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Jumping requires high actuation power for achieving high speed in a short time. Especially, organisms and robots at the insect scale jump in order to overcome size limits on the speed of locomotion. As small jumpers suffer from intrinsically small power output, efficient jumpers have devised various ingenuous schemes to amplify their power release. Furthermore, semi‐aquatic jumpers have adopted specialized techniques to fully exploit the reaction from water. We review jumping mechanisms of natural and robotic insects that jump on the ground and the surface of water, and compare the performance depending on their scale. We find a general trend that jumping creatures maximize jumping speed by unique mechanisms that manage acceleration, force, and takeoff duration under the constraints mainly associated with their size, shape, and substrate. [ABSTRACT FROM AUTHOR]

Adaptive and extreme changes in shape and configuration are the functional and morphological uniqueness of soft robots, but existing design approaches still rely on the predefined coordination of their "muscle" and "nerve" functions to produce such behaviors. Herein, a strategy is introduced for building modular soft machines that can be innervated in ways that conform to their body extension or shape changes, based on modular soft electronics. The development of soft electronic adhesive interlocking (SEAL) technology allows for instant, robust, and repeatable integration of soft electronic modules that can "innervate" and activate modular soft actuators and machines in a reconfigurable manner. Demonstrations of soft robotic tentacles and their grasping capability show that the robot function can be adapted to or reconfigured within the body with a length extended more than 10 times. The modular strategy presented herein can offer a unique promise to build up future robots with dynamic, reconfigurable functions. [ABSTRACT FROM AUTHOR]

Soft fluidic actuators produce continuous and life‐like motions that are intrinsically safe, but current designs are not yet mature enough to enable large deployment with high force and low‐cost fabrication methods. Herein, soft fluidic actuators with two superimposed origami architectures are reported. Driven by a fluid input, the presented dual‐origami soft actuators produce quasisequential deployment and bending motion that is guided by unsymmetric unfolding of low‐stretchable origami components. The dominance between the deployment and bending can be shifted by varying the unfolding behavior, enabling preprogramming of the motion. The proposed origami‐inspired soft actuators are directly fabricated by low‐cost fused deposition modeling 3D printing and subjected to heat treatment postprocessing to enhance the fluid sealing performance. Finally, soft gripper applications are presented and they successfully demonstrate gripping tasks where each requires strength, delicacy, precision, and dexterity. The dual‐origami approach offers a design guidance for soft robots to embody grow‐and‐retract motion with a small initial form factor, promising for applications in next‐generation soft robotic systems. An interactive preprint version of the article can be found here: https://www.authorea.com/doi/full/10.22541/au.163698906.68661340. [ABSTRACT FROM AUTHOR]

4D printing can address time‐evolving structural functions that are unattainable by conventional 3D printing. Despite the advance in materials and printing techniques, however, 4D printing of continuity of shape representation that generally characterizes 3D matters is still challenging, because the existing methodologies mostly rely on a few discrete levels of strain and their spatial distributions. Here, a 4D printing strategy of shape memory polymers (SMPs) that can program continuous levels of shape‐recovery strain is proposed. It is found that the irrecoverable state of the SMP and the corresponding recovery strain can be controlled in a continuous and precise manner by a single printing parameter. Importantly, the continuity of strain programming provides an opportunity for the translation into mathematical function representation (F‐rep), which allows the systematic derivation and implementation of 4D‐printed bilayer strain functions that are matched to the continuously varying curvatures of the target geometry. Combined with the custom‐built software, the F‐rep 4D printing strategy can produce 4D‐printed architectures that involve continuously varying strain profiles of almost any function type. The effectiveness of the framework is highlighted by a set of 3D face masks with facial feature transformation driven by a function operator. [ABSTRACT FROM AUTHOR]

The military backpack used by the infantry imposes the greatest load on the body and, thus, is also the cause of most user complaints. This study (1) establishes a systematic development procedure for a military backpack that reflects user opinion; (2) suggests a usability questionnaire tool that can identify realistic user needs; and (3) proposes usability verification experiments that can quantitatively measure the usability of the military backpacks. The military backpack development procedure was created in accordance with user‐centered design principles. The "context of use" of the military backpack was extracted from a literature review and interviews with experts and actual users. In addition, the usability questionnaire tool and usability verification experiments were devised based on the identified context of use. An analysis of the usability questionnaire answered by 100 infantry soldiers confirms that the region of pain felt by users varies on the size of the human body. Thus, it was possible to recognize the necessity of diversifying the specification of the military backpack. The usability verification experiments did not produce statistical results because only four infantry soldiers performed the pilot test, but the applicability and effectiveness of the proposed experiments could be confirmed through this pilot test. The seven proposed experiments are expected to help confirm the usability differences among different military backpacks or body sizes. The military equipment development procedure, usability evaluation tool, and usability verification experiments are expected to improve user satisfaction and military operations when applied to the development of various military supplies. [ABSTRACT FROM AUTHOR]

Abstract: To add more functionalities and overcome the limitation in conventional soft robots, highly anisotropic soft actuators with color shifting function during actuation is demonstrated for the first time. The electrothermally operating soft actuators with installed transparent metal nanowire percolation network heater allow easy programming of their actuation direction and instantaneous visualization of temperature changes through color change. Due to the unique direction dependent coefficient of thermal expansion mismatch, the suggested actuator demonstrates a highly anisotropic and reversible behavior with very large bending curvature (2.5 cm−1) at considerably low temperature (≈40 °C) compared to the previously reported electrothermal soft actuators. The mild operating heat condition required for the maximum curvature enables the superior long‐term stability during more than 10 000 operating cycles. Also, the optical transparency of the polymer bilayer and metal nanowire percolation network heater allow the incorporation of the thermochromic pigments to fabricate color‐shifting actuators. As a proof‐of‐concept, various color‐shifting biomimetic soft robots such as color‐shifting blooming flower, fluttering butterfly, and color‐shifting twining tendril are demonstrated. The developed color‐shifting anisotropic soft actuator is expected to open new application fields and functionalities overcoming the limitation of current soft robots. [ABSTRACT FROM AUTHOR]

4D Printing: 4D Printing of Continuous Shape Representation (Adv. Keywords: 4D printing; function representation; fused deposition modeling; shape memory polymer EN 4D printing function representation fused deposition modeling shape memory polymer 1 1 1 06/07/21 20210601 NES 210601 In article number 2100133, Kyu-Jin Cho and colleagues establish a 4D printing strategy of shape memory polymers that can program continuous levels of shape-recovery strain by controlling a single printing parameter. 4D printing, function representation, fused deposition modeling, shape memory polymer. [Extracted from the article]