Flexible and Stretchable Strain Sensing Actuator for Wearable Soft Robotic Applications

Yeo, Joo Chuan; Yap, Hui-Kim; Xi, Wang; Wang, Zhiping; Yeow, Chen-Hua; Lim, Chwee Teck

doi:10.1002/admt.201600018

Cited by 206 publications

(121 citation statements)

References 48 publications

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“…This provides them with many advantages, such as greater ability to grasp objects (Pfeifer et al, 2012), increased conformability to a wide variety of objects and environments (Shen, 2016), and high deformability and capability to absorb energy (Kim et al, 2013). These soft robots are highly capable and diverse, including pneumatic grippers (Ilievski et al, 2011;Martinez et al, 2013;Maeder-York et al, 2014;Katzschmann et al, 2015;Galloway et al, 2016;Yeo et al, 2016), manipulators inspired by the octopus (Calisti et al, 2011;Cianchetti et al, 2011;Mazzolai et al, 2012), electroactive polymer grippers (Alici and Huynh, 2007), and granular jamming (Brown et al, 2010).…”

Section: Figure 1 | the Fin Raymentioning

confidence: 99%

Fin Ray® Effect Inspired Soft Robotic Gripper: From the RoboSoft Grand Challenge toward Optimization

et al. 2016

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A soft robotic gripper for a Tele-operable In-Home Robotic Assistant (TIHRA) for the mobility impaired is presented. This gripper is inspired by the Fin Ray ® Effect, which is derived from the physiology of fish fins. The gripper fingers are soft and triangular with hard crossbeams that buckle and deform in to conform around objects. The fingers of the TIHRA were altered from the original Fin Ray ® design in order to create a preferred bending direction, resulting in less force required to obtain a good grip on an object. The entire gripper can be 3D printed as part of a soft robotic hand made from hard and soft materials, and the motor-tendon actuation system attaches in a limited number of steps. Testing of the gripper included modeling the fingers and comparing grip strength them to the original Fin Ray ® to verify their optimization. Models show that the TIHRA fingers deform 15% more than traditional fingers when subjected to the same force. The TIHRA gripper was capable of holding 560 g, approximately 40% more than the gripper equipped with traditional fingers. This difference was statistically significant (p ≪ 0.001).The TIHRA hand was also tested at the 2016 RoboSoft Grand Challenge in Livorno, Italy. The gripper successfully completed some tasks, highlighting its conformability, deformability, and morphology, but performed poorly in others, demonstrating the need to increase the gripper strength to prevent out of plane twisting and bending and to increase the force that the gripper can exert. The gripper was attached to a Baxter robot to demonstrate its ability to interface with existing technology, and other versions of the gripper were designed and manufactured to show the scalability and versatility of the design.

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Section: Figure 1 | the Fin Raymentioning

confidence: 99%

Fin Ray® Effect Inspired Soft Robotic Gripper: From the RoboSoft Grand Challenge toward Optimization

et al. 2016

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“…The incorporation of soft sensors in the glove of upper‐limb systems should not affect the overall system performance. For example, Yeo et al proposed an integrated solution for hand rehabilitation . The solution was achieved by integrating a flexible pneumatic actuator with a stretchable strain sensor to form a soft sensorized actuator.…”

Section: Sensing and Intelligent Control Algorithmmentioning

confidence: 99%

A review of recent advancements in soft and flexible robots for medical applications

Zhang

2020

Robotics Computer Surgery

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Background: Soft and flexible robots for medical applications are needed to change their flexibility over a wide range to perform tasks adequately. The mechanism and theory of flexibility has been a scientific issue and is of interest to the community. Methods: Recent advancements of bionics, flexible actuation, sensing, and intelligent control algorithms as well as tunable stiffness have been referenced when soft and flexible robots are developed. The benefits and limitations of these relevant studies and how they affect the flexibility are discussed, and possible research directions are explored. Results: The bionic materials and structures that demonstrate the potential capabilities of the soft medical robot flexibility are the fundamental guarantee for clinical medical applications. Flexible actuation that used to provide power, intelligent control algorithms which are the exact executors, and the wide range stiffness of the soft materials are the three important influence factors for soft medical robots. Conclusion: Some reasonable suggestions and possible solutions for soft and flexible medical robots are proposed, including novel materials, flexible actuation concepts with a built-in source of energy or power, programmable flexibility, and adjustable stiffness. K E Y W O R D S bionics, flexible actuation, sensing and intelligent control algorithm, soft and flexible robots, tunable stiffness 1 | INTRODUCTION The application of robots in the medical field dates back to a few decades ago, but the recent use of soft materials in medical robots has enabled new capabilities that create possibilities for medical treatments in which much safer human-robot interaction is preferred. 1-3 Soft medical robots are defined as soft and flexible electro-mechanical systems with high flexibility performing medical applications. Soft medical robots are multidisciplinary emerging technologies 4 such as materials science, bionics, mechanics, electronics, and computer science. At present, soft medical robots have been used for surgery, 5diagnosis, 6 rehabilitation, 7 prostheses, 8 artificial organs, 9 drug delivery 10 and many other medical applications. [11][12][13][14][15][16] The movements such as bending, torsion, extension, and contact operations 17 required high flexibility and deformability 18 of soft medical robots.Soft medical robots exhibit a range of degrees of flexibility during medical applications. In this paper, flexibility is used to describe the characteristics of soft medical robots that have a proper combination of stiffness and compliance and it is on the scientific level. Actually, flexibility reflects in three aspects: the variety of shape, the wide range of stiffness, and the adequate force applied. It is necessary for soft medical robots that it can change their flexibility degree over a wide range to perform tasks adequately. For example, there has certainly been a longterm demand in minimally invasive surgery (MIS) applications for soft medical robots that can move, deform, navigate narrow gaps, and int...

