Validation of Screen-Printed Electronic Skin Based on Piezoelectric Polymer Sensors.

Hoda Fares,Maurizio Valle,Lucia Seminara,Yahya Abbass

doi:10.3390/s20041160

Hoda Fares, Maurizio Valle + Show 2 more

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https://doi.org/10.3390/s20041160

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Abstract

This paper proposes a validation method of the fabrication technology of a screen-printed electronic skin based on polyvinylidene fluoride-trifluoroethylene P(VDF-TrFE) piezoelectric polymer sensors. This required researchers to insure, through non-direct sensor characterization, that printed sensors were working as expected. For that, we adapted an existing model to non-destructively extract sensor behavior in pure compression (i.e., the d33 piezocoefficient) by indentation tests over the skin surface. Different skin patches, designed to sensorize a glove and a prosthetic hand (11 skin patches, 104 sensors), have been tested. Reproducibility of the sensor response and its dependence upon sensor position on the fabrication substrate were examined, highlighting the drawbacks of employing large A3-sized substrates. The average value of d33 for all sensors was measured at incremental preloads (1–3 N). A systematic decrease has been checked for patches located at positions not affected by substrate shrinkage. In turn, sensor reproducibility and d33 adherence to literature values validated the e-skin fabrication technology. To extend the predictable behavior to all skin patches and thus increase the number of working sensors, the size of the fabrication substrate is to be decreased in future skin fabrication. The tests also demonstrated the efficiency of the proposed method to characterize embedded sensors which are no more accessible for direct validation.

Highlights

Electronic skin (e-skin) is a touch-sensitive, electronic system that incorporates functional and structural materials coupled to a suitable electronic interface for sensor signal acquisition
It isrequire worth remarking thatsystem the alignment was critical in this case: small was sensor size would an alignment to more procedure was critical in this case: the small sensor size would require an alignment precisely align the indenter with the sensor center for reliable sensor characterization using the current system to more precisely sensor for reliable sensor characterization model
A laser-like positioning system could be used in the future to align the indenter precisely, avoiding In Section 2.2, we described how we coupled the sensing patch to the substrate and to the errors due to wrong positioning

Summary

Introduction

Electronic skin (e-skin) is a touch-sensitive, electronic system that incorporates functional and structural materials coupled to a suitable electronic interface for sensor signal acquisition. Artificial skin systems are implemented in a wide range of applications, such as robotics, prosthetics and teleoperation systems [6,7,8]. As the functional properties of the electronic skin mostly depend on the sensor type, it is worth focusing on the sensor itself. Various tactile sensors have been developed, like piezoelectric, piezoresistive, capacitive, optical, electromagnetic, ultrasonic, etc. The development of tactile sensors based on piezoelectric polymers has been extensively investigated in recent years due to their interesting features

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