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Theoretical Concepts for Describing a Replication-levels-based Uncertainty Analysis Approach
Full text linkHuman-Centred Design in the context of Servitization in Industry 4.0: A Collaborative Approach
Full text linkThe competitiveness of the business today will depend on empowering hu-man intelligence and creativity, capturing and capitalizing on available infor-mation and knowledge for the total product and service lifecycle. To realize this beyond technical aspects, the collaborative work of multidisciplinary and inter-sectoral teams is constituted to develop an appropriate methodology of human-centred design (HCD) with advanced service innovation in indus-try 4.0. Based on the state-of-the-art analysis and industrial requirements, the methodology is tested with European industrial cases in various sectors to validate its implementation and benefits. This paper aims to provide the well-rounded collaborative framework to deliver the new HCD methodology
Code-to-code nonlinear hydrodynamic modelling verification for wave energy converters: Wec-sim vs. nlfk4all
Full text linkIn the wave energy conversion field, simulation tools are crucial for effective converter and controller design, but are often prone to become very casespecific, in both structure and parameter selection. This is due to majorly different working principles and diverse importance of nonlinear effects, at times requiring adhoc modelling approaches. To tackle this challenge, WECSim (Wave Energy Converter SIMulator) was born from the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories, providing a unique simulation platform for all WECs. Nonlinearities related to timevarying wetted surface, especially important in floating WECs, are included in WEC-Sim through a mesh-based computation of nonlinear Froude-Krylov forces. Virtually arbitrary geometries can be considered, thanks to the discretized representation of wetted surfaces, at the price of a significant increase in computational burden. This paper considers a time-effective alternative, implemented in the open-source toolbox called NLFK4ALL, applicable to the popular and wide family of axisymmetric floaters. The Spar-buoy floating oscillating water column device is considered, particularly challenging due to a submerged volume composed of several different sections. The accuracy of WEC-Sim and NLFK4ALL is verified by a preliminary cross-comparison, using independent methods to compute virtually same effects. Fixed-body numerical experiments are used to quantify nonlinearities and compare not only he accuracy, but also the computation burden. Results show that both methods provide almost identical results, although WEC-Sim doubles computational requirements
Genetic Algorithm-based Testing of Industrial Elevators under Passenger Uncertainty
Full text linkElevators, as other cyber-physical systems, need to deal with uncertainty during their operation due to several factors such as passengers and hardware. Such uncertainties could affect the quality of service promised by elevators and in the worst case lead to safety hazards. Thus, it is important that elevators are extensively tested by considering uncertainty during their development to ensure their safety in operation. To this end, we present an uncertainty testing methodology supported with a tool to test industrial dispatching systems at the Software-in-the-Loop (SiL) test level. In particular, we focus on uncertainties in passenger data and employ a Genetic Algorithm (GA) with specifically designed genetic operators to significantly reduce the quality of service of elevators, thus aiming to find uncertain situations that are difficult to extract by users. An initial experiment with an industrial dispatcher revealed that the GA significantly decreased the quality of service as compared to not considering uncertainties. The results can be used to further improve the implementation of dispatching algorithms to handle various uncertainties
Substitutive Press-Bolster and Press-Ram Models for the Virtual Estimation of Stamping-Tool Cambering
Full text linkToday’s stamping simulations are realized by ignoring the elastic deformation of the press and tooling system through the assumption of a rigid behavior and a perfect press stroke. However, in reality, the press and tool components deform elastically and are one of the major error sources for the final adjustment and blue-spotting of the dies. In order to tackle this issue, a new approach is proposed in this study that substitutes the press stiffness by means of a substitutive model composed of cost-effective shell and beam elements. The substitute model was calibrated using full-scale measurements, in which a 20,000 kN trial press was experimentally characterized by measuring its deformation under static loads. To examine the robustness of the substitute model, a medium-size tool and a large-size tool were simulated together with the substitutive model. To this end, a B-pillar tool was re-machined based on the substitute-model results and a new cambering procedure was proposed and validated throughout the blue-painting procedure. The newly developed substitute model was able to replicate the global stiffness of the press with a high accuracy and affordable calculation time. The implementation of the findings can aid toolmakers in eliminating most of the reworking and home-line trials
Integration of Cutting-Edge Interoperability Approaches in Cyber-Physical Production Systems and Industry 4.0
