Artificial Roughness Encoding with a Bio-inspired MEMS-based Tactile Sensor Array

Abstract

A compliant 2×2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad.

A mechatronic platform for human touch studies

“…The system was conceived to enable parametric, precise, repeatable and smooth stimulus presentation with standardized conditions, no vibrations and simple programming for indenting and sliding the surfaces on the fingerpad. Moreover, the chosen FPGA solution guaranteed to the platform adequate throughput together with design upgradeability [8,33], which was not typical of tactile stimulation systems previously reported in the literature [22,14,34]. Future works will present results of ongoing studies on the measurement of peripheral neural firing and brain responses by means of microneurography and EEG, and of (even combined) psychophysical experiments on human touch.…”

“…Future works will present results of ongoing studies on the measurement of peripheral neural firing and brain responses by means of microneurography and EEG, and of (even combined) psychophysical experiments on human touch. In parallel, the same system is enabling studies on artificial tactile sensors in robotics [8,33] and future investigations will focus on artificial touch evaluation of a variety of tactile surfaces, such as textiles.…”

MEMS-based contact stress field measurements at a rough elastomeric layer: local test of Amontons’ friction law in static and steady sliding regimes

“…In order to perform such local measurements, we take advantage of the recent development of Micro Electro Mechanical Systems (MEMS) sensors [37][38][39]. Local contact stress measurements are performed with a MEMS force sensor embedded at the rigid base of an elastomer film (Fig.…”

Forefinger direction based haptic robot control for physically challenged using MEMS sensor

“…Finite element analyses using human finger model during dynamic touch showed that spatial information of the textured surface are related to temporal frequency changes at the position of tactile receptors [2]- [6]. In touch activities, if humans have the ability to estimate somehow the relative hand velocity v between the textured surface and the exploring finger, the spatial period p of the surface can be perceived by detecting the temporal frequency of the vibration [7], such that:…”