Analysis of stiffness of human fingertips skin and comparison with artificial fingertips

摘要

Detailed measurement and analysis of the physical characteristics of human fingers arc an important step towards the design of robot fingers to manipulate objects dexterously. This paper describes stiffness properties of the human fingertips under various conditions. Models to express the stiffness property are proposed from nonlinear curve fitting of the experimental results. Also, on the basis of the experimental results, it is pointed out that the contact area of human fingertips is proportional to displacement in the normal direction. As a result, it is observed that the stiffness varies linearly with the mean pressure which is calculated from the force and the contact area. By using the measurement results, it is revealed how the naturalfrequency in peg-in-hole tasks is changed depending on nonlinear stiffness and the mass of the peg. These properties are compared with those of artificial fingertips made of silicone rubber and silicone gel.