biomechanical features of the human hand step
by step. The key of success lies in a thorough understanding of the biome-
chanics of the human hand from the engineering point of view and the abil-
ity to materialize the findings.

6.3 THE IMPORTANT ANATOMY OF THE HUMAN HAND

From an anatomical point of view, the human hand is composed of bones,
joints, ligaments, tendons, muscles, nerves, blood vessels, and layered skin.
With our current technology, we are not able to copy 100% of the human
hand with self-healing materials. However, we should still be able to directly
harvest the wisdom of nature with the help of 3D scanning and printing
technologies, and replicate a subset of these important features in the design
of anthropomorphic robotic hands.
Instead of examining the structure of the hand directly from a hand sur-
geon’s perspective, important features of the human hand should be trans-
lated into an engineering language so that roboticists can better understand
what are the important things to mimic when designing their robotic hands.