1,721,011 research outputs found
Review of digital twin applications in manufacturing
Full text linkIn the Industry 4.0 era, the Digital Twin (DT), virtual copies of the system that are able to interact with the physical counterparts in a bi-directional way, seem to be promising enablers to replicate production systems in real time and analyse them. A DT should be capable to guarantee well-defined services to support various activities such as monitoring, maintenance, management, optimization and safety. Through an analysis of the current picture of manufacturing and a literature review about the already existing DT environment, this paper identifies what is still missing in the implemented DT to be compliant to their description in literature. Particular focuses of this paper are the degree of integration of the proposed DT with the control of the physical system, in particular with the Manufacturing Execution Systems (MES) when the production system is based on the Automation Pyramid, and the services offered from these environments, comparing them to the reference ones. This paper proposes also a practical implementation of a DT in a MES equipped assembly laboratory line of the School of Management of the Politecnico di Milano. The application has been created to pose the basis to overcome the missing implementation aspects found in literature. In such a way, the developed DT paves the way for future research to close the loop between the MES and the DT taking into consideration the number of services that a DT could offer in a single environment
Ensuring consistency in scalable-detail models for DT-based control
No full textDigital Twins (DTs for short) are a powerful aid for creating, assessing and maintaining control strategies. This use of DTs however requires that the physical entities to control be described at different levels of detail. For example, simple I/O models are used to compute parameters of modulating controllers, more time-accurate ones may be required to set up and assess logic controls, high-accuracy, possibly nonlinear ones may serve for overall strategy verification, and for software-in-the-loop testing, also the host computing/network architecture needs representing. In such a complex scenario, guaranteeing that all the descriptions of all elements are consistent with one another is a relevant problem. We discuss this matter and propose a solution, in the form of a modelling paradigm where - as a novel contributions - relationships (in a sense analogous to what the term means in database theory) can be instated and enforced. This allows to create and maintain knowledge based made of interrelate data and models, embracing all the major DT interpretations proposed so far in the literature, or said more explicitly, combining data-driven and model-driven DTs in a single framework. We also provide an illustrative example
Harmonising and integrating the Digital Twins multiverse: A paradigm and a toolset proposal
Full text linkDigital Twins are of paramount relevance in the Industry 4.0 framework. However, the idea of Digital Twin has many different interpretations. These are tied to the intended use of a Digital Twin, thus to the viewpoint of the involved professionals (process designers, control specialists, managers, and so on). The said interpretations are often highly incompatible with one another, since they can involve as heterogeneous entities as a CAD drawing and a neural network. A convergence of Digital Twin interpretations is desirable, to take full profit of the contained knowledge. In this research we argue that this desired convergence cannot be found at the same abstraction level of the available Digital Twin interpretations, and calls for a higher one. We consequently propose a paradigm – that we name Digital Multiverse – to comprehend the major Digital Twin interpretations not only in the sense of data integration, which is the goal of promising complementary ideas like that of Asset Administration Shell, but also by establishing and enforcing consistency rules that involve both data and models. We also show some examples to support the usefulness and viability of our proposal
Digital Twins based on integrated models: Supporting joint decisions on maintenance and production planning
Full text linkWithin Industry 4.0 (I4.0), technological advancement has brought manufacturing to the adoption of different Digital Twins (DTs) for the same physical system - or Physical Twin (PT) - in order to make different decisions. Nevertheless, independent decisions with DTs not integrated among each other and/or with their reference models can affect production efficiency. This paper focuses its attention on production planning control and maintenance and proposes an approach for models' integration that support those analyses in order to use them as the basis for the creation of a DT that can provide structured support through the whole system's lifecycle. With this aim, the paper proposes a model for DEVS simulation capable of integrating production planning with preventive and corrective maintenance to support joint decisions
Teaching to design control applications with coordinated modulating and logic functions
No full textIn the literature on control education, a minority of papers concern logic control. Out of this minority, an even smaller one addresses the problem of designing an application composed of both modulating and logic control functions, interacting and coordinating with one another. In the opinion of the authors this is a gap to be filled, as it easily leads to an inefficient use of the available development tools, and sometimes results in cumbersome design and poor maintainability. In this paper we discuss the matter, and propose a compact teaching activity based on the experience gathered along the last years
On the criticality of the model parametrisation method in industrial autotuning controllers
No full textWith reference to model-based (auto)tuning, we discuss the somehow overlooked role of the procedure used to parametrise the chosen process model structure. We evidence the detrimental effect of neglecting that procedure, particularly when evaluating/comparing tuning rules, thus when setting up a tuning procedure for a given application. We finally formulate a proposal for choosing the best model parametrisation procedure, in a given set, based on the information available in the tuning phase, and on the selected control quality indicator(s)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Toward a New Generation of Design Tools for the Digital Multiverse
No full textWithin the Industry 4.0 context, different digital twins (DTs) are used to analyse manufacturing systems and assist decision-making processes throughout their entire life cycle. This means that many professionals, with various roles and cultures, build and use their own DTs; hence, methods and tools are required to ensure that the so taken decisions are consistent. This chapter formally proposes a design tool that will help professionals deal with this important issue, allowing them not only to establish and check relations among project data but also to integrate different model-based DTs with one another. The tool specification builds on the recently introduced digital multiverse (DM) paradigm, where all DTs are viewpoints on the same common knowledge corpus, called Model and Data Base
- …
