A previous study (1) aimed at describing the structural needs for an artificial finger to
reproduce the friction behavior of a finger against textiles. The investigated parameters
: shape, hardness, texture and adhesion properties showed to be the most effective
parameters on the reproduction of the friction behavior of the finger. The hardness and
friction are responsible for the transmission of internal forces in the finger and how the
textile surface reacts to interaction with the finger. In the reaction to the finger friction
against the textile, the adhesion properties will act on the deformation of the finger
and on the resulting visible contact area. Friction and normal forces act and may cause
deformation of the textile surface if the friction force is too high. It has been seen that
coefficient of friction (COF) of silicones against textile ( 1.5 (33)) is usually too high to
compare to COF of human fingers with textiles ( 0.5 (1)). The designing of this artificial

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1. ARTIFICIAL FINGER DESIGN

Figure 1.7: Description of functionality of mechanoreceptors. Extracted from (6)

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1.2 Conception of the artificial finger

finger is aiming at textile description, a special attention to the COF against textiles
will be held. The fore mentioned parameters are mandatory for the reproduction of the
friction behavior of the finger.
The texture parameter takes place in the friction with hairy textiles, for example a
velvet fabric. It has been shown in (1) that the linear alternative movement of the slider
against a hairy textile will cause the pile to flip, and by doing this a peak in the forces
can be recorded (fig. 1.8). As a consequence, the texture of the dimension of fingerprints
is essential and will be reproduced on the instrumented artificial finger.

### Language ###
English

### Assessment ###
The text mentions a specific coefficient of friction (COF) value for human fingers against textiles, which could be a straightforward information request.

### Query ###
What is the coefficient of friction between a human finger and textile materials?
What is the coefficient of friction between a human finger and textile materials?