Ontologies in Digital Twins: A Systematic Literature Review

Digital Twins (DT) facilitate monitoring and reasoning processes in cyber–physical systems. They have progressively gained popularity over the past years because of intense research activity and industrial advancements. Cognitive Twins is a novel concept, recently coined to refer to the involvement of Semantic Web technology in DTs. Recent studies address the relevance of ontologies and knowledge graphs in the context of DTs, in terms of knowledge representation, interoperability and automatic reasoning. However, there is no comprehensive analysis of how semantic technologies, and specifically ontologies, are utilized within DTs. This Systematic Literature Review (SLR) is based on the analysis of 82 research articles, that either propose or benefit from ontologies with respect to DT. The paper uses different analysis perspectives, including a structural analysis based on a reference DT architecture, and an application-specific analysis to specifically address the different domains, such as Manufacturing and Infrastructure. The review also identifies open issues and possible research directions on the usage of ontologies and knowledge graphs in DTs

On alternative uses of structural compliance for the development of adaptive robot grippers and hands

Adaptive robot hands are typically created by introducing structural compliance either in their joints (e.g., implementation of flexures joints) or in their finger-pads. In this paper, we present a series of alternative uses of structural compliance for the development of simple, adaptive, compliant and/or under-actuated robot grippers and hands that can efficiently and robustly execute a variety of grasping and dexterous, in-hand manipulation tasks. The proposed designs utilize only one actuator per finger to control multiple degrees of freedom and they retain the superior grasping capabilities of the adaptive grasping mechanisms even under significant object pose or other environmental uncertainties. More specifically, in this work, we introduce, discuss, and evaluate: (a) a design of pre-shaped, compliant robot fingers that adapts/conforms to the object geometry, (b) a hyper-adaptive finger-pad design that maximizes the area of the contact patches between the hand and the object, maximizing also grasp stability, and (c) a design that executes compliance adjustable manipulation tasks that can be predetermined by tuning the in-series compliance of the tendon routing system and by appropriately selecting the imposed tendon loads. The grippers are experimentally tested and their efficiency is validated using three different types of tests: (i) grasping tests that involve different everyday objects, (ii) grasp quality tests that estimate the contact area between the grippers and the objects grasped, and (iii) dexterous, in-hand manipulation experiments to evaluate the manipulation capabilities of the Compliance Adjustable Manipulation (CAM) hand. The devices employ mechanical adaptability to facilitate and simplify the efficient execution of robust grasping and dexterous, in-hand manipulation tasks

Development of a Two-Wheel Inverted Pendulum and a Cable Climbing Robot

The research work in this thesis constitutes two parts: one is the development and control of a Two-wheel inverted pendulum (TWIP) robot and the other is the design and manufacturing of a cable climbing robot (CCR) for suspension bridge inspection. The first part of this research investigates a sliding mode controller for self-balancing and stabilizing a two-wheel inverted pendulum (TWIP) robot. The TWIP robot is constructed by using two DC gear motors with a high-resolution encoder and zero backlashes, but with friction. It is a highly nonlinear and unstable system, which poses challenges for controller design. In this study, a dynamic mathematical model is built using the Lagrangian function method. And a sliding mode controller (SMC) is proposed for auto-balancing and yaw rotation. A gyro and an accelerometer are adopted to measure the pitch angle and pitch rate. The effect on the sensor’s installation location is analyzed and compensated, and the precision of the pose estimation is improved accordingly. A comparison of the proposed SMC controller with a proportional-integral-derivative (PID) controller and state feedback controller (SFC) with linear quadratic regulation (LQR) has been conducted. The simulation and experimental test results demonstrate the SMC controller outperforms the PID controller and SFC in terms of transient performance and disturbance rejection ability. In the second part of the research, a wheel-based cable climbing robotic system which can climb up and down the cylindrical cables for the inspection of the suspension bridges is designed and manufactured. Firstly, a rubber track climbing mechanism is designed to generate enough adhesion force for the robot to stick to the surface of a cable and the driving force for the robot to climb up and down the cable, while not too big to damage the cable. The climbing system includes chains and sprockets driven by the DC motors and adhesion system. The unique design of the adhesion mechanism lies in that it can maintain the adhesion force even when the power is lost while the system works as a suspension mechanism. Finally, a safe-landing mechanism is developed to guarantee the safety of the robot during inspection operations on cables. The robot has been fully tested in the inspection of Xili bridge, Guangzhou, P.R. China

