scholarly journals Soft Adaptive Mechanical Metamaterials

2021 ◽  
Vol 8 ◽  
Author(s):  
Romik Khajehtourian ◽  
Dennis M. Kochmann
Keyword(s):  
Soft Materials ◽  
Building Blocks ◽  
Soft Robotics ◽  
Energy Potential ◽  
Soft Robots ◽  
Strongly Nonlinear ◽  
Mechanical Metamaterials ◽  
Unit Cells ◽  
Potential Applications ◽  
Mechanical Logic

Soft materials are inherently flexible and make suitable candidates for soft robots intended for specific tasks that would otherwise not be achievable (e.g., smart grips capable of picking up objects without prior knowledge of their stiffness). Moreover, soft robots exploit the mechanics of their fundamental building blocks and aim to provide targeted functionality without the use of electronics or wiring. Despite recent progress, locomotion in soft robotics applications has remained a relatively young field with open challenges yet to overcome. Justly, harnessing structural instabilities and utilizing bistable actuators have gained importance as a solution. This report focuses on substrate-free reconfigurable structures composed of multistable unit cells with a nonconvex strain energy potential, which can exhibit structural transitions and produce strongly nonlinear transition waves. The energy released during the transition, if sufficient, balances the dissipation and kinetic energy of the system and forms a wave front that travels through the structure to effect its permanent or reversible reconfiguration. We exploit a triangular unit cell’s design space and provide general guidelines for unit cell selection. Using a continuum description, we predict and map the resulting structure’s behavior for various geometric and material properties. The structural motion created by these strongly nonlinear metamaterials has potential applications in propulsion in soft robotics, morphing surfaces, reconfigurable devices, mechanical logic, and controlled energy absorption.

scholarly journals Guided transition waves in multistable mechanical metamaterials

2020 ◽  
Vol 117 (5) ◽  
pp. 2319-2325 ◽  
Author(s):  
Lishuai Jin ◽  
Romik Khajehtourian ◽  
Jochen Mueller ◽  
Ahmad Rafsanjani ◽  
Vincent Tournat ◽  
...  
Keyword(s):  
Network Architecture ◽  
Building Blocks ◽  
Structural Level ◽  
Free Surfaces ◽  
Precise Control ◽  
Strongly Nonlinear ◽  
Reconfigurable Devices ◽  
Mechanical Metamaterials ◽  
Mechanical Logic ◽  
Transition Fronts

Transition fronts, moving through solids and fluids in the form of propagating domain or phase boundaries, have recently been mimicked at the structural level in bistable architectures. What has been limited to simple one-dimensional (1D) examples is here cast into a blueprint for higher dimensions, demonstrated through 2D experiments and described by a continuum mechanical model that draws inspiration from phase transition theory in crystalline solids. Unlike materials, the presented structural analogs admit precise control of the transition wave’s direction, shape, and velocity through spatially tailoring the underlying periodic network architecture (locally varying the shape or stiffness of the fundamental building blocks, and exploiting interactions of transition fronts with lattice defects such as point defects and free surfaces). The outcome is a predictable and programmable strongly nonlinear metamaterial motion with potential for, for example, propulsion in soft robotics, morphing surfaces, reconfigurable devices, mechanical logic, and controlled energy absorption.

scholarly journals Well, Actuate(ly)...: Parametric Multi-Material 3D Printed Soft Robotics

2021 ◽  
Author(s):  
Patrick Coulson
Keyword(s):  
Complex Geometry ◽  
Casting Process ◽  
Soft Materials ◽  
Research Field ◽  
Soft Robotics ◽  
Soft Robots ◽  
3D Print ◽  
Parametric Control ◽  
3D Printed ◽  
Polyjet Printing

