Community detection is an important issue due to its wide use in designing network protocols such as data forwarding in Delay Tolerant Networks (DTN) and worm containment in Online Social Networks ...(OSN). However, most of the existing community detection algorithms focus on binary networks. Since most networks are naturally weighted such as DTN or OSN, in this article, we address the problems of community detection in weighted networks, exploit community for data forwarding in DTN and worm containment in OSN, and demonstrate how community can facilitate these network designs. Specifically, we propose a novel community detection algorithm, and introduce two metrics: intra-centrality and inter-centrality, to characterize nodes in communities, based on which we propose an efficient data forwarding algorithm for DTN and a worm containment strategy for OSN. Extensive trace-driven simulation results show that the proposed community detection algorithm, the data forwarding algorithm, and the worm containment strategy significantly outperform existing works.
Materials that undergo shape morphing in response to external stimuli have numerous applications, e.g., in soft robotics and biomedical devices. Shape memory polymers utilize kinetically trapped ...states to, typically irreversibly, transfer between a programmed morphed shape and an equilibrium shape. Liquid crystal elastomers (LCEs), in turn, can undergo reversible actuation in response to several stimuli. This study combines the irreversible and reversible shape morphing processes to obtain LCEs that undergo shape‐programming via the shape memory effect and subsequent reversible actuation of the programmed shape. This is enabled by an LCE crosslinked via dynamic hydrogen bonds that break at high temperatures and reform upon cooling, endowing the shape memory effect, while mild thermal or photothermal stimulation yields the reversible actuation. Through this combination, proof‐of‐concept robotic application scenarios such as grippers that can adjust their shape for grabbing different‐sized objects and crawling robots that can morph their shape to adapt to constrained spaces, are demonstrated. It is anticipated that this work adds new diversity to shape‐programmable soft microrobotics.
A liquid crystal elastomer (LCE) actuator that can be programmed into multiple temporary shapes while maintaining reversible actuation capability is designed by incorporating hydrogen‐bond crosslinks into a chain‐extended LCE. The shape programming is enabled via the shape memory effect, while reversible actuation is obtained via mild thermal or photothermal stimulus. Potential applications in light‐controlled grippers with adjustable shapes to grab different‐sized objects, and locomotors that can be shape‐programmed to fit into tight spaces, are anticipated.
This article presents a planner for a master dual-arm robot to manipulate tethered tools with the help of an assistant dual-arm robot. The assistant robot assists the master robot by manipulating the ...tool cable and avoiding collisions. The provided assistance allows the master robot to perform tool placements on the robot workspace table and regrasp it, which would typically fail since cable tension may change the tool positions. It also allows the master robot to perform tool handovers, which would normally cause entanglements or collisions with the cable and the environment without assistance. Simulations and real-world experiments are performed to validate the proposed planner. Experimental results show that with the help of the assistant dual-arm robot and the proposed method, the master robot obtained improved flexibility in working with tethered tools.
Untethered Microgrippers for Precision Medicine Zhou, Huaijuan; Zhang, Shengchang; Liu, Zijian ...
Small (Weinheim an der Bergstrasse, Germany),
03/2024, Volume:
20, Issue:
11
Journal Article
Peer reviewed
Microgrippers, a branch of micro/nanorobots, refer to motile miniaturized machines that are of a size in the range of several to hundreds of micrometers. Compared with tethered grippers or other ...microscopic diagnostic and surgical equipment, untethered microgrippers play an indispensable role in biomedical applications because of their characteristics such as miniaturized size, dexterous shape tranformation, and controllable motion, which enables the microgrippers to enter hard‐to‐reach regions to execute specific medical tasks for disease diagnosis and treatment. To date, numerous medical microgrippers are developed, and their potential in cell manipulation, targeted drug delivery, biopsy, and minimally invasive surgery are explored. To achieve controlled locomotion and efficient target‐oriented actions, the materials, size, microarchitecture, and morphology of microgrippers shall be deliberately designed. In this review, the authors summarizes the latest progress in untethered micrometer‐scale grippers. The working mechanisms of shape‐morphing and actuation methods for effective movement are first introduced. Then, the design principle and state‐of‐the‐art fabrication techniques of microgrippers are discussed. Finally, their applications in the precise medicine are highlighted, followed by offering future perspectives for the development of untethered medical microgrippers.
Untethered microgrippers can be manipulated on a microscopic scale and can reach hard‐to‐access regions in the body, holding great promise in precision medicine and personalized medicine. This review is focused on the shape‐morphing mechanisms, actuation methods, design principles, and fabrication techniques of untethered microgrippers. Their representative biomedical applications are highlighted and future prospects are provided.
