In recent years, soft robotic grippers have emerged as a promising solution for versatile and safe manipulation of objects in various fields. However, precise force control is critical, especially when handling delicate or fragile objects, to avoid excessive grip force application or to prevent object slippage. Herein, we propose a novel three-degree-of-freedom force sensor incorporated within a soft robotic gripper to realize stable grasping with force feedback. The proposed optical sensor employs lightweight and compact optical fibers, thereby allowing for cost-effective fabrication, and a robust sensing system that is immune to electromagnetic fields. By innervating the soft gripper with optical fibers, a durable system is achieved with the fibers functioning as a strengthening layer, thereby eliminating the need for embedding an external stiffening structure for efficient bending actuation. The innovative contact-based light loss sensing mechanism allows for a robust and stable sensing mechanism with low drift (<0.1% over 9000 cycles) that can be applied to soft pneumatic bending grippers. We used the developed sensor-incorporated soft gripper to grasp various objects, including magnetic materials, and achieved slip detection along with grip force feedback without any signal interference. Overall, this study proposes a robust measuring multi-degree-of-freedom force sensor that can be incorporated into grippers for improved grasping stability.
Get full access to this article
View all access options for this article.
References
1.
LaschiC, MazzolaiB, CianchettiM. Soft robotics: Technologies and systems pushing the boundaries of robot abilities. Sci Robot, 2016; 1(1):eaah3690; doi: 10.1126/scirobotics.aah3690
ZaidiS, MaselliM, LaschiC, et al.Actuation technologies for soft robot grippers and manipulators: A review. Curr Robot Rep, 2021; 2(3):355–369; doi: 10.1007/s43154-021-00054-5
4.
AliciG, CantyT, MutluR, et al.Modeling and experimental evaluation of bending behavior of soft pneumatic actuators made of discrete actuation chambers. Soft Robot, 2017; 5(1):24–35; doi: 10.1089/soro.2016.0052
5.
NavasE, FernándezR, SepúlvedaD, et al.Soft grippers for automatic crop harvesting: A review. Sensors, 2021; 21(8):2689; doi: 10.3390/s21082689
6.
HombergBS, KatzschmannRK, DogarMR, et al.Robust proprioceptive grasping with a soft robot hand. Auton Robots, 2019; 43(3):681–696; doi: 10.1007/s10514-018-9754-1
7.
LiY, ChenY, LiY. Pre-charged pneumatic soft gripper with Closed-Loop Control. IEEE Robot Autom Lett, 2019; 4(2):1402–1408; doi: 10.1109/lra.2019.2895877
8.
DilibalS, SahinH, DanquahJO, et al.Additively manufactured custom soft gripper with embedded soft force sensors for an industrial robot. Int J Precis Eng Manuf, 2021; 22(4):709–718; doi: 10.1007/s12541-021-00479-0
9.
YuenMC-S, LearTR, TonoyanH, et al.Toward closed-loop control of pneumatic grippers during pack-and-deploy operations. IEEE Robot Autom Lett, 2018; 3(3):1402–1409; doi: 10.1109/lra.2018.2800079
10.
BillardA, KragicD. Trends and challenges in robot manipulation. Science, 2019; 364(6446):eaat8414; doi: 10.1126/science.aat8414
11.
HaoY, ZhangS, FangB, et al.A review of smart materials for the boost of soft actuators, soft sensors, and robotics applications. Chin J Mech Eng, 2022; 35(1):37; doi: 10.1186/s10033-022-00707-2
12.
PyoS, LeeJ-I, KimM-O, et al.Polymer-based flexible and multi-directional tactile sensor with multiple NiCr piezoresistors. Micro Nano Syst Lett, 2019; 7(1):1-8; doi: 10.1186/s40486-019-0085-6
13.
VogtDM, ParkY-L, WoodRJ. Design and characterization of a soft multi-axis force sensor using embedded microfluidic channels. IEEE Sens J, 2013; 13(10):4056–4064; doi: 10.1109/jsen.2013.2272320
14.
WangL, MaF, ShiQ, et al.Study on compressive resistance creep and recovery of flexible pressure sensitive material based on carbon black filled silicone rubber composite. Sens Actuat A Phys, 2011; 165(2):207–215.
15.
Hyung-KewL, JaehoonC, Sun-IlC, et al.Normal and shear force measurement using a flexible polymer tactile sensor with embedded multiple capacitors. J Microelectromechanical Syst, 2008; 17(4):934–942; doi: 10.1109/jmems.2008.921727
16.
ViryL, LeviA, TotaroM, et al.Flexible three-axial force sensor for soft and highly sensitive artificial touch. Adv Mater, 2014; 26(17):2659–2664; doi: 10.1002/adma.201305064
17.
WangH, De BoerG, KowJ, et al.Design methodology for magnetic field-based soft tri-axis tactile sensors. Sensors, 2016; 16(9):1356; doi: 10.3390/s16091356
18.
YanY, HuZ, YangZ, et al.Soft magnetic skin for super-resolution tactile sensing with force self-decoupling. Sci Robot, 2021; 6(51):eabc8801; doi: 10.1126/scirobotics.abc8801
19.
AksoyB, HaoY, GrassoG, et al.Shielded soft force sensors. Nat Commun, 2022; 13(1):4649; doi: 10.1038/s41467-022-32391-0
20.
YuanW, DongS, AdelsonE. GelSight: High-resolution robot tactile sensors for estimating geometry and force. Sensors, 2017; 17(12):2762; doi: 10.3390/s17122762
LlamosiA, ToussaintS. Measuring force intensity and direction with a spatially resolved soft sensor for biomechanics and robotic haptic capability. Soft Robot, 2019; 6(3):346–355; doi: 10.1089/soro.2018.0044
23.
