This manuscript describes a unique class of locomotive robot: A soft robot, composed exclusively of soft materials (elastomeric polymers), which is inspired by animals (e.g., squid, starfish, worms) that do not have hard internal skeletons. Soft lithography was used to fabricate a pneumatically actuated robot capable of sophisticated locomotion (e.g., fluid movement of limbs and multiple gaits). This robot is quadrupedal; it uses no sensors, only five actuators, and a simple pneumatic valving system that operates at low pressures (<10 psi). A combination of crawling and undulation gaits allowed this robot to navigate a difficult obstacle. This demonstration illustrates an advantage of soft robotics: They are systems in which simple types of actuation produce complex motion.biomimetic | mobile R obotics developed to increase the range of motions and functions open to machines, and to build into them some of the characteristics [including autonomous motion (1-3), adaptability to the environment (4-7), and capability of decision making (8, 9)] of animals, particularly animals with skeletons. Most mobile robots are built with hard materials (hard robots), either by adding treads or wheels (10, 11) to conventional machines to increase their mobility, or by starting with conceptual models based on animals [e.g., Big Dog (12) and many others (13-15)], and replicating some of their features in hard structures. Although robotics has made enormous progress in the last 50 years, hard robots still have many limitations. Some of these limitations are mechanical, and include instability when moving in difficult terrain; some have to do with the ranges of motions afforded by actuators and structures (e.g., metal rods, mechanical joints, and electric motors); some stem from the complexity in control (especially when handling materials and structures that are soft, delicate, and complex in shape). Hard robots fabricated from metals are also often heavy and expensive, and thus are not suitable for some applications.New classes of robots may thus find uses in applications where conventional hard robots are unsuitable. We are interested in a unique class of robots: That is, soft robots fabricated in materials (predominantly elastomeric polymers) that do not use a rigid skeleton to provide mechanical strength. The objective of this work is to demonstrate a soft robot that requires only simple design and control to generate mobility. In this demonstration, we begin to address some of the issues that have limited the development of soft robots. Instead of basing this and other designs on highly evolved animals as models, we are using simpler organisms [e.g., worms (16) and starfish (17)] for inspiration. These organisms, ones without internal skeletons, suggest designs that are simpler to make and are less expensive than conventional hard robots, and that may, in some respects, be more capable of complex motions and functions. Simple, inexpensive systems will probably not replace more complex and expensive ones, but may have different...

No abstract

In areas from assembly of machines [1] to surgery, [2] and from deactivation of improvised explosive devices (IEDs) to unmanned flight, robotics is an important and rapidly growing field of science and technology. It is currently dominated by robots having hard body plans-constructions largely of metal structural elements and conventional joints [3] -and actuated by electrical motors, or pneumatic or hydraulic systems. Handling fragile objects-from the ordinary (fruit) to the important (internal organs)-is a frequent task whose importance is often overlooked and is difficult for conventional hard robots; moving across unknown, irregular, and shifting terrain is also. Soft robots may provide solutions to both of these classes of problems, and to others. Methods of designing and fabricating soft robots are, however, much less developed than those for hard robots. We wish to expand the methods and materials of chemistry and soft-materials science into applications in fully soft robots.A robot is an automatically controlled, programmable machine.[4] The limbs of animals or insects-structures typically based on rigid segments connected by joints with constrained ranges of motion [5]