Remanufacturing of precision metal components using additive manufacturing technology

Critical metallic components such as jet engine turbine blades and casting die/mold may be damaged after servicing for a period at harsh working environments such as elevated temperature and pressure, impact with foreign objects, wear, corrosion, and fatigue. Additive manufacturing has a promising application for the refurbishment of such high-costly parts by depositing materials at the damaged zone to restore the nominal geometry. However, several issues such as pre-processing of worn parts to assure the repairability, reconstructing the repair volume to generate a repair tool path for material deposition, and inspection of repaired parts are challenging. The current research aims to address crucial issues associated with component repair based on three research topics. The first topic is focusing on the development of pre-repair processing strategies which includes pre-repair machining to guarantee the damaged parts are ready for material deposition and pre-repair heat-treatment to restore the nominal mechanical properties. For this purpose, some damaged parts with varied defects were processed based on the proposed strategies. The second topic presents algorithms for obtaining the repair volume on damaged parts by comparing the damaged 3D models with the nominal models. Titanium compressor blades and die/mold were used as case studies to illustrate the damage detection and reconstructing algorithms. The third topic is the evaluation of repaired components through material inspection and mechanical testing to make sure the repair is successful. The current research contributes to metallic component remanufacturing by providing knowledge to solve key issues coupled with repair. Moreover, the research results could benefit a wide range of industries, such as aerospace, automotive, biomedical, and die casting --Abstract, page iv

Bibliometric Studies and Worldwide Research Trends on Global Health

Global health, conceived as a discipline, aims to train, research and respond to problems of a transboundary nature, in order to improve health and health equity at the global level. The current worldwide situation is ruled by globalization, and therefore the concept of global health involves not only health-related issues, but also those related to the environment and climate change. Therefore, in this Special Issue, the problems related to global health have been addressed from a bibliometric approach in four main areas: environmental issues, diseases, health, education and society

Physical Diagnosis and Rehabilitation Technologies

The book focuses on the diagnosis, evaluation, and assistance of gait disorders; all the papers have been contributed by research groups related to assistive robotics, instrumentations, and augmentative devices

Integración de un robot móvil en el entorno ROS (Robot Operating System). Análisis de la implementación en diferentes versiones

Trabajo Fin de Máster. Máster Universitario en sistemas inteligentes. Curso académico 2022-2023.[ES]En los últimos años, el campo de la robótica ha experimentado una evolución exponencial, y el uso de robots móviles se ha vuelto cada vez más común en diversos sectores de la sociedad, como la industria, la medicina, la agricultura y la logística. Por ello, cada vez más los desarrolladores optan por el uso de herramientas o recursos que les permitan un desarrollo de software ágil. Para poder desarrollar software en la robótica, se requiere de herramientas y plataformas de desarrollo software especializadas. Una de las más destacadas y ampliamente utilizadas es el Robot Operating System (ROS). En esta memoria, se realizará un análisis detallado de las diferentes versiones de ROS, desde las primeras versiones hasta las más recientes. Se examinarán las características y mejoras introducidas en cada una de ellas, así como las posibles limitaciones y desafíos asociados durante la prueba de las mismas. Además, en este proyecto se abordará el proceso de integración de un robot móvil en las versiones de ROS 1 y ROS 2. Indicando el proceso seguido desde la selección de componentes principales, como la percepción, el control, los recursos software y la planificación de movimiento. En este proceso se explorarán diferentes paquetes, repositorios y herramientas disponibles en ROS que facilitan esta integración. El objetivo principal de esta memoria es proporcionar a los lectores una visión global de la integración de un robot móvil en el entorno de ROS, abarcando las diferentes versiones de esta plataforma y su evolución a lo largo del tiempo. En conclusión, se espera que esta investigación fomente el uso y la investigación en el campo de la robótica, impulsando el avance de la tecnología y su aplicación en diversas áreas de la sociedad.[EN]In recent years, the field of robotics has undergone an exponential evolution, and the use of mobile robots has become increasingly common in various sectors of society, such as industry, medicine, agriculture and logistics. As a result, more and more developers are opting for the use of tools or resources that enable agile software development. In order to develop software in robotics, specialised software development tools and platforms are required. One of the most prominent and widely used is the Robot Operating System (ROS). In this report, a detailed analysis of the different versions of ROS, from the ear liest versions to the most recent ones, will be carried out. It will examine the features and improvements introduced in each of them, as well as the possible limitations and challenges associated with testing them. In addition, this project will address the process of integrating a mobile robot into ROS 1 and ROS 2 versions, indicating the process followed from the selection of main components, such as perception, control, software resources and motion planning. In this process, different packages, repositories and tools available in ROS that facilitate this integration will be explored. The main objective of this report is to provide readers with an overview of the integration of a mobile robot in the ROS environment, covering the different versions of this platform and its evolution over time. In conclusion, it is hoped that this research will encourage the use of and research in the field of robotics, driving the advancement of the technology and its application in various areas of society

