Effective thermal management is critical for the operation of many modern technologies, such as electronic circuits, smart clothing, and building environment control systems. By leveraging the static infrared-reflecting design of the space blanket and drawing inspiration from the dynamic color-changing ability of squid skin, we have developed a composite material with tunable thermoregulatory properties. Our material demonstrates an on/off switching ratio of ~25 for the transmittance, regulates a heat flux of ~36 W/m2 with an estimated mechanical power input of ~3 W/m2, and features a dynamic environmental setpoint temperature window of ~8 °C. Moreover, the composite can manage one fourth of the metabolic heat flux expected for a sedentary individual and can also modulate localized changes in a wearer's body temperature by nearly 10-fold. Due to such functionality and associated figures of merit, our material may substantially reduce building energy consumption upon widespread deployment and adoption.

membro robotico continuo inspirado na biologia. a presente invencao refere-se a um membro robotico compreendendo um involucro tubular fechado (2) feito de material viscoelastico definindo uma câmara (4), contendo um fluido imcompressivel (f), o dito involucro (2) incorporando uma bainha (3) formada pelos fios entrelacados substancialmente inextensiveis, na câmara (4) sendo providos grupos de acionadores transversais (5) espacados axialmente um do outro, ligados a dita bainha (3) e adaptados para contrair de modo reversivel o involucro (2) pelo menos parcialmente na direcao radial, meios de acionamento longitudinais (6) adaptados para contrair de modo reversivel o involucro (2) pelo menos parcialmente na direcao axial, sendo conectados a cada grupo de acionadores tranversais.

Bistable minimum energy structures (BiMES) are devices derived from the union of the concepts of dielectric elastomer minimum energy structures and bistable systems. This article presents this novel approach to active, elastic and bistable structures. BiMES are based on dielectric elastomer actuators (DEAs), which act as antagonists and provide the actuation for switching between the two equilibrium positions. A central elastic beam is the backbone of the structure and is buckled into the minimum energy configurations by the action of the two DEAs. The theory and the model of the device are presented, and also its fabrication process. BiMES are considered as fundamental units for more complex structures, which are presented and fabricated as proof of concept. Two different ways of combining the multiple units are proposed: a parallel configuration, to make a simple gripper, and a serial configuration, to generate a binary device. The possibility of using the bistable system as a continuous bender actuator, by modulating the actuation voltage of the two DEAs, was also investigated.

Bistable mechanisms are widely used in the applications where two stable positions must be held for long time without energy consumption. The main advantage of bistable mechanisms is a sensible reduction in bulkiness and energy cost. Among the possible active triggering systems, dielectric elastomer actuators (DEAs) are gaining attention, for their efficiency and strain rate, as a viable alternative to traditional technologies. In the present work, a novel design of a bistable system is proposed, counting on a cross-like shape bistable element coupled with two axially arranged conical DEAs. Analytical and FEM models have been used to implement and analyze the behavior of the single components and the final coupled system. The obtained results confirm the feasibility of the switching process between the equilibrium points and the capability to capture and numerically describe the interactions between the actuators and the bistable beams. A specific device has been finally envisaged to exemplify the possibility to develop a light-weight and compact system able to sustain and passively maintain a linear displacement which equals the 46 % of its own total length.

Octopus suckers are able to attach to all nonporous surfaces and generate a very strong attachment force. The well-known attachment features of this animal result from the softness of the sucker tissues and the surface morphology of the portion of the sucker that is in contact with objects or substrates. Unlike artificial suction cups, octopus suckers are characterized by a series of radial grooves that increase the area subjected to pressure reduction during attachment. In this study, we constructed artificial suction cups with different surface geometries and tested their attachment performances using a pull-off setup. First, smooth suction cups were obtained for casting; then, sucker surfaces were engraved with a laser cutter. As expected, for all the tested cases, the engraving treatment enhanced the attachment performance of the elastomeric suction cups compared with that of the smooth versions. Moreover, the results indicated that the surface geometry with the best attachment performance was the geometry most similar to octopus sucker morphology. The results obtained in this work can be utilized to design artificial suction cups with higher wet attachment performance.

The design of structures that combine the principles of minimum energy and bistable mechanisms is presented. A minimum energy configuration is achieved by the interaction of one or more elastic elements and two strips of stretched elastomer, which also operate as dielectric actuators. The system has two equilibrium states, and the actuators are used to trigger the switch from one state to the other. An analytical model, based on the approach of energy minimization, was implemented to assist the design of the geometrical parameters. A prototype shows bistability and is able to switch equilibrium state varying its bending angle from −40° to 40°.

