This PDF file contains the front matter associated with SPIE Proceedings Volume 10965, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

Smart materials and soft robotics have been seen to be particularly well suited for developing biomimetic devices and are active fields of research. In this presentation, the design, modeling, and optimization of a new biomimetic soft robot is discussed. In particular, we will discuss the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic design. Particularly, the capability of the model to account for the mass and geometry of the robot design. Also, the linear beam theory is coupled to an equivalent circuit model to actuate the robot with ionic polymer-metal composite (IPMC) actuators. The newly created physics-based model of the soft robot is compared to that of the geometric model as well as biological jellyfish swimming to highlight its improved efficiency. The optimized design shows clear improvement over the unoptimized counterpart, with the newly proposed biomimetic swimming mode offering enhanced swimming efficiency.

We demonstrate a new approach to the design of a synthetic jellyfish that imitates the morphology and kinematics of the actual animal. Since jellyfish usually move at low speeds, the locomotion can be mimicked using shape memory alloy (SMA) springs as artificial muscles. Compared to previous attempts at biomimetic underwater robots, the current research aims to simplify the design, generate larger stroke, and lower the actuation cycle for propulsion. The robot consists of a soft silicone rubber disk with an embedded pre-stretched SMA spring along its circumference, which when heated contracts to initiate large shape changes in the structure. Our approach harnesses the buckling instability of the main body to create a relatively quick motion that produces a pulsed jet of water to generate thrust. The rubber disk is also equipped with several flaps that contribute to the swimming motion by displacing the surrounding water through a rowing-like mechanism. The influence of different operation parameters, including the amplitude of the input power and the actuation frequency, are investigated on the swimming motion and propulsive thrust.

Biological pennate muscles, denoted by muscle fibers arranged obliquely relative to the line of action, have shown the ability to passively regulate the effective transmission ratio coupling fiber contraction to overall muscle contraction. In this paper, a model for a bio-inspired variable-stiffness pennate actuator is developed. The pennate topology observed in natural musculature is leveraged to create an actuator capable of varying stiffness based on its mutable configuration. Variable Stiffness Actuators (VSA’s) are useful for roboticists and engineers because they enable features atypical of traditional, stiff kinematic linkages, such as energy storage or increased human-interactive safety. Typically, VSA’s are constructed of rigid materials, such as motors and springs. However, by utilizing non-rigid actuators in a pennate configuration, a pliable, soft VSA can be conceived. Previous studies have experimentally utilized McKibben artificial muscles and Twisted Coil Polymer wires in lieu of muscle fibers to recreate the pennate muscle architecture. This paper expands on previous pennate actuator studies by providing a general modeling framework, allowing roboticists to make informed design decisions and understand associated tradeoffs when recreating the remarkable properties of pennate musculature. Theoretical case studies are performed to better understand the design tradeoffs. The Variable Stiffness Pennate Actuator is a promising actuator configuration that can readily integrate with other bio-inspired actuator technologies, such as orderly recruitment.

Understanding the role of hydrodynamic interactions in fish swimming may help explain why and how fish swim in schools. In this work, we designed controlled experiments to study fish swimming in a disturbed flow. Specifically, we recorded the tail beat frequency of a fish swimming in the presence of an actively-controlled airfoil pitching at varying frequencies. We propose an information-theoretic approach to quantify the influence of the motion of the pitching airfoil on the animal swimming. The theoretical framework developed in this work may inform future investigations on the mechanisms underlying schooling in groups.

Humans have always sought to mimic the appearance, mobility, functionality, intelligent operation, and thinking process of biological creatures. In recent years, significant advances have been made in making sophisticated biologically inspired systems. Using these advances, scientists and engineers are increasingly reverse engineering many animals' capabilities. Progress in artificial intelligence, artificial vision, and many other biomimetic related fields are leading to many benefits to humankind. The mimicking of humans is the ultimate and most challenging goal of developing biologically inspired technologies. Lifelike robots that appear and function like humans are becoming increasingly an engineering reality. The use of biomimetic technologies are enabling the possibility of making realistically looking and operating robots. New actuators, sensors and software control algorithms are being developed to support the mobility and the operation in the vicinity and in cooperation with humans. The accelerated pace of the advances in biomimetics seems to make inevitable the development of such machines as our household appliance or even companion. This paper covers the current state-of-the-art and challenges to making humanlike robots.

