Curved shape memory alloy-based soft actuators and application to soft gripper

Research in soft matter engineering has introduced new approaches in robotics and wearable devices that can interface with the human body and adapt to unpredictable environments. However, many promising applications are limited by the dependence of soft systems on electrical or pneumatic tethers. Recent work in soft actuation and electronics has made removing such cords more feasible, heralding a variety of applications from autonomous field robotics to wireless biomedical devices. Here we review the development of functional untethered soft robotics. We focus on recent advances in soft robotic actuation, sensing and integration as they relate to untethered systems, and consider the key challenges the field faces in engineering systems that could have practical use in real-world conditions.

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“…2f). Other work has employed SMAs in an elastomeric matrix to create improved gripping 52,56 and untethered biomimetic locomotion 57 .…”

Section: Nature Electronicsmentioning

confidence: 99%

Untethered soft robotics

2018

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“…For example, in order to optimize the bending actuation of the SMA-embedded soft actuators, a rigid thin layer is commonly placed in the mid-plane of the actuator to increase the axial stiffness, and reduce the axial contraction caused by the contraction of the SMA wire [3]. Moreover, both ends of the actuator must be fabricated from a rigid material to ensure that during the actuation process, the metal connections fixing the SMA wire to the actuator body do not damage the soft matrix at elevated temperatures [3,5,18]. These requirements add steps to the conventional manufacturing processes, therefore increase the time and cost of fabrication.…”

Section: Design Of Soft Actuatorsmentioning

confidence: 99%

“…Further simulations are ongoing to evaluate these parameters and compare them with the data obtained from characterization tests usually performed for this type of actuators [3,4,36,37].…”

Section: Bending Actuatormentioning

confidence: 99%

“…Although SMAs are manufactured in a variety of shapes, including plates, springs, wires, and ribbons, the most widely used shape is the onedimensional SMA wire, which can be integrated into soft matrices to fabricate actuators that transform one-dimensional deformation of the SMA wires into a broad range of three-dimensional deformations. For instance, Rodrigue et al developed soft actuators comprised of a polydimethylsiloxane (PDMS) matrix embedded with Nitinol (Nickel-Titanium) SMA wires arranged in different configurations to create a variety of bending [2][3][4][5], twisting [6][7][8], and extensional [9] actuators, which have potential applications in soft robotics [10][11][12], aerospace [13,14], and biomedical [15,16] fields.…”

Section: Introductionmentioning

confidence: 99%

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Multimaterial 3D Printed Soft Actuators Powered by Shape Memory Alloy Wires

Akbari

Sakhaei

Panjwani

et al. 2019

Sensors and Actuators A: Physical

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Shape memory alloys (SMAs) have been widely used to fabricate soft actuators by embedding SMA wires into various soft matrices manufactured by conventional moulding methods or novel threedimensional (3D) printing techniques. However, soft matrices of SMA based actuators are typically fabricated from only one or two different materials. Here, we exploit the great manufacturing flexibility of multimaterial 3D printing to fabricate various bending, twisting and extensional actuators by precisely controlling the spatial arrangements of different printing materials with different stiffnesses. In order to achieve a broad range of deformations, ten different printing materials were characterized and used in the actuators design. In addition, we developed a finite element model to simulate complex deformations of the printed actuators and facilitate the design process. The model incorporates a user defined material subroutine that describes the nonlinear temperature dependant behavior of SMAs. The results show the efficiency and flexibility of multimaterial 3D printing in tailoring the deformed shape of the SMA based soft actuators, which cannot be accomplished using conventional manufacturing methods such as moulding.

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“…Actuators, which can move in response to input energies [1][2][3], have had increasing attention paid to them over the years for different applications such as biomedical devices [4,5], soft robots [6,7] and artificial muscles [8,9]. Various smart materials have been utilized for actuation to meet different demands, such as the shape memory polymer (SMP) [10][11][12], shape memory alloy [13][14][15][16][17] shape memory hydrogels [18][19][20][21][22] and ionic electroactive polymer(including ionic polymer-metal composites, conductive polymer and polyelectrolyte [23][24][25]) to realize the flexibility, large actuation displacement and high actuation force properties [26][27][28][29]. Bodaghi et al have designed adaptive structures of SMP to achieve self-expanding and self-shrinking by means of four-dimensional printing technology [12].…”

Section: Introductionmentioning

confidence: 99%

Dual-Stimuli Responsive Carbon Nanotube Sponge-PDMS Amphibious Actuator

Yufeng

et al. 2019

Nanomaterials

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A dual-stimuli responsive soft actuator based on the three-dimensional (3D) porous carbon nanotube (CNT) sponge and its composite with polydimethylsiloxane (PDMS) was developed, which can realize both electrothermal and electrochemical actuation. The bimorph actuator exhibited a bending curvature of 0.32 cm−1·W−1 under electrothermal stimulation on land. The displacement of the electrochemical actuator could reach 4 mm under a 5 V applied voltage in liquid. The dual-responsive actuator has demonstrated the applications on multi-functional amphibious soft robots as a crawling robot like an inchworm, a gripper to grasp and transport the cargo and an underwater robot kicking a ball. Our study presents the versatility of the CNT sponge-based actuator, which can be used both on land and in water.

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Curved shape memory alloy-based soft actuators and application to soft gripper

Cited by 115 publications

References 60 publications

Untethered soft robotics

Untethered soft robotics

Multimaterial 3D Printed Soft Actuators Powered by Shape Memory Alloy Wires

Dual-Stimuli Responsive Carbon Nanotube Sponge-PDMS Amphibious Actuator

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