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Scientific innovation and technical achievements challenge people’s beliefs and understanding of robots. In the meanwhile, the language used to talk about new technology is often pointed out as encouraging the confusion between machines and living organisms. As a matter of fact, many are the words used in robotics that are borrowed from the living: machines can learn, think, feel… are intelligent, autonomous, etc. Yet, and while it is popular to use words such as ‘intelligent’ or ‘autonomous’ when talking about robots, the question of whether we should replace these words is also commonly raised. Do we encourage sensationalism if we keep talking about robotics in this way? Are there better alternatives? The main argument of the book is the following one: our chance to conduct constructive debates about robotics rather depends on our ability to rethink our own relation to language than agreeing on which words to use or how we should define them., info:eu-repo/semantics/inPress, 1, 1

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Post-assembly magnetization can significantly simplify the manufacturing of the rotor of permanent magnet (PM) electrical machines. The optimization of the post-assembly magnetizing device using finite element analysis (FEA) is time-consuming; therefore, a globally optimal solution aiming at achieving an adequate magnetizing level and minimal energy consumption is difficult to achieve. In this paper, a field–circuit coupling analysis (FCCA) model is proposed to optimize the auxiliary stator-type magnetizing device for interior permanent magnet synchronous machines (IPMSMs). A reasonable simplification of the highly saturated magnetic circuit is made based on FEA results so that the magnetic equivalent circuit (MEC) model can be established. On the other hand, the eddy currents in the PMs are equivalent to an eddy current short-circuit; thus, by converting the field calculation into a circuit calculation, the time cost can be reduced significantly, which greatly improves the speed of multi-objective optimization of the magnetizing device with multiple degrees of freedom. A V-type IPMSM is taken as a study case, and its post-assembly magnetizing device is optimized with the proposed method. FEA and experimental results show that the PMs are fully magnetized, while the required energy consumption is greatly reduced when compared with an existing magnetizing device., SCOPUS: ar.j, info:eu-repo/semantics/published

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Condition monitoring and fault diagnosis are essential to improve the reliability and availability of wind turbines (WTs). In such systems, power switches and sensors are some of the components most susceptible to faults. In this context, this article proposes a new diagnostic method for WTs based on doubly-fed induction generators with the ability to handle insulated gate bipolar transistor (IGBT) faults, rotor and stator current sensor outages, and stator voltage sensor outages. The proposed method is based on an augmented state and disturbance observer combined with a statistical chi-square (X2) test, adaptive thresholds, and normalized diagnostic variables to ensure reliable diagnosis regardless of the operating conditions. The robustness and effectiveness of the proposed approach have been verified experimentally on a 15-kW test bench under the various faults considered., SCOPUS: ar.j, info:eu-repo/semantics/published

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This article proposes adaptive continuous-control-set model predictive control (CCS-MPC) for three-phase LCL-filter grid-tied inverters in the stationary frame. The proposed control provides stability against the LCL-filter resonance and removes the need for active damping or passive damping. Furthermore, it can track sinusoidal references in the stationary frame close to zero offsets. Inductance variation of a grid is a challenging issue, which can shift the LCL-filter resonance. Even though CCS-MPC generally has good stability for parameter mismatches, the control is optimized for the nominal value of the parameters. A relatively large variation may deteriorate the performance of the control and cause instability in the closed-loop system. To solve this problem, the concept of CCS-MPC is developed to work with a variety of the grid-inductance changes. The controller coefficients are chosen with a sensitivity analysis to provide enough gain margins and phase margins for the whole interval of the presumption grid-inductance variation. Also, this selection guarantees the control robustness against mismatches of the LCL-filter capacitance and inductance. The real-time computation of advanced controllers is a challenging issue. The computation burden of the proposed CCS-MPC is mostly performed offline and just some simple numerical expression is executed in real time. Thus, it does not require a powerful but expensive processor for implementation. The simulation and experimental results prove the performance of the proposed controller for handling the LCL-filter resonance, grid-inductance variations, and tracking sinusoidal references., SCOPUS: ar.j, info:eu-repo/semantics/published

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The ability to significantly contribute to the frequency regulation and provide valuable ancillary services to the transmission system operator (TSO) is one of the present wind farm (WF) challenges, due to the limitations of wind speed forecasting and insufficient power reserve in certain operating conditions notably. In this work, the feasibility of WFs to participate in frequency restoration reserve (FRR) through yaw control is assessed. To this end, a distributed yaw optimization method is developed to evaluate the power gain achieved by yaw redirection based on wind turbine cooperation and compared with a greedy approach. The method relies on a static wake model whose parameters are estimated in a systematic way from simulation data generated with FAST.Farm. Through a case study based on a scaled version of the Belgian Mermaid offshore WF, it is demonstrated that the requirements of the TSO are fulfilled both in terms of response time and level of power reserve for most wind directions. The assessment is limited to wind speeds below the rated speed of the considered wind turbines., SCOPUS: ar.j, info:eu-repo/semantics/published