In this paper, the design, development, and laboratory testing of a pipe crawling robot for autonomous piping maintenance is presented. The robot consists of a modular design with four cylindrical modules for navigation which uses worm-type locomotion. Two gripping modules at a given sequence alternate gripping action simultaneously to create forward motion along with the other two modules holding the robot in place between gripping sequences. The gripping modules are designed for light-weight, optimized radial traction and to provide the maximum pull force. Then an active inspection mechanism equipped with a computer vision camera is used in the design of a conceptual nondestructive evaluation module. The bio-mimic design of the robot not only provides significant traction with pipe walls to carry NDE equipment, but it also allows conducting multi-scale mechanism tasks. Inspired by peristaltic locomotion, the proposed pipe inspection crawler can perform gripping action using radial motions to adjust to variations of pipes diameter within 4-5 inches inside pipes sloped from 0 to 180 degrees. The initial crawler’s prototype is manufactured using an additive manufacturing process. A laboratory scale test set-up is manufactured for experimentation. Testing performance of the crawler shows that the robot can accomplish horizontal and vertical motions in both upward and downward directions with adjustable gripping force. It also, demonstrated fitting and T-joint compatibility for pipe transitioning.

The consensus is that nature is a tremendous source of ideas for innovative designs that can meet various specific functional needs, relevant to society. Designs rely on structural, constructional, process-based and behavioral traits that all result from a natural trial-and-error cycle: evolution. Being one of the pillars of biomimicry, through billion years of evolution, nature has experimented and found what works and lasts, and what does not. Evidently, this has attracted scientists, especially engineers, trying to understand working natural designs, and translate them into applicable, working synthetic designs. The ‘Biomimetic Design Method’ forms the underlying conceptual framework to analytically decode biologically functions and designs. However, even though the evolutionary process is considered key to all this, it is generally overlooked in this conceptual thinking. The general assumption is that particular functions in organisms result from a natural selection process that optimized the underlying design for a particular function, thereby overlooking that an organism actually represents the possibly best compromise between all its functions needed to survive, to reproduce and to produce fit offspring. Many evolutionary processes thus yield suboptimal design components that, when put together, provide an optimized organismal design that manages to perform as good as needed, within a given environment. Such evolutionary limitations thus create possible pitfalls for bio-inspired design thinking. But, when considering them as a structural part of the design thinking process (‘evomimetics’), they actually create opportunities for an improved translation of biology into optimally functioning designs. Using specific examples from evolutionary biology, these processes are explained, and recommendations are formulated.

Cities are built and designed to encompass many considerations and needs. When compared to multi-celled organisms, single structures imitate individual cells while communities and cities embody the organisms. For the organism to survive and thrive, all of its individual cells need to operate together. Appropriately, the next step in civic smart design is to apply smart organization to benefit a community’s collective ability to survive storms rather than simply its pieces. This paper presents a design method for the protection of communities from severe windstorm events. The design method is inspired by the biomimicry of the school of fish. The method of smart organization for fluid survivability is inspired by aquatic life and school of fish. Some of the identified adaptations to marine life include the layout of a community in terms of spacing between building structures, the shape of the overall community and roof systems that can be designed mimicking the school of the fish cross-section. This paper presents seven adaptations that have been identified from fluid-structure envelope design (nano-level) to single building structure geometry (micro-level) to community layout design (macro-level).

Zebrafish is a widely used animal model in behavioral neuroscience. However, zebrafish learning capabilities are not completely understood. Technological advancements in robotics promise fine behavioral control of artificial conspecifics to study complex aspects of social behavior. In this work, we developed a training system aimed at investigating individual and social learning of zebrafish. The system consists of a shallow water tank, a 2- dimensional robotic platform, and a real-time tracking software. In the tank, a focal individual is separated from a shoal of conspecifics by a one-way glass and a transparent partition, allowing the focal fish to see the shoal. In the transparent partition are two doors, one that automatically opens when the focal individual spends a predetermined amount of time in front of it and another that remains closed regardless of the fish behavior. We tested the system by training one na¨ıve fish in individual learning and one fish in social learning over 20 sessions. Test results show that the fish can learn to open the door and also validated the effectiveness of the developed system applying on individual and social learning.