Applications in Electronics Pervading Industry, Environment and Society

This book features the manuscripts accepted for the Special Issue “Applications in Electronics Pervading Industry, Environment and Society—Sensing Systems and Pervasive Intelligence” of the MDPI journal Sensors. Most of the papers come from a selection of the best papers of the 2019 edition of the “Applications in Electronics Pervading Industry, Environment and Society” (APPLEPIES) Conference, which was held in November 2019. All these papers have been significantly enhanced with novel experimental results. The papers give an overview of the trends in research and development activities concerning the pervasive application of electronics in industry, the environment, and society. The focus of these papers is on cyber physical systems (CPS), with research proposals for new sensor acquisition and ADC (analog to digital converter) methods, high-speed communication systems, cybersecurity, big data management, and data processing including emerging machine learning techniques. Physical implementation aspects are discussed as well as the trade-off found between functional performance and hardware/system costs

Predicción de fuerzas de corte y topografía superficial para la mejora de fresado de rotores de álabes integrados.

179 p.Los rotores de álabes integrados consisten en discos rotativos con álabes fabricados en una sola pieza, los cuales están siendo cada vez más utilizados en los motores aeronáuticos debido a sus ventajas en cuanto a fiabilidad, reducción del peso, eficiencia y reducción de ruido. Estos componentes plantean uno de los problemas más difíciles desde el punto de vista del mecanizador, ya que se combinan tres factores críticos: 1) el fresado de superficies complejas en 5 ejes continuos, 2) materiales de baja maquinabilidad que generan grandes fuerzas de corte y altas temperaturas durante el mecanizado y, por último, 3) presencia de paredes delgadas y estructuras poco rígidas que son propensas a deformarse o vibrar durante el mecanizado.En este trabajo se define una metodología fiable de diseño y verificación de operaciones de fresado en cinco ejes de IBR-s. En una primera fase experimental de fabricación de geometrías de impeller y blisk, se han estudiado y analizado los diferentes tipos de operaciones de desbaste y acabado, así como lasherramientas de geometría tradicional y las de nuevo diseño. En concreto, existe gran interés enintroducir las nuevas geometrías de fresa de barril en el sector aeronáutico en operaciones desemiacabado y acabado de álabes. El elevado radio de curvatura del contorno permite reducir el númerode pasadas, y por lo tanto el tiempo de mecanizado, sin aumentar el tamaño de la herramienta.Para completar la metodología propuesta se han desarrollado herramientas predictivas de la topografía yrugosidad superficial de la pieza, y de las fuerzas de corte del proceso. Por un lado, se ha validado unmodelo de predicción basado en la substracción de sólidos, para operaciones de fresado periférico confresa cilíndrica considerando la flexión estática de la pared. Por otro lado, se han desarrollado dosmodelos enfocados a las operaciones de cinco ejes con fresas de barril. El primero de ellos permite simular la topografía y rugosidad teniendo en cuenta el runout de la herramienta y la orientación de la fresa. El segundo modelo propuesto predice las fuerzas de corte en mecanizados utilizando fresas de barril, para condiciones de corte estacionarias y en las que no se producen de flexión de pieza o herramienta