Full text linkInteroperability in smart manufacturing refers to how interconnected cyber-physical components exchange information and interact. This is still an exploratory topic, and despite the increasing number of applications, many challenges remain open. This chapter presents an integrative framework to understand common practices, concepts, and technologies used in trending research to achieve interoperability in production systems. The chapter starts with the question of what interoperability is and provides an alternative answer based on influential works in the field, followed by the presentation of important reference mod4els and their relation to smart manufacturing. It continues by discussing different types of interoperability, data formats, and common ontologies necessary for the integration of heterogeneous systems and the contribution of emerging technologies in achieving interoperability. This chapter ends with a discussion of a recent use case and final remarks
Data-Driven Fault Diagnosis for Electric Drives: A Review
Full text linkThe need to manufacture more competitive equipment, together with the emergence of the digital technologies from the so-called Industry 4.0, have changed many paradigms of the industrial sector. Presently, the trend has shifted to massively acquire operational data, which can be processed to extract really valuable information with the help of Machine Learning or Deep Learning techniques. As a result, classical Condition Monitoring methodologies, such as model- and signal-based ones are being overcome by data-driven approaches. Therefore, the current paper provides a review of these data-driven active supervision strategies implemented in electric drives for fault detection and diagnosis (FDD). Hence, first, an overview of the main FDD methods is presented. Then, some basic guidelines to implement the Machine Learning workflow on which most data-driven strategies are based, are explained. In addition, finally, the review of scientific articles related to the topic is provided, together with a discussion which tries to identify the main research gaps and opportunities
Electrochemical Model and Sigma Point Kalman Filter Based Online Oriented Battery Model
Full text linkThis paper presents a reduced-order electrochemical battery model designed for online implementation of battery control systems. This model is based on porous-electrode and concentratedsolution theory frameworks and is able to predict voltage as well as the internal electrochemical variables of a battery. The reduction of the model leads to a physics-based one-dimensional discrete-time state-space
reduced-order model (ROM) especially beneficial for online systems. Models optimized around different operational setpoints are combined in order to predict the cell variables over a wide range of temperature and state of charge (SOC) using the output-blending method. A sigma-point Kalman filter is further used in order to cope with inaccuracies generated by the reduction process and experimental-related issues such as measurement error (noise) on the current and voltage sensors. The state-estimation accuracies are measured against a full-order model (FOM) developed in COMSOL. The whole system is able to track the internal variables of the cell as well as the cell voltage and SOC with very high accuracy, demonstrating its suitability for an online battery control system
Wind Turbine Oriented Solutions to Improve Power Quality and Harmonic Compliance of AC Offshore Wind Power Plants
Full text linkThe operation of offshore wind power plants with respect to power quality and grid code compliance must be verified for different conditions in the design phase using harmonic analysis methods. This paper addresses this verification by first considering a scenario in which wind turbines operate with a typically used modulation strategy, carrier-based pulse width modulation. The studies are performed at several operating points, not only at the rated condition, and at two points of the electrical infrastructure, at the point of connection of the wind turbine and at the point of common coupling of the offshore wind farm. For this type of modulation technique and according to the resonance conditions of the studied offshore system, the harmonic distortion of current signals is relatively high and the compliance of the German – grid code is not achieved. To tackle this, wind turbine manufacturer oriented solutions are proposed with the aim of improving the harmonic emission of the offshore wind farm. The implementation of a particular solution of selective harmonic elimination is presented together with complementary solutions to further improve the harmonic emission of the wind power facility. Furthermore, this paper discloses the modeling approach to account for an adequate harmonic assessment of the wind power plant under study
Novel High Accuracy Resolver Topology for Space Applications
Full text linkIn recent years, the space industry has experienced a significant change mainly due to the incursion of private companies, which has shaken up the sector. This new situation allows for a reduction regarding the reliability of conventional instrumentation for space while reducing the development time and manufacturing volume. Consequently, even though it has been typical to use equipment that was previously tested in space, this could be the right moment to introduce new technologies due to the previously mentioned reasons. One of the interesting technologies with great potential is the rotary sensor in applications with motors. Historically, the resistive potentiometer has been the most used due to its simplicity and robustness; however, it has several drawbacks. Due to this, the aim of this paper is to identify an interesting rotary sensor. Hence, in this article, different sensor types are studied. Then, we review the literature regarding resolvers in order to find the best topology. We designed and compared different single speed absolute position resolvers to find the ones that offered the best results. In this process, a novel resolver topology was designed that improved on the performances of any other studied topology