In nature, many natural organisms display very conspicuous visual appearances. Most of these appearances are due to pigments located within the biological tissues. In addition, fluorescence emission is also known to arise from several organisms. Upon contact with liquids, the colours and fluorescence of some species such as a few from the class Insecta were reported to change reversibly. However, these optical effects are so far not totally elucidated. In this study, the colour and fluorescence properties of Euchroea auripigmenta beetle were investigated. This insect exhibits a yellow visual appearance on its head, thorax and elytra when it is illuminated by either visible white light or UV light. After soaking into liquids, both the colour and the fluorescence emission from its integuments are modified. The displayed colour turns from yellow to brown. Using optical, fluorescence and electron microscopy techniques, we morphologically characterised the beetle’s integuments. This allowed to observe spike-like protuberances covering the yellow areas of the beetle and from where the yellow visual appearance originates. These protuberances are thought to give rise to further light scattering in addition to the scattering by pigments. Thanks to spectrophotometry, imaging scatterometry and spectrofluorimetry observations, the reflectance and fluorescence properties of this beetle were characterised. Whereas the liquid- induced colour change is attributed to a change in the scattering pattern, the fluorescence emission is most likely due to a chemical influence of the liquids on the two different types of embedded fluorophores.

Silicon photovoltaic solar cells generally have a black or blue appearance that makes them aesthetically very different from traditional red roofs that either comprise burned-clay tiles or composite-material shingles. Rooftop solar cells may become more acceptable if they are similar in appearance to traditional roofs. This objective requires that the red part (620–700 nm wavelength) of the incoming solar spectrum be reflected so that it becomes unavailable for photovoltaic generation of electricity. Complete reflection of red photons would result in the reduction of useful solar photons (300– 1200 nm wavelength) by 12.5%. Calculations show that the optical short-circuit density will then decline by: 17% for 100-μm-thick crystalline-silicon solar cells, 20–22% for triple-junction tandem thin-film solar cells of amorphous silicon, 15-16% for 2.2-μm-thick CIGS solar cells, and 16–20% for ultrathin CIGS solar cells. On average, the efficiency of a typical solar cell will have to be multiplied by a factor of 0.8 if all red photons were reflected. This reduction in efficiency can be offset by wider adoption of rooftop solar cells. Red-rejection filters can be made of particulate composite materials containing, say, silica nanospheres. Typically, the solar cells will be iridescent then, which may not be aesthetically pleasing to many. Non-iridescent red-rejection filters can be fabricated by upscaling the linear dimensions of biomimetic filters nano-imprinted to reproduce the Morpho blue, this possibility being guaranteed by the scale invariance of the Maxwell equations and the weak dispersion of the refractive indexes of numerous polymers in the visible spectral regime. Non-uniformly red rooftop solar cells would also become feasible.

Navigation is a challenging problem, particularly in the underwater marine environment. The maximum visibility in pure water is 80 m but such clarity is rarely present in nature, limiting the utility of vision-based navigation techniques to much shorter distances in clear waters. A further challenge is the lack of visual features in open waters. Using an underwater polarization video system inspired by the mantis shrimp eye, we have previously shown that it is possible to bypass this limitation and perform celestial navigation without direct observation of the sun. The heading and elevation of the sun can be inferred from polarization angle measurements of the scattered, in-water light field. Our proof-of-concept system achieved an accuracy of 61 km in global positioning, or 0.38° in heading. To reduce the material, computational, and energy costs of the system, we have applied the biological design principles of sparsity and matched filtering. That is, we sense and compute the minimum information necessary for specific levels of accuracy and our sensors are tuned to the most informative set of signals in the environment. This work brings us closer to a practical realization of a new method for long-distance navigation in underwater vehicles, without the need to surface, and shows how biological design principles can ease requirements for real-time and resource-constrained systems.