Table of Contents:Mazzeo et al. describe methods of patterning metallized paper to create touch pads of arrayed buttons that are sensitive to contact with both bare and gloved fingers. The paper-based keypad shown detects the change in capacitance associated with the touch of a finger to one of its buttons. Mounted to an alarmed cardboard box, the keypad requires the appropriate sequence of touches to disarm the system. Image for Table of Contents:Submitted to 2 This paper describes low-cost, thin, and pliable touch pads constructed from a commercially available, metallized paper commonly used as packaging material for beverages and book covers. The individual keys in the touch pads detect changes in capacitance or contact with fingers by using the effective capacitance of the human body and the electrical impedance across the tip of a finger. To create the individual keys, a laser cutter ablates lines through the film of evaporated aluminum on the metallized paper to pattern distinct, conductive regions. This work includes the experimental characterization of two types of capacitive buttons and illustrates their use with applications in a keypad with 10 individually addressable keys, a keypad that conforms to a cube, and a keypad on an alarmed cardboard box. With their easily arrayed keys, environmentally benign material, and low cost, the touch pads have the potential to contribute to future developments in disposable, flexible electronics, active, "smart" packaging, user interfaces for biomedical instrumentation, biomedical devices for the developing world, applications for monitoring animal and plant health, food and water quality, and disposable games (e.g., providers of content for consumer products).There is no simple method of integrating buttons with structures on single-use or throwaway devices. Current commercial buttons are not thin enough, inexpensive enough, or easy enough to array seamlessly with paper-based products for disposable applications. The touch pads in this work are thin (~60 µm in some cases), simple to array, fabricated by etching patterns into metallized paper, low-cost (< $0.25 m -2 for the thin grade of metallized paper we use in this work), and lightweight (100s of g m -2 ). The individual keys measure changes in capacitance when touched by a user, and the buttons require no physical displacement of conductive elements. Even though the individual keys on the touch pads detect changes in capacitance, the paper-based keypads are still functional when touched by fingers in nitrile gloves. Submitted to 3Developments in paper-based electronics include ring oscillators with organic electronics [1] , transistors [2][3][4] , methods for patterning conductive traces [5][6][7] , speakers [8] , super capacitors [9] , batteries [10] , MEMS [11] , and solar cells [12] . Each of these developments focuses on a single technological advance that would enable new types of consumer products. Many types of new consumer products will require some form of user interface or input. In order to gather ke...

This manuscript describes the use of explosions to power a soft robot-one composed solely of organic elastomers (e.g., silicones). The robot has three pneumatic actuators (pneu-nets) in a tripedal configuration. Explosion of a stoichiometric mixture of methane and oxygen within the microchannels making up the actuators produced hot gas that rapidly inflated the pneu-nets, and caused the robot to launch itself vertically from a flat surface (e.g., to jump). A soft flap embedded in the pneu-net acted as the valve of a passive exhaust system, and allowed multiple sequential actuations. The flame and temperature increase from the explosions are short-lived, and do not noticeably damage the robots over dozens of actuation cycles.1 Soft robots have emerged as a new set of machines capable of manipulation [1][2][3][4] and locomotion. [5][6][7][8] Pneumatic expansion of a network of microchannels (pneu-nets) fabricated in organic elastomers, using low-pressure air (<10 psi; 0.7 atm; 71 kPa), provides a simple method of achieving complex movements: [1, 5] grasping and walking. Despite their advantages (simplicity of fabrication, actuation, and control; low cost; light weight), pneu-nets have the disadvantage that actuation using them is slow, in part because the viscosity of air limits the rate at which the gas can be delivered through tubes to fill and expand the microchannels. Here we demonstrate the rapid actuation of pneu-nets using a chemical reaction (the combustion of methane) to generate explosive bursts of pressure.Although the combustion of hydrocarbons is ubiquitous in the actuation of hard systems (e.g., in the metal cylinder of a diesel or spark-ignited engine [9]), it has not been used to power soft machines. Here, we demonstrate that explosive chemical reactions [10] producing pulses of high temperature gas for pneu-net actuation provides simple, rapid, co-located power generation, and enables motion, in soft robots. In particular, we used the explosive combustion of hydrocarbons triggered by an electrical spark to cause a soft robot to "jump" (a gait previously only demonstrated for hard systems [11][12][13][14][15][16]).We fabricated a tripedal robot ( Fig. 1; Fig. S4) using soft lithography.[1] This robot incorporated a passive valving system (Fig. 1a, inset) that allowed us to (i) pressurize the pneunets easily, (ii) exhaust the product gases automatically (without external control), and (iii) actuate the same pneu-net repeatedly. By actuating all three legs simultaneously, we caused the robot to jump more than 30 times its height in less than 0.2 s, at a maximum vertical velocity of ~3.6 m/s. 2Our choice of explosive chemical reactions for actuation was based on several factors, one being their high volumetric energy density (in units of MJ/L). The energy density of a compressed gas, which we previously used to power soft robots, is ~0.1 MJ/L at 2,900 psi from the potential for mechanical work, w, done by the change in pressure (P), and volume (V) when decompressed to atmospheric pressure; ...

