999 research outputs found
Correction to: Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production
No full textIn the published article “Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9” the order of author's name is given incorrectly. Erratum: Verna Elisa, Genta Gianfranco, Galetto Maurizio & Franceschini Fiorenzo was the Authors list in the article. Corrige: the correct Authors list should be: Elisa Verna, Gianfranco Genta, Maurizio Galetto & Fiorenzo Franceschini. Erratum: the previous citation of the article was: “Elisa, V., Gianfranco, G., Maurizio, G. et al. Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9”. Corrige: the article should be cited as “Verna, E., Genta, G., Galetto, M., et al. Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9”. Original article corrected
Misurare per decidere
No full textNel campo tecnico-scientifico molte decisioni sono supportate da misurazioni. Ma per poter decidere correttamente è importante assegnare ai risultati di misura il loro effettivo significato. Ciò è soprattutto importante, ed espressamente richiesto, quando si opera in Sistemi Qualità. In tal caso la gestione delle misure e prove deve essere rigorosa, e può trovare un concreto supporto negli argomenti qui trattati, per l'attenzione posta a curare insieme la correttezza sostanziale e l'eliminazione di vincoli inutili.
Giulio Barbato, Alessandro Germak e Gianfranco Genta sono docenti di “Statistica sperimentale e Misure Meccaniche” ed “Experimental Statistics and Mechanical Measurement” presso il Politecnico di Torino
Uncertainty evaluation of small wear measurements on complex technological surfaces by machine vision-aided topographical methods
No full textWear assessment is an essential feature within the Industry 4.0 framework to optimise machining and control durability of components made of innovative materials. Complex topographies often make wear measurement a challenging task. Literature tackles it by comparing the final topography with the unworn state, either by empirical methods or by registration via machine vision algorithms. This paper develops a framework to evaluate the related measurement uncertainty, so far lacking, by exploiting instruments metrological characteristics and statistical modelling. This framework is applied to an industrially relevant case study to compare the performances of accredited methods for wear measurement available in literature
Misurare per decidere. Misure e statistica di base.
No full textNel campo tecnico-scientifico molte decisioni sono supportate da misurazioni. Ma per
poter decidere correttamente è importante assegnare ai risultati di misura il loro effettivo
significato. Ciò è soprattutto importante, ed espressamente richiesto, quando si opera in
Sistemi Qualità. In tal caso la gestione delle misure e prove deve essere rigorosa, e può
trovare un concreto supporto negli argomenti qui trattati, per l’attenzione posta a curare
insieme la correttezza sostanziale e l’eliminazione di vincoli inutili.
Giulio Barbato, Alessandro Germak e Gianfranco Genta sono docenti di “Statistica sperimentale
e Misure Meccaniche” ed “Experimental Statistics and Mechanical Measurement”
presso il Politecnico di Torino.
Giulio Barbato, professore ordinario di Misure Meccaniche e Termiche presso il Politecnico
di Torino, ha lavorato per oltre vent’anni presso l’Istituto di Metrologia “G. Colonnetti”
del C.N.R. (ora confluito a formare l’INRiM) ove si è occupato sia dei campioni primari
nazionali di forza e durezza, sia degli accreditamenti dei Centri di taratura SIT (ora
LAT-ACCREDIA). Dal 1997 è titolare di corsi di Misure Meccaniche e Statistica Applicata
alla Sperimentazione.
Alessandro Germak, primo tecnologo all’Istituto Nazionale di Ricerca Metrologica dove
svolge attività di ricerca da oltre trent’anni, è responsabile dei campioni primari di forza e
durezza e dei metodi primari per la misura dell’accelerazione di gravità locale. È esperto
tecnico per gli accreditamenti dei Centri di taratura LAT-ACCREDIA ed è membro dei Comitati
Consultivi del CIPM e dei comitati tecnici EURAMET per le grandezze di interesse.
Gianfranco Genta è ricercatore in “Tecnologie e Sistemi di Lavorazione” presso il Dipartimento
di Ingegneria Gestionale e della Produzione del Politecnico di Torino, dove ha
conseguito nel 2010 il titolo dottore di ricerca in “Metrologia: Scienza e Tecnica delle
Misure”. Si occupa, principalmente, di metrologia industriale, ingegneria della qualità e
applicazione di metodi statistici in ambito tecnologico
Prove preliminari su anelli di contenimento sollecitati dall'esplosione di rotori metallici
No full textIntroduction to the Mechanics of Space Robots
No full textThis text is based on the research work of the author in the field of space robots. It started as a collection of notes of the lectures on Space Robotics given by the author to the students of the International Master on Space Exploration and Development Systems (SEEDS) but evolved to a research monograph on the subject. Its aim is the study of the automatic machines aimed to operate both autonomously and as a support to astronauts in space exploration and exploitation missions, with particular attention to the devices designed for planetary environment, including small planets, comets and asteroids. This material was then completed and made more systematic so that it can hopefully be useful not only to the students of that course but also to those who have an interest in the wide and much interdisciplinary field of space robotics, and in particular in its mechanical aspects. The focus is drawn mainly on the mechanics of space robots: the author is well aware that, even in this specific field, it is far from being complete and that robots, like all mechatronic systems, are so integrated that no single aspect can be dealt separately. Many important aspects are either dealt with only marginally or altogether left out. The very important topics of the control and the behavior of robots, for instance, are only marginally touched, even if their influence on the mechanical aspect to which this book is dedicated is not at all marginal. The structure of the book is so organized: ∙ Chapter 1: a very short introductory overview of human and robotic space exploration, stressing the need for man-machine cooperation in exploration. The various types of robotic missions in LEO, deep space and on planets and their basic requirements are shortly summarized. ∙ Chapter 2 deals in a synthetic way with the main characteristics of the environments space robots are facing and will face in the future. Since space environment is a specialized subject, dealt with in many books, this subject is only briefly summarized. ∙ The configurations of robot arms and the basic kinematic and dynamic relationships needed for their design are described in Chapter 3. ∙ Chapter 4 is devoted to the study of mobility on planetary surfaces, using different kind of supporting devices, like wheels, legs and aerodynamic or aerostatic devices. ∙ The basic characteristics of wheeled robots and vehicles are summarized in Chapter 5. The behavior of wheeled devices is studied in its various aspects, like longitudinal, lateral and suspension dynamics. The consequences of operating wheeled machines in the various environments are analyzed in some detail. The chapter is concluded by a description of the only vehicle that successfully carried humans on the surface of the Moon, the Apollo Lunar Roving Vehicle. ∙ Vehicles and robots that use legs, tracks or other devices to move on a solid surface are described in Chapter 6. Since a great number of different architectures were proposed and sometimes even used in the past, not all the possible configurations are illustrated: the choice was based on the actual existing applications and on the perspectives of future use. ∙ Chapter 7 is devoted to a short overview of the transducers used for actuation and sensing in space robots. ∙ A short overview of the energy sources and storage devices that can be used for space robots is reported in