Blade geometry and stiffness variations lead to advantages that have been proved in several fields, from aerospace to turbomachinery. The advent of innovative materials as Shape Memory Alloys (SMA), have allowed non-conventional design approaches, targeting adaptive, smooth and extensive modifications of aerodynamic shapes and local stiffness. The Project “Shape Adaptive Blades for Rotorcraft Efficiency” (SABRE) within the EU program H2020, has the main objective of maturing blade morphing technologies and related processes, moving from the assessment of predictive codes integrated with novel philosophies of geometry alterations, till experimental validation within lab and wind tunnel environments. In this paper, an SMA demonstrator for active twist is proposed, aimed at modulating spanwise blade torsion angle for rotorcraft performance improvement. The idea is to combine the reference structure with embedded torque actuators. Quasi-steady operations are targeted because of the low frequency bandwidth of the addressed devices (under 1 Hz). Thus, single flight regimes are considered (hover, climb, forward flight). Actuation authority is a critical aspect for the proper design of that system. It is influenced by many geometrical and physical parameters like the cross section geometry or the materials Young modulus. The presented demonstrator is made of three main elements: an SMA rod system, structural elements representative of the blade body stiffness, and the connecting fixtures. An experimental campaign is carried out to verify the relations among alloys activation temperatures, induced stiffness levels, and forces and installation angles (pre-twist).

Superior nanometre-scale structures mostly endow the unique properties in natural creatures to adapt the extremely harsh living environments. The cicada and drangonfly wings with the nanocone and the nanopillar structures, respectively, display excellent antireflection and antiwetting properties. In this work, the biomimetic nanocones and nanopillars on various polymer substrates inspired by cicada and drangonfly wings were fabricated by the combination of the plasma etching and the plasma polymerization deposition. The natural crystalline state and degree of different polymer materials could have obvious effect on the size and distribution of nanostructures. All polymer surfaces with nanocones and nanopillars demonstrated the reduced reflectance over the visible and near-infrared spectrum compared with the pristine surfaces. The weaker angle dependence of reflectance was achieved for the surfaces with nanocones. The surfaces with nanocones and nanopillars exhibit also superhydrophobicity due to the plasma polymerization deposition of fluorocarbon film. The stable superhydrophobicity of the nanocones and nanopillars with the Cassie state was found in waterdrop-impact experiments. The nanocone arrays exhibit better anti-warterdrop impacting ability than the nanopillars. The nanocones and nanopillars on flexible and curved polymeric materials enhance the superhydrophobicity showing reduce of the impalement probability and the contact time of waterdrops. The plasma nanotexturing methods composed of the plasma etching and the plasma polymerization deposition could be appropriate to fabricate biomimetic nanostructures of cicada and drangonfly wings on the polymer substrates.

Multifunctional lifting surfaces can expand the mission capabilities of aerial vehicles with a minimal number of components added to the vehicle. This paper presents a bio-inspired segmented wingtip concept for lift enhancement enabled by passive structural tailoring and active bistable truss mechanisms. The development of wingtips stems from studies of birds with desirable flight capabilities. The structural characteristics and maneuverable changes of a bird’s primary feathers during flight have identified three notable feather degrees of freedom: incidence angle, dihedral angle, and gap spacing. Wind tunnel experiments conducted on multi-wingtip systems have determined that different wingtip orientations and spacings are desired to enhance aerodynamic performance depending on the flight conditions. These results suggest that the wingtip degrees of freedom must be varied during flight to achieve optimal aerodynamic performance. This paper presents two structural concepts, one passive and one active, to achieve desired morphological wingtip parameters during flight. The passive structural concept exploits bend-twist coupling of additively manufactured composite laminate wingtips by using aerodynamic loads to induce passive shape adaptation of the composite wingtips to control the twist and dihedral angles. The active concept utilizes bistable truss mechanisms to vary the wingtip gap spacing. The force-displacement responses of bistable mechanisms and the bending and twist of bend-twist coupled composite wingtips are measured using a universal testing machine and Digital Image Correlation, respectively. Experimental results include the energy storage characterization of the bistable mechanisms as a function of material characteristics and the bend-twist coupling of the composite wingtips as a function of fabrication process and laminate properties.

