After introductory considerations on the main functional and design differences
between anthropomorphic hands conceived as robotic end effectors or as prostheses, this
chapter presents two topics related to advances in robotic hand design that seem transferable
to prosthetic hands, in order to increase their functional capability yet coping with
specific constraints like simplicity, lightweight, cost effectiveness, robustness, etc. The
development of a bio-inspired robotic hand, called UB Hand IV, based on an endoskeletal
articulated structure, actuated by tendons and covered by a soft dermal-epidermal layer is
briefly illustrated, in order to show the potential of its design solutions to be transferred
into prosthetic hands. The first part of the chapter presents alternative design approaches
for articulated joints and finger structures based on purposely designed compliant hinges.
The basic problem of compliant hinges adoption in robotic structures, that is the limitation
of secondary compliance effects, is analyzed and considerations about comparative metrics
are proposed. Two hinge morphologies which show promising features are critically
compared and pros and cons the production of fully integral fingers with compliant joints
are discussed. The second part reports on the development of thin soft covers for robotic
(and prosthetic) hands capable of strictly mimicking the actual compliance of human
finger pulps. A design method, called by the authors Differentiated Layer Design (DLD),
is reviewed and its potential for application on both robotic and prosthetic devices is
underlined. Conclusions summarize the main aspects that encourage the transfer of the
described results from the world of robots to that of human portable devices.
Keywords: Robotic/Prosthetic Hands, Large Displacement Compliant Joints, Soft Fingertips, Design Methods,
Performance Indexes