Soft robotics requires technologies that are capable of generating forces even though the bodies are composed of very light, flexible and soft elements. A soft actuation mechanism was developed in this work, taking inspiration from the arm of the Octopus vulgaris, specifically from the muscular hydrostat which represents its constitutive muscular structure. On the basis of the authors’ previous works on shape memory alloy (SMA) springs used as soft actuators, a specific arrangement of such SMA springs is presented, which is combined with a flexible braided sleeve featuring a conical shape and a motor-driven cable. This robot arm is able to perform tasks in water such as grasping, multi-bending gestures, shortening and elongation along its longitudinal axis. The whole structure of the arm is described in detail and experimental results on workspace, bending and grasping capabilities and generated forces are presented. Moreover, this paper demonstrates that it is possible to realize a self-contained octopus-like robotic arm with no rigid parts, highly adaptable and suitable to be mounted on underwater vehicles. Its softness allows interaction with all types of objects with very low risks of damage and limited safety issues, while at the same time producing relatively high forces when necessary.

Suction cups are often found in nature as attachment strategy in water. Nevertheless, the application of the artificial counterpart is limited by the dimension of the actuators and their usability in wet conditions. A novel design for the development of a suction cup inspired by octopus suckers is presented. The main focus of this research was on the modelling and characterization of the actuation unit, and a first prototype of the suction cup was realized as a proof of concept. The actuation of the suction cup is based on dielectric elastomer actuators. The presented device works in a wet environment, has an integrated actuation system, and is soft. The dimensions of the artificial suction cups are comparable to proximal octopus suckers, and the attachment mechanism is similar to the biological counterpart. The design approach proposed for the actuator allows the definition of the parameters for its development and for obtaining a desired pressure in water. The fabricated actuator is able to produce up to 6 kPa of pressure in water, reaching the maximum pressure in less than 300 ms.

Octopuses are an example of dexterous animals found in nature. Their arms are flexible, can vary in stiffness, grasp objects, apply high forces with respect to their relatively light weight, and bend in all directions. Robotic structures inspired by octopus arms have to undertake the challenges of a high number of degrees of freedom (DOF), coupled with highly flexible continuum structure. This paper presents a kinematic and dynamic model for underwater continuum robots inspired by Octopus vulgaris. Mass, damping, stiffness, and external forces such as gravity, buoyancy, and hydrodynamic forces are considered in the dynamic model. A continuum arm prototype was built utilizing longitudinal and radial actuators, and comparisons between the simulated and experimental results show good agreement.

Octopus show great adhesion capabilities thanks to their suckers covering their ventral side of their arms. Starting from biological investigation, we identified preliminary specifications for the design of innovative artificial suction cups, which could be used in the field of soft robotics. The main features of the biological sucker are maintained as leading criteria for the choice of the actuation technology and mechanism. In this preliminary work, we focused on the imitation of the functionality of the specific muscle bundles which generate suction to obtain adhesion. Dielectric Elastomers Actuators (DEA) were identified as a suitable solution. A study on materials and manufacturing techniques was made. Different possible solutions in the use of DEA are also described.

Continuum structures with a very high or infinite number of degrees of freedom (DOF) are very interesting structures in nature. Mimicking this kind of structures artificially is challenging due to the high number of required DOF. This paper presents a kinematic and dynamic model for an underwater robotic manipulator inspired by Octopus vulgaris. Then, a prototype arm inspired by live octopus is presented and the model validated experimentally. Initial comparisons of simulated and experimental results show good agreement.

This paper examines the design and control of a robotic arm inspired by the anatomy and neurophysiology of Octopus vulgaris in light of embodiment theory. Embodiment in an animal is defined as the dynamic coupling between sensorymotor control, anatomy, materials, and the environment that allows for the animal to achieve effective behaviour. Octopuses in particular are highly embodied and dexterous animals: their arms are fully flexible, can bend in any direction, grasp objects and modulate stiffness along their length. In this paper the biomechanics and neurophysiology of octopus have been analysed to extract relevant information for use in the design and control of an embodied soft robotic arm. The embodied design requirements are firstly defined, and how the biology of the octopus meets these requirements presented. Next, a prototype continuum arm and control architecture based on octopus biology, and meeting the design criteria, are presented. Finally, experimental results are presented to show how the developed prototype arm is able to reproduce motions performed by live octopus for contraction, elongation, bending, and grasping.

The octopus arms totally lack of rigid skeleton, and show unique motor and manipulation capabilities thanks to the skill of varying and controlling the stiffness. To take inspiration for the design of innovative technological actuators for soft robotic systems, we investigated the architecture of the muscle fibers in the octopus arm, and we measured their mechanical performance in vivo. The key features "extracted" from the octopus arm have been "translated" into engineering specifications, and the identified requirements have been used to design an artificial muscular hydrostat unit, obtaining an actuating component with controllable stiffness capabilities and various applications for a novel generation of soft-bodied robots.