Recently, accidents in homes of elderly people are increasing due to an increase in single elderly people and shortage of nursing care workers in Japan. 70% of elderly accidents occur in their houses, and it is urgently needed to develop a system to watch residents. In Biofied Building, we are conducting a research on watching over the resident by introducing a small sensor agent robot into the house. It acquires physical information near the resident and acts as a communication robot. The robot must move carefully reflecting the position of the resident. The motion flow of the previously proposed robot continues to follow people at all times. There were concerns such as the possibility of a collision accident with people and furniture and discomfort due to the behavior of the robot. In this research, we propose a motion flow in which people and robots move alternately by incorporating standby behaviors in the motion flow of robot. These are intended to reduce the collision accident and discomfort by applying the potential method using the walking history of the resident. By setting the walking history of the resident as the repulsive potential, we estimated the place away from the flow line of the person as the standby position of the robot. Regarding the movement route, by using the walking history of a person as an attraction field, we generated a path away from furniture and walls. We conducted simulation studies and implemented the propose method to the robot.

Mineralization of inorganic materials in (bio)polymers became one of the most fruitful approaches towards designing materials with outstanding properties in the past decades. The concept of biomieralization is adapted from nature and has witnessed numerous fascinating developments, which in many cases have changed our lives. Among those functional materials hybrid materials play an increasingly important role. Hybrid materials are in most cases blends of inorganic and organic materials and are considered to be key for the next generation of materials research. The main goal while fabricating such materials is to bridge the worlds of polymers and ceramics, ideally uniting the most desirable properties within a singular material. In our work, we extend the concept of biomineralization towards fabrication of (bio)polymer-inorganic hybrid materials by applying a solvent-free vapor phase infiltration (VPI) process rather than making use of wet chemistry. The VPI process can be seen as a chemical reactor that allows precise dosing of a chemical, allowing for chemical interaction and modification of the subsurface area of a substrate. In this talk, some approaches will be discussed that show great promise for establishing VPI as the method-of-choice for innovation. The VPI process allows infusing metals or ceramics into polymeric substrates, which leads to novel material blends that cannot easily be obtained in other ways. The chemical or physical properties of the initial substrate are improved or new functionalities added. With some showcases, this talk will discuss approaches towards fabrication of novel materials with great promise in personal protection or flexible electronics.

We observed the changes in fluorescence intensity which was based on fluorescent protein (mCherry) when the fluorescent protein expressed E-coli attached on the natural and artificial nanostructural surface. Time-lapse imaging was used to analyze the changes in fluorescence intensity caused by the effusion of intercellular fluid, including fluorescent protein, at the single cell level. We found that there were three stages of changes in the fluorescence intensity gradient. These characteristics were observed both on the natural and artificial nanostructural surface.

Soft robotics promise to enable large reconfigurability in robotic systems, in turn allowing interaction with unknown objects in unstructured environments. Most applications in soft robotics draw from natural examples for inspiration in sensing, actuation and control functions needed to achieve desired operations. In this respect, many organisms realize complex tasks with minimal efforts exploiting material system architectures that store mechanical energy that can be used for reconfiguration. Examples include the fast motion exhibited by the Venus Flytrap and the remarkable multifunctionality of the Earwig wing, both of which exploit prestress and multistability. We present a bioinspired spring origami gripper that is capable of conforming and holding objects several times its weight with minimal sensing and actuation systems drawing from the characteristics of the Earwig wing. This is achieved by exploiting the multiple functions afforded by the multistability that allows functional geometries for gripping and holding onto objects. We extend a previously developed model to design the bistable gripper and validate the obtained results with experimental tests.

The objective of this research is to design and analyze a novel hydraulic orderly recruitment valve (ORV) for actuation of fluidic artificial muscle (FAM) systems. More recently artificial muscles are gaining popularity due to their increased efficiency by employing strategies such as variable muscle recruitment. Variable recruitment employs selective recruitment of muscles depending on the load, akin to mammalian muscles. However, existing active variable recruitment systems use as many valves as the muscle actuators in the system. The proposed design of the ORV enables orderly recruitment of multiple FAMs in the system using a single valve. Modeling and analysis of the ORV is carried out to characterize its behavior and understand the dynamics of the system. The analytical model of the ORV is simulated along with an equivalent multi-valve setup to compare the abilities of both the systems to track a prescribed trajectory.