Abstract

This manuscript describes the use of explosions to power a soft robot-one composed solely of organic elastomers (e.g., silicones). The robot has three pneumatic actuators (pneu-nets) in a tripedal configuration. Explosion of a stoichiometric mixture of methane and oxygen within the microchannels making up the actuators produced hot gas that rapidly inflated the pneu-nets, and caused the robot to launch itself vertically from a flat surface (e.g., to jump). A soft flap embedded in the pneu-net acted as the valve of a passive exhaust system, and allowed multiple sequential actuations. The flame and temperature increase from the explosions are short-lived, and do not noticeably damage the robots over dozens of actuation cycles.1 Soft robots have emerged as a new set of machines capable of manipulation [1][2][3][4] and locomotion. [5][6][7][8] Pneumatic expansion of a network of microchannels (pneu-nets) fabricated in organic elastomers, using low-pressure air (<10 psi; 0.7 atm; 71 kPa), provides a simple method of achieving complex movements: [1, 5] grasping and walking. Despite their advantages (simplicity of fabrication, actuation, and control; low cost; light weight), pneu-nets have the disadvantage that actuation using them is slow, in part because the viscosity of air limits the rate at which the gas can be delivered through tubes to fill and expand the microchannels. Here we demonstrate the rapid actuation of pneu-nets using a chemical reaction (the combustion of methane) to generate explosive bursts of pressure.Although the combustion of hydrocarbons is ubiquitous in the actuation of hard systems (e.g., in the metal cylinder of a diesel or spark-ignited engine [9]), it has not been used to power soft machines. Here, we demonstrate that explosive chemical reactions [10] producing pulses of high temperature gas for pneu-net actuation provides simple, rapid, co-located power generation, and enables motion, in soft robots. In particular, we used the explosive combustion of hydrocarbons triggered by an electrical spark to cause a soft robot to "jump" (a gait previously only demonstrated for hard systems [11][12][13][14][15][16]).We fabricated a tripedal robot ( Fig. 1; Fig. S4) using soft lithography.[1] This robot incorporated a passive valving system (Fig. 1a, inset) that allowed us to (i) pressurize the pneunets easily, (ii) exhaust the product gases automatically (without external control), and (iii) actuate the same pneu-net repeatedly. By actuating all three legs simultaneously, we caused the robot to jump more than 30 times its height in less than 0.2 s, at a maximum vertical velocity of ~3.6 m/s. 2Our choice of explosive chemical reactions for actuation was based on several factors, one being their high volumetric energy density (in units of MJ/L). The energy density of a compressed gas, which we previously used to power soft robots, is ~0.1 MJ/L at 2,900 psi from the potential for mechanical work, w, done by the change in pressure (P), and volume (V) when decompressed to atmospheric pressure; ...

In vitro 3D culture could provide an important model of tissues in vivo, but assessing the effects of chemical compounds on cells in specific regions of 3D culture requires physical isolation of cells, and thus currently relies mostly on delicate and low-throughput methods. This paper describes a technique (“cells-in-gels-in-paper” CiGiP) that permits rapid assembly of arrays of 3D cell cultures, and convenient isolation of cells from specific regions of these cultures. The 3D cultures were generated by stacking sheets of 200-μm-thick paper, each sheet supporting 96 individual “spots” (thin circular slabs) of hydrogels containing cells, separated by hydrophobic material (wax, PDMS) impermeable to aqueous solutions, and hydrophilic and most hydrophobic solutes. A custom-made 96-well holder isolated the cell-containing zones from each other. Each well contained media to which a different compound could be added. After culture, and disassembly of the holder, peeling the layers apart ‘sectioned’ the individual 3D cultures into 200-μm-thick sections which were easy to analyze using 2D imaging (e.g., with a commercial gel scanner). This 96-well holder brings new utilities to high-throughput, cell-based screening, by combining the simplicity of CiGiP with the convenience of a microtiter plate. This work demonstrated the potential of this type of assays by examining the cytotoxic effects of phenylarsine oxide (PAO) and cyclophosphamide (CPA) on human breast cancer cells positioned at different separations from culture media in 3D cultures.