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“…[1][2][3][4] Compared to rigid sensors, sensors that are flexible, stretchable, and bendable have shown enormous potential in health monitoring, [5][6][7] soft robotics, [8,9] electronics skins, [10][11][12] and prosthetics. [1][2][3][4] Compared to rigid sensors, sensors that are flexible, stretchable, and bendable have shown enormous potential in health monitoring, [5][6][7] soft robotics, [8,9] electronics skins, [10][11][12] and prosthetics.…”

Section: Wearable Sensorsmentioning

confidence: 99%

“…[34][35][36] Recently, several liquid metals that exist in a fluid state in room temperatures are gaining popularity. [1][2][3][4] Compared to rigid sensors, sensors that are flexible, stretchable, and bendable have shown enormous potential in health monitoring, [5][6][7] soft robotics, [8,9] electronics skins, [10][11][12] and prosthetics. [37] Microfluidic devices based on the liquid metals have therefore been increasingly employed as wearable pressure sensors, [38] strain sensors, [39] temperature sensors, [40] and even more recently as a thermotherapy platform.…”

mentioning

confidence: 99%

Ultrathin and Wearable Microtubular Epidermal Sensor for Real‐Time Physiological Pulse Monitoring

Yeo

et al. 2017

Adv Materials Technologies

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high performance of these sensors, their complicated structures, in many cases, require more expensive and complex production routes, limiting its scalability and reproducibility. [33] Conductive liquids belong to another class of materials suitable for deployment in soft and stretchable sensing platforms. These liquids assume the shape of the microchannels within the soft silicone elastomer due to the weak intermolecular forces of attraction between particles. As such, they are highly patternable and reconfigurable. [34][35][36] Recently, several liquid metals that exist in a fluid state in room temperatures are gaining popularity. Among which, Gallistan and eutectic gallium-indium (eGaIn) are two widely reported electrically conductive liquid metallic alloys that are nontoxic and highly deformable. [37] Microfluidic devices based on the liquid metals have therefore been increasingly employed as wearable pressure sensors, [38] strain sensors, [39] temperature sensors, [40] and even more recently as a thermotherapy platform. [41] However, the macroscopic monolithic film format of microfluidics may not fully meet the requirements of imperceptibility and affect conformability due to many subtle but nonflat topologies on the surface of human skin. Thus, an ultrasensitive tactile sensor that is ultrathin, ultralight, and shape configurable is highly desirable.Here, we report an ultrathin microtubular resistive sensor that is soft, flexible, stretchable, and simple to manufacture. The microtube facilitates the deployment of liquid metallic alloy eGaIn which serves as a thin flexible conduit with excellent electrical conductivity and mechanical deformability. Specifically, by considering the radius and thickness of the microtube, we realize an ultrasensitive liquid-based tactile sensor with high flexibility and durability. The self-sustaining fiber-like shape of the sensor is entirely conformal to human interfaces due to its ability to twist around 3D curvatures and objects. In addition, its tiny footprint of 120 µm in diameter makes it almost imperceptible when worn on bare skin. The results of this work establish an attractive option for imperceptible epidermal healthcare diagnostics and monitoring platform.To achieve sensitive force measurements, we utilize liquid metallic alloy within a tubular structure in a submillimeter regime. Liquid metal core fiber of ≈400 µm inner diameter and ≈100 µm in wall thickness has been previously demonstrated as a strain sensor. [42] However, in our current study, we developed a facile manufacturing strategy to achieve an ultrathin, soft core fiber that was previously unattainable. The fabrication process A flexible, stretchable, soft, and ultrathin wearable microtubular sensor that is highly sensitive to mechanical perturbations is developed. The sensor comprises a unique architecture consisting of a liquid-state conductive element core within a soft silicone elastomer microtube. The microtubular sensor can distinguish forces as small as 5 mN and possesses a high force sensitivity ...

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Flexible and Stretchable Strain Sensing Actuator for Wearable Soft Robotic Applications

Cited by 206 publications

References 48 publications

Fin Ray® Effect Inspired Soft Robotic Gripper: From the RoboSoft Grand Challenge toward Optimization

Fin Ray® Effect Inspired Soft Robotic Gripper: From the RoboSoft Grand Challenge toward Optimization

A review of recent advancements in soft and flexible robots for medical applications

Ultrathin and Wearable Microtubular Epidermal Sensor for Real‐Time Physiological Pulse Monitoring

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