Chapter 2. Prehension

Appendix D. Prosthetic and Robotic Hands
“..the ideal prosthesis would serve its wearer as a natural
extension of his human system.”
--Mann (1974)
D.l Introduction
40 1
The complex nature of the human hand, under the control of the
central nervous system, is only highlighted by the loss of that hand,
and the amputee looks to engineers for a prosthetic device that captures
the beauty and versatility of the original hand. “Hands have their gifts
inscribed in their very shape and design ... the mind makes the hand,
the hand makes the mind” (Focillon, 1947). Sterling Bunnell (1944)
stated that “Our hands become extensions of the intellect.” When
people lose a hand, they are losing an intimate partner of their minds
that combines fine coordinated movement, tactile sensation,
proprioceptive feedback, expression and aesthetic appearance.
For centuries, engineers have attempted to reproduce this amazing
human structure. The first recorded instance of an artificial hand was
in 200 B.C. when a Roman general lost his hand during a war and
was fitted with an iron hand. In modern times, the split hook was
developed in the 1890’s by D.W. Dorrance. An effective terminal
device, the split hook controlled by a body-powered shoulder harness.
Use of electrical energy in prosthetic hands was described by
Borchard et al. (1919), although it was not usable with the available
batteries. In this electromagnetically powered hand, the index and
middle fingers pushed against the thumb. World War I1 spurned a
national treatment program by the U.S. armed forces medical arms and
a national research program to improve prostheses. The electrically
powered Vaduz hand, patented in 1949, used the circumferential
difference between a contracted and released muscle. The first artificial
hand controlled by EMG was developed in Russia by Kobrinski et al.
(1960). During the 1960’s, the goal of Otto Bock Orthopedic
Industries was to develop an electromechanically driven prosthetic
hand that was functional and cosmetic. In 1965, they developed a
hand that could grip using a thumb, index, and middle fingers.
In the 1980’s and ~O’S, high-tech solutions are emerging to use
new materials and miniaturized components, while attempting to