TY - JOUR

T1 - Super-elastic ultrasoft natural rubber-based piezoresistive sensors for active sensing interface embedded on soft robotic actuator

AU - Banerjee, Shib Shankar

AU - Arief, Injamamul

AU - Berthold, Rebecca

AU - Wiese, Mats

AU - Bartholdt, Max

AU - Ganguli, Debashis

AU - Mitra, Siddhartha

AU - Mandal, Subhradeep

AU - Wallaschek, Jörg

AU - Raatz, Annika

AU - Heinrich, Gert

AU - Das, Amit

N1 - Funding Information: This work is financially supported by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project ID 330167 under SPP2100 program. A.D thankfully acknowledges René Jurk (IPF Dresden) for mechanical experiments. R.B., M.W. and M.B. also acknowledge Deutsche Forschungsgemeinschaft (DFG) project ID 405032969-SPP 2100 for financial assistance. G.H. acknowledges the DFG project (Grant No. 380321452/GRK2430) for financial support. The authors D.G. and S.M. express their gratitude to the management of Bharat Petroleum Corporation Ltd. for granting permission to publish this work. The authors would also like to thank G. Krishnakumar, ED (Lubes), R. Subramanian and B. Newalkar of Bharat Petroleum Corporation Limited for their support.

PY - 2021/12

Y1 - 2021/12

N2 - Piezoresistive soft composites are ubiquitous in strain sensing that manifests in a dramatic increment of electrical resistivity upon elongation. A piezoresistive strain sensor embedded-soft robotic arm has been a challenging task in terms of surface compatibility, shape and dynamics of the soft robotic components. We present a super-elastic, ultrasoft natural rubber composite containing multiwalled carbon nanotubes in presence of a hydrofinished oil-based softener. The resulting conducting elastomer offered a line-up of compelling characteristics such as low electrical percolation (<2 vol%), ultra-softness (Shore A harness ∼19), elastic modulus in the kPa range (∼350 kPa at 100% elongation), ultra-stretchability (∼800%) and high tensile strength (∼10.5 MPa). In addition, the sensor exhibited low hysteresis (3.5%), high piezoresistive sensitivity (gage factor≈472) and switching response over wide strain range (70%) and stable sensing performance for multiple test cycles (>1000). On account of the excellent responses mentioned, the sensor could detect human motion and has also been demonstrated in this paper. Furthermore, the sensing strip embedded on a soft robotic pneumatic actuator mounted on a test rig showed excellent movement detection response upon actuation. This proof-of-concept sensor-integrated soft robotic interface could be instrumental in the future development of proprioceptive sensing robots and soft robotic segments.

AB - Piezoresistive soft composites are ubiquitous in strain sensing that manifests in a dramatic increment of electrical resistivity upon elongation. A piezoresistive strain sensor embedded-soft robotic arm has been a challenging task in terms of surface compatibility, shape and dynamics of the soft robotic components. We present a super-elastic, ultrasoft natural rubber composite containing multiwalled carbon nanotubes in presence of a hydrofinished oil-based softener. The resulting conducting elastomer offered a line-up of compelling characteristics such as low electrical percolation (<2 vol%), ultra-softness (Shore A harness ∼19), elastic modulus in the kPa range (∼350 kPa at 100% elongation), ultra-stretchability (∼800%) and high tensile strength (∼10.5 MPa). In addition, the sensor exhibited low hysteresis (3.5%), high piezoresistive sensitivity (gage factor≈472) and switching response over wide strain range (70%) and stable sensing performance for multiple test cycles (>1000). On account of the excellent responses mentioned, the sensor could detect human motion and has also been demonstrated in this paper. Furthermore, the sensing strip embedded on a soft robotic pneumatic actuator mounted on a test rig showed excellent movement detection response upon actuation. This proof-of-concept sensor-integrated soft robotic interface could be instrumental in the future development of proprioceptive sensing robots and soft robotic segments.

KW - Active sensing interface

KW - Hydrofinished softener

KW - Multiwalled carbon nanotubes

KW - Piezoresistive sensor

KW - Soft robotic pneumatic actuators

KW - Super-elastic stretchable elastomers

UR - http://www.scopus.com/inward/record.url?scp=85122787494&partnerID=8YFLogxK

U2 - 10.1016/j.apmt.2021.101219

DO - 10.1016/j.apmt.2021.101219

M3 - Article

VL - 25

JO - Applied Materials Today

JF - Applied Materials Today

M1 - 101219

ER -