Design of an Underactuated Finger With a Monolithic Structure and Largely Distributed Compliance Available to Purchase

Many existing problems in conventional prosthetic fingers are related to the use of rigid links and kinematic joints and to the lack of adaptability of the finger. In this paper these problems are addressed by proposing a new design of a fully compliant underactuated prosthetic finger. First a general topology was defined. Subsequently a Pseudo Rigid Body method was used for a type synthesis and rough dimensional analysis in order to determine the conceptual design. In order to evaluate the grasping behavior of the conceptual design, four mock-ups were created. Detailed dimensional design was performed by a semi-automatic numerical analysis using a finite element method. A prototype based on this final design was manufactured and experimentally evaluated. It was found that the combination of underactuation and compliance is promising for the design of simple adaptive prosthetic fingers. As a result of the design process and the use of a predefined structure a fully compliant under-actuated finger with a monolithic structure and largely distributed compliance was obtained. The design shows potential of being applied in the field of prosthetics as well as robotic graspers.