Abstract: Predicting energy consumption has become a critical issue for energy-intensive industrial contexts. A significant contribution to their overall energy load is due to the Heating Ventilation and Air Conditioning (HVAC) systems. This work, therefore, aims to validate the applicability of a probabilistic graphical approach, the Bayesian Network, in predicting the HVAC systems' energy consumption. As a data-driven approach, it is compared with more common AI-based models like Support Vector Machine, Artificial Neural Networks and Random Forest. The graphical approach ensures a better interpretation of the main factors determining the energy consumption and the relationships underlying these dependences. After an initial contextualisation and an analysis of the state of the art, the design methodology of a Bayesian network is investigated in detail, deepening in the various solutions for each step and evaluating their performance through the application on two industrial case studies. The results show that Bayesian networks, despite not always providing the best results, are a valid solution, trading off between simplicity, flexibility, and performance. Moreover, the possibility to provide a physical interpretation of the results is one of its main strengths. The critical aspect encountered, instead, is the need for discretisation, which strongly influences the quality of the results.

Keywords: Bayesian networks | Energy consumption prediction | HVAC systems | Industrial engineering | Machine learning

Abstract: This work proposes a multi-domain modelling methodology to support the design of new battery packs for automotive applications. The methodology allows electro-thermal evaluation of different spatial arrangements of the storage cells by exploiting the implementation of numerical and geometrical battery pack models. Concerning the case study on Li-NMC battery technology, the study has completed the electro-thermal characterization of the storage cells starting from the collected experimental data, considering both the thermal interactions among cells and the effects of the state of health. This work also investigates the effects of forced air-cooling systems focusing on battery pack hot spots and temperature distributions. The results show a good fit between numerical models and data obtained from single-cell experiments. The virtual linking of geometric and numerical lumped-parameter models proved to be effective in rapid battery pack prototyping for electric vehicles, helping designers and manufacturers find suitable solutions for specific automotive applications.

Keywords: Battery electric vehicles | Electro-thermal analysis | Multi-domain modelling

Abstract: Virtual prototyping is a strategic practice in the research and development of innovative products and machine tools. Virtual prototyping allows the integration of multidomain simulations into the designing process to replicate and analyze the impact of design choices on the overall system performance, reducing time-to-market while simultaneously improving quality. The current paper provided a methodological approach to model complex machine tools and perform virtual testing. As a use case for this study, a parallel kinematic machine (Pentapod P800, METROM Mechatronische Maschinen GmbH, Germany) is investigated. The adoption of these complex machine tools within the industrial context and the design of parallel kinematic machines can be eased by the implementation of methodologies capable of reducing efforts and risks during the analysis and the testing phases, prior to actual commissioning. In this scenario, virtual testing guarantees generality, completeness, and quick response. Therefore, the multibody model of the Pentapod P800 was developed following the proposed framework. Then, the simulation of a test trajectory was successfully carried out. The results show that this approach might lead to the design and implementation of a parallel kinematics machine reducing risks, time, and costs.

Keywords: Digital modelling | Multibody modelling | Parallel kinematic machines | Virtual prototyping

Abstract: Nowadays, the high competitiveness in the global market pushes companies to pursue innovation with the aim of reaching profitable results. Even if the adoption of Model-Based System Engineering (MBSE) as an innovative approach for robust design is rapidly spreading in companies, there is still a lack of collaboration between system engineers involved in the requirements management and architectures modelling, and designers of specific systems. For this reason, the present work aims to better connect the system description process with the solving process through the adoption of specific SysML diagrams during preliminary design steps. A direct connection between requirements and design parameters is proposed by means of a well-defined process that fits into the wider V-Model for system development. The whole process enables (i) the rapid development of new models focusing on the connection between requirements and parameters, (ii) tracking of the designing process as well as (iii) the evaluation of performance requirements. This approach is applied to a case study of the Thermal Management System for a hybrid-electric aircraft, focusing on enabling the connection between system description and system development.

Keywords: Model-Based Systems Engineering (MBSE) | Parametric Analysis | Requirements Management | Sizing Modelling Framework | SysML

Abstract: According to the Industry 5.0 framework, the smart factory should combine digitalization and prediction activities with a greater sustainability and human centrality within working processes. Indeed, the optimization and improvement of the manufacturing processes have to meet cost criteria related to energy consumption, safety, and implementation of new technologies. The development of better and more advanced technologies boosts Human-Robot Interaction (HRI) in the manufacturing processes. However, due to the high number of safety standards about collaborative robotics and the absence of tools and specific design approaches, collaborative robots (cobots) are still widely adopted as traditional industrial robots wasting the huge potential of a properly Human-Robot Collaboration (HRC). The layout designing is a crucial activity in achieving a proper and effective HRC. This work illustrates how to transfer standard-compliant layout solutions towards an interactive three-dimensional (3D) visualization environment in order to enable the digital prototyping of HRC workplaces. The possibility to automatically generate and visualize multiple layout solutions of collaborative workplaces, and then, to simulate the interaction between human and robot, represents one of the most significant tasks during the designing process. HRC workplace layout is designed according to an optimization criterion, by using the full integration of a numerical computing platform with an interactive 3D visualization environment. Then, by means of the variation of the input parameters, the visualization of new layout solutions is enabled in a fast and effective way.

Keywords: Human-robot collaboration | Industry 5.0 | Interactive prototyping | Workplace layout

Abstract: In the Model-Based Enterprise (MBE) paradigm, digital product models are the primary source of information to support the design, analysis, and manufacturing of products. The master geometry of these product models is generally built procedurally in a CAD system, typically as history-based parametric geometry. However, some model conversion and exchange processes imply losing procedural information (i.e. the internal structure that represents how the model was built). In this position paper, we review the state of the art in procedural CAD model exchange and discuss an approach for conveying procedural information during model exchange. Although not available in practice, the approach is currently theoretically feasible, as the exchange of procedural information is already supported in modern neutral formats. Finally, we develop our position by advocating for defining Conformance Classes to facilitate the practical development of the ISO 10303 AP 242 standard, thus enabling official implementations that can provide full exchange capabilities for procedural CAD models.

Keywords: Neutral formats | Procedural CAD models | STEP

Abstract: Managing the complexity of modern systems is a current challenge involving all the phases of a system development process. Complex systems also mean a great number of stakeholders involved and just as many needs to satisfy. In the Systems Engineering approach for complex systems design, Requirements Engineering provides methods to collect stakeholders needs and to translate them into system requirements. Furthermore, several tools currently allow creating requirements repository and manage their properties and changes. Traceability is also implemented to verify design against requirements. Although there are several standards and guidelines which provide criteria and rules for writing requirement statements, it is still missed a process that drives the user in the correct requirement construction. The present paper faces the requirement specification process in order to provide tools that can support and drive designers in the requirements writing. In particular, the paper (i) provides a framework for writing syntactically correct requirements that can be early verified against pre-defined criteria such as clarity, singularity, conformity, and descriptiveness; (ii) presents a software tool for creating well-defined requirements statements offering the user the possibility to formulate “correct requirements by construction”. The driven definition of system requirements leads to a well-defined specification, thus allowing time and efforts reduction during the following steps of system development process.

Keywords: Consistency analysis | Requirements specification | Rules implementation | Systems Engineering

Abstract: Describing and supplementing geometric shapes (parts) and layouts (assemblies) with relevant information is key for successful product design communication. 3D annotation tools are widely available in commercial systems, but they are generally used in the same manner as 2D annotations in traditional engineering drawings. The gap between technology and practices is particularly evident in plain text annotations. In this paper, we introduce a functional classification of text annotations to provide an information framework for shifting traditional annotation practices towards the Model-Based Definition (MBD) paradigm. In our view, the current classification of dimensions, tolerances, symbols, notes, and text does not stress the inherent properties of two broader categories: symbols and text. Symbol-based annotations use a symbolic language (mostly standardized) such as Geometric Dimensioning and Tolerancing (GD&T) to provide precise information about the implications of geometric imperfections in manufacturing, whereas notes and text are based on non-standardized and unstructured plain text, and can be used to convey design information. We advocate that text annotations can be characterized in four different functional types (objectives, requirements, rationale, and intent), which should be classified as such when annotations are added to a model. The identification and definition of a formalized structure and syntax can enable the management of the annotations as separate entities, thus leveraging their individual features, or as a group to gain a global and collective view of the design problem. The proposed classification was tested with a group of users in a redesign task that involved a series of geometric changes to an annotated assembly model.

Keywords: Annotations | Model-based definition | Text annotations

Abstract: Optimizing and predicting the energy consumption of industrial manufacturing can increase its cost efficiency. The interaction of different aspects and components is necessary. An overarching framework is currently still missing, and establishing such is the central research approach in this paper. This paper provides an overview of the current demands on the manufacturing industry from the perspective of digitalization and sustainability. On the basis of the developed fundamentals and parameters, a superordinate framework is proposed that allows the modelling and simulation of energy-specific properties on several product and process levels. A detailed description of the individual methods concludes this work and demonstrates their application potential in an industrial context. As a result, this integrated conceptual framework offers the possibility of optimizing the production system, in relation to different energy flexibility criteria.

