Soft robots should move in an unstructured environment and explore it and, to do so, they should be able to measure and distinguish proprioceptive and exteroceptive stimuli. This can be done by embedding mechanosensing systems in the body of the robot. Here, we present a polydimethylsiloxane block sensorized with an electro-optical system and a resistive strain gauge made with the supersonic cluster beam implantation (SCBI) technique. We show how to integrate these sensing elements during the whole fabrication process of the soft body and we demonstrate that their presence does not change the mechanical properties of the bulk material. Exploiting the position of both sensing systems and a proper combination of the output signals, we present a strategy to measure simultaneously external pressure and positive/negative bending of the body. In particular, the optical system can reveal any mechanical stimulation (external from the soft block or due to its own deformation), while the resistive strain gauge is insensitive to the external pressure, but sensitive to the bending of the body. This solution, here applied to a simple block of soft material, could be extended to the whole body of a soft robot. This approach provides detection and discrimination of the two stimuli (pressure and bending), with low computational effort and without significant mechanical constraint.
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References
1.
RusD, TolleyMT. Design, fabrication and control of soft robots. Nature, 2015; 521:467–475.
2.
LaschiC. Soft robotics research, challenges, and innovation potential, through showcases (Soft Robotics, Transferring Theory to Application)VerlA, Albu-SchäfferA, BrockO, RaatzA. (Eds). Springer Berlin Heidelberg, 2015, pp. 255–264.
3.
PaikJ. Soft components for soft robots (Soft Robotics, Transferring Theory to Application)VerlA, Albu-SchäfferA, BrockO, RaatzA. (Eds). Springer Berlin Heidelberg, 2015, p. 272.
4.
LuN, KimD-H. Flexible and stretchable electronics paving the way for soft robotics. Soft Robotics, 2014; 1:53–62.
5.
ShepherdRF, IlievskiF, ChoiW, MorinSA, StokesAA, MazzeoAD, et al.Multigait soft robot. Proc Natl Acad Sci U S A, 2011; 108:20400–20403.
6.
SuzumoriK, EndoS, KandaT, KatoN, SuzukiH. A bending pneumatic rubber actuator realizing soft-bodied manta swimming robot. Proceedings 2007 IEEE International Conference on Robotics and Automation, April 10–14, 2007, p. 4975.
BeccaiL, LucarottiC, TotaroM, TaghaviM. Soft robotics mechanosensing. Soft Robotics: Trends, Applications and Challenges: Proceedings of the Soft Robotics Week, April 25–30, 2016, Livorno, Italy. LaschiC, RossiterJ, IidaF, CianchettiM, MargheriL. (Eds). Cham: Springer International Publishing, 2017, p. 11.
13.
CaseJC, WhiteEL, KramerRK. Soft material characterization for robotic applications. Soft Robotics, 2015; 2:80–87.
14.
LarsonC, PeeleB, LiS, RobinsonS, TotaroM, BeccaiL, et al.Highly stretchable electroluminescent skin for optical signaling and tactile sensing. Science, 2016; 351:1071–1074.
15.
XuS, ZhangY, JiaL, MathewsonKE, JangK-I, KimJ, et al.Soft microfluidic assemblies of sensors, circuits, and radios for the skin. Science, 2014; 344:70–74.
16.
ParkY-L, ChenB-R, WoodRJ. Design and fabrication of soft artificial skin using embedded microchannels and liquid conductors. IEEE Sensors J, 2012; 12:2711–2718.
17.
LaflammeS, KolloscheM, ConnorJJ, KofodG. Soft capacitive sensor for structural health monitoring of large-scale systems. Struct Control Health Monit, 2012; 19:70–81.
18.
MajidiC, KramerR, WoodRJ. A non-differential elastomer curvature sensor for softer-than-skin electronics. Smart Mater Struct, 2011; 20:7.
YanC, WangJ, KangW, CuiM, WangX, FooCY, et al.Highly stretchable piezoresistive graphene–nanocellulose nanopaper for strain sensors. Adv Mater, 2014; 26:2022–2027.
25.
LipomiDJ, VosgueritchianM, TeeBCK, HellstromSL, LeeJA, FoxCH, et al.Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. Nat Nano, 2011; 6:788–792.
26.
WichmannMHG, BuschhornST, BögerL, AdelungR, SchulteK. Direction sensitive bending sensors based on multi-wall carbon nanotube/epoxy nanocomposites. Nanotechnology, 2008; 19:475503.
27.
GongS, SchwalbW, WangY, ChenY, TangY, SiJ, et al.A wearable and highly sensitive pressure sensor with ultrathin gold nanowires. Nat Commun, 2014; 5:3132 (2014).
28.
SekitaniT, ZschieschangU, KlaukH, SomeyaT. Flexible organic transistors and circuits with extreme bending stability. Nat Mater, 2010; 9:1015–1022.
29.
SomeyaT, KatoY, SekitaniT, IbaS, NoguchiY, MuraseY, et al.Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes. Proc Natl Acad Sci U S A, 2005; 102:12321–12325.
30.
SchwartzG, TeeBCK, MeiJ, AppletonAL, KimDH, WangH, et al.Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring. Nat Commun, 2013; 4:1859.
31.