AwajaF, GilbertM, KellyG, et al.Adhesion of polymers. Progr Polym Sci, 2009; 34(9):948–968.
24.
BilodeauRA, WhiteEL, KramerRK. Monolithic Fabrication of Sensors and Actuators in a Soft Robotic Gripper. In: 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Hamburg, Germany; 2015.
25.
MorrowJ, ShinH-S, Phillips-GrafflinC, et al.Improving Soft Pneumatic Actuator Fingers Through Integration of Soft Sensors, Position and Force Control, and Rigid Fingernails. In: 2016 IEEE International Conference on Robotics and Automation (ICRA), Stockholm, Sweden; 2016.
26.
ZouZ, ChenY, YuanS, et al.3D printing of liquid metals: Recent advancements and challenges. Adv Funct Mater, 2023; 33(10):2213312; doi: 10.1002/adfm.202213312
27.
YangY, ChenY. Innovative design of embedded pressure and position sensors for soft actuators. IEEE Robot Autom Lett, 2018; 3(2):656–663; doi: 10.1109/lra.2017.2779542
28.
TrubyRL, WehnerM, GrosskopfAK, et al.Soft somatosensitive actuators via embedded 3D printing. Adv Mater, 2018; 30(15):1706383; doi: 10.1002/adma.201706383
29.
GuoJ, YangC, DaiQ, et al.Soft and stretchable polymeric optical waveguide-based sensors for wearable and biomedical applications. Sensors, 2019; 19(17):3771.
30.
GallowayKC, ChenY, TempletonE, et al.Fiber optic shape sensing for soft robotics. Soft Robot, 2019; 6(5):671–684; doi: 10.1089/soro.2018.0131
31.
YangM, LiuQ, NaqaweHS, et al.Movement detection in soft robotic gripper using sinusoidally embedded fiber optic sensor. Sensors, 2020; 20(5):1312; doi: 10.3390/s20051312
32.
ZhaoH, O'BrienK, LiS, et al.Optoelectronically innervated soft prosthetic hand via stretchable optical waveguides. Sci Robot, 2016; 1(1):eaai7529; doi: 10.1126/scirobotics.aai7529
33.
ZhouJ, ShaoQ, TangC, et al.Conformable and compact multiaxis tactile sensor for human and robotic grasping via anisotropic waveguides. Adv Mater Technol, 2022; 7(11):2200595; doi: 10.1002/admt.202200595
34.
PretiML, TotaroM, FaloticoE, et al.Online pressure map reconstruction in a multitouch soft optical waveguide skin. IEEE ASME Trans Mechatron, 2022; 27(6):4530–4540.
35.
TotaroM, MondiniA, BellaciccaA, et al.Integrated simultaneous detection of tactile and bending cues for soft robotics. Soft Robot, 2017; 4(4):400–410; doi: 10.1089/soro.2016.0049
36.
YunS, ParkS, ParkB, et al.Polymer-waveguide-based flexible tactile sensor array for dynamic response. Adv Mater, 2014; 26(26):4474–4480; doi: 10.1002/adma.201305850
37.
Van MeerbeekIM, De SaC, ShepherdRF. Soft optoelectronic sensory foams with proprioception. Sci Robot, 2018; 3(24):eaau248; doi: 10.1126/scirobotics.aau2489
38.
YunS, JeongJ, MunS, et al.A highly stretchable optical strain sensor monitoring dynamically large strain for deformation-controllable soft actuator. Smart Mater Struct, 2021; 30(10):105020; doi: 10.1088/1361-665x/ac1f63
39.
YounJ-H, MunH, JangS-Y, et al.Highly stretchable-compressible coiled polymer sensor for soft continuum manipulator. Smart Mater Struct, 2022; 31(1):015043; doi: 10.1088/1361-665X/ac3d9e
40.
ZhaoH, JalvingJ, HuangR, et al.A helping hand: Soft orthosis with integrated optical strain sensors and EMG control. IEEE Robot Autom Mag, 2016; 23(3):55–64; doi: 10.1109/mra.2016.2582216
41.
JamilB, YooG, ChoiY, et al.Proprioceptive soft pneumatic gripper for extreme environments using hybrid optical fibers. IEEE Robot Autom Lett, 2021; 6(4):8694–8701; doi: 10.1109/lra.2021.3111038
42.
MosadeghB, PolygerinosP, KeplingerC, et al.Pneumatic networks for soft robotics that actuate rapidly. Adv Funct Mater, 2014; 24(15):2163–2170; doi: 10.1002/adfm.201303288
43.
FryńP, LalikS, GórskaN, et al.Comparison of the dielectric properties of Ecoflex® with L,D-poly(lactic acid) or polycaprolactone in the presence of SWCN or 5CB. Materials, 2021; 14(7):1719; doi: 10.3390/ma14071719
44.
IadiciccoA, PaladinoD, CampopianoS, et al.Evanescent wave sensor based on permanently bent single mode optical fiber. Sens Actuators B Chem, 2011; 155(2):903–908.
45.
SnyderAW, LoveJD. Optical Waveguide Theory. Chapman and Hall: London; 1983.
46.
VaicekauskaiteJ, MazurekP, VudayagiriS, et al.Mapping the mechanical and electrical properties of commercial silicone elastomer formulations for stretchable transducers. J Mater Chem C, 2020; 8(4):1273–1279; doi: 10.1039/c9tc05072h
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