Keywords: digital transformation | digital twin | energy management | life cycle assessment | sustainability

Abstract: This paper deals with the thermal management of Li-NMC battery packs for their use in electric vehicle applications. In particular, starting from a literature analysis, different kinds of battery thermal management systems (BTMSs) are evaluated and compared, in terms of their main advantages and drawbacks related to cost and complexity. A specific case study focused on a BTMS, based on forced air cooling, for a Li-NMC battery pack is then proposed, with the application of a simple temperature control strategy. Numerical evaluations are carried out in simulation environment by means of a Matlab/Simulink storage cell electro-thermal model, which has been parametrized and validated through experimental procedures. Simulation results, obtained in different operative conditions, highlight the positive effects of using BTMS with particular reference to high power demanding battery charging and discharging operations.

Keywords: Battery Pack | Battery Thermal Management System | Electric Vehicle | Lithium-ion | Thermal Modelling

Abstract: In this paper, a human-centered design methodology is proposed to support the interiors design of a Maritime Patrol Aircraft (MPA). The combined use of Immersive Virtual Reality (VR) tools and Digital Human Models (DHMs) are exploited to include both objective and subjective measurements in the ergonomic evaluation process. The main issue consisted in defining the optimal ergonomic design configuration for Operator Console Area and Observer Window Area of MPA's digital mock-up, provided by Leonardo S.p.A. The methodology is based on a five-step iteration process: once having identified the requirements, required input data and the design variables, the ideated configuration is evaluated using DHMs in order to retrieve objective measurements (i.e., interferences, visibility, reachability); finally, a subjective assessment within immersive VR environment is conducted. A real-time RULA analysis is carried out on DHMs, calibrated on selected users representing specific percentages of target population, by means of a full-body tracking system. The subjective assessment in immersive VR allows to take into account also other human factors (i.e. human ability, dexterity and cognitive aspects) that have not been previously considered and may significatively influence the validation of the final design configuration of MPA interiors.

Keywords: Digital Human Modeling | Digital Mock-up | Ergonomic Validation | Maritime Aircraft | Virtual Reality

Abstract: This study aims to investigate the impact of laser beam shaping on metal mixing and molten pool dynamics during laser beam welding of Cu-to-steel for battery terminal-to-casing connections. Four beam shapes were tested during LBW of 300 µm Cu to 300 µm nickel-plated steel. Both experiments and simulations were used to study the underlying physics. A CFD model was firstly calibrated against experiments and then deployed to explore the effect of the increasing ring-to-core diameter, as well as a tandem laser spot configuration. The study showed that metal mixing is influenced by the keyhole dynamics and collapse events, but also there is an intricate interplay between keyhole geometry, fluid dynamics via Marangoni forces and buoyancy forces. Notably, the buoyance forces due to the different densities of steel and Cu, along with the recoil pressure contribute to the upward flow of steel towards Cu, and hence impact meaningfully the material mixing. The study pointed-out that the selection of a custom ring-to-core diameter and ring-to-core power is a decision with a trade-off between the need of stabilising the keyhole dynamics and the need to reduce the mixing. Findings indicated that 350 µm ring and 90 µm core with 30% of ring power (weld configuration C3) resulted in more stable dynamics of the keyhole, with significant reduction of collapse events, and ultimately controlled migration of steel towards Cu. Additionally, the pre-heating approach with the tandem beam only led to local fusion of Cu and no significant improvement in keyhole stability was observed.

Keywords: Battery pack manufacturing | CFD simulation | Cu-to-steel welding | Laser beam shaping | Metal mixing and molten pool dynamics

Abstract: The automotive production sector plays a significant role in the energy consumption of all the industrial sphere, which currently represents approximately 38% of the total global energy use. Especially in production sites with several manufacturing lines working in parallel, the occurrence of failures and anomalies or sudden changes in the production volume may require a re-scheduling of the entire production process. In this regard, a digital twin of each phase of the process would give several indications about the new re-scheduled manufacture in terms of energy consumption and the control strategy to adopt. Therefore, the main goal of this paper is to propose different modeling approaches to a degreasing tank process, which is a preliminary phase at automotive production sites before the application of paint to car bodies. In detail, two different approaches have been developed: the first is a physics-based thermodynamic approach, which relies on the mass and energy balances of the system analyzed, and the second is machine learning-based, with the calibration of several artificial neural networks (ANNs). All the investigated approaches were assessed and compared, and it was determined that, for this application and with the data at our disposal, the thermodynamic approach has better prediction accuracy, with an overall mean absolute error (MAE) of 1.30 °C. Moreover, the model can be used to optimize the heat source policy of the tank, for which it has demonstrated, with historical data, an energy saving potentiality of up to 30%, and to simulate future scenarios in which, due to company constraints, a re-scheduling of the production of more work shifts is required.

Keywords: artificial neural network | automotive production process | digital twin | model predictive control | paint shop | physics-based model

Abstract: In the context of Industry 4.0 and Industry 5.0, the introduction of collaborative workplaces, where humans and robots work together, represents a growing trend to improve the productivity, adaptability, and flexibility of production plants. Indeed, human–robot collaboration (HRC) is a very deepened topic in the scientific community and the designing of collaborative workplaces is a challenging issue due to the high level of complexity and multidisciplinary of its features. This work tackles the complexity of collaborative workplaces and proposes a structured framework to support strategic decisions in designing. A multi-level designing framework is proposed as a supporting tool for designers. Within five domains of collaborative robotics, the elements of a collaborative workplace are identified and proposed in a framework in order to better consider human safety and working conditions during the designing process. A decomposition matrix and an adjacency matrix are used to develop a multi-level designing workflow. Finally, an interactive tool is presented, named “Smart Graph Interface” (SGI), to read and exploit the contents of the framework. The SGI is applied to three case studies from the literature, to spread out principal outcomes in terms of applicability and robustness.

Keywords: Collaborative workplace design | Graph theory | Human–robot collaboration | Multi-level design | User interface

Abstract: This paper addresses sensor characterization to detect variations in part-to-part gap and weld penetration depth using photodiode-based signals during remote laser welding (RLW) of battery tab connectors. Photodiode-based monitoring has been implemented largely for structural welds due to its relatively low cost and ease of automation. However, research in sensor characterization, monitoring, and diagnosis of weld defects during joining of battery tab connectors is at an infancy and results are inconclusive. Motivated by the high variability during the welding process of dissimilar metallic thin foils, this paper aims to characterize the signals generated by a photodiode-based sensor to determine whether variations in weld quality can be isolated and diagnosed. Photodiode-based signals were collected during RLW of copper-to-steel thin-foil lap joint (Ni-plated copper 300 μm to Ni-plated steel 300 μm). The presented methodology is based on the evaluation of the energy intensity and scatter level of the signals. The energy intensity gives information about the amount of radiation emitted during the welding process, and the scatter level is associated with the accumulated and un-controlled variations. Findings indicated that partto- part gap variations can be diagnosed by observing the step-change in the plasma signal, with no significant contribution given by the back-reflection. Results further suggested that over-penetration corresponds to significant increment of the scatter level in the sensor signals. Opportunities for automatic isolation and diagnosis of defective welds based on supervised machine learning are discussed.

Keywords: advanced materials and processing | inspection and quality control | laser processes | sensors | welding and joining

Abstract: Nowadays, several manufacturing systems are evolving towards a greater collaboration between human and robots. The development of such systems requires integrated design tasks involving many disciplines and domains such as systems engineering, safety analyses and multiphysics. Furthermore, the increasing presence of multiple and structured requirements makes the use of models inevitable during the designing phases and also strongly helpful during other phases of the system life-cycle. Besides, for a better efficiency, there is an increasing demand to have a Digital Twin of the system to be used for different purposes such as design improvements by playing different scenarios, virtual commissioning and controlling maintenance activities. In this paper, we first summarize the research context, the reference methodologies, and the emerging needs for Digital Twin creation. Then, we apply a design approach including Model-Based Systems Engineering (MBSE), Model-Based Safety Assessment (MBSA) and multi-physics modeling for the design of a collaborative workplace for the assembly of Electro-Mechanical Actuators on an aircraft wing. An operational flow to integrate MBSE, MBSA and multi-physics modelling activities is provided. Then, after having identified some relevant scientific barriers, we provide a meta-model for system models integration within a digital twin framework.

Keywords: Collaborative workplace | Digital twin definition | MBSA | MBSE | Multiphysics modelling and simulation | Safety critical systems

Abstract: Enabling technologies that drive Industry 4.0 and smart factories are pushing in new equipment and system development also to prevent human workers from repetitive and non-ergonomic tasks inside manufacturing plants. One of these tasks is the order-picking which consists in collecting parts from the warehouse and distributing them among the workstations and vice-versa. That task can be completely performed by a Mobile Manipulator that is composed by an industrial manipulator assembled on a Mobile Robot. Although the Mobile Manipulators implementation brings advantages to industrial applications, they are still not widely used due to the lack of dedicated standards on control and safety. Furthermore, there are few integrated solutions and no specific or reference point allowing the safe integration of mobile robots and cobots (already owned by company). This work faces the integration of a generic mobile robot and collaborative robot selected from an identified set of both systems. The paper presents a safe and flexible mechatronic interface developed by using MBSE principles, multi-domain modeling, and adopting preliminary assumptions on the hardware and software synchronization level of both involved systems. The interface enables the re-using of owned robot systems differently from their native tasks. Furthermore, it provides an additional and redundant safety level by enabling power and force limiting both during cobot positioning and control system faulting.

