Smart material composites for discrete stiffness materials

Allen, Emily A.; Taylor, Lee D.; Swensen, John

doi:10.1088/1361-665x/ab1ec9

Cited by 14 publications

(7 citation statements)

References 41 publications

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“…Numerous wire‐based actuators have been described 36,39–42. For example, Allen et al employ a Nitinol wire embedded with a polycaprolactone (PCL) rod, both of which are encapsulated in a silicone rubber to form a composite actuator ( Figure a) 43. The PCL is also thermally responsive.…”

Section: Shape Memory Alloysmentioning

confidence: 99%

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Materials as Machines

2020

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of responsive materials as machines is in robotics. The vision, leadership, and research of Bar-Cohen is seminal in both invigorating and focusing current-day research activities to develop responsive materials [2] and implement [3] them as lightweight, dexterous, and gentle (e.g., soft) robotic elements. In this spirit, this review exhaustively details the materials, the nature of their stimuli-response, and discusses considerations for their implementation in robotic systems and subsystems.Robotics is a well-established but growing field of research. Sustained progress in both performance and functionality continue to be realized in commercial robotic systems largely based on conventional materials and their integration with mechanisms. A recent example is the Atlas robot from Boston Dynamics [4] (Figure 1a). The incorporation of stimuli-responsive materials in robotics has largely focused on component-level demonstrations to extend the performance of a subsystem (such as a hand or gripper).Stimuli-responsive materials, spanning nearly all classes of materials and size scales, are currently subject to widespread examination in corporate, government, and academic research laboratories (Figure 1b-d). [5][6][7] In some cases, these materials have already found widespread commercial implementation in end use and are comparatively mature. The materials and fundamentals of their responses are summarized in Figure 2. Shape memory alloys (SMAs) and ceramic piezoelectric materials are distinctive in that they are hard, stimuli-responsive materials. Deformation of these materials can produce large energy densities due to their inherent stiffness. Electroactive polymers (EAPs) remain a topic of considerable interest, particularly dielectric elastomer actuators (DEAs). Engineered systems are rapidly emerging and enabling performance gains in robotics, largely based on pneumatic or fluidic (such as HASEL [8] actuators) transport processes that localize deformation to generate force or produce motion. Soft materials, such as shape memory polymers (SMPs), hydrogels, and liquid crystalline polymer networks (LCNs) and elastomers (LCEs) may offer distinctive functional performance to robotic systems in allowing local control of deformation without the need for complex interfacing with mechanisms. As will be evident, each of these materials has inherent advantages and performance tradeoffs that must be considered in functional implementations. However, responsive material systems have a common obstacle to widespread use: the performance and Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walk...

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Section: Shape Memory Alloysmentioning

confidence: 99%

Section: Shape Memory Alloysmentioning

confidence: 99%

Materials as Machines

2020

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“…These materials branch away from the traditional silicone rubber material and offer new incentives of construction from the ability to self-repair, which would cut costs in case of damage to the structure, to more cost efficient materials so that they could be mass produced and readily available for more people to expand their field of research. Some materials can be variably stiffened, allowing more freedom and specificity of design [99]. One of the main focus areas in the material construction of soft robotics is regarding the movement of the mechanism.…”

Section: Materials and Constructionmentioning

confidence: 99%

Soft Robotics: A Review of Recent Developments of Pneumatic Soft Actuators

et al. 2020

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This paper focuses on the recent development of soft pneumatic actuators for soft robotics over the past few years, concentrating on the following four categories: control systems, material and construction, modeling, and sensors. This review work seeks to provide an accelerated entrance to new researchers in the field to encourage research and innovation. Advances in methods to accurately model soft robotic actuators have been researched, optimizing and making numerous soft robotic designs applicable to medical, manufacturing, and electronics applications. Multi-material 3D printed and fiber optic soft pneumatic actuators have been developed, which will allow for more accurate positioning and tactile feedback for soft robotic systems. Also, a variety of research teams have made improvements to soft robot control systems to utilize soft pneumatic actuators to allow for operations to move more effectively. This review work provides an accessible repository of recent information and comparisons between similar works. Future issues facing soft robotic actuators include portable and flexible power supplies, circuit boards, and drive components.

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“…In other words, the stiffness of the soft composite could be easily tuned by applying different aspects of the external field, such as the magnetic field, temperature, and electric field. Recently, Allen et al [16] have proposed a smart composite for soft robots whereby a localized geometric patterning of smart materials could provide discrete levels of stiffness through the combinations of smart materials. They have fabricated a shape-memory-alloy-(Nitinol)-based composite finger and demonstrated the stiffness controllability by applying different temperatures as an external input source.…”

Section: Introductionmentioning

confidence: 99%

3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability

Hong¹,

Yoon²,

Kim³

et al. 2019

Micromachines

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In this study, a soft structure with its stiffness tunable by an external field is proposed. The proposed soft beam structure consists of a skin structure with channels filled with a magnetorheological fluid (MRF). Two specimens of the soft structure are fabricated by three-dimensional printing and fused deposition modeling. In the fabrication, a nozzle is used to obtain channels in the skin of the thermoplastic polyurethane, while another nozzle is used to fill MRF in the channels. The specimens are tested by using a universal tensile machine to evaluate the relationships between the load and deflection under two different conditions, without and with permanent magnets. It is empirically shown that the stiffness of the proposed soft structure can be altered by activating the magnetic field.

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Smart material composites for discrete stiffness materials

Cited by 14 publications

References 41 publications

Materials as Machines

Materials as Machines

Soft Robotics: A Review of Recent Developments of Pneumatic Soft Actuators

3D-Printed Soft Structure of Polyurethane and Magnetorheological Fluid: A Proof-of-Concept Investigation of its Stiffness Tunability

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