In many civil engineering problems, soil is stabilized by a combination of binders and water. The success of stabilization is evaluated using seismic tests with measured P-wave velocities. Optimization of process, laboratory testing and data modelling are essential to reduce the costs of the industrial projects. This paper reports the optimized workflow of soil stabilization through evaluated effects from the two factors controlling the development of strength: (1) the ratio between water and binder; (2) the proportions of different binders (cement/slag) were changed experimentally in a mixture of samples to evaluate the strength of soil. The experimental results show an optimal combination of 30% cement and 70% slag with a binder content of 120 kg/m3 and a maximum water binder ratio (w/b) of 5. Such proportions of mixture demonstrated effective soil stabilization both on a pilot test scale and on full scale for industrial works. The correlation between the compressive strength and relative deformation of specimens revealed that strength has the highest values for w/b = 5 and the lowest for w/b = 7. In case of high water content in soil and wet samples, the condition of a w/b ≤ 5 will require a higher amount of binder., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

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The effect of electrical steel degradation due to punching on the performance of fractional-kW electrical machines in terms of torque and iron losses is investigated. The local degradation of the steel is considered in the BH curve and iron losses model by continuous variation of the magnetic proprieties as a function of the distance from the cut edges. The newly introduced parameters are identified by fitting the proposed relations for the BH curve and iron losses with measured values obtained via standard Epstein frame test. The position-dependent BH curve is incorporated into magnetostatic FE equations. Then, the performance of two different synchronous machines, i.e. with permanent magnets and reluctance rotor, is analyzed by means of FE simulations. Considering punching, the average torque decreases by 0.5-2 %, while the iron losses can undergo an increase of 30-40 %. Moreover, in order to check the validity of the model, the magnetic friction torque of two permanent-magnet motors, one with an annealed stator and the other one with a non-annealed stator, is measured and compared with calculated values based on the FE model, SCOPUS: ar.j, info:eu-repo/semantics/published

This paper proposes an adaptive equivalent RL-circuit model for eddy-current devices with a single electrical port (one terminal voltage and current) and translational movement. The device is first characterised by means of frequency-domain finite-element computations in the relevant frequency and position intervals, for subsequently fitting constant-coefficient RL-ladder circuits of adjustable size (i.e. variable number of branches and loops). The accuracy of the ladder-circuit model is assessed in both frequency and time domain. The time-varying position involves the force computation from the circuit and the coupling with the mechanical equation. By way of validation, we study the axisymmetric magnetic-levitation device of TEAM Workshop problem 28. Results exhibit good convergence to reference finite-element ones with the increasing number of branches., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper proposes a data-driven structural modeling approach for electrical machine air-born vibration that can be used both in the design stage for fast optimization routines and in system-level simulations. This method is able to capture both in-plane and out-of-plane modal behavior along with local effects, such as tooth bending. The model relies on fitting unitary-force shape responses to transfer function models using a zero-pole representation. These frequency response functions are obtained from applying the vibration synthesis process to a series of finite element stator models that have material properties updated using experimental modal analysis. The obtained zeros and poles are used to construct three look-up table models with their accuracy varying between the three of them with the number of samples used in the data-generation process. The accuracy of these models is validated at the unitary force shape response level using four stator finite element model samples. Also, at the run-up vibration spectrogram level, the models are validated, with good results, using radial and tangential force excitation obtained from an updated electromagnetic finite element model of an interior permanent magnet synchronous machine designed for electric power steering. The computational cost compared to the standard finite-element vibration-synthesis method is shown., SCOPUS: ar.j, info:eu-repo/semantics/published

Evaluating soil strength by geophysical methods using P-waves was undertaken in this study to assess the effects of changed binder ratios on stabilisation and compression characteristics. The materials included dredged sediments collected in the seabed of Timrå region, north Sweden. The Portland cement (Basement CEM II / A-V, SS EN 197-1) and Ground Granulated Blast Furnace Slag (GGBFS) were used as stabilisers. The experiments were performed on behalf of the Svenska Cellulosa Aktiebolaget (SCA) Biorefinery Östrand AB pulp mill. Quantity of binder included 150, 120 and 100 kg. The properties of soil were evaluated after 28, 42, 43, 70, 71 and 85 days of curing using applied geophysical methods of measuring the travel time of primary wave propagation. The P-waves were determined to evaluate the strength of stabilised soils. The results demonstrated variation of P-waves velocity depending on stabilising agent and curing time in various ratios: Low water / High binder (LW HB), High water / Low binder (HW LB) and percentage of agents (CEM II / A-V/GGBFS) as 30%/70%, 50%/50% and 70%/30%. The compression characteristics of soils were assessed using Uniaxial Compressive Strength (UCS). The P-wave velocities were higher for samples stabilized with LW HB compared to those with HW LB. The primary wave propagation increased over curing time for all stabilized mixes along with the increased UCS, which proves a tight correlation with the increased strength of soil solidified by the agents. Increased water ratio gives a lower strength by maintained amount of binder and vice versa., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

There are applications like electric-power-assisted steering system in which strict requirements on the cogging torque of the machine should be fulfilled. Numerous techniques and methods are introduced to minimize the inherent cogging torque of the machine, but manufacturing tolerances and imperfections still can cause extra cogging torque. In this article, the impact of punching on the manufacturing-induced cogging torque of segmented permanent-magnet synchronous machines is investigated. The punching model is implemented by modifying the BH curve of the steel as a function of distance from the cut edges. The parameters of the new BH curve are identified by means of standard Epstein frame measurements using steel strips with different widths. Then, the punching model is incorporated into the finite element (FE) model of a 10-pole 12-tooth segmented stator machine designed for power steering application. It is observed that deviation among the magnetic properties of the teeth caused by punching can introduce extra low-order harmonics in the cogging torque of the machine. The amplitude of the new orders can be comparable or even much bigger than the inherent orders, where not only the magnitude of deviation but also the arrangement of teeth with given punching parameters play a role., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper presents and validates a method for early estimation of the high-frequency impedance response for a real Permanent Magnet Synchronous Machine (PMSM). The main contribution of this work lays on the simplicity of the data required to tackle the prediction, which do not require any experimental tuning or 3D simulations. The required inputs for the method are the 2D cross-section of the machine and the material characteristics of the conductors, insulation and iron laminations. An approach using the Finite Element Method (FEM) coupled with a circuit simulator is utilized to obtain the machine common-mode and differential-mode impedances over a broad frequency range. Experimental measurements are performed up to the resonance band to validate the methodology. In addition, the influence of the machine rotor and housing on the impedance curves is experimentally assessed. A machine with concentrated winding is used as a case study machine to test the model., SCOPUS: ar.j, info:eu-repo/semantics/published

In this article, a multiphysics simulation workflow based on the use of reduced-order models to decrease the computation time is presented. Using finite-element (FE) precomputed flux-linkage and lumped force lookup-tables in function of dq0 currents and rotor position, an electromagnetic model of a permanent-magnet synchronous machine (PMSM) is developed. Coupled to a mechanical state-space representation, the complete workflow allows to predict the vibrations of the motor. Using our model, the influence of the 0-sequence current on the vibration spectrum is investigated. A detailed description on the parameter identification for homogenized stator core of the considered 12-slot 10-pole delta-connected fractional-slot concentrated-winding spoke-type PMSM is also given. The numerical results are validated with experimental data for the machine at hand. Because of the large amount of FE data required, the workflow is best suited for the optimization of motor control schemes (instead of the initial design optimization) with the purpose of reducing the noise, vibration, and harshness., SCOPUS: ar.j, info:eu-repo/semantics/published

Geomorphology of Lebanon presents a unique pattern of contrasting landforms. These include two notable mountain ranges, the Lebanon and Anti-Lebanon Mountains, the Beqaa Valley, the elongated coastal area and a significant amount of karst relief forms. This study focuses on the investigation of the topographic and geologic setting of Lebanon by visualizing datasets covering Lebanon and Anti-Lebanon mountains and the Beqaa Valley. Data were collected using the open source repositories of the high-resolution data (GEBCO, ETOPO1, DEM embedded in R). Three 3D models of the relief of the country are presented based on the ‘grdview’ package of GMT with azimuth rotations of the view point at 205°/30° and 165°/30°. The geologic map is based on the compiled datasets of the USGS. The R based modelling allowed division of the raster grid into several geomorphological zones according to the slope steepness and aspect orientation. The extreme elevations of the study area range from -2007 m and 2973 m. The key contribution of this work is the topographic and geologic data synthesis for 2D and 3D modelling of Lebanon. Another aspect concerns technical integration of GMT and R scripting approaches with QGIS mapping into the cartographic framework for visualizing of the Lebanese topography as a multi-tool approach. For the future similar studies on Lebanon this paper can serve as a guide for completing a project on the multi-source 2D and 3D data mapping as a conceptual foundation for research on Lebanese environment., info:eu-repo/semantics/published

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This article proposes a new control algorithm that improves the dynamic performance in distributed maximum power point tracking systems. Systems with these architectures allow to increase the photovoltaic power harvested in case of partial shading and irradiance mismatch. The classical approach adopts distributed DC/DC power electronics and control without any centralized action, which makes difficult to know whether the system is working on its optimal operating point or not. The new control algorithm presented in this paper exploits the benefits of the vectorial multi-variable perturb & observe logic and acts on the control sequence under varying irradiance conditions, reducing voltage stresses at the DC/DC converters output terminals. In addition, the matching with the DC-bus voltage control is discussed, providing a centralized control to the overall system, a fact barely addressed in literature. Simulation results and experimental measurements validate the proposed approach showing improved dynamic performance and system stability., SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper, we propose a homogenization technique for the terminal-capacitance computation of multi-Turn windings in electrostatic finite-element methods. The approach is based on a characterization of the elementary zones where the electrical energy is concentrated. It is valid for conductors of arbitrary cross-section and packing with standard or fly-back connections and orthogonal or orthocyclic dispositions. The results of the homogenized approach present excellent agreement with those obtained by accurate but expensive finite-element models, wherein all turns and insulation layers are explicitly discretized, and by experimental validation., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper presents a nonlinear multi-scale Model Order Reduction (MOR) method based on a piece-wise linearization technique. On the material scale, the eddy-current (EC) field in laminated cores is expressed through Legendre polynomials. The Cauer Ladder Network (CLN) method is applied to the homogenized nonlinear EC problem to generate the equivalent electric circuit. The accuracy and efficiency of the proposed method are verified by mean of a test case with saturated stacked core and Pulse Width Modulation (PWM) excitation., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper develops a multi-scale Model Order Reduction (MOR) method including both material and machine scale MOR. The material-scale MOR homogenizes the eddy-current (EC) field in laminated cores using the Legendre expansion of magnetic induction along the stacking direction within each steel sheet. The machine-scale MOR represents the EC field in electromagnetic devices with their equivalent Cauer Ladder Network (CLN). The former MOR is built into the latter by applying the CLN procedure to the homogenized EC field equation., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper presents a current shaping method for torque ripple and mean air-gap radial forceshape harmonics reduction, under minimum Joule losses, used for air-born and structure-born vibration reduction in 3-phase PMSM electric drives. The main source for structure-born noise in electric powertrains is the torque ripple, while the main source for air-born noise are the radial air-gap forces. The proposed method uses a Fourier-decomposed LUT model obtained from updating the 2D electromagnetic FE model using test-bench results. Modal testing is used to update the structural model, and the vibration response on the machine full RPM range is determined using the vibration-synthesis method. The proposed current shaping algorithm is deterministic and can be used on any topology of 3-phase PMSMs. The torque and mean air-gap force harmonics that are intended for reduction can be arbitrary selected and their minimization can be fully completed if the maximum current and voltage constraint are respected. On the machine under test, vibration reduction is accomplished, especially for the mechanical orders that interact with the second mode-shape., SCOPUS: ar.j, info:eu-repo/semantics/published

A multiphysical time- and frequency-domain fault detection and isolation method for power-electronic converters of wind turbines is presented in this article, with focus on open-circuit faults in doubly-fed induction generator drivetrain topology. In order to reduce the risk of false alarms, the proposed approach combines fault indicators based on a time- and frequency-domain analysis of electrical signals, as well as a frequency-domain analysis of vibration signals. The effectiveness of the method is demonstrated via test bench data recorded under different healthy and faulty operating conditions., SCOPUS: ar.j, info:eu-repo/semantics/published

A method for BH curve identification of the magnetic core of synchronous reluctance machines is presented. It starts from the knowledge of machine torque or phase voltages measured at normal operation with ac balanced currents or obtained from dedicated experiments proposed for the BH curve identification. The identification is formulated as an inverse optimization problem where the experimental data based on appropriate experiments serve as the inputs and the BH curve parameters represented with a closed-form expression as the optimization variables. The influence of the different types of measurements on the identified parameters and the optimization process is discussed and compared. Moreover, the impact of geometrical uncertainties due to manufacturing tolerances is investigated and addressed. Virtual measurements obtained from finite-element simulations are used for the study. It is shown that the proposed method can identify the BH curve of the machine core with good accuracy., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

MPEG-I, the upcoming standard for immersive video, has steadily explored immersive video technology for free navigation applications, where any virtual viewpoint to the scene is created using Depth Image-Based Rendering (DIBR) from any number of stationary cameras positioned around the scene. This exploration has recently evolved towards a rendering pipeline using camera feeds, as well as a standard file format, containing all information for synthesizing a virtual viewpoint to a scene. We present an acceleration of our Reference View Synthesis software (RVS) that enables the rendering in real-time of novel views in a head mounted display, hence supporting virtual reality (VR) with 6 Degrees of Freedom (6DoF) including motion parallax within a restricted viewing volume. In this paper, we explain its main engineering challenges., SCOPUS: cp.p, info:eu-repo/semantics/published

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In this article, we propose an alternative time-domain approach for the homogenization of multiturn windings with frequency-dependent parameters in finite-element (FE) models. First, an elementary 2-D FE characterization of the conductors is carried out over the frequency range of interest to obtain the frequency-dependent parameters and account for the eddy-current effects in the winding. These complex coefficients are subsequently associated with an equivalent Foster network and translated into the time domain via the inverse Laplace transform. The resulting time-domain equations are solved with a recursive convolution scheme. No extra degrees of freedom are required in the homogenized winding. The results of the homogenized model present an excellent agreement with those obtained by an accurate but expensive FE model in which all turns are explicitly discretized. The proposed approach is further compared with a previously developed time-domain homogenization technique based on RL Cauer networks., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper proposes an Indirect Matrix Converter (IMC)-based grid-tied Photovoltaic (PV) system for Smart Grids (SGs). The PV array injects current in the ‘dc link’ of the IMC through an inductive link, and is connected to the SG with shunt and series connections, allowing for the compensation of current- and voltage-related Power Quality (PQ) issues, respectively, for the sensitive loads and the SG connection. A direct sliding mode-based controller is proposed to guarantee nearly sinusoidal currents in the connection to the SG, and sinusoidal voltages guaranteeing compliance with international standards, when supplying the sensitive loads. Additionally, a novel control approach for the ‘dc link’ voltage is synthesised to allow for the control of both the PV array current and the power flow to the SG. To guarantee the semiconductors safe commutation an asynchronous commutation strategy is derived. Simulation and experimental results show that the proposed system significantly improves PQ in the SG, minimizing the total harmonic distortion of the currents injected in the SG, and guaranteeing the quality of the voltage supplied to the sensitive loads, even in the occurrence of voltage sags or overvoltages., SCOPUS: ar.j, info:eu-repo/semantics/published

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We propose a new instructional theory, the Domain of Validity (DoV) Framework, which offers a new way forward for designing teaching for conceptual change, while also resolving conflicts between existing theories related to common, difficult-to-change conceptions students have about particular scientific topics. We propose that knowledge consists of two connected elements: a model and a domain of validity (or DoV). Foregrounding the notion of DoV for given models allows us to reconceptualise and diagnose many problematic preconceptions as examples of an oversized DoV. Mapping the different elements of knowledge – both the model and its domain of validity – allows teachers to pinpoint precisely the cognitive conflict that students need to confront in a conceptual change approach to teaching. We highlight the instructional implications related to these scientific learning difficulties and conclude by proposing particular teaching strategies based on this new framework, emphasising the domains of validity of particular scientific models., SCOPUS: re.j, info:eu-repo/semantics/published

Facing an uncertain and rapidly changing future, Fablabs are a great environment to teach social and technical skills that are relevant for the 21st century [1-3].At Fablab ULB, we, a professor of architecture and a professor of physics, are experiencing and developing an agile teaching method to make students work with digital tools [4] in interdisciplinary teams and to make a real-world impact.Starting with a "real world" problem, we guide the students to define their own assignment. To run the class, we use collective intelligence and tools from sociocracy [5-6]. We help the students to use the digital tools within a Fablab and have a conversation with authentic audiences from all around the world.In this paper, written as a “Making Of”, we are sharing our commented “Class Journal” that we built all along the class. We will go through all the steps on how we got 45 students coming from different faculties such as Architecture, Sciences, Engineering and Law, to work together developing open-source projects related to the humanitarian emergencies due to the Kerala floods that happened in India in August 2018 [7].Building on this experience, we believe that Fablabs are a great opportunity to transform learning and to create resilient citizens ready for tomorrow., info:eu-repo/semantics/published

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