Keywords: Human safety | Mbse | Mechatronic system | Mobile cobot | Mobile manipulator | Mobile robot

Abstract: In the paradigm of Industry 4.0, innovative workplaces characterized by Human-Robot Collaboration represent an important topic to improve productivity and adaptability of manufacturing plants. In this context, the design of a collaborative workplace is a challenging issue because of the high level of complexity due to multidisciplinary and non-homogeneity of its features, as well as the presence of human very close to the robot. This work faces with the complexity of collaborative workplace and proposes a structured framework to support strategic decisions in designing. It suggests a clusterization of factors and effects, based on five domains involved in collaborative workplace, in order to better consider the human safety and working conditions. Consequently, the main elements of a collaborative workplace are highlighted in a matrix decomposed in relevant features and main incident factors, and a multi-level designing workflow is described to report collaborative performances. The proposed approach manages connections among the elements by means of the graph theory in the form of an adjacency matrix in order to show and manage the complexity of the problem. A user interface named Smart Graph Interface was developed to read and manipulate the contents of the adjacency matrix. Main results are reported on an assembly and sealing of a refrigerator, to spread out principal outcomes in terms of applicability and robustness.

Keywords: Collaborative workplace design | Graph theory | Human-robot collaboration (HRC) | Multi-level designing | User interface

Abstract: Nowadays, the commercial translation of additive manufacturing technologies for scaffolds fabrication is still a challenge. The production methodology of 3D scaffolds for tissue regeneration is a complex and discontinuous process involving several stages, from the isolation of the stem cells to the dynamic cell culture in vitro. Even though in this scenario industries are increasingly implementing automated robotic systems, current technologies are not enough to realize a large industrial scale scaffold fabrication. Accordingly, a relevant improvement could raise from the implementation of a modern collaborative workplace in an existing production line, combining strength endurance and accuracy of cobots, with intelligence, flexibility, and adaptability of the human being. Such a solution overcomes limits related to the low level of process control, low productivity, and risk of contaminations. Therefore, the current work proposes a systematic approach to the design of a collaborative workplace for biomanufacturing of 3D scaffolds. Starting from an overview of basic concepts on scaffolds for tissue engineering and additive manufacturing, as well as from an analysis of automation solutions in cell culture applications, a design methodology section is reported. The paper provides a further insight into the potentials to upscale the scaffolds manufacturing process, taking advantage of the huge possibilities given from the Human-Robot Collaboration and gives evidence of critical features for workplace definition.

Keywords: Automatic layout generation | Biomanufacturing | Human-Robot Collaboration (HRC) | Workplace design

Abstract: Remote Laser Welding (RLW) of dissimilar metallic thin foils (below 500 µm) has fundamental importance in battery pack manufacturing where high repeatability is a strict requirement. Since the welding process is very sensitive to part-to-part gaps, it is critical to understand the physical phenomena during melting, formation of the keyhole and solidification. This study has been designed to investigate the underlying physics of the welding process and understand the influence of the laser beam wobbling and part-to-part gap on temperature fields and metal mixing. A CFD multi-physics model has been implemented and then calibrated with experimental data. Two scenarios with part-to-part gap (0 and 100 µm) have been considered during lap welding of 300 µm copper to 300 µm nickel-plated steel, with circular beam wobbling. The study has highlighted that the part-to-part gap leads to uncontrolled metal mixing. Potential strategies for weld optimization are discussed throughout the paper.

Keywords: battery pack manufacturing | CFD simulation | dissimilar metals & metal mixing | laser beam wobbling | part-to-part gap | remote laser welding

Abstract: This paper has been designed to study whether photodiodes and supervised machine learning (ML) algorithms are sufficient to automatically classify weld defects caused by simultaneous variation of the part-to-part gap and laser power during remote laser welding (RLW) of thin foils, with applications in battery tabs. Photodiodes are used as the primary source of data and are collected in real-time during RLW of copper-to-steel thin foils in the lap joint. Experiments are carried out by the nLight Compact 3 kW fiber laser integrated with the Scout-200 2D scanner. The paper reviews and compares seven supervised ML algorithms (namely, k-nearest neighbors, decision tree, random forest, Naïve-Bayes, support vector machine, discriminant analysis, and discrete wavelet transform combined with the neural network) for automatic classification of weld defects. Up to 97% classification rate is obtained for scenarios with simultaneous variations of weld penetration depth and part-to-part gap. The main causes of misclassification are imputed to the interaction between welding parameters (part-to-part gap and laser power) and process instability at high part-to-part gap (high variation in the process not captured by the photodiodes). Arising opportunities for further development based on sensor fusion, integration with real-time multiphysical simulation, and semi-supervised ML are discussed throughout the paper.

Keywords: Classifiers | Decision trees | Defects | Discrete wavelet transforms | Discriminant analysis | Electric batteries | Laser beam welding | Nearest neighbor search | Photodiodes

Abstract: Nowadays, mechatronic systems are used in every field and all around us, going through micro, small, medium and large power systems. Due to their widespread use, mechatronic system design plays an important role in energy sustainability.Mechatronic systems are generally complex systems from a modelling point of viewdue to the presence of several domains and a set of related interfaces for energy exchanges. Such a context needs a multi-domain and integrated design to correctlyevaluate mechatronic system performances. Modelling and simulation tasks are generally adopted to evaluate the behaviour of mechatronic systems in order to meet system requirements. Unfortunately, energy saving is not always considered among the set of primary requirements, while it is tackled only after reaching the expected system behaviour. The present chapter tackles themulti-domainmodelling and simulationof mechatronic systems according to V-model steps and using the RFLP approach driven by sustainability requirements. The key idea is to perform a concurrent evaluation of energy and domain performances. It summarises a case study, by using Matlab/Simscape environment, to illustrate the used approach. Moreover, it introduces the design of mechatronic systems pulled by environmental sustainability as a new paradigm in opposition to the design pushed by system performances.

Abstract: The innovation-driven Industry 5.0 leads us to consider humanity in a prominent position as the center of the manufacturing field even more than Industry 4.0. This pushes us towards the hybridization of manufacturing plants promoting a full collaboration between humans and robots. However, there are currently very few workplaces where effective Human–Robot Collaboration takes place. Layout designing plays a key role in assuring safe and efficient Human–Robot Collaboration. The layout design, especially in the context of collaborative robotics, is a complex problem to face, since it is related to safety, ergonomics, and productivity aspects. In the current work, a Knowledge-Based Approach (KBA) is adopted to face the complexity of the layout design problem. The framework resulting from the KBA allows for developing a modeling paradigm that enables us to define a streamlined approach for the layout design. The proposed approach allows for placing resource within the workplace according to a defined optimization criterion, and also ensures compliance with various standards. This approach is applied to an industrial case study in order to prove its feasibility. A what-if analysis is performed by applying the proposed approach. Changing three control factors (i.e., minimum distance, robot speed, logistic space configuration) on three levels, in a Design of Experiments, 27 layout configurations of the same workplace are generated. Consequently, the inputs that most affect the layout design are identified by means of an Analysis of Variance (ANOVA). The results show that only one layout is eligible to be the best configuration, and only two out of three control factors are very significant for the designing of the HRC workplace layout. Hence, the proposed approach enables the designing of standard compliant and optimized HRC workplace layouts. Therefore, several alternatives of the layout for the same workplace can be easily generated and investigated in a systematic manner.

Keywords: Digital layout optimization | Human–robot collaboration (HRC) | Knowledge-based approach (KBA) | What-if analysis

Abstract: Design process is usually based on past experiences and best practises which compose the company know-how. The challenge is to identify common patterns in the design solutions generated for different design problems. The present paper focuses on the identification of product patterns by using a graph-based approach. It deals with the designing of automotive gearboxes and with the development of an approach and a software tool aimed to support preliminary design and CAD modelling activities in gearbox designing. The approach is applied to two different architectures of manual transverse gearboxes characterized by two and three shafts. It aims at the identification of common design features through the detection of the directed graphs matching. A Matlab software tool for gearbox preliminary design is implemented according to the detected common features. The proposed approach and the developed software tool provide an effective way to keep and re-use company know-how, especially in the context of large automotive companies.

Keywords: CAD modelling | Graph theory | Graphical user interfaces | KBE | Product pattern

Abstract: Human–robot collaboration (HRC) solutions are replacing classic industrial robot due to the possibility of realizing more flexible production systems. Collaborative robot systems, named cobot, can work side by side with humans combining their strengths. However, obtaining an efficient HRC is not trivial; indeed, the potential advantages of the collaborative robotics increase as complexity increases. In this context, the main challenge is to design the layout of collaborative workplaces facing the facility layout problem and ensuring the safety of the human being. To move through the high number of safety standards could be very tiring and unproductive. Therefore, in this work a list of key elements, linked to reference norms and production needs, characterizing the collaborative workplace has been identified. Then, a graph-based approach has been used in order to organize and easily manage this information. The management by means graphs has facilitated the implementation of the acquired knowledge in a code, developed in Matlab environment. This code aims to help the designer in the layout organization of human–robot collaborative workplaces in standards compliance. The paper presents the optimization code, named Smart Positioner, and the operation is explained through a workflow diagram.

Keywords: Facility layout problem | Human–robot collaboration | Knowledge-based approach | Optimization criteria

Abstract: In Industry 4.0, the growing incorporation of cyber-physical systems (CPS) into manufacturing facilities composed of mechatronic products brings the need of reducing development cost while maintaining the quality and in parallel the need to adapt changes in the product development. It is then essential to identify the criticalities of mechatronic system development and to introduce an optimised product development approach. As a result, our research work focuses on combining traditional and agile approaches to improve mechatronic products development. To illustrate the advantages of such hybridisation, we propose a first hybrid approach along with the case study, consisting of some elements of the scrum method into the V-model which include the freedom to propagate necessary changes in product architecture during the development of its different modules. This new approach also focuses on the required guidelines to adopt and use for enhanced mechatronic products development and criteria for evaluation of the proposed method. Finally, in order to provide flexibility in product architecture and modules design, the hybrid development process is presented with illustrative case study.

