Page 123 - Human Inspired Dexterity in Robotic Manipulation

Hand Design—Hybrid Soft and Hard Structures 121

Prescale mat
Force gauge
Fingertip

Pressure sensitive paper
Fig. 7.7 Experimental set up for investigating contact pressure distribution when the tip
makes contact with a flat surface.

cover with a constant pushing force controlled by a force gauge, the paper
turned red. The intensity of the color corresponds to the magnitude of the
applied pressure. Moreover, colored dot patterns appeared on the paper
because the Prescale mat has dot-patterned cones to indicate where the pres-
sure is high, thus facilitating pressure measurement. The resulting colored
patterns on the pressure sensitive paper were scanned with EPSON
GT-X820, as shown in Fig. 7.8. The distance between dots (cones) is
2 mm. Table 7.2 shows the other experimental conditions.

(A) (B) (C)
Fig. 7.8 Scanned dot patterns for each fingertip in contact with the flat surface. (A) Fluid
fingertip (fluid pressure at no-contact: 30 kPa). (B) Fluid fingertip (fluid pressure at
no-contact: 10 kPa). (C) Silicon fingertip.

Table 7.2 Experimental conditions [22]
Load Loading time Temperature Humidity
30 N 5 s 25.5°C 47.5%