Chapter 2. Prehension

Chapter 9 - Reevaluation and Future Directions 345
symbolic descriptions of prehensile postures. By separating anatomy
from function, it provides a way to study the complexity of motor
control, as well as suggests ways to design and control versatile
dextrous robot hands. Coming full circle, once better mechanical
hands are designed, that closely resemble human hands in terms of
performance, the next step is to replace the dysfunctional hand with a
versatile prosthetic device. Remembering the triangle strategy, the
CNS can be viewed as the central nervous system controlling human
hands or as the computational nervous system controlling robot or
prosthetic hands.
The potential ways that the hand can generate opposing forces
must be balanced with the acquisition of sensory information in order
to accomplish the key aspects of the task (control, affixment, and
dextrous manipulation). It is this balance that teleologically gives rise
to the posture observed at any time. The posture emerges within a
constraint space in which all the constraints of the task must be
satisfied. In summary, detailed examination of the phases of
prehension provides a start towards an explicit vocabulary for
prehension, bringing together current knowledge from behavioral,
biological, and analytic disciplines into a common framework.