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Electromagnetic actuators (EMAs) serve the majority of motion control needs in fields ranging from industrial robotics to automotive systems and biomedical devices, due to their unmatched combination of speed, precision, force, and scalability. This paper describes the design and fabrication of miniature soft EMAs that operate based on the Lorentz force principle. The actuators are fabricated from silicone polymer, liquid metal (LM) alloy (eutectic gallium indium, EGaIn), and magnetic (NdFeB) powder. They are small, intrinsically deformable, and can be fabricated using simple techniques. The central elements of the actuators are fine, 3D helical coil conductors, which are used as electromagnetic inductors. The coils are formed from stretchable filaments that are filled with a LM alloy. To achieve high power densities, the filaments themselves may be fabricated from colloids of EGaIn microdroplets in a silicone polymer matrix, allowing them to dissipate heat and accommodate high currents, and thus high forces. Millimeter-scale cylindrical actuators are demonstrated for linear high frequency motion and articulated devices for bending motion. These actuators are applied in a vibrotactile feedback display and in a miniature soft robotic gripper.

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Conformable robotic systems are attractive for applications in which they can be used to actuate structures with large surface areas, to provide forces through wearable garments, or to realize autonomous robotic systems. We present a new family of soft actuators that we refer to as Fluidic Fabric Muscle Sheets (FFMS). They are composite fabric structures that integrate fluidic transmissions based on arrays of elastic tubes. These sheet-like actuators can strain, squeeze, bend, and conform to hard or soft objects of arbitrary shapes or sizes, including the human body. We show how to design and fabricate FFMS actuators via facile apparel engineering methods, including computerized sewing techniques. Together, these determine the distributions of stresses and strains that can be generated by the FFMS. We present a simple mathematical model that proves effective for predicting their performance. FFMS can operate at frequencies of 5 Hertz or more, achieve engineering strains exceeding 100%, and exert forces greater than 115 times their own weight. They can be safely used in intimate contact with the human body even when delivering stresses exceeding 10 6 Pascals. We demonstrate their versatility for actuating a variety of bodies or structures, and in configurations that perform multi-axis actuation, including bending and shape change. As we also show, FFMS can be used to exert forces on body tissues for wearable and biomedical applications. We demonstrate several potential use cases, including a miniature steerable robot, a glove for grasp assistance, garments for applying compression to the extremities, and devices for actuating small body regions or tissues via localized skin stretch.forces upon, or generate shape changes in complex or compliant structures. 1-3 Wearable soft robotic devices interfaced with the human body may prove valuable for rehabilitation, movement assistance, or virtual reality. [4][5][6] Soft actuators are also of interest for controlling motion in distributed or deformable structures. They can be used for tasks such as grasping, terrestrial locomotion, surgery, or underwater operation. 7-9 Such applications span systems of greatly varying length scales, ranging from millimeter-scale biomedical robots to large, deployable structures. 10,11 Biological systems provide a rich source of information to guide the design of soft robots. 12 The motile capabilities of animals are enabled by composite systems of muscle, connective, and other tissues. The forces and motions they can produce depend on the properties of individual muscle fibers, the arrangement of fibers, and the muscle morphology and attachments. Muscle morphologies vary widely. There are fusiform shapes like the human biceps brachii, that produce large-amplitude motion. There are also fan shapes, such as the pectoralis major, that yield larger forces, sphincter morphologies that contract, and layered muscle sheets, like the transverse abdominis (Fig. 1A), that compress or transfer forces around the torso. 13 The great variety of biologica...

