Browsing by Keyword "Mechanical Engineering"
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Item AC Magnetron Sputtering: An Industrial Approach for High-Voltage and High-Performance Thin-Film Cathodes for Li-Ion Batteries(2021-05-21) Rikarte, Jokin; Madinabeitia, Iñaki; Baraldi, Giorgio; Fernández-Carretero, Francisco José; Bellido-González, Víctor; García-Luis, Alberto; Muñoz-Márquez, Miguel Ángel; Fernández‐Carretero, Francisco José; Bellido‐González, Víctor; García‐Luis, Alberto; Muñoz‐Márquez, Miguel Ángel; TECNOLOGÍAS DE HIDRÓGENOIndustrial-oriented mid-frequency alternating current (MF-AC) magnetron sputtering technique is used to fabricate LiNi0.5Mn1.5O4 high-voltage thin-film cathodes. Films are deposited on bare stainless-steel substrate at room temperature and then annealed to induce crystallization in disordered spinel phase. In situ X-ray diffraction is used to follow film structural evolution from room temperature to 900 °C. Scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy are used to study the evolution with temperature of film morphology, surface chemical composition, and crystal structure arrangement, respectively. Film structure evolves almost continuously in the studied temperature range. A pattern corresponding to spinel phase is observed after annealing at 600 °C, while poor crystallization is obtained for lower temperatures, and additional unwanted phase changes are observed for higher temperatures. Cyclic voltammetry, rate capability, and cycling performance of fabricated films are tested. Only the film annealed at 600 °C shows redox peaks corresponding to Ni oxidation from 2+ to 3+ and 3+ to 4+ oxidation states, confirming that this film crystallizes in disordered spinel phase. The thin-film cathode shows good rate performance and outstanding cyclability, despite the impurities formed upon electrolyte decomposition at high voltage.Item Acoustic emission characterisation of two pre-cracked specimens(British Institute of Non-Destructive Testing, 2022) Gálvez, Antonio; Galar, Diego; Alonso, Asier; Errasti-Alcalá, Borja; Bienvenido, Ismael; Ortego, Patxi; Juuso, Esko; Tecnalia Research & InnovationThis article contains the experiments carried-out to study the capabilities of Acoustic Emissions (AE) in a Ship To Shore (STS) crane. This solution studies the implementation of Structural Health Monitoring (SHM) in an STS crane based on acoustic emissions (AE) technique for detecting cracks and assessing their growth in steel elements subjected to fatigue. The first experiment is performed using a compact tension specimen (CT) made of steel S355 whose dimensions are 125x120x50 mm and its cracks and dimensions are defined based on ASTM and ISO standards. The CT is monitored using AE sensors, and then, the features are extracted from the raw data and used to train, test and validate an unsupervised model. The crack detection model obtains a remarkable accuracy; crack detection at sizing of 3 mm length. As the CT dimensions are small, it is difficult to evaluate the attenuation of AE signals, which is completely necessary for monitoring STS cranes. Therefore, a second experiment is performed using a panel made of steel S355, whose dimensions are 2120x200x8 mm; the panel contains a crack of 50x3 mm. This experiment is performed to analyse the AE signals that come from cracks; specifically, to assess signals attenuation, how the attenuation affects cracks detection in the panel, and features evolution while crack propagation. This is led by monitoring the crack growth with crack detection gauges and installing the AE sensors at different distances of the crack. The assessment is used to develop an unsupervised model to detect cracks and an algorithm for localizing them.Item An admittance based hierarchical control framework for dual-arm cobots(2022-10) Tarbouriech, Sonny; Navarro, Benjamin; Fraisse, Philippe; Crosnier, André; Cherubini, Andrea; Sallé, Damien; ROBOTICA_FLEXDual-arm robotic platforms have solid arguments to match the growing need for versatility in the industry. Coupling the control of two manipulators for cooperative purposes enlarges the scope of feasible operations, while adding perception capabilities allows to navigate in dynamic environments. In this respect, we propose a complete online kinematic control framework for dual-arm robots operating in unstructured industrial settings. We base our approach on admittance control in the cooperative task space. Regulating internal and external efforts offer safe bimanual task execution and enables physical interaction. We implement a hierarchical quadratic programming architecture that applies a prioritization of tasks: most efforts are concentrated on the proper tracking of relative motions of the arms, which is the most critical for safety reasons. We demonstrate the performance of our framework through a “teaching-by-demonstration” experiment on the dual-arm mobile cobot BAZAR.Item Admittance control for collaborative dual-arm manipulation(Institute of Electrical and Electronics Engineers Inc., 2019-12) Tarbouriech, Sonny; Navarro, Benjamin; Fraisse, Philippe; Crosnier, Andre; Cherubini, Andrea; Salle, Damien; ROBOTICA_FLEXHuman-robot