Keywords: Agile approach | Black box analysis | Case study | Hardware-in-loop | HIL | Hybrid approach | Mechatronic products development | MIL | Model-in-loop | Scrum | SIL | Software-in-loop | V-model | White box analysis

Abstract: This paper addresses in-process monitoring of part-to-part gap and weld penetration depth using photodiode-based signals during Remote Laser Welding (RLW) of battery tab connectors. Photodiode-based monitoring has been largely implemented for structural welds due to its relatively low cost and ease of automation. However, the application of photodiode-based monitoring to RLW of thin foils of dissimilar metals for battery tab connectors remains an unexplored area of research and will be addressed in this paper. Motivated by the high variability during the welding process of thin foils of dissimilar metals, this paper aims to evaluate the photodiode-based signals to determine if variations in weld quality can be isolated and diagnosed. The main focus is in diagnosing defective weld conditions caused by part-to-part gap variations and/or excessive weld penetration depth. Photodiode-based signals have been collected during RLW of copper-to-steel thin foils lap joint (Ni-plated copper 300 µm to Ni-plated steel 300 µm). The methodology is based on the evaluation of the energy intensity and scatter level of the signals. The energy intensity gives information about the amount of radiation emitted during the welding process, and the scatter level is associated to the accumulated and un-controlled variations. Findings indicated that part-to-part gap variations can be diagnosed by observing the step-change in the plasma signal, with no significant contribution given by the back-reflection. Results further suggested that over-penetration corresponds to significant increment of the scatter level in the sensor signals. Opportunities for automatic isolation and diagnosis of defective welds based on supervised machine learning will be discussed throughout the paper.

Keywords: Battery manufacturing | Battery tab connectors | Dissimilar materials | In-process monitoring | Photodiodes | Remote laser welding

Abstract: Complexity of dynamical systems are increasing more and more as well as their mathematical models. At the same time, simulation of system behaviour assumes a key role to assure the fulfillment of requirements as performances, quality, safety, and robustness. Therefore, due to model complexity, it is often very complex to assess a system behaviour but a reduction of model complexity could enhance the simulation aimed to specific characteristics of the system. Several useful model order reduction (MOR) techniques exist but each of them is often powerful for specific applications. This review paper deals with MOR by critically comparing the most popular MOR techniques from the fields of structural dynamics, numerical mathematics and systems and control. In particular, after different reduction techniques have been presented, a table summarizing their most important features is proposed, for comparison purpose. The motivation for such comparison stems from the fact that the insight obtained by the comparison allows to make a motivated choice for a particular model reduction technique, on the basis of the desired properties retained in the reduced model. Particular attention is paid on reduction techniques from the area of structural dynamics. Finally, the differences among some of the presented reduction techniques are illustrated, on a quantitative level, by means of their application to the case of a slewing flexible beam. In particular, in the application of the different reduction techniques, a consistent-mass finite element model, with only translational degrees of freedom, is employed as beam full model.

Abstract: The measurement of geometric and dimensional variations in the context of large-sized products is a complex operation. One of the most efficient ways to identify deviations is by comparing the nominal object with a digitalisation of the real object through a reverse engineering process. The accurate digitalisation of large geometric models usually requires multiple acquisitions from different acquiring locations; the acquired point clouds must then be correctly aligned in the 3D digital environment. The identification of the exact scanning location is crucial to correctly realign point clouds and generate an accurate 3D CAD model. To achieve this, an acquisition method based on the use of a handling device is proposed that enhances reverse engineering scanning systems and is able to self-locate. The present paper tackles the device's locating problem by using sensor data fusion based on a Kalman filter. The method was first simulated in a MatLAB environment; a prototype was then designed and developed using low-cost hardware. Tests on the sensor data fusion have shown a locating accuracy better than that of each individual sensor. Despite the low-cost hardware, the results are encouraging and open to future improvements.

Keywords: Handling device | Large-scale metrology | Position measurement | Product design | Sensor data fusion

Abstract: This paper deals with collaborative robotics by highlighting the main issues linked to the interaction between humans and robots. A critical study of the standards in force on human-robot interaction and the current principles on workplace design for human-robot collaboration (HRC) are presented. The paper focuses on an anthropocentric paradigm in which the human becomes the core of the workplace in combination with the robot, and it presents a basis for designing workplaces through two key concepts: (i) the introduction of human and robot spaces as elementary spaces and (ii) the dynamic variations of the elementary spaces in shape, size and position. According to this paradigm, the limitations of a safety-based approach, introduced by the standards, are overcome by positioning the human and the robot inside the workplace and managing their interaction through the elementary spaces. The introduced concepts, in combination with the safety prescriptions, have been organised by means of a multi-level graph for driving the HRC design phase. The collaborative workplace is separated into sublevels. The main elements of a collaborative workplace are identified and their relationships presented by means of digraphs.

Keywords: Anthropocentric approach | Collaborative environment | Digraph | Graph theory | Human-robot collaboration

Abstract: Traditional design processes must adapt to new industrial challenges, to the rapid evolution of technologies and the resulting complexity of systems. Today's industry, particularly in the field of mechatronics, must design and develop ever more innovative products while reducing time-to-market in order to maintain a competitive edge. As late changes during the realization and detailed design phases lead to a considerable increase in costs and design time, it is necessary to introduce more flexibility during the development process. The agile approach has already proven successful in the design of software system and offer many benefits, as it aims to limit the rigidity of the specifications, interfaces and organization, and to involve in a more flexible way the different actors, customers, specifiers and partners. In this context, we propose a MBSE approach to identify the set of requirements related both to the mechatronic product development and to the dynamic market, companies and current new trends, in order to define the SCRUM++ framework key concepts that aim to meet previous requirements, by supporting agile hybridization methods.

Keywords: Agile Hybrid Approach | Agility | Mechatronic Product Development | SCRUM

Abstract: In industry 4.0, the growing incorporation of cyber-physical systems (CPS) into manufacturing facilities composed of mechatronic products brings forth the need of reducing development cost while maintaining the quality and in parallel the need to adapt changes along the lifecycle of the product development. Most of the traditional development methods fail to solve such new challenges. However, some agile methods, widely used in the software industry, could meet these requirements. It is then essential to identify the criticalities of agile methods regarding mechatronic system development specificities. As a result, our research work focuses on combining traditional and agile approaches to improve mechatronic products development in a changing market context. The development of hybrid approach is based on the analysis of traditional, agile methods and consideration of challenges in the development of mechatronic products. To illustrate the advantages of such hybridization, we propose a first hybrid approach consisting of some elements of the Scrum method (the most popular agile approach) into the V-Model. Differentiating advantages of this new approach, compared to other agile methods, include the freedom to propagate necessary changes in product architecture during the development of its different modules. This new approach focuses on the hybridization of traditional and agile methods and the required guidelines to adopt and use for enhanced mechatronic products development. These guidelines are the base for changing the organizational culture and values which were previously associated with traditional development approaches.

Keywords: Agile approach | Hybrid approach | Mechatronic products development | Scrum | V-Model

Abstract: Collaborative robotic solutions, where humans and robots share a common workspace performing tasks concurrently without physical safety barriers dividing them, are entering the 4.0 manufacturing market. Some proven and tested use cases of Human-Robot Collaboration have been implemented, but their identification process is often just based on the intuition of planning engineers. The purpose of this work is to propose a systematic approach for the identification of potential collaborative workstations within an industrial production plant. In order to do this a multi-layer modelling approach was used and enriched. The multi-layer approach defines the overall goal of the industrial process, the sub-processes that made it possible, the activity models that enables a flow of activities and, finally, a set of methods to carry out the activities. A morphological box of methods that can be used to achieve the specific goal of identifying suitable collaborative workplaces in an industrial plant, through a process of HRC potential analysis is, therefore, ready to be deeply investigated and used.

Keywords: Collaborative workplaces | Evaluation criteria | Multi-layer approach

Abstract: The key findings about the use of a MOOC (Massive Open Online Course) at University of Naples Federico II are shown. In particular, the Engineering Drawing course for Industrial Engineering students was the pilot to evaluate the benefits of new Web-Based Platforms and Environments in higher education. The combination of In-Class and On-Line lessons is defined “Blended Course” and can be attended by students both in traditional classrooms and On-Line. It was provided during the last four academic years allowing the use of new tools (e.g., multimedia contents, interactive files). Thanks to about 7000 students involved in this project, several data were gathered for statistics and analysis purposes. Therefore, the access to the MOOC was monitored and the correlation with the homework was examined. At the end of the course, the level of satisfaction of the students about the interaction with the new platform was evaluated. The analysis of the results provided useful hints for the updating of the course in order to improve skills and interactive experience.

Keywords: Distant learning | eLearning | Engineering design education | Interactive learning

Abstract: The measurement of geometric deviations within large-size products is a challenging topic. One of the most applied technique compares the nominal product with the digitalization of real product obtained by a reverse engineering process. Digitalization of big geometric models is usually performed by means of multiple acquisitions from different scanning locations. Therefore, digitalization needs to correctly place the acquired point clouds in 3D digital environment. For this purpose, it is very important identifying the exact scanning location in order to correctly realign point clouds and generate an accurate 3D CAD model.The present paper faces the locating problem of a handling device for reverse engineering scanning systems. It proposes a locating method by using sensor data fusion based on Kalman filter, implemented in Matlab environment by using a low-cost equipment.

