The development of a cost-efficient braille device is
a crucial
challenge in haptic technology to improve the integration of visually
impaired people. Exclusion of any group threatens the proper functioning
of society. Commercially available braille devices still utilize piezoelectric
actuators, which are expensive and bulky. The challenge of a more
adapted braille device lies in the integration of a high number of
actuatorson a millimeter scalein order to independently
move a matrix of pins acting as tactile cues. Unfortunately, no actuation
strategy has been adapted to tackle this challenge. In this study,
we develop a soft actuator based on a thermosensitive poly(N-isopropylacrylamide) (PNIPAM) gel. We introduce macroporosity
to the gel (pores of 10 to 100 μm). It overcomes the
diffusionwhich is the limiting kinetic factorand accelerates
the gel response time from hours for the bulk gel to seconds for the
macroporous gel. We study the properties of porous gels with various
porosities. We also compare a mechanically reinforced nanocomposite
gel (made of PNIPAM and Laponite clay) to a “classic”
gel. As a result, we develop a fast-actuating gel with high cyclic
performance. We then develop a single-pin braille setup, where actuation
is controlled thanks to a swift temperature control of a macroporous
gel cylinder. This new strategy offers a very promising actuation
technology. It offers a simple and cost-efficient alternative to the
current braille devices.
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