collaboration is an appealing solution to increase the flexibility of production lines. In this context, we propose a kinematic control strategy for dual-arm robotic platforms physically collaborating with human operators. Based on admittance control, our approach aims at improving the performance of object transportation tasks by acting on two levels: estimating and compensating gravity effects on one side, and considering human intention in the cooperative task space on the other. An experimental study using virtual reality reveals the effectiveness of our method in terms of reduced human energy expenditure.Item Advanced Prognostics for a Centrifugal Fan and Multistage Centrifugal Pump Using a Hybrid Model(Springer Science and Business Media Deutschland GmbH, 2023) Vila-Forteza, Marc; Jimenez-Cortadi, Alberto; Diez-Olivan, Alberto; Seneviratne, Dammika; Galar-Pascual, Diego; Juuso, Esko; Galar, Diego; Tecnalia Research & Innovation; IA; INDUSTRY_THINGSPredictive maintenance is fully implemented in the oil and gas industry, and the impressive development of field sensors, big data, and digital twins offers a wide field for the ongoing experimentation and development of diagnostic and prognostic tools for machinery. Although a wide range of technologies and sensors is available, vibration analysis remains the preferred predictive technique for rotating machinery diagnostics. It is well-known, widely used, and has proven efficacious in evaluating the health of rotating machinery and preventing failures. Taking advantage of vibration analysis development and computing capabilities, this study develops three digital twins of one multistage centrifugal pump and two centrifugal fans using real vibration data and synthetic data. This hybrid model approach permits the use of failure data which are not usually found in the normal operation of these machines. The study improves and tunes the accuracy of those models using real operating data obtained from a distributed control system (DCS), thus obtaining results in accordance with process conditions. Maintenance decisions can be supported by these models. They are based on online vibration and process data; they diagnose the health of a machine and give its remaining useful life (RUL). The models may also be used for other API plant assets (multistage centrifugal pumps or centrifugal fans) by changing the configuration parameters and process DCS tags.Item An agile manufacturing system for large workspace applications(2016-07-01) Yang, Hai; Baradat, Cédric; Krut, Sébastien; Pierrot, François; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationREMORA aims at offering an agile robotic solution for manufacturing tasks done on very large parts (e.g., very long and slender parts found in aeronautic industries). For such tasks, classical machine tools are designed at several tens of meters. Both their construction and operation require huge infrastructure supports. REMORA is a novel lightweight concept and flexible robotic solution that combines the ability of walking and manufacturing. The robot is a mobile manufacturing system which can effectuate operations with good payload capacity and good precisions for large workspace applications. This new concept combines parallel kinematics to ensure high stiffness but low inertia and mobile robotics to operate in very large workspaces. This results in a machining center of new generation: (1) agile manufacturing system for large workspace applications, (2) heavy load and good precisions, (3) 5-axis machining and 5-axis locomotion/clamping, (4) self-reconfigurable for specific tasks (workspace and force), and (5) flexible and multifunctional.Item AIR2, un robot parallèle à actionnement pneumatique à deux degrés de liberté pour les applications de prise et dépose d'objets(2011) Chikh, Lotfi; Baradat, Cédric; Poignet, Philippe; Pierrot, François; Michelin, Micaël; Tecnalia Research & InnovationA two degrees-of-freedom pneumatically driven parallel robot has been developed for pick-and-place of payloads comprised between 5 and 20 kg using standard double acting cylinders cheaper than electrical motors. After the general presentation of the robot, the actuator models are developed and a novel control strategy is introduced based on a cascade scheme with a predictive position controller and an inner H∞ force control. Some experimental results are then presented and analyzed in order to show the effectiveness of the controllers.Item L'Al-TiB 2, un matériau pour les applications du secteur des transports nécessitant résistances aux températures élevées et à l'usure(2002-12) Goñi, J.; Egizabal, P.; Coleto, J.; Poutier, M. A.; Guridi, J. R.