Keywords: Kalman filter | Position measurement | Product design | Prototypes | Reverse Engineering | Sensor data fusion

Abstract: The present paper deals with collaborative robotics and proposes to enable collaborative workstations by means of the critical study of the in-force standards on Human Robot Cooperation. The paper introduces the anthropocentric paradigm and presents a new basis for designing workstation composed by two key concepts: (i) human and robot spaces are elementary spaces able to generate all other spaces; (ii) dynamic variations of the elementary spaces in terms of shape, size and position occur. Moreover, dynamic positions of human and robot spaces enable collaborative operations in case of mobile robots.

Keywords: anthropocentric design | dynamic workspace | human-robot interaction | safety

Abstract: Robot programming usually consists of four steps: (1) task planning; (2) task sequencing; (3) path planning and (4) motion planning. Task (2) and (3-4) are strongly coupled. For example, the optimal robot path, which is function of the robot kinematics, relies on the pre-defined schedule of tasks, whose sequencing is computed based on the assumption that the travelling 'cost' from one task to the next is only driven by the Euclidean distance in Cartesian space. Current methods tends to decouple the problem and sequentially compute the task sequencing in the T-space, and then compute the robot path by solving the inverse kinematics in the C-space. However, those approaches suffer the capability to reach a global optimum. This paper aims at developing a novel approach which integrates some of the key computational requirements of the path planning in the early stage of the task sequencing. Multi-attribute objectives are introduced to take into account: robot pose and reachability, data quality, obstacles avoidance, overall cycle time. The paper introduces a novel multi-attribute approach to find the optimized task sequencing via candidate poses solving inverse kinematics in the T-space. This is based on the core idea to combine T-space and C-space. The proposed solution has been tested on a vision-based inspection robot system with application to automotive body assembly systems. Results could however impact a wider area, from navigation systems, game and graph theory, to autonomous driving systems.

Keywords: Multi-attribute Optimization | Robot vision system | Robotic task sequencing | TSPN

Abstract: High accuracy digitalisation of geometric models, related to big size objects, usually is performed by means of multiple acquisitions from different scanning locations. It needs to correctly place the acquired point clouds in 3D digital environment. For this purpose, it is very important identifying the exact scanning location in order to correctly realign point clouds and automatically generate an accurate 3D CAD model. The present paper focuses on design and prototype of a mobile handling device for reverse engineering scanning systems, named Dedalo. It is able to locate itself using a sensor fusion method based on a Kalman Filter. The sensor equipment is composed by wheel encoders and an ultrasonic sensor for measuring the distance from a known reference. Although Dedalo is equipped with low-cost hardware, results have showed a location accuracy by 0,1% error/meter, better than each sensor accuracy.

Keywords: Kalman filter | Position measurement | Product design | Prototypes | Reverse Engineering | Sensor data fusion

Abstract: This paper is aimed to experimentally analyse the effectiveness of a hybrid storage system, when powering a commercial vehicle for urban use. The hybrid energy storage system is composed by two ZEBRA batteries, combined with an electric double layer capacitor (EDLC) module. The integration of those storage systems is obtained by means of a bidirectional DC/DC converter, which balances the electric power fluxes between batteries and super-capacitors, depending on the driving operative conditions. Modeling and simulations are preliminarily conducted with reference to the specific case study of an electric version of the Renault Master, supplied by the above described hybrid storage system. That theoretical activity allows the optimization of rule based energy management strategies for the hybrid energy storage system, in terms of the effectiveness in reducing the negative effects of high charging/discharging currents on battery durability. Then, the experimentation of the real power train, connected to the mentioned hybrid storage system, is carried out through a 1:1 laboratory test bench, able to perform the analysed energy management strategies on standard driving cycles, representative of the urban mission of the commercial vehicle under study. The obtained experimental results, expressed through electrical and mechanical parameters in a wide range of road operative conditions, show that the super-capacitors can improve the expected battery lifespan, with values of maximum effectiveness up to 52%, for driving patterns without negative road slopes. The procedure followed and presented in this paper definitely demonstrates the good performance of the evaluated hybrid storage system, controlled by the DC/DC power converter, to reduce the negative consequences of the power peaks associated with the urban use of commercial vehicles.

Keywords: Dynamic test bench | Electric double layer capacitors | Electric vehicles | Energy management strategies | Hybrid storage systems | ZEBRA batteries

Abstract: The purpose of this paper is to assess the main effects on the geometric errors in terms of flatness, circularity and cylindricity based on the size of the printed benchmarks and according to the position of the working plane of the 3D printer. Three benchmark models of different sizes, with a parallelepiped and cylinder shape placed in five different positions on the working plane are considered. The sizes of models are chosen from the Renard series R40. Benchmark models are fabricated in ABS (Acrylonitrile Butadiene Styrene) using RepRap Prusa i3 3D printer. A sample of five parts for each geometric category, as defined from the R40 geometric series of numbers, is printed close to each corner of the plate, and in the plate center position. Absolute Digimatic Height Gauge 0–450 mm with an accuracy of ± 0.03 mm by Mitutoyo is used to perform all measurements: flatness on box faces, and circularity/cylindricity on cylinders. Results show that the best performances, in terms of form accuracy, are reached in the upper-left printable area while they decrease with the sample size. Being quality a critical factor for a successful industrial application of the AM processes, the results discussed in this paper can provide the AM community with additional scientific data useful to understand how to improve the quality of parts which may be obtained through new generations of 3D printer.

Keywords: Additive manufacturing | Fused deposition modelling | GD&T | Geometric errors

Abstract: The paper deals with the problem of tolerance specification and, in particular, proposes a graph-based method and a preliminary software tool: (i) to accomplish the tolerance specification for a mechanical assembly; (ii) to verify the consistency of the specification and, (iii) to allow the tracing of relationships among parts and features of the assembly. The method adopts Minimum Reference Geometric Elements (MRGE), directed graphs (di-graphs) and a set of dedicated algorithms to tackle the problems of consistency that occur during an interactive tolerance specification activity. Finally, an application illustrates the proposed method and its actual implementation.

Keywords: Datum | GD&T | graph theory | MRGE | tolerance specification

Abstract: Simulation results are not representative of a real system behavior up to its model validation. Validation activity needs a model characterization to match real system and model parameters. This activity impacts more on mechatronics systems which are affected by both physical and control characterizations. This work deals with single bowden power window systems; it improves a system model, previously developed, by deepening window aspects and force system. Force types and modules have been obtained by several experimental tests, in different operating conditions. Experimental automated tests have been carried out by means of a new virtual instrument developed in LabVIEW® environment. Comparison of test results highlights three main components related to: sliding friction, window friction and gravity. These components are affected by window shape which induces module variations. We named these variations 'window shape effect and these results bring to a new procedure for system validation.

Keywords: experimental test | mechatronic system | single bowden power window system | system model validation | validation

Abstract: In this paper we present an approach for the automatic generation of simulation workflow diagrams used for system verifications. By using this approach, the system engineer can specify the verification components at the system development phases. The workflow description is generated with an algorithm that converts the system level specifications to XDSM diagrams. These diagrams help in the communication and collaboration between system engineers and other discipline engineers. They also help in implementing the verification process in dedicated MDO/MSDO software frameworks. An example of a speed reducer system is considered to illustrate the usefulness of the proposed approach.

Keywords: MSDO | Speed Reducer | System verification | XDSM

Abstract: Design team belonging to powertrain divisions can speed up the process of managing information, within gearbox design activities, by adopting digital pattern tools. These tools, belonging to a knowledge-based engineering (KBE) system, can assist engineers in re-using company knowledge in order to improve time-consuming tasks as retrieval and selection of previous architectures and to modify and virtually test a new gearbox design. A critical point in the development of a KBE system is the usability of user’s interface to demonstrate effective reduction of development time and satisfaction in its use. In this paper, the authors face the problem of usability improvement of the graphical user interface (GUI) of the tool belonging to the KBE system and previously proposed. An approach based on analytic hierarchy process and multiple-criteria decision analysis is used. A participatory test is performed for evaluating the usability index of the GUI. Taking into account the data analysis, some changes are carried out and a new GUI release is validated through new experimentations.

Keywords: Gearbox design | Graphical user interface | Participatory design | Usability assessment

Abstract: Recent advances in manufacturing industry, and notably in the Industry 4.0 context, promote the development of CPSs and consequently give rise to a number of issues to be solved. The present paper describes the context of the extension of mechatronic systems to cyber-physical ones, firstly by highlighting their similarities and differences, and then by underlining the current needs for CPSs in the manufacturing sector. Then, the paper presents the main research issues related to CPS design and, in particular, the needs for an integrated and multi-scale designing approach to prevent conflicts across different design domains early enough within the CPS development process. To this aim, the impact of the extension from mechatronic to Cyber-Physical Systems on their design is examined through a set of existing related modelling techniques. The multi-scalability requirement of these techniques is firstly described, concerning external/internal interactions, process control, behaviour simulation, representation of topological relationships and interoperability through a multi-agent platform, and then applied to the case study of a tablets manufacturing process. Finally, the proposed holistic description of such a multi-scale manufacturing CPS allows to outline the main characteristics of a modelling-simulation platform, able notably to bridge the semantic gaps existing between the different designing disciplines and specialised domains.