<b>In recent years, soft robotics has gained wide interest in the research field and has also garnered some commercial success. This is because soft robots are comprised of soft materials that have inherent compliance which lends them to a wide variety of applications that are not suited to traditional hard-bodied robots. </b><p>Soft robots are generally created using a casting process, which comes with limitations to the geometry due to the removal of the cast body from the mould. This research seeks to enhance the capabilities of soft robotic limbs using multi-material Polyjet printing – a recently developed additive manufacturing technology – which allows for geometric freedom and variable materials within a singular soft 3D print which is not feasible using other fabrication methods. </p> <p>This research draws inspiration from natural mechanisms such as muscular hydrostats, to enable the exploration of singular channel soft robots that exhibit bending, twisting, elongation, and expansion all in one 3D print. The geometric freedom and variable materiality of the Stratasys J750 produce actuation results for each motion that cannot be easily replicated using traditional fabrication techniques. The printable materials of the Stratasys J750 were found to have tendencies to tear upon inflation, however, a large array of prints with complex geometry were able to successfully actuate despite this. In some areas, results outperformed actuators made using other fabrication techniques, as was particularly evident in the twisting actuators. Through fine-tuned parametric control with equation-driven modelling, this portfolio presents a method for soft robotic design and construction that can produce a limb with multiple motions and up to 5 axes of movement that can be tailored to specific pre-defined applications.</p>

scholarly journals Analysis of Soft Robotics Based on the Concept of Category of Mobility

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Hayato Saigo ◽  
Makoto Naruse ◽  
Kazuya Okamura ◽  
Hirokazu Hori ◽  
Izumi Ojima
Keyword(s):  
Category Theory ◽  
Soft Materials ◽  
Design Principles ◽  
Theoretical Background ◽  
Rigid Bodies ◽  
The Body ◽  
Soft Robotics ◽  
Soft Robots ◽  
Natural Processes ◽  
Rigorous Description

Soft robotics is an emerging field of research where the robot body is composed of flexible and soft materials. It allows the body to bend, twist, and deform to move or to adapt its shape to the environment for grasping, all of which are difficult for traditional hard robots with rigid bodies. However, the theoretical basis and design principles for soft robotics are not well-founded despite their recognized importance. For example, the control of soft robots is outsourced to morphological attributes and natural processes; thus, the coupled relations between a robot and its environment are particularly crucial. In this paper, we propose a mathematical foundation for soft robotics based on category theory, a branch of abstract mathematics where any notions can be described by objects and arrows. It allows for a rigorous description of the inherent characteristics of soft robots and their relation to the environment as well as the differences compared to conventional hard robots. We present a notion called the category of mobility to well describe the subject matter. The theory has been applied to a model system and analysis to highlight the adaptation behavior observed in universal grippers, which are a typical example of soft robotics. The aim of the present study is not to offer concrete engineering solutions to existing robotics but to provide clear mathematical description of soft robots by category theory and to imply its potential abilities by a simple soft gripper demonstration. This paper paves the way to developing a theoretical background and design principles for soft robotics.

scholarly journals Soft robotics: the route to true robotic organisms

2021 ◽  
Author(s):  
Jonathan Rossiter
Keyword(s):  
Environmental Impact ◽  
Soft Materials ◽  
Soft Robotics ◽  
Biodegradable Materials ◽  
Soft Robots ◽  
Soft Systems ◽  
Biological Organisms ◽  
The Way

AbstractSoft Robotics has come to the fore in the last decade as a new way of conceptualising, designing and fabricating robots. Soft materials empower robots with locomotion, manipulation, and adaptability capabilities beyond those possible with conventional rigid robots. Soft robots can also be made from biological, biocompatible and biodegradable materials. This offers the tantalising possibility of bridging the gap between robots and organisms. Here, we discuss the properties of soft materials and soft systems that make them so attractive for future robots. In doing so, we consider how future robots can behave like, and have abilities akin to, biological organisms. These include huge numbers, finite lifetime, homeostasis and minimal—and even positive—environmental impact. This paves the way for future robots, not as machines, but as robotic organisms.

scholarly journals Well, Actuate(ly)...: Parametric Multi-Material 3D Printed Soft Robotics

2021 ◽  
Author(s):  
Patrick Coulson
Keyword(s):  
Complex Geometry ◽  
Casting Process ◽  
Soft Materials ◽  
Research Field ◽  
Soft Robotics ◽  
Soft Robots ◽  
3D Print ◽  
Parametric Control ◽  
3D Printed ◽  
Polyjet Printing