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoThe transport industry is continuously seeking new light materials to comply with the low fuel consumption policies and enhanced technical requirements. The use of Metal Matrix Composites (MMCs) is seen as a feasible alternative to substitute several grey cast iron steel and non reinforced aluminium alloys components as they present outstanding specific properties, high wear resistance as well as low Coefficient of Thermal Expansion (CTE). The results obtained during a research project that studied the actual possibilities, processing optimisation and mechanical properties of an aluminium matrix composite reinforced with in-situ produced TiB 2 ceramic particles are presented. Railway and automotive components were produced by Gravity Casting, High Pressure Die Casting (HPDC) and a variant of the Sand Casting process called "Multipouring" and the melt behaviour and obtained mechanical properties were analysed and evaluated. The material presented a remarkable improvement of properties when compared with the corresponding non-reinforced alloys. Furthermore, the presence of the TiB 2 particles conferred a thixotropic nature to the melt whose positive effects during the filling step could also be noticed during the production of prototypes.Item Al-TiB2: Un materiau alternatif pour des applications resistant a l'usure et aux hautes temperatures dans l'industrie du transfert(2002-08) Goni, J.; Egizabal, P.; Coleto, J.; Poutier, M. A.; Guridi, J. R.; Centros PRE-FUSION TECNALIA - (FORMER); Tecnalia Research & Innovation; MercadoResults obtained in a study of real-life possibilities, process optimization and mechanical properties of aluminum metal matrix composites reinforced by particles of ceramic TiB2 are presented and discussed. Vehicle and train components have been made of those materials by gravity molding, high-pressure casting and the so-called Pultipouring process. The results have been analyzed and evaluated from the standpoint of casting and mechanical properties. Reinforcement resulted in a significant improvement and the presence of TiB2 made the alloy thixotropic, which had a positive effect on the process.Item Analysis of life-cycle boundaries for environmental and economic assessment of building energy refurbishment projects(2017-02-01) Oregi, Xabat; Hernandez, Patxi; Hernandez, Rufino; Tecnalia Research & Innovation; PLANIFICACIÓN ENERGÉTICADespite the standardization of the life-cycle assessment methodology for the construction sector, analysts tend to apply some simplifications in relation to the system boundaries, omitting some of the life-cycle stages. In particular, for building energy refurbishment projects, there is a general focus on the operational stage, linked to the main objective of reducing operational energy use. This paper evaluates the relevance of each life-cycle stage in relation to the overall environmental and economic impact on residential building energy refurbishment projects. The results from the analysis of the refurbishment strategies at a case study in Spain show the relatively minor importance of the transport and end of life stages. The construction process stage is also of relatively minor importance regarding the environmental performance. The product, maintenance and replacement stages are generally of higher importance, particularly for economic evaluation. An extensive sensitivity analysis demonstrates the difficulties of simplifying the life-cycle boundaries, suggesting that potential simplifications should take into account various parameters, including the climate region, building typologies, and expected service life. As an example, the results have shown that for cold climate zones and buildings, where large energy savings from energy refurbishment strategies can be achieved, the other life-cycle phases are less important and, in most cases, represent less than 10% of life-cycle environmental impacts.Item Analysis of ultrasonic-assisted drilling of Ti6Al4V(2009-05) Pujana, J.; Rivero, A.; Celaya, A.; López de Lacalle, L. N.; SGIn this study ultrasonic vibration was applied on the drilling of Ti6Al4V workpiece samples. Several parameters of ultrasonic-assisted drilling were monitored, including feed force, chip formation by means of high-speed imaging, and temperature measurement on the drill tip by means of infrared radiation thermometry. Ultrasonic assistance offered lower feed force and higher process temperatures as compared to conventional drilling. It has also shown higher force reductions and higher temperature increments when vibration amplitude was increased.Item Analytical thermal model of orthogonal cutting process for predicting the temperature of the cutting tool with temperature-dependent thermal conductivity(2021-08-15) Veiga, F.; Arizmendi, M.; Jiménez, A.; Val, A. Gil Del; Tecnalia Research & Innovation; FABRIC_INTELHigh temperatures generated in cutting processes significantly affect the surface integrity of machined parts and tool wear, leading to workpiece thermal damage, tensile residual stresses in the workpiece and a reduction in tool life. In recent years, different analytical thermal models to predict cutting temperatures have been developed in literature based on 2D modeling of the cutting process and the assumption that thermal conductivities of workpiece and chip are not dependent on temperature. However, this dependence of conductivity on temperature may have a significant influence on predicted temperatures and must be taken into account. In this paper, a thermal model of the orthogonal cutting process that considers thermal conductivity of materials (chip and tool) to be dependent on temperature is developed. A linear