Keywords: CPS design | Manufacturing systems | Mechatronic design | Multi-scalability

Abstract: The purpose of this paper is to assess the main effects on the geometric errors in terms of flatness, circularity and cylindricity based on the size of the printed benchmarks and according to the position of the working plane of the 3D printer. Three benchmark models of different sizes, with a parallelepiped and cylinder shape placed in five different positions on the working plane are considered. The sizes of models are chosen from the Renard series R40. Benchmark models are fabricated in ABS (Acrylonitrile Butadiene Styrene) using Zortrax M200 3D printer. A sample of five parts for each geometric category, as defined from the R40 geometric series of numbers, is printed close to each corner of the plate, and in the plate center position. Absolute Digimatic Height Gauge 0-450mm with an accuracy of ±0.03mm by Mitutoyo is used to perform all measurements: flatness on box faces, and circularity/cylindricity on cylinders. Results show that the best performances, in terms of form accuracy, are reached in the area center printable while they decrease with the sample size. Being quality a critical factor for a successful industrial application of the AM processes, the results discussed in this paper can provide the AM community with additional scientific data useful to understand how to improve the quality of parts which may be obtained through new generations of 3D printer.

Keywords: Additive manufacturing | Fused deposition modelling | Geometric errors

Abstract: The paper deals with the model based systems engineering (MBSE) approach, focused on the designing process of propulsion systems for road electric vehicles. In particular, the paper adopts multi-domain Modelling, in accordance with a top-down approach. The process, in fact, starts from the main requirement analysis of the road electric vehicle which is considered as reference. Then, a wide range of parameters, related to the characteristics of propulsion system components and resistance forces, are evaluated to build a parametric model of the propulsion system running on a road. In this way, a procedure for the evaluation of vehicle performance is accomplished within the developed simulation environment. Therefore, the procedure allows all the requirements to be satisfied, under different operative conditions, through an iterative procedure of verification for the imposed parameters. The tested operative conditions are represented in this paper by standard driving cycles, expressed in terms of vehicle speed and autonomy requirement.

Keywords: Electric vehicles | MBSE approach | Object-oriented modelling and simulation | Systems engineering

Abstract: The present paper deals with methods for product development aimed to support designing activities and to re-use company know-how. The work is addressed to complex products i.e. products characterized by several components and dependencies among them. Then, the paper presents both the methodological approach and the application to the 3D CAD modelling of an automotive car door assembly. The work uses directed graphs and a series of algorithms to provide a Graphical User Interface (GUI) able to support a designer by reducing the development time of new car door assemblies and increasing the accuracy of the design activities. According to a digital pattern approach, the GUI is used to determine the set of changes to 3D CAD models that typically occur in the automotive field, during the development of new car door assemblies.

Keywords: Automotive car door design and development | CAD modelling | Digital pattern for product development | Directed graphs

Abstract: Fleets of commercial vehicles for delivery services in urban areas constitute road transportation means which are required to run relatively short distances and to respect anti-pollution laws commonly imposed by many municipalities. For this kind of commercial applications, high efficiency and eco-friendly electric propulsion systems offer an interesting alternative to thermal engines. This paper is focused on the analysis of such solution, by presenting experimental results obtained with a ZEBRA battery based propulsion system, designed to power a specific urban unit within the category of electric commercial vehicles. A novel contribution is added to the relevant literature concerning battery based electric powertrains for road vehicles. The main novelty consists in a wide range of experimental results and performance analysis carried out with reference to the real behavior of both the whole propulsion system and each main component, when powering the commercial vehicle, on the urban part of the NEDC (New European Driving Cycle) standard driving cycle, at different slopes. The experimental results, expressed through electrical and mechanical parameters, are initially evaluated by means of a quasi-static numerical model of the electric powertrain and then experimentally verified with the support of a 1:1 scale laboratory dynamic test bench. The procedure followed and presented in this paper definitely demonstrates the good design and performance, obtained for the evaluated propulsion system, in satisfying the real energy and power requirements, specific of an urban use for delivery commercial vehicles, in terms of daily autonomy and slopes. The collections of experimental results, analyzed in the paper, represent in addition a useful set of data for simulation in order to build, verify and improve models in their outputs.

Keywords: Dynamic test bench | Electric drives | Electric vehicles | ZEBRA batteries

Abstract: Modern engineering systems are getting complex and integrate multi-physical objects. The Model-Based System Engineering (MBSE) seems to be the best way to manage complex system design and the Systems Modeling Language (SysML) may be considered one of the computer languages to perform the designing of a complex system. MBSE also seems to be a valid solution to integrate tolerance specification into design process. In particular, in the present work SysML is used to create a set of libraries containing simple and complex volumes, primary datum and tolerance zones, according to ASME Y14.5M and ISO 1101 standards. The generation of these libraries is based on the Technologically and Topologically Related Surfaces (TTRS) model and uses the set of thirteen positioning constraints able to represent every condition between assembly features. The paper summarizes the characteristics of the created SysML objects, able to represent Datum, Datum Reference Frame (DRF) and tolerance zones. In particular, the Datum included in ASME Y14.5-M are modelled. Then, all the tolerance zones included in both standards are modelled. Finally, a three-step procedure is summarized to preliminary illustrate the way of use the developed set of SysML objects.

Keywords: Assembly tolerance specification | Model-based Systems Engineering | SysML | TTRS model

Abstract: This paper aims to realize an eco-comparison among power-train configurations of hybrid busses in terms of performance, fuel consumption and CO2 emission. The present study has been carried out in the context of the international research program PLACIS (PLAteforme Collaborative d'Ingénierie Systèmes). In this work, experimental data of a pure electric power-train, evaluated in a dedicated laboratory of Istituto Motori-the National Research Council of Italy, have been used to carry out a pre-design phase of the modelling procedure. From that point on, in order to optimize the powertrain performance, a series hybrid vehicles configuration and a parallel one have been modeled and simulated on DYMOLA-MODELICA environment. The vehicle that has been taken into account, as reference for the comparison, is a «RENAULT-Master» minibus. Power-trains have been modeled with a backward-forward configuration in order to have a physical approach to the problem, respecting the required performances. The study has been developed with System Engineering approach that aims to manage the complexity of systems with a multidisciplinary proposal.

Keywords: Backward-forward configuration | CO emission 2 | Dymola | Eco-comparison | Electrical power-train | Hybrid Electric Vehicles | Modelica | PLACIS | System Engineering

Abstract: The chapter tackles the issue of improving the robustness of mechatronic systems. In particular, the chapter highlights the need to operate at two levels, in order to accomplish both the mechatronic system, conceptual architecture, and the mechatronic parameter design. The chapter gives evidence to the criticalities in operating at the conceptual level and some tools for the evaluation of the variability of system performances. The approach presented in the chapter is then applied to an automotive power windows system. The recognition of the most significant design parameters within the mechatronic system and the understanding of their variations allow the conscious identification of system configuration that assures the minimal variation of system response under the effects of noise factors.

Abstract: The paper tackles an integrated use of object-oriented modelling (OOM) and design of experiments (DoE) to determine the performance of a double bowden power window system in order to accomplish the expected system performances during the preliminary designing phase and, therefore, by accelerating the product development process. A DoE has been carried out by using the power window model, developed in Dymola environment. The response surface method (RSM) and ANOVA analysis are used to identify the significant factors. Then, an empirical equation is derived. It predicts the main system response i.e. the stroke time, expressed as dependency related to the significant factors. Finally, the use of the empirical relation inside a design flow of a power window, based on digital patterns, is presented.

Keywords: Design of experiments | Digital pattern for product development | Mechatronic systems | Object-oriented modeling | Power window systems

Abstract: EPICES is an Erasmus plus strategic partnership project (September 2014-August 2016) co-funded by the EU. There are seven academic partners and one association engaged in this project. The purpose of EPICES is to develop a European collaboration on at-a-distance project-based learning framework and method, based on already existing and still developing technical platforms, i.e. collaborative and engineering tools. A special focus will be made on teachers' role and students' coaching, from the analysis of what a coach should be in project based learning to training packages for teachers and development of assessment methods. This focus is a key issue to be discussed in order to develop project based learning for engineer students, especially in international and/or industrial context, which requires strong and effective collaboration of all actors to succeed and innovate within the project based learning framework. In EPICES, sub-projects are developed, which place students in the middle of real industrial European at a distance projects, i.e. in the heart of the future job of every current engineer student. These sub-projects are study cases, study materials, and allow many feedbacks and intellectual outputs on coaching, teachers' role and assessment issues. Since its beginning, EPICES has gained in maturity and in this work-in-progress the objective is to present the first achievements of three intellectual outputs: establishing a model of facilitator roles and skills in project-based learning in European engineering education; studying teacher facilitation in preparation for training of teacher, creating assessment methodology for project-based learning in engineering studies and development of tools for assessment of skills.

Keywords: assessment | project-based learning | Teacher roles

Abstract: The paper deals with automotive power window systems and, in particular, tackles the problem of validating the object-oriented model of a single bowden system, to be used within a Model-Based System Engineering (MBSE) approach. Therefore, the paper tackles the problem of increasing accuracy of object-oriented models by defining model refinements i.e. by identifying objects whose modelling has to be improved. Firstly, the role of object-oriented modelling and the main characteristics of the power window system are summarized. Then, the object-oriented model of an automotive single bowden power window system is presented. Finally, the experimental phase, performed to characterize the behavior of the real system is summarised and the validation of simulation model, as well as the identification of model refinement, are accomplished.

