A Periodic Deformation Mechanism of a Soft Actuator for Crawling and Grasping

Li, Zhengjie; Huang, Rong

doi:10.1002/admt.201900653

Cited by 30 publications

(26 citation statements)

References 46 publications

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“…[ 10,11 ] They also show increased safety and dexterity can be lightweight and used within constrained environments with restricted access. [ 12,13 ] Many soft robots have a biologically inspired design coming from snakes, [ 14–17 ] worms, [ 18–20 ] fishes, [ 21–24 ] manta rays, [ 25,26 ] and tentacles. [ 27–29 ] The scope of applications includes minimally invasive surgery, [ 30,31 ] rehabilitation, [ 32,33 ] elderly assistance, [ 34 ] safe human–robot interaction, [ 35,36 ] and handling of fragile materials.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

Xavier

Fleming

Yong

2020

Advanced Intelligent Systems

171

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Soft robotics has experienced an exponential growth in publications in the last two decades. [1] Unlike rigid conventional manipulators, [2,3] soft robots based on hydrogels, [4,5] electroactive polymers, [6,7] and elastomers [7-9] are physically resilient and can adapt to delicate objects and environments due to their conformal deformation. [10,11] They also show increased safety and dexterity can be lightweight and used within constrained environments with restricted access. [12,13] Many soft robots have a biologically inspired design coming from snakes, [14-17] worms, [18-20] fishes, [21-24] manta rays, [25,26] and tentacles. [27-29] The scope of applications includes minimally invasive surgery, [30,31] rehabilitation, [32,33] elderly assistance, [34] safe human-robot interaction, [35,36] and handling of fragile materials. [37,38] Important features of soft robotics design, fabrication, modeling, and control are covered in the soft robotics toolkit. [39,40] The building blocks of soft robots are the soft actuators. The most popular category of soft actuator is the soft fluidic actuator (SFA), where actuation is achieved using hydraulics or pneumatics. [8,41] These actuators are usually fabricated with silicone rubbers following a 3D molding process, [42] although directly 3D printing the soft actuators is also possible. [43,44] Silicone rubber is a highly flexible/extensible elastomer with high-temperature resistance, lowtemperature flexibility, and good biocompatibility. [45] Elastomers can withstand very large strains over 500% with no permanent deformation or fracture. [46] For relatively small strains, simple linear stress-strain relationships can be used, and two of the following parameters can be used to describe the elastic properties: bulk compressibility, shear modulus, tensile modulus (Young's modulus of elasticity), or Poisson's ratio. [45] For large deformations, nonlinear solid mechanic models using hyperelasticity should be considered. [8,32,47-50] Due to the strong nonlinearities in SFAs and their complex geometries, analytical modeling is challenging. [51] A brief review of the analytical methods for modeling of soft robotic structures is provided in the following. 1.1. Analytical Modeling of Soft Actuators The majority of soft/continuum robots with bending motion can be approximated as a series of mutually tangent constant curvature sections, i.e., piecewise constant curvature. [52] This is a result of the fact that the internal potential energy is uniformly distributed along each section for pressure-driven robots. [53] This approach has also been validated using Hamilton's principle by Gravagne et al. [54] As discussed by Webster and Jones, [52] the kinematics of continuum robots can be separated into robotspecific and robot-independent components in this approach. The robot specific mapping transforms the input pressures P or actuator space q to the configuration space κ, ϕ, l, and the robot-independent mapping goes from the configuration space to the task space x. The actuator space contai...

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Section: Introductionmentioning

confidence: 99%

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

Xavier

Fleming

Yong

2020

Advanced Intelligent Systems

171

View full text Add to dashboard Cite

show abstract

“…Lots of the soft robots are inspired by natural creatures, such as octopus [6,7], fish [8,9], elephant trunk [10,11], and inchworms [12,13]. Those bionic soft robots are capable of achieving adaptive and complex motion patterns such as grabbing [14], climbing [15], swimming [16], crawling [17], and jumping [18]. While crawling is one of the motions that has been studied intensely, as it is particularly suitable for tasks such as drug delivery, rescue, and infrastructure inspection [19].…”

Section: Introductionmentioning

confidence: 99%

A Twisted and Coiled Polymer Artificial Muscles Driven Soft Crawling Robot Based on Enhanced Antagonistic Configuration

Zhang

Zheng

2022

Machines

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Twisted and coiled polymer (TCP) actuators are becoming increasingly prevalent in soft robotic fields due to their powerful and hysteresis-free stroke, large specific work density, and ease of fabrication. This paper presents a soft crawling robot with spike-inspired robot feet which can deform and crawl like an inchworm. The robot mainly consists of two leaf springs, connection part, robot feet, and two TCP actuators. A system level model of a soft crawling robot is presented for flexible and effective locomotion. Such a model can offer high-efficiency design and flexible locomotion of the crawling robot. Results show that the soft crawling robot can move at a speed of 0.275 mm/s when TCP is powered at 24 V.

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“…Because nitinol is conductive, this phase transition can be induced through Joule (Ohmic) heating by applying voltage and passing current through the actuator. In this way, SMA has been used for actuation in a large number of soft robotic systems ( Lin et al, 2011 ; Jin et al, 2016a ; Huang et al, 2018 , Huang et al, 2019b ; Li et al, 2019 ). However, while promising for these implementations, more widespread application of SMA for robotic actuation is limited by challenges with thermal management and control.…”

Section: Introductionmentioning

confidence: 99%

Shape Memory Alloy (SMA) Actuator With Embedded Liquid Metal Curvature Sensor for Closed-Loop Control

et al. 2021

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We introduce a soft robot actuator composed of a pre-stressed elastomer film embedded with shape memory alloy (SMA) and a liquid metal (LM) curvature sensor. SMA-based actuators are commonly used as electrically-powered limbs to enable walking, crawling, and swimming of soft robots. However, they are susceptible to overheating and long-term degradation if they are electrically stimulated before they have time to mechanically recover from their previous activation cycle. Here, we address this by embedding the soft actuator with a capacitive LM sensor capable of measuring bending curvature. The soft sensor is thin and elastic and can track curvature changes without significantly altering the natural mechanical properties of the soft actuator. We show that the sensor can be incorporated into a closed-loop “bang-bang” controller to ensure that the actuator fully relaxes to its natural curvature before the next activation cycle. In this way, the activation frequency of the actuator can be dynamically adapted for continuous, cyclic actuation. Moreover, in the special case of slower, low power actuation, we can use the embedded curvature sensor as feedback for achieving partial actuation and limiting the amount of curvature change.

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A Periodic Deformation Mechanism of a Soft Actuator for Crawling and Grasping

Cited by 30 publications

References 46 publications

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

A Twisted and Coiled Polymer Artificial Muscles Driven Soft Crawling Robot Based on Enhanced Antagonistic Configuration

Shape Memory Alloy (SMA) Actuator With Embedded Liquid Metal Curvature Sensor for Closed-Loop Control

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