variation of thermal conductivity with temperature is assumed for chip (workpiece) and tool materials. The model is based on application of: (1) the Kirchhoff transformation in order to convert the nonlinear heat conduction problem into a linear one, (2) the theory of moving and stationary heat sources in semi-infinite and infinite mediums in order to model primary and secondary deformation zones and (3) imaginary heat sources to meet adiabatic boundary conditions in the chip and tool. Imaginary heat sources were defined in the thermal model proposed in this paper in such a way that the effect of the tool-chip interface dimensions and of cutting tool width on the tool temperature could be taken into account. This allows the temperature on the rake face and lateral faces of the tool to be predicted. To this end, a new methodology that considers the temperature-dependent thermal conductivity of materials was developed in order to estimate heat partition ratio along the secondary heat source (tool-chip interface), which is assumed to be non-uniform. Orthogonal cutting tests were also performed in order to verify model predictions by comparing them to tool temperature distributions measured using an IR camera.Item Anomaly detection of a 5-phase AC electric motor using Machine Learning classification methods(Institute of Electrical and Electronics Engineers Inc., 2023) Robles, Nerea; Madariaga, Danel; Alvarez-Gonzalez, Fernando; Sierra-Gonzalez, Andres; POWERTRAINWith the goal of performing condition monitoring and anomaly detection applied to electric machines, tagged datasets are synthetically generated, consisting of time series of electrical and mechanical variables from a 5-phase AC synchronous motor, in different conditions of health or abnormal states. Different off-the-shelf Machine Learning classification methods are then applied to those datasets, to generate models that can identify the different abnormal states from the measured variables. Models' performance is compared, and the best candidate selected for doing real-time anomaly detection and predictive maintenance of similar AC electric motors.Item Applicability of existing models for the strength development of 3D-printed thixotropic concretes during hardening(2023) Castano-Alvarez, Ruben; Calderon-Uriszar-Aldaca, Iñigo; Marcos, Ignacio; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; Tecnalia Research & InnovationThe special properties of 3 D-Printed Concrete in terms of rheology, deposition technology, and dosage substantially modify its mechanical properties after hardening. In this paper, comparisons are drawn between different concrete strength development models specified in the main Building-Codes and Standards and experimental data from tests on various thixotropic mortar mixes suitable for 3DPC. The aim was to develop an empirical procedure to improve the current models, so that their results could predict the properties of the 3DPC bulk materials more closely. An updated set of parameters for the models was obtained via curve-fitting of the models to the experimental data.Item Application of double loop electrochemical potentiodynamic reactivation test to austenitic and duplex stainless steels(1997-06-30) Lopez, Nathalie; Cid, Mariano; Puiggali, Monique; Azkarate, Inaki; Pelayo, Alberto; Tecnalia Research & InnovationDouble loop electrochemical potentiodynamic reactivation (DLEPR) tests are performed on an austenitic (317L) and an austeno-ferritic (UNS S31803) stainless steels. In order to optimise results, the standard electrochemical solution has been modified by adding NaCl to the composition and by increasing the concentration of H2SO4. Results show a high resistance to intergranular corrosion of the 317L heat treated at 675°C for 30 min to 24 h. On contrast, the duplex stainless steel corrosion resistance decreases with time of sensitisation. Low exposure time (1 h at 675°C) provides low reactivation current density whereas longer exposure time (10 h) shows an increase in the value of this reactivation current, which is due to the formation of chromium carbides and sigma phase at grain boundaries leading to more chromium depleted areas. Heat treatment at 900°C shows a high reactivation proportional to σ-phase precipitation. The aim of this work is to validate the DLEPR technique for detecting susceptibility to intergranular corrosion of duplex stainless steels. This test is not yet normalised and could be used for on-site measurement.Item An Approach to Holonic Components in Control of Machine Tools(1996) Bengoa, A.; Gluch, S.; Jacobs, H. J.; Bueno, R.; Tecnalia Research & InnovationThis paper describes a first step in transfer of machine tools to HOLONIC MACHINING UNITS (HMU). The solution proposed is based on dynamic, NC-internal self-planning of cutting conditions. Supposing this approach, real time adaption of the required machining time to the available time budget can be carried out. In this way the autonomous HMU is able to survive disturbances without any reaction on job-shop-control. Cooperation of machine tools with the same properties to fulfil an order is possible, too. The first soft- and hardware implementation of holonic behaviour