Keywords: mechatronic systems | model validation | object-oriented modeling | single bowden power window system

Abstract: The current critical environmental context has increased the interest in electric vehicles. However, the evaluation of which one is the best choice, for the electric vehicle components, generally requires a series of experimental tests to be carried out, which can be quite costly and not as adequate as an engineering project must be. Therefore, this paper presents an approach, based on the RFLP method, which can help the designer, during the pre-design of an electric propulsion system, to choose the best configuration for the components of an electric vehicle power-train, reducing the costs related to physical experimentation on a laboratory test benches or on a real electric vehicle. The aim of this paper is to provide a computational tool that could virtually simulate the behavior of a designed electric propulsion system facilitating the solution of the most common problems encountered on the domain of battery-powered vehicles. The case study considered in this work is power-train for an electric scooter. The first step of this work consists in defining simulation models to simulate the power-train in terms of vehicle performance and energetic consumption. In the second step, those models are parameterized and validated through experimentations on a physical electric power-train installed in a laboratory of Istituto Motori (National Research Council of Italy). The validation of the evaluated models allows to carry out simulation tests on different alternative configurations of the electric power-train in the most varied drive conditions. At the end, the proposed model of the whole power-train system is used to carry out a study for the right design of the battery pack.

Keywords: Battery | Dymola | Electric Motor | Electric Vehicle | ModelCenter ® | RFLP method | Systems Engineering | Test-bench

Abstract: The paper deals with the relationship between geometrical or topological entities of complex systems and the physics in which the systems are involved. In particular, the paper deepens the integration of thermal physics with geometrical constraints. Therefore, the results of the work could be used within the development of a 3D-multiphysical sketcher viz., a tool for the preliminary design of complex systems, characterized by the presence of one or more overlapping physics. Firstly, the model of Topologically & Technologically Related Surfaces (TTRS) is used and related Minimal Reference Geometrical Elements (MRGEs) and constraint conditions are implemented by means of Modelica language. Then, the implementation of new objects for MRGEs and constraint conditions are applied to a mechanical assembly. Finally, the integration of TTRS model within thermal physics is applied to the case of the layout designing for electronic boards.

Keywords: Modelica language | Multiphysics | preliminary design | TTRS

Abstract: PLACIS (Collaborative Platform for Systems Engineering) is a project funded by the French National Agency for Research under the 'Investments for the future' program. PLACIS started in September 2012 and is run by Institut Polytechnique Grand Paris (IPGP, gathering ISMEP - Supméca, ENSEA and EISTI). In the framework of both a rapid change in engineering education and a need of young engineers able to think 'systems', PLACIS aims to promote active learning and teaching through industrial, international and at-a-distance collaborative projects, carried out by engineer students. The main general objectives of PLACIS are to develop or create the involvement of teachers and students into new teaching practice, but also to answer the needs of the industry. We train students not only to become classic engineers, but also to be able to understand multidisciplinary and industrial issues, to work in teams with people from different cultures, all these points giving them the ability to move easily in today's and tomorrow's industrial world and to think 'systems', to really understand a context and be able to propose adapted answers that are more than the old 'think global, act local'. In order to illustrate concretely what is PLACIS, we can easily rely on the example of an industrial project started at the beginning of PLACIS in September 2012 and which is still in progress between Istituto Motori - CNR (IM-CNR), Università di Napoli Federico II (UNINA) and Institut Polytechnique Grand Paris (IPGP).

Keywords: multidisciplinary approach | project-based learning | systems engineering

Abstract: This paper is focused on the designing process of propulsion systems for road electric vehicles, by means of the RFLP approach for System Engineering. The process starts from the analysis of the main requirements for the vehicle considered, in relation to its specific mission. The vehicle behavior is then simulated on standard driving cycles, evaluating the performance figures of different power-train configurations, under different operative conditions. The presented designing procedure reaches the 3D CAD model of the identified propulsion system, coupled with a specific laboratory test bench, based on an eddy current brake and flywheel for the simulation of the vehicle inertia. The obtained simulation results show the good performance of the power-train in terms of vehicle speed following its reference on driving cycle and vehicle autonomy.

Keywords: Electric Vehicles | RFLP approach | Systems Engineering

Abstract: The paper deals with a digital pattern (DP) approach to the design of an automotive power window, using object-oriented modelling. Therefore, the paper faces the designing of a mechatronic system by using an integrated approach to product development. Then, Dymola/Modelica environment is used as a tool of a decision support system that makes possible the DP approach. The paper briefly sum up the results of simulations related to a power window system characterized by a double bowden sliding mechanism. Finally, the paper highlights the parameters that could be easily integrated in a graphical user interface, aimed to reduce both the development time of new power window system and to increase the accuracy of design activities.

Keywords: Digital pattern for product development | Mechatronic systems | Objectoriented modeling | Power window systems

Abstract: One of most demanding tasks in the manufacturing field is controlling the variability of parts as it may affect strongly the deliverability of key characteristics defined at the final (product) assembly level. Current CAT systems offer a good solution to the tolerance analysis/synthesis task, but to handle flexible objects with shape errors more effort is needed to include methods able to capture the elastic behaviour of parts that adds more variability on the final assembly. Usually, sheet metal assemblies require dedicated fixtures and clamps layout to control the gap between parts in the specific location where a join must be placed. Due to the variability of parts the position of clamps can also be varied. The paper describes a FEM-based method able take into account part flexibility and shape error to parametrically analyse sheet metal assemblies by acting on some key parameters to look for the optimal clamp layout that guarantee the gap between parts to be under control after joining parts together. This method offers, with respect to commercial solutions, the ability to model fixtures, clamps and different joint types with no matter on the node positions of the mesh. Locations of such elements are based on the shape functions defined at element (shell) mesh level and modelled as local constraints. So the user can generate a mesh without a previous knowledge of the exact positions of clamps, for example. This allows to conduit a parametric analysis without remeshing the surfaces and with no need to physically model the clamps. An aeronautic case study is described with a four-part assembly riveted on a quite complex fixture by using several clamps.

Keywords: Clamp layout optimisation | Compliant assemblies | Free shape variability | Sheet metal parts | Shell.

Abstract: The present paper proposes a novel general approach to automatically calculate the variational parameters for planar or cylindrical features for a given set of tolerance specifications, according to ANSI or ISO Standards. Variational parameters correspond to those directions along/around which variation, in terms of small translation and rotation, may propagate for a given feature with tolerance specifications. A graph representation of these tolerance specifications is adopted and it is used along with screw theory and Davies's laws to automatically calculate the variational parameters, and then the net variational space of each toleranced feature, by capturing nominal geometries directly from a CAD environment (SolidWorks). From screw theory, twist matrices, able to capture the motion properties of any kinematic joint in mechanical assemblies, are here adopted at part level and collected for every feature-to-datum relationship. Davies's laws are then recalled to put those matrices together to calculate the variational parameters. In this way, both single-datum and multi-datum tolerance specifications can be handled. The proposed approach for the automatic calculation of variational parameters could be successfully implemented in a more general expert system for designing mechanical assemblies where an added-value interaction could allow user to detect relationships between geometric features. In this way, the leading of activities aimed to tolerance analysis could be accomplished both during the preliminary design stages and throughout the manufacturing and reviewing sessions. © 2012 Springer-Verlag France.

Keywords: CAD automation | Graph representation | Mechanical networks | Screw theory | Tolerance analysis | Variational parameters

Abstract: The challenge of reducing designing time for new mechanical assemblies, especially in the context of large companies, encourages the use of methods and tools aimed to support designing activities and to re-use the company know-how. Furthermore, the design choices must be rapidly check to avoid errors that could cause delay or expensive re-designing. In such a context, the graph theory and related algorithms could be used to define a transfer function, easily to implement, that governs a software tool able to support the designing activities. Therefore, the paper presents a designing approach, based on the graph theory, aimed to generate the geometric modeling of mechanical assemblies. The approach and the software tool are useful both for designer and companies that want to customize and improve such activities. Finally, the paper shows the case study related to the design of a transversal manual gearbox and the generation of a GUI, developed in Mat LAB® environment, to validate the approach.

Keywords: CAD modeling | Digital pattern | Graph theory | Graphical user interfaces | Mechanical design

Abstract: In the variational modeling of assemblies it is important to define the location of a part both in absolute terms and with respect to the position/orientation of other assembled parts. The present paper proposes a programming optimization approach to solve this problem. The algorithm, by using the heuristic Nelder-Mead technique - combined with a penalty function - simulates and solves sequential assembly strategies to find the optimal geometric configuration of a rigid part with variational features satisfying all the assembly constraints in the given sequence. The algorithm best aligns mating features avoiding, at the same time, feature-to-feature interferences, and automatically calculating the amount of movement the part being assembled must obey to satisfy assembly constraints, at that state of the assembly process. Thus, different assembly sequences can be simulated also including variational features. © 2013 The Authors.