ViryL, LeviA, TotaroM, MondiniA, MattoliV, MazzolaiB, et al.Flexible three-axial force sensor for soft and highly sensitive artificial touch. Adv Mater, 2014; 26:2659–2664.
32.
CastanoLM, FlatauAB. Smart fabric sensors and e-textile technologies: a review. Smart Mater Struct, 2014; 23:053001.
33.
SyduzzamanM, PatwarySU, FarhanaK, AhmedS. Smart textiles and nano-technology: a general overview. J Textile Sci Eng, 2015; 5:181.
34.
ChouH-H, NguyenA, ChortosA, ToJWF, LuC, MeiJ, et al.A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing. Nat Commun, 2015; 6:8011 (2015).
35.
ParkJW, JangJ. Fabrication of graphene/free-standing nanofibrillar PEDOT/P(VDF-HFP) hybrid device for wearable and sensitive electronic skin application. Carbon, 2015; 87:275–281.
36.
ParkJ, LeeY, HongJ, LeeY, HaM, JungY, et al.Tactile-direction-sensitive and stretchable electronic skins based on human-skin-inspired interlocked microstructures. ACS Nano, 2014; 8:12020–12029.
37.
KimD-H, LuN, MaR, KimY-S, KimR-H, WangS, et al.Epidermal electronics. Science, 2011; 333:838–843.
38.
ShaoQ, NiuZ, HirtzM, JiangL, LiuY, WangZ, et al.High-performance and tailorable pressure sensor based on ultrathin conductive polymer film. Small, 2014; 10:1466–1472.
39.
WebbRC, BonifasAP, BehnazA, ZhangY, YuKJ, ChengH, et al.Ultrathin conformal devices for precise and continuous thermal characterization of human skin. Nat Mater, 2013; 12:938–944.
40.
KaltenbrunnerM, SekitaniT, ReederJ, YokotaT, KuribaraK, TokuharaT, et al.An ultra-lightweight design for imperceptible plastic electronics. Nature, 2013; 499:458–463.
41.
YuenM, CherianA, CaseJC, SeipelJ, KramerRK. Conformable actuation and sensing with robotic fabric. Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference, September 14–18, 2014, p. 580.
42.
LeonovV. Thermoelectric energy harvesting of human body heat for wearable sensors. IEEE Sensors J, 2013; 13:2284–2291.
43.
NesenbergsK, SelavoL. Smart textiles for wearable sensor networks: review and early lessons. Medical Measurements and Applications (MeMeA), 2015 IEEE International Symposium on IEEE, 2015, p. 402.
44.
KongJ-H, JangN-S, KimS-H, KimJ-M. Simple and rapid micropatterning of conductive carbon composites and its application to elastic strain sensors. Carbon, 2014; 77:199–207.
45.
LeeJ, KwonH, SeoJ, ShinS, KooJH, PangC, et al.Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics. Adv Mater, 2015; 27:2433–2439.
KimSY, ParkS, ParkHW, ParkDH, JeongY, KimDH. Highly sensitive and multimodal all-carbon skin sensors capable of simultaneously detecting tactile and biological stimuli. Adv Mater, 2015; 27:4178–4185.
48.
ParkJ, LeeY, HongJ, HaM, JungY-D, LimH, et al.Giant tunneling piezoresistance of compositeelastomers with interlocked microdome arrays for ultrasensitive and multimodal electronic skins. ACS Nano, 2014; 8:4689–4697.
49.
EngelJ, NannanC, TuckerC, ChangL, Sung-HoonK, JonesD. Flexible multimodal tactile sensing system for object identification, sensors, 2006. 5th IEEE Conference, October 22–25, 2006, p. 563.
50.
LucarottiC, TotaroM, SadeghiA, MazzolaiB, BeccaiL. Revealing bending and force in a soft body through a plant root inspired approach. Sci Rep, 2015; 5:8788.
51.
CianchettiM, RendaF, LicofonteA, LaschiC. Sensorization of continuum soft robots for reconstructing their spatial configuration. Biomedical Robotics and Biomechatronics (BioRob), 2012 4th IEEE RAS & EMBS International Conference, June 24–27, 2012, p. 634.
52.
ChossatJ-B, ShinH-S, ParkY-L, DuchaineV. Soft tactile skin using an embedded ionic liquid and tomographic imaging. J Mechanisms Robotics, 2015; 7:021008.
LeviA, PiovanelliM, FurlanS, MazzolaiB, BeccaiL. Soft, transparent, electronic skin for distributed and multiple pressure sensing. Sensors, 2013; 13:6578–6604.
57.
ZhaoH, O'BrienK, LiS, ShepherdRF. Optoelectronically innervated soft prosthetic hand via stretchable optical waveguides. Sci Robotics, 2016; 1:eaai7529.
58.
CorbelliG, GhisleriC, MarelliM, MilaniP, RavagnanL. Highly deformable nanostructured elastomeric electrodes with improving conductivity upon cyclical stretching. Adv Mater, 2011; 23:4504–4508.
59.
BorghiF, MelisC, GhisleriC, PodestàA, RavagnanL, ColomboL, et al.Stretchable nanocomposite electrodes with tunable mechanical properties by supersonic cluster beam implantation in elastomers. Appl Phys Lett, 2015; 106:121902.
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