<b>In recent years, soft robotics has gained wide interest in the research field and has also garnered some commercial success. This is because soft robots are comprised of soft materials that have inherent compliance which lends them to a wide variety of applications that are not suited to traditional hard-bodied robots. </b><p>Soft robots are generally created using a casting process, which comes with limitations to the geometry due to the removal of the cast body from the mould. This research seeks to enhance the capabilities of soft robotic limbs using multi-material Polyjet printing – a recently developed additive manufacturing technology – which allows for geometric freedom and variable materials within a singular soft 3D print which is not feasible using other fabrication methods. </p> <p>This research draws inspiration from natural mechanisms such as muscular hydrostats, to enable the exploration of singular channel soft robots that exhibit bending, twisting, elongation, and expansion all in one 3D print. The geometric freedom and variable materiality of the Stratasys J750 produce actuation results for each motion that cannot be easily replicated using traditional fabrication techniques. The printable materials of the Stratasys J750 were found to have tendencies to tear upon inflation, however, a large array of prints with complex geometry were able to successfully actuate despite this. In some areas, results outperformed actuators made using other fabrication techniques, as was particularly evident in the twisting actuators. Through fine-tuned parametric control with equation-driven modelling, this portfolio presents a method for soft robotic design and construction that can produce a limb with multiple motions and up to 5 axes of movement that can be tailored to specific pre-defined applications.</p>

scholarly journals Hierarchical mechanical metamaterials built with scalable tristable elements for ternary logic operation and amplitude modulation

2021 ◽  
Vol 7 (9) ◽  
pp. eabf1966
Author(s):  
Hang Zhang ◽  
Jun Wu ◽  
Daining Fang ◽  
Yihui Zhang
Keyword(s):  
Structural Diversity ◽  
Cell Number ◽  
Structural Elements ◽  
Ternary Logic ◽  
Stable States ◽  
One Dimensional ◽  
Logic Operation ◽  
Artificial Materials ◽  
Mechanical Metamaterials ◽  
Unit Cells

Multistable mechanical metamaterials are artificial materials whose microarchitectures offer more than two different stable configurations. Existing multistable mechanical metamaterials mainly rely on origami/kirigami-inspired designs, snap-through instability, and microstructured soft mechanisms, with mostly bistable fundamental unit cells. Scalable, tristable structural elements that can be built up to form mechanical metamaterials with an extremely large number of programmable stable configurations remains illusive. Here, we harness the elastic tensile/compressive asymmetry of kirigami microstructures to design a class of scalable X-shaped tristable structures. Using these structure as building block elements, hierarchical mechanical metamaterials with one-dimensional (1D) cylindrical geometries, 2D square lattices, and 3D cubic/octahedral lattices are designed and demonstrated, with capabilities of torsional multistability or independent controlled multidirectional multistability. The number of stable states increases exponentially with the cell number of mechanical metamaterials. The versatile multistability and structural diversity allow demonstrative applications in mechanical ternary logic operators and amplitude modulators with unusual functionalities.

scholarly journals A Structurally Variable Hinged Tetrahedron Framework from DNA Origami

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
David M. Smith ◽  
Verena Schüller ◽  
Carsten Forthmann ◽  
Robert Schreiber ◽  
Philip Tinnefeld ◽  
...  
Keyword(s):  
Self Assembly ◽  
Gel Electrophoresis ◽  
Imaging Techniques ◽  
Building Blocks ◽  
Dna Origami ◽  
Microscopy Technique ◽  
Wire Frame ◽  
Wide Range ◽  
Potential Applications ◽  
Linker Molecules

Nanometer-sized polyhedral wire-frame objects hold a wide range of potential applications both as structural scaffolds as well as a basis for synthetic nanocontainers. The utilization of DNA as basic building blocks for such structures allows the exploitation of bottom-up self-assembly in order to achieve molecular programmability through the pairing of complementary bases. In this work, we report on a hollow but rigid tetrahedron framework of 75 nm strut length constructed with the DNA origami method. Flexible hinges at each of their four joints provide a means for structural variability of the object. Through the opening of gaps along the struts, four variants can be created as confirmed by both gel electrophoresis and direct imaging techniques. The intrinsic site addressability provided by this technique allows the unique targeted attachment of dye and/or linker molecules at any point on the structure's surface, which we prove through the superresolution fluorescence microscopy technique DNA PAINT.