In comparison to traditional camera-eye visual system of mammals such as human beings, the compound vision system of a common house fly, Musca domestica, is capable of enhanced motion detection and tracking. Most computer vision systems today have higher spatial resolution but lower motion detection and tracking capabilities when compared to compound vision. In applications requiring obstacle avoidance and quick visual data processing, compound vision is more suitable as compared to normal mammalian inspired vision systems. Proof-of-concept has shown that even without using a computer processing system, compound vision sensors can mimic the motion hyperacuity characteristic of the fly’s visual system and at the same time provide near instantaneous edge detection and motion tracking results. While these early prototypes were successfully implemented in device-level analog components, we were interested in determining if a similar system could be implemented as an embedded system. The first step of this process is determining the best way to digitize the signals without losing the key feature of compound vision, motion hyperacuity.

With developments in software and micro-measurement technology and finite element analysis software, a threedimensional Basilar membrane finite element (BMFE) model can now be further straightforwardly created to investigate the physics and sound transfer function of basilar membrane. Numerous FE studies of the middle ear have been investigated to date, and each has its own specific advantages and shortcomings. In this conference paper, the latest PVDF-based development of the Basilar membrane and its FE modeling technology in both COMSOL Multiphysics and ANSYS software has been investigated and verified. The output responses versus the sound frequency is recorded and caparisoned.

We present a liquid flow sensor inspired by cupula structures found on a variety of fish. Our 5mm x 5mm x 1.75mm artificial cupula uniquely comprises a pair of differential liquid metal capacitors encased in silicone. Deflection of the structure – manually or by fluid flow – increases capacitance on one side and decreases on the other. To fabricate the complex internal structure, a commercial 3D printer is used to create a mold out of a sacrificial wax-like material. After casting uncured rubber, internal mold structures are melted and dissolved away, leaving channels and voids for liquid metal vacuum injection. The measured sensitivity of ~0.05pF/mm is compared to theoretical capacitance versus deflection values based on kinematics. To test behavior under water flow, a custom flow channel consisting of a 7.5mm x 7.5mm cross-section is employed with rates up to 1L/min. The parabolic capacitive response as a function of flowrate is compared to analytic theory based on kinematics and drag as well as to fluid-structure interaction (FSI) simulations using COMSOL. This device has future applications in the control of bio-inspired soft robotics. [Work sponsored by the Office of Naval Research.]

Based on social background such as aging and diversification of individual's lives, we propose the concept of Biofied building. The Biofied building is a concept that provides a safe, secure and comfortable space for residents by using small robots. The small robots used in the Biofied building sense the human position and motion. However, in the current system it is difficult to prevent accidents such as falls. The robots are not designed not disturb residents. Therefore, in this research, in order to realize more natural space control of the robot, the purpose is to incorporate motion prediction in the system in addition to motion recognition. Many conventional motion prediction methods use RNN (Recurrent Neural Networks), which is considered to be difficult to implement due to the necessity of big data and the large calculation cost. Furthermore, in RNN, it was a problem that physical constraints of the human body were not taken into consideration. Therefore, this study aims to propose a simple motion prediction method using a human body model based on dynamics.

Day flying butterflies often use species-specific colors in sexual communication. Structural colors often can be found in polyommatine butterflies to accomplish this type of communication. The photonic nanoarchitectures of biological origin, for example in the wing scales of these butterflies, can be used as inexpensive sensor materials for vapor detection. These are nanocomposites of chitin and air, with structural elements typically 100 nm in size. The small dimensions of the air-filled pores facilitate the capillary condensation of the vapors into the nanostructure which results in the spectral shift of the structural color. In this work, we studied the photonic nanoarchitectures of the wing scales of blue polyommatine butterflies using different microscopic techniques and the optical properties of the generated structural color using spectrophotometry. It was shown that photonic nanoarchitectures and the structural colors of closely-related butterfly species living in the same habitat are species-specific. We applied the blue wings of polyommatine butterflies for optical vapor sensing. It was found that the spectral shift is vapor-specific and proportional with the vapor concentration. We showed that the conformal modification of the scale surface by ethanol pretreatment can significantly enhance the both optical response and the chemical selectivity.