Keywords: Assembly simulation | Constrained optimization | Rigid assemblies | Sequential constraint solver | Tolerance analysis

Abstract: In automotive and aeronautic fields, controlling the final shape of flexible assemblies (with sheet metal parts) is a key issue. Even assuming as known the shape errors in single manufactured parts, the assembly process can cause wide variability due to their flexibility and to the choice of fixtures and clamps as well as to the fastening technique adopted. Here it is strategic to analyse different assembly configurations at the beginning of the design phase and chose the one that assures less variability on the key characteristics to be achieved. This paper presents a FEM-based computer tool able to statistically analyse variations occurring in assembly processes of flexible parts. After assigning fixtures, clamping points, fastening joints and assembly sequence, the tool quickly outputs the statistical variability of the key characteristics. It is so possible to span a variety of design solutions predicting failures and controlling final variations. A case study will show how it works. Copyright © 2013 Inderscience Enterprises Ltd.

Keywords: Computer aided tolerancing | Finite element analysis | Fixture configurations | Flexible assembly

Abstract: The paper deals with a functional approach to optimal dimensioning of automotive transmission shafts. In particular, the paper summarizes the results of a research activity developed on automotive transmission shafts to reduce the unpleasant movement of the transmission lever known as "shift lever movement". The design problem was faced by focusing the axial clearances of the wheels assembled on the transmission shaft. First, the functional approach to optimal dimensioning proceeds from the study of different working conditions of the automotive manual transmission and focuses on corresponding geometrical constraints and design parameters. Then, it uses simplified schemes, each of them related to a different working condition, to set a series of functional dimensioning loops for the transmission shaft. Subsequently, the approach introduces an appropriate index to evaluate the Information Content for each dimensioning scheme and it addresses the optimal dimensioning scheme, related to the minimization of the Information Content. After this, the approach foresees worstcase to check the axial clearances of the wheels assembled on the shaft. In a such way the effect of the dimensioning are directly evaluated in terms of performances of the transmission. In fact, the reduction of axial clearances for the wheels assembled on the shaft causes a direct reduction of the "shift lever movement". The functional approach to optimal dimensioning is applied to an automotive transmission set and the proposed dimensioning schema of the shaft is compared with different dimensioning schemes including one currently used in an international automotive company. A final discussion of the results, in terms of reduction of axial clearances of the parts assembled on the shaft, is provided. Copyright © 2012 by ASME.

Keywords: Functional dimensioning | Information content | Transmission set

Abstract: Variation analysis of assemblies is a strategic task in many industrial applications. Parts manufactured through plastic deformation processes exhibit appreciable shape deviations from the nominal geometry due mainly to spring-back phenomena. When these parts are assembled, initial shape deviations at part level highly influence the final assembly shape. This work focuses on the modeling and simulation of shape errors in order to perform variation analysis of compliant assemblies. The aim is to simulate variational shape of parts according to a small number of control points chosen on the part geometry through a morphing mesh procedure. These points are typically related to measurement or inspection points of manufactured parts. From the mesh model of parts, mesh nodes are moved by applying the morphing procedure. In particular, in order to assure control points belong to the "perturbed" shape, a linear-constrained approach is adopted. The so-morphed parts are used to accomplish the variational assembly analysis following the classical place, clamp, fasten, and release cycle. In order to achieve statistical results, Monte Carlo simulation is performed: a set of control points driving the perturbed parts is generated at each iteration; these parts are then assembled and results are stored. Numerical results are compared with ones coming from commercial software that uses a linear approach based on the sensitivity matrix.

Keywords: Geometric covariance | Monte Carlo FEA | Morphing mesh | Shape errors | Variational assemblies

Abstract: In this paper, a general methodology to do tolerance analysis of rigid assemblies is proposed. Firstly, tolerance specification sets, according to GD&T or ISO specifications, are translated into variational features by using 4∈×∈4 homogenous transformation matrices. In particular, planar and cylindrical features are considered. Then, once all variational features are modeled, assembly constraints among parts are introduced. To solve assembly constraints, an assembly transformation matrix is evaluated. By using point, line, and plane entities and their combinations, kinematic joints are modeled. A numerical procedure is proposed to solve fully and over-constrained assemblies. The best-fit alignment among variational mating features is performed by using optimization algorithms. The proposed method for tolerance analysis of rigid part assemblies allows to simulate different assembly sequences. Finally, in order to show the effectiveness of the proposed methodology, three case studies are described and analyzed. © 2009 Springer-Verlag London Limited.

Keywords: Assembly constraints | Assembly simulation | Feature modeling | GD&T/ISO specifications | Tolerance analysis | Variational features

Abstract: During last years, several numerical methods have been proposed to accomplish analysis and synthesis of 3D tolerance chains. These methods allow predicting final assembly variations, starting from tolerance specification set defined at part level. Nevertheless, few specific methodologies are available today to check the global consistency of a tolerance specification set, related to a mechanical assembly. In this work, an approach to validate the global consistency of a 3D tolerance specification set is proposed. The approach is mainly composed by two different analyses. The first analysis is aimed to verify, at assembly level, the adequacy of a tolerance specification set by determining the assembly subsets of parts which influence each assembly key characteristic. The second analysis is aimed to verify the consistency of the tolerance specification set by using rules, mainly based on the TTRS theory. In order to show the effectiveness of the methodology, two case studies are illustrated by using a friendly graphical user interface (GUI) developed in MatLab® environment. © 2009 Springer-Verlag.

Keywords: Global consistency | Tolerance graph | Tolerance specification | TTRS theory

Abstract: The present paper deals with the manufacturing process of a railway carriage. In the first part of the paper, the authors focus on a "virtual railway factory" that uses a very innovative assembly cycle, if compared to the traditional manufacturing processes in the railway field. The case study refers to a railway carriage consisting of four modules, that are singularly set up of furnishings and other systems in dedicated workplaces. On one hand, the virtual simulation has highlighted several critical aspects to be improved, in order to achieve a greater feasibility and to reduce time and cost. On the other hand, the designers have been able to evaluate the movements of the parts and the assembly sequences of the components, by considering each geometric, functional and technological constraint and also some safety requirements. The second part of the paper deals with the simulation of the assembling operations and the analysis of tolerance chains, which have been performed through a Computer Aided Tolerancing system. In particular, the precision requirements have been also evaluated and we have compared the accumulation of dimensional and geometric deviations when using both rivets and traditional welds to fasten the modules. © 2009 Springer-Verlag.

Keywords: Computer Aided Tolerancing | Train design | Virtual manufacturing

Abstract: The paper aims at providing a methodological contribution to the concept design of train interior in order to improve the quality perceived by users in compliance with railway standards. Indeed, the combined use of advanced CAD tools, experimental statistical methods and Virtual Reality tools allows developing, selecting and experimentally evaluating new concepts. The design cycle starts both from designers' proposal and the identification of user's needs; then, it makes use of datum-based CAD models in order to generate virtual concepts that satisfy railway standards; the cycle proceeds with the immersive evaluation of virtual prototypes, performed by potential and expert users in Virtual Reality. The identification of the optimal concept closes the design process. This procedure can be iterated in order to improve the quality of train interiors, evaluated thanks to the user's involvement in the design cycle. In this work a case study on seat design of a regional train is presented, developed at the Virtual Reality laboratory, named, of the Regional Centre for the qualification of transportation systems set up by Campania Regional Authority. © 2009 Springer-Verlag.

Keywords: CAD models | Concept design | Designfor quality | Kano methodology | Virtual reality

Abstract: The present work deals with the re-designing of a locomotive, according to in force European standards, in the field of active and passive safety. The paper illustrates the use and the management of heterogeneous product information (2D drawings, technical documentation, photos), Virtual Reality tools and digital human models, for the re-designing of a locomotive, using a collaborative approach with a total absence of the reference digital models. The project development has been organised using a top-down approach in a collaborative environment. Finally, by means of the digital prototype of locomotive, a series of aesthetic, functional and ergonomic analyses, in virtual environment, has been performed. © Springer Verlag France 2007.

Keywords: Collaborative design | Ergonomics | Top-downapproach | Virtual reality

Abstract: A new method for tolerance/variation analysis of multi-station assemblies of compliant parts is presented. Based mainly on the 'unit displacement' and 'sensitivity matrix' method, it allows for the use of statistical variations in key points to predict the final shape variation of multi-station assemblies. 'Linear contacts' between parts are included to avoid part-to-part intersections. The evaluation of what happens at the end of the assembly process enables users to analyse different assembly configurations in the early design phase. Implemented in the Matlab environment, it requires two linear FEA runs for each assembly station. Two case studies are presented and discussed. Copyright © 2008 Inderscience Enterprises Ltd.

Keywords: Compliant parts/assemblies | Contact modelling | FEA | Finite element analysis | Linear static analysis | Multi-station assemblies | Statistical variations | Tolerance analysis

Abstract: In this work the Authors propose a methodology based on the use of an ergonomic software in alternative to the traditional methods to evaluate muscular-skeletal diseases caused by incongruous postures or conditions of mechanical overload. This methodology allows to simulate, in a virtual environment, both a workplace and a digital human model whose behaviours are similar, from a kinematical and a dynamical point of view, to that ones of a real person. Through the simulation in a virtual environment of an operation of Manual Material Handling (MMH) in a pharmaceutics industry, the Authors have evaluated, in real time, the strengths and the reaction-moments in the axial, sagittal and lateral plane on the L4 and L5 lumbar vertebras and on the shoulder of the workers. In the work the single movements carried out by the operator are analysed using manikins of different percentiles. The results are compared with the ones coming from the use of the traditional methods to evaluate muscular skeletal disease. © PI-ME, Pavia 2005.

Keywords: Digital human models | Ergonomics | Manual material handling | Virtual simulations