Chapter 2. Prehension

418 Appendices
D.3.1 Stanford/JPL hand
The Stanford/JPL hand (see Figure D.l) was built by Ken
Salisbury in 1982 with two requirements: 1) it should be able to exert
arbitrary forces or impress arbitrary small motions on the grasped
object when the joints are allowed to move; and 2) it should be able to
constrain a grasped object totally by locking all the joints (Salisbury,
1985 or Salisbury & Craig, 1982).
Figure D.l The Stanford/JPL hand. It consists of three fingers,
each of which has four degrees of freedom.
In determining a suitable design for the hand, only three fingered,
three link per finger configurations were analyzed; an additional
constraint on the choices were that all contacts allowed the same
freedom of motion, ignoring zero and six DOF contacts. Other design
parameters include link lengths, relative locations, joint limits, desired
grip points, object sizes, kinematics. Using a program to help in the
search for choosing parameter values based on maximizing per-
formance criteria, the design seen in Figure D. 1 was settled upon. The
performance criteria were based on the working volume, mechanical
design criteria, palm areas, ability to perform power grasp. It has three
fingers, each having three degrees of freedom. Tendons are arranged
in an n+l arrangement, meaning that there is only one tendon that acts