Geometrical and material properties of plant leaves are known to influence heat/moisture dissipation. In many species, exposed “sun” leaves are typically more dissected and possibly better convective heat dissipaters than entire shade leaves. By affecting the overall leaf boundary layer, lower-scale morphology patterns such as toothed edges can also have an important role in heat/moisture dissipation, as pointed by experiments with wetted paper models where outward teeth increased evaporative dissipation rates. Additional leaf morphological traits potentially influencing dissipation are surface corrugations, textures, trichomes and sunken stomata. Such structures can work as “dissipative” or “retaining” geometries depending on how they couple with environmental conditions and modulate leaf boundary layer. The oneweek intensive Kosmos interdisciplinary workshop at the cluster Image Knowledge Gestaltung (Berlin) was an opportunity to explore leaf design and achieve microclimate control for potential applications in technology, specifically building façades. The "Breathing skins” concept was to apply shape-related leaf dissipation strategies into folding structures that can be produced in a typical “maker-lab” setting. After a thematic introduction, participants were asked to target evapotranspiration behavior and shape-change characteristics derived from leaves, and to deliver prototypical designs using a set of prepared materials. Workshop results show the transfer of new findings in research on evapotranspiration of biological plant leaves into 3D structures for technical application. The biomimetic approach taken delivered a first translation of design abstracted from leaves into the realm of foldable geometry, for future development and technological transfer to useable products in architecture, building and fluid-assisted heat transfer systems in general.

Various types of soft actuators have been developed for application in wearable movement-assist devices or soft robots. The authors have developed a straight-fiber-reinforced pneumatic rubber artificial muscle (SF-ARM). The SFARM is composed of rubber that is reinforced with fibers aligned only in the axial direction. When air pressure is applied to the SF-ARM, the reinforced fibers limit the rubber expansion to the radial direction so that the muscle contracts in the axial direction. The SF-ARM contracts by 38% at maximum, and this contraction rate exceeds the contraction rate of the McKibben artificial muscle. However, the SF-ARM is not well-suited for practical use because the strain on the SF-ARM while it is actuated is large which can cause fatigue failure of the rubber. This study focuses on suppressing the growth of cracks using strain-induced crystallization of the natural rubber, to prolong the lifetime of the SF-ARM. Natural rubbers form a crystalline layer in the direction perpendicular to the direction of stretching. This crystal layer effectively suppresses the growth of cracks in the SF-ARM when under strain. Deliberately developing a crystal layer should extend the lifetime of the SF-ARM. First, this study confirmed the formation of a crystal layer under extension of natural rubber (NR) and styrene butadiene rubber (SBR) using wide-angle X-ray diffraction measurements. Next, the strain concentration near the crack was analyzed using finite element method simulations. Finally, fatigue-life tests were conducted with SF-ARMs made of NR and SBR.

The strong demand for an easy light control system using gesture is observed. Especially the system that can deal with multicolor illumination will be favored. However, there are very few studies considering light color control with gesture as the input. Connecting light colors and gestures is a tough task. Therefore, in this research, we evaluated the relationship among light color, gesture and emotion, and proposed a method to connect light color and gesture via emotion. Furthermore, we investigated light color control by gesture using this proposed method. First, the relationship between light color and emotion was expressed by Russell’s circumplex model. This model is a representation of all emotions with two independent axes. Next, gestures were comprehensively extracted, and three types of gestures were selected based on Laban theory, emotional expression and sign language. Using three kinds of selected motions, we implemented the experiments of light color control and compared and evaluated. As a result of evaluating in terms of the qualitative viewpoint (questionnaire evaluation) and the quantitative viewpoint (NEM), it was shown that the gesture of emotional expression is the most emotional gesture in light color control and the possibility to perform light color control using gesture. From the results of this research, we showed that the gesture based on emotional expression is the most suitable gesture in light color control. Further studies on more intuitive gestures are needed.