The octopus is a marine animal whose body has no rigid structures. It has eight arms composed of a peculiar muscular structure, named a muscular hydrostat. The octopus arms provide it with both locomotion and grasping capabilities, thanks to the fact that their stiffness can change over a wide range and can be controlled through combined contractions of the muscles. The muscular hydrostat can better be seen as a modifiable skeleton. Furthermore, the morphology the arms and the mechanical characteristics of their tissues are such that the interaction with the environment (i.e., water) is exploited to simplify control. Thanks to this effective mechanism of embodied intelligence, the octopus can control a very high number of degrees of freedom, with relatively limited computing resources. From these considerations, the octopus emerges as a good model for embodied intelligence and for soft robotics. The prototype of a robot arm has been built based on an artificial muscular hydrostat inspired to the muscular hydrostat of the Octopus vulgaris. The prototype presents the morphology of the biological model and the broad arrangement of longitudinal and transverse muscles. Actuation is obtained with cables (longitudinally) and with shape memory alloy springs (transversally). The robot arm combines contractions and it can show the basic movements of the octopus arm, like elongation, shortening and bending, in water.

In the presented paper the realization of an artificial functional unit of muscular hydrostat inspired by the octopus is shown. The octopus has been chosen because it shows high manipulation capabilities and dexterity without a skeletal support, thus it is a good example of Embodied Intelligence. Inspiration from Nature concerns the features that are interesting from a robotic point of view for the development of an artificial muscular hydrostat: in particular actuators arrangement and their antagonistic mechanism. The main focus was on the two key elements of the unit: soft actuators and support structure. Shape memory alloys (SMA) has been chosen for actuation technology, whereas the support structure is a braided sleeve, that provides spatial continuity to the action of the actuators. Two contiguous units have been built and tested in water. Capabilities of shortening, elongation and bending have been observed and their performances evaluated. A maximum elongation of 43% has been recorded from shortened to elongated condition, with a diameter variation of 25%, finding a good match with the expected results from the support structure models. Relative angle between extremities has been measured during bending in two conditions and their efficiency has been compared.

Shape memory alloys have been widely proposed as actuators, in fields such as robotics, biomimetics and microsystems: in particular spring actuators are the most widely used, due to their simplicity of fabrication. The aim of this paper is to provide a general model and the techniques for fabricating SMA spring actuators. All the steps of the design process are described: a mechanical model to optimize the mechanical characteristic for a given requirement of force and available space, and a thermal model for the estimation of the electrical power needed for activation. The parameters of both models are obtained by experimental measurements, which are described in the paper. The models are then validated on springs manufactured manually, showing also the fabrication process. The design method is valid for the dimensioning of SMA springs, independently from the external ambient conditions. The influence on the actuator bandwidth was investigated for different working environments, providing numerical indications for the utilization in underwater applications. The spring characteristics can be calculated by the mechanical model with an accuracy of 5%. The thermal model allows one to calculate the current needed for activation under different ambient conditions, in order to guarantee activation in the specific loading conditions. Moreover, two solutions were found to reduce the power consumption by more than 40% without a dramatic reduction of bandwidth.

The octopus is a marine animal whose body has no rigid structures. It has eight arms mainly composed of muscles organized in a peculiar structure, named muscular hydrostat, that can change stiffness and that is used as a sort of a modifiable skeleton. Furthermore, the morphology of the arms and the mechanical characteristics of their tissues are such that the interaction with the environment, namely water, is exploited to simplify the control of movements. From these considerations, the octopus emerges as a paradigmatic example of embodied intelligence and a good model for soft robotics. In this paper the design and the development of an artificial muscular hydrostat are reported, underling the efforts in the design and development of new technologies for soft robotics, like materials, mechanisms, soft actuators. The first prototype of soft robot arm is presented, with experimental results that show its capability to perform the basic movements of the octopus arm (like elongation, shortening, and bending) and demonstrate how embodiment can be effective in the design of robots.

The octopus is an invertebrate sea animal, considered as an interesting model of inspiration in robotics, due to its high dexterity, variable stiffness, and very complex behaviours, if compared with its position in the evolutionary scale. This paper reports the design of an artificial muscular hydrostat for developing an octopus-like robot. The experimental study consists of the fabrication of a set of mock-ups demonstrating some of the key features and patterns of movement of the octopus arm.The experimental trials performed with the different mock-ups demonstrated the suitability of the silicone materials used and the patterns of actuators activation to replicate the typical octopus movements of elongation, shortening, bending, and reaching. They also confirm that control is simplified by the arrangement of muscles as well as by the mechanical properties of the muscular hydrostat. (C) 2010 Elsevier B.V. All rights reserved.