1,720,957 research outputs found
FORCE-OPTIMIZED MONOLITHIC PNEUNETS SOFT ACTUATORS: DESIGN, SIMULATION AND CHARACTERIZATION
No full textThis study investigates the design, simulation, and characterization of force-optimized, monolithic, PneuNets-based soft actuators for applications in robotics and rehabilitation. Building on previous work, the research explores the optimization of actuator geometry through Finite Element Method (FEM) simulations and experimental validation. By refining the actuator’s geometry, particularly regarding chamber count and structural elements, the study aims to improve force output and efficiency while maintaining a simple, cost-effective design process. The elastomer Dragon Skin 30 was selected for its favorable mechanical properties, ensuring high deformation tolerance and efficient force control. The optimization process involved a detailed analysis of force and stress distribution using FEM, followed by actuator fabrication and testing. The results indicate that increasing the number of chambers enhances force output, with a maximum tip force of 1.2 N achieved in the final design. A comparison between the initial and final designs revealed significant improvements in force generation, thereby validating the FEM model as a reliable tool for actuator design. The study concludes that the optimized actuator design offers a promising solution for flexible and efficient soft actuators, suitable for rehabilitation and other delicate manipulation tasks
Hybrid Soft-Rigid Robotic System for Hand Rehabilitation
No full textThis article proposes the design and development of a cost-effective hand rehabilitation system based on the principle of mirror therapy, and a hybrid soft-rigid structure. The developed system uses mirror therapy, by focusing on cortical reorganization to improve the recovery of hand movements. The system integrates a sensory glove on the healthy hand equipped with bending sensors to detect finger movements. Two different types of bending sensors (one of which is a soft sensor) were considered and compared, and the sensors were extensively characterized. The movements of the healthy hand, detected by the sensing glove, control an exoskeleton-like rehabilitation glove worn on the affected hand. The presented rehabilitation glove contains 3D-printed components with compliant flexural hinges that are actuated by electric servomotors and wires. The extension of the fingers is active (for the hand opening), and the finger flexion is mixed passive/active, thanks to the flexural hinges. The finger interface ensures a customized fit. The modular design of the system facilitates adjustments and optimizations. This cost-effective hand rehabilitation system offers a promising approach to improving motor recovery through mirror therapy for patients with various hand problems, including rehabilitation at home through a low-cost personalized device
Monolithic PneuNets Soft Actuators for Robotic Rehabilitation: Methodologies for Design, Production and Characterization
Full text linkSoft-robotics for biomedical applications, such as rehabilitation robots, is a field of intense research activity. Different actuation solutions have been proposed in the last decades, involving study and development of soft actuators of different types and materials. The purpose of the paper is to present procedures for an optimized design, and for easy and low cost production and characterization of monolithic PneuNets soft-actuators. An innovative design approach has been developed. The parameterization of the geometry, combined with FEM simulations is the basis for an optimized design of the actuator, as a function of the obtained bending and of the generated forces. Simple and cheap characterization setup and procedures have been identified for the actuator characterization and for simulation results validation. An easy and low-cost fabrication method based on lost wax core obtained through a silicone based mold has been developed for a monolithic PneuNets soft-actuator. The proposed solution performs well in bending, without the need for a strain limiting layer. Experimental results validated simulations, confirming the feasibility of adopting an optimized simulation-based design approach
Modeling of cutting force in micro-end-milling process with experimental validation on additive manufactured Nickel-based superalloy
Full text linkNowadays aerospace, microelectronics, biotechnology industries require small sized components with complex shape and high mechanical properties, often operating in aggressive environment. In this framework, Additive Manufacturing (AM) of Nickel-based superalloys is an interesting and cost effective process. Fewer design constraints and the weight reduction achievable through the topology optimization are the most relevant AM advantages. Furthermore, micro-scale features on the additively fabricated parts can be manufactured by using micro machining. Subtractive processes ensure to achieve high-precision mechanical coupling due to better surface finishes and tighter tolerances. A lack of scientific studies focusses on the material removal behavior of difficulty-to-cut alloys produced via Additive Manufacturing is evident. This work describes a machining analytical force models which considers the presence of ploughing- and shearing- dominated cutting regimes. The undefined cutting force model parameters and the Minimum Uncut Chip Thickness (MUCT) can be identified through proper experimental tests. The refinement procedure of the model was utilized to characterize Inconel 625 samples fabricated by LaserCUSINGTM. The cutting force data were elaborated with an iterative methodology based on a search algorithm. The model successfully predicted how the cutting force changes as a function of the process parameters
Analytical force modelling for micro milling additively fabricated Inconel 625
Full text linkIn recent years, miniaturization of components has been concerned with several industrial fields including aerospace, energy, and electronics. This phenomenon resulted in increasing demand of micro-components with complex shape and high strength, often in high-temperature environment. Nickel-based superalloys such as Inconel 625 are a class of material suitable to aforementioned applications and can be successfully processed with Additive Manufacturing (AM). Moreover, micro-milling can be employed to manufacture micro-scale features on the additively fabricated parts or to achieve better surface finishes, as required for high-precision mechanical assemblies. In micro machining, it is possible to notice a lack of scientific study focusses on the material removal behavior of difficulty-to-cut alloys produced via Additive Manufacturing. This paper describes an analytical cutting force model suitable also for AM’d parts which considers the presence of ploughing- and shearing- dominated cutting regimes. A refinement procedure of the cutting force model was defined and applied by performing an experimental work on Inconel 625 samples fabricated by LaserCUSINGTM. A search algorithm was employed to develop an iterative methodology to determine the unknown cutting force model parameters. The model was successfully utilized to predict how the cutting force is affected as the process parameters change
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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