Stretchable and flexible multifunctional electronic components, including sensors and actuators, have received increasing attention in robotics, electronics, wearable, and healthcare applications. Despite advances, it has remained challenging to design analogs of many electronic components to be highly stretchable, to be efficient to fabricate, and to provide control over electronic performance. Here, we describe highly elastic sensors and interconnects formed from thin, twisted conductive microtubules. These devices consist of twisted assemblies of thin, highly stretchable (>400%) elastomer tubules filled with liquid conductor (eutectic gallium indium, EGaIn), and fabricated using a simple roller coating process. As we demonstrate, these devices can operate as multimodal sensors for strain, rotation, contact force, or contact location. We also show that, through twisting, it is possible to control their mechanical performance and electronic sensitivity. In extensive experiments, we have evaluated the capabilities of these devices, and have prototyped an array of applications in several domains of stretchable and wearable electronics. These devices provide a novel, low cost solution for high performance stretchable electronics with broad applications in industry, healthcare, and consumer electronics, to emerging product categories of high potential economic and societal significance.

compliance of constituent materials enables soft grippers to safely work with flexible, fragile, and delicate objects. A great number of actuation methods have been investigated, including cable-driven mechanisms, [19] fluid elastomer actuators (FEA), [20,21] dielectric elastomer actuators, [22,23] magnetic actuators, [24-26] and shape memory materials including metal alloys [27,28] and polymers. [29] Among these actuation methods, FEA is one of the oldest and the most widespread technologies employed for soft robotic grippers owing to a number of advantages such as lightweight, high power-to-weight ratio, large stroke and force production, ease of fabrication, robustness, and low-cost materials. [30,31] FEA-based soft grippers have been mostly developed based on claws or human-like structures consisting of multiple inward-bending fingers. This design is suitable for gripping objects spanning a wide range of sizes. However, existing FEA-based grippers are ill-suited for applications that require high conformability or high-load sustainability. The integration of electro-adhesion, [23,32] gecko adhesion, [33,34] or variable stiffness structures (VSSs) can help improve the load capacity. Several studies also address both the issues by designing robotic fingers that can adjust their effective length via the use of segments of VSS. [21] Two main types of VSSs for soft grippers include vacuum-driven jamming of granules [35,36] or layers, [6] and phase-change materials such as thermoplastics, [12,37] shape memory polymers (SMPs), [20,21,38] and low-melting-point alloys (LMPAs). [22,39,40] In another approach, grippers with closed structures have been investigated in an attempt to improve both conformability and load capacity. [23,24,38-40] However, grippers with closed structures are not able to grip objects that are either smaller or larger than the opening orifice of the gripper. Another approach that has also been investigated involves the use of helical winding to enclose objects. This gripping strategy was inspired by natural instances such as elephant trunks, python body constriction, or cephalopod tentacles that use a continuum finger to helically grasp around the objects, thereby increasing the area of contact and stability between the gripper and objects. [41] Continuum, helical grippers that are not constrained by any host have the advantage of being free to wrap around objects and adapt to a wide range of object sizes, shapes, and orientations. There are many instances in nature where continuum, helical manipulators are used to efficiently grasp different objects with various shapes and sizes. Inspired by nature, this paper introduces a continuum, flat, scalable, helical soft-fabric robotic gripper that is thin and lightweight with stiffness tunability and sensory feedback. The gripper is fabricated by a facile method of simple insertion using a computerized technique from apparel engineering and controlled by a miniature hydraulic source to grasp different objects at different scales and weights. It uses a ...

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Surgical robots have had clinical use since the mid‐1990s. Robot‐assisted surgeries offer many benefits over the conventional approach including lower risk of infection and blood loss, shorter recovery, and an overall safer procedure for patients. The past few decades have shown many emerging surgical robotic platforms that can work in complex and confined channels of the internal human organs and improve the cognitive and physical skills of the surgeons during the operation. Advanced technologies for sensing, actuation, and intelligent control have enabled multiple surgical devices to simultaneously operate within the human body at low cost and with more efficiency. Despite advances, current surgical intervention systems are not able to execute autonomous tasks and make cognitive decisions that are analogous to those of humans. Herein, the historical development of surgery from conventional open to robotic‐assisted approaches with discussion on the capabilities of advanced intelligent systems and devices that are currently implemented in existing surgical robotic systems is reviewed. Also, available autonomous surgical platforms are comprehensively discussed with comments on the essential technologies, existing challenges, and suggestions for the future development of intelligent robotic‐assisted surgical systems toward the achievement of fully autonomous operation.