Study on non-uniform axial magnetic field induced deformation of soft cylindrical magneto-active actuator

Soft Matter ◽  
2021 ◽  
Author(s):  
Xiaocheng Hu ◽  
Yimou Fu ◽  
Tonghao Wu ◽  
Shaoxing Qu
Keyword(s):  
Magnetic Field ◽  
Magnetic Stimulation ◽  
Axial Magnetic Field ◽  
Soft Robots ◽  
Potential Applications

The magneto-active polymers (MAPs) can undergo rapid and noticeable deformation through the external wireless magnetic stimulation, offering a possibility to develop potential applications such as actuators, flexible micro-grippers, soft robots,...

Substantially Transparent Pt, Pd, Rh, And Re Films: Preparation and Properties

1987 ◽  
Vol 111 ◽  
Author(s):  
D. E. Aspnes ◽  
A. Heller
Keyword(s):  
Light Transmission ◽  
Building Blocks ◽  
Poor Quality ◽  
Model Calculations ◽  
Transmission Electron ◽  
Metal Volume ◽  
Potential Applications ◽  
Metallic Catalyst ◽  
Anomalous Transparency ◽  
Best Fit

AbstractFilms of Pt, Pd, Rh, and Re with metal volume fractions of 0.3 to 0.5 have been prepared by mass-transport-limited photoelectrodeposition onto (001) p-InP photocathodes from ∼5 × 10−5 M solutions of the metal ions in 1 M HClO4. These films exhibit their normal catalytic activities (e.g., in hydrogen evolution) and have normal crystal structures, yet are substantially more transparent than equivalent dense films of the same metal loading per unit area. Effective-medium analysis of the spectroellipsometrically measured dielectric functions of these films shows that the anomalous transparency is due to microstructure: depolarization factors and metal packing fractions obtained by best-fit model calculations indicate dendritic (Rh), particulate (Pt, Pd), or platelet (Re) forms that are poorly interconnected in directions parallel to the surface, and whose dimensions are all small compared to the wavelength of light. Transmission electron micrographs confirm these results and reveal that these films consist of primary building blocks of ca. 5 nm crystallites that are organized into relatively loosely packed secondary structures. Potential applications of these films include the formation of efficient metallic-catalyst-coated photoelectrodes on poor-quality semiconductors.

scholarly journals Cyclic cis-1,3-Diamines Derived from Bicyclic Hydrazines: Synthesis and Applications

Synlett ◽  
2020 ◽  
Author(s):  
Erica Benedetti ◽  
Laurent Micouin ◽  
Claire Fleurisson
Keyword(s):  
Bond Cleavage ◽  
Building Blocks ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Chemical Similarity ◽  
Active Compounds ◽  
General Overview ◽  
Biological Interest ◽  
Potential Applications ◽  
Rna Binders

AbstractCyclic cis-1,3-diamines are versatile building blocks frequently found in natural molecules or biologically active compounds. In comparison with widely studied 1,2-diamines, and despite their chemical similarity, 1,3-diamines have been investigated less intensively probably because of a lack of general synthetic procedures giving access to these compounds with good levels of chemo-, regio-, and stereocontrol. In this Account we will give a general overview of the biological interest of cyclic cis-1,3-diamines. We will then describe the synthesis and potential applications of these compounds with a particular focus on the work realized in our laboratory.1 Introduction2 Biological Relevance of the cis-1,3-Diamine Motif3 Classical Synthetic Strategies towards cis-1,3-Diamines4 N–N Bond Cleavage of Bicyclic Hydrazines: A Versatile Method to Access cis-1,3-Diamines4.1 Preparation of Five-Membered Cyclic cis-1,3-Diamino Alcohols4.2 Access to Fluorinated 1,3-cis-Diaminocyclopentanes4.3 Synthesis of cis-1,3-Diaminocyclohexitols4.4 Formation of Cyclic cis-3,5-Diaminopiperidines5 Applications of Cyclic cis-1,3-Diamines5.1 Small-Molecular RNA Binders5.2 Fluorinated 1,3-Diamino Cyclopentanes as NMR Probes6 Concluding Remarks

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