Automation in the food services industry is not as developed as in the automotive and electrical industries. This may be because (1) the tasks involve high-speed operations in unstructured ...environments and (2) the lack of effective robotic end-effectors. In this letter, we focus on the automation of dishwashing operations and propose a robotic hand capable of withdrawing and grasping a dish plate from a pile, even when there is water or oil left on the plate in a post-meal scenario. The robotic hand consists of withdrawing and grasping mechanisms. Each mechanism is actuated by two bellows actuators. Soft pads with special groove patterns were fabricated and used to provide sufficient friction when they come into contact with the plate. A theoretical analysis of the withdrawing and grasping operations was performed, and an analytical model of the bellows actuator was established by considering both the pressure thrust force and the elastic force. Bellows actuators were designed based on the analysis and fabricated using both 3D printing and casting methods. Characterization of bellows actuator was performed to validate the analytical model, and agreement was found on the thrust force, but discrepancy occurred in the elastic force due to the complex structure and deformation mode of bellows. Finally, handling experiments on different plates were conducted and results demonstrated that the proposed robotic hand can successfully withdraw and grasp a plate from a pile.
This paper presents the design and fabrication of a new microelectromechanical systems microgripper with integrated electrostatic actuator and capacitive force sensor. One uniqueness of the proposed ...microgripper is that it possesses a single force sensor which can measure the gripping force and environmental interaction force in two axes in an alternate manner. The gripper structure is devised based on compliant rotary bearing and linear guiding flexure mechanisms, which enable the generation of a compact size. Analytical models are established to facilitate the parametric design of the gripper, which are verified by performing finite-element analysis simulation study. The microgripper is fabricated by the silicon-on-insulator-based process. Experimental calibrations are conducted to demonstrate the gripping and sensing performances. The feasibility and effectiveness of the developed gripper device are validated through the experimental investigations on gripping a human hair.
With an estimation of 220 million people playing badminton on a regular basis, it was particularly popular in Asia but has growing popularity in different regions of the world. The demands of the ...relevant products, such as shuttlecocks and rackets, are also increasing in the sports industry. Synthetic shuttlecock, produced to offer similar experience and feel as feather shuttlecocks to players, is a more economical alternative to feather shuttlecocks. In addition to maintaining high throughput production for synthetic shuttlecocks with cost reduction, a more substantial improvement in quality control is desired as well. Since the defect detection of synthetic shuttlecocks is a challenging task, it heavily relies on human visual inspection at present. The existing manual quality-inspection process is not only error-prone but also considerably less efficient. In this paper, we propose an intelligent system to overcome these difficulties and bridge the gap between research and practice. Two cylinder grippers are designed to automatically deliver the shuttlecocks, a camera is used for capturing images and an end-to-end objection detection approach based on the Transformer model is investigated to recognize defects. Empirical results show that the proposed system obtains encouraging performance with AP 50 value of 87.5% and outperforms other methods. Ablation studies demonstrate that our approach can considerably boost the detection performance of synthetic shuttlecocks. Moreover, the processing speed is much faster than human operators and suitable for industrial applications.
Robotic process automation (RPA) is automating various job processes in many offices. However, most existing RPA systems automate only processes that are performed on computers. It is highly ...desirable to develop physical RPA systems that incorporate real robots to automate physical job processes. When developing physical RPA systems, handling paper is particularly important because many physical office jobs involve handling paper documents. However, it is not easy for robots to handle paper because paper is fragile. To address this issue, we propose an electroadhesive paper gripper in this study. The use of electroadhesion enables a robot to handle paper in a simple, non-destructive, and quiet manner. We provide (1) a mechanism for lifting a sheet of paper without accurate control of robot hands, (2) a mechanism for a small gripper to hold a large sheet of paper without bending it, and (3) a method for quickly releasing a sheet of paper. Furthermore, we apply the proposed paper gripper to a document-sorting robot. The robot that we have developed automatically arranges a given stack of paper documents in a predetermined order (e.g., alphabetical or numerical). Experimental results show the validity of the paper gripper and the sorting robot.
The end effector is a major part of a robot system and it defines the task the robot can perform. However, typically, a gripper is suited to grasping only a single or relatively small number of ...different objects. Dexterous grippers offer greater grasping ability but they are often very expensive, difficult to control and are insufficiently robust for industrial operation. This paper explores the principles of soft robotics and the design of low-cost grippers able to grasp a broad range of objects without the need for complex control schemes. Two different soft end effectors have been designed and built and their physical structure, characteristics, and operational performances have been analyzed. The soft grippers deform and conform to the object being grasped, meaning they are simple to control and minimal grasp planning is required. The soft nature of the grippers also makes them better suited to handling fragile and delicate objects than a traditional rigid gripper.
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