within a machine tool's CNC is represented by the so-called Optimizing Controller.Item ArmAssist: An integrated solution for telerehabilitation of post-stroke arm impairment(Springer International Publishing, 2013) Perry, Joel C.; Zabaleta, Haritz; Belloso, Aitor; Rodríguez-de-Pablo, Cristina; Cavallaro, Francesca I.; Keller, Thierry; Tecnalia Research & InnovationThere is growing consensus that new technologies in rehabilitation robotics and telerehabilitation systems can lessen the strain on the healthcare system by shifting the focus toward at-home rehabilitation and providing patients with more training autonomy. In this paper, a recently developed integrated solution for providing at-home telerehabilitation is presented. The system combines a low-cost mobile device and table mat for arm reach support, a large touchscreen PC, and a web-based telerehabilitation platform with serious games for assessment and training. The ArmAssist system represents a new generation of tools for reducing the burden of hands-on supervision in clinical stroke rehabilitation and has been met with initial praise for its ease of use in the clinical setting and motivational benefits for the patient.Item ArmAssist: Development of a functional prototype for at-home telerehabilitation of post-stroke arm impairment(2012) Perry, Joel C.; Zabaleta, Haritz; Belloso, Aitor; Rodriguez-De-Pablo, Cristina; Cavallaro, Francesca I.; Keller, Thierry; Tecnalia Research & InnovationGrowing numbers of stroke survivors are leading to increasing numbers of motor deficits, the majority of which include deficiencies in arm function. There is a strong need, therefore, to find new tools and strategies for providing efficient and effective sub-acute patient care. The requirements for such a device are outlined from both patient and therapist perspectives, and a new prototype system for sub-acute arm training in post-stroke care is presented. The complete system is composed of a base module with quick-connecting hand and forearm orthoses, a global position detection mat, and an all-in-one touchscreen PC with telerehabilitation software and interfaces. The size and portability of the system allow it to be easily moved and setup in the patient home to enable increased durations and intensity of training outside of the standard inclinic care.Item Assessment of an Adaptive Cruise Control Based on Model Predictive Control for Buses under Passenger Load Distribution Variation(Institute of Electrical and Electronics Engineers Inc., 2021-09-19) Matute, Jose A.; Diaz, Sergio; Zubizarreta, Asier; CCAMCar and pedestrian impacts are one of the most frequent accidents on the roads due to driver distraction or misjudgment of traffic. In urban environments, these accidents normally occur at relatively low speeds where the impacted car is already at standstill, or the pedestrian suddenly crosses the path. Although current Adaptive Cruise Control (ACC) technology is available for different vehicle types, it mostly addresses use cases that may have limited applicability for urban passenger buses (e.g., high speeds on divided highways). In this work, the design and verification of a novel ACC based on Model Predictive Control (MPC) for a 12m urban bus is presented. As in transit applications, the influence of the passenger bus load distribution is considered to evaluate the ACC capability to offer both safety and comfort. Moreover, performance limitations such as maximum deceleration, sensor ranging, and actuation time-lag are modeled to resemble real systems. The approach is verified in a virtual environment considering three challenging driving scenarios under 30km/h: Car-to-Car Rear (CCR) stationary, CCR braking, and car-to-pedestrian. Results demonstrate the robustness of the verified system, assuring both safe and comfortable behavior regardless of the load distribution and performance limitations.Item AUDRIC2: A Modular and Highly Interconnected Automated Driving Framework Focus on Decision Making and Vehicle Control(Institute of Electrical and Electronics Engineers Inc., 2021-09-19) Lattarulo, Ray; Hidalgo, Carlos; Arizala, Asier; Perez, Joshue; CCAMLast years, automated vehicle technologies made considerable progress in academia and the industry. However, there is still a need for more scalable solutions which ensure fast progress between the prototypes and the final deployments. In this sense, this work introduces the updated version of the AUtomated DRIving Core framework (AUDRIC), which aims for robust and reliable vehicle decision-making and control algorithms. The solution is modular and provides MATLAB and ROS interfaces. Also, it has the integration links between the CARLA simulator and Dynacar (in-house simulator). The Autoware. AI framework was integrated to support vehicle perception. This framework targets non-holonomic ground vehicles, such as passenger cars, buses, shuttles, non-holonomic industrial AGV, etc. A simulation around Tecnalia premises was used to verify the provided functionalities (Basque Country, Spain). This framework will continue its development with the support of the European project SHOW. Vehicle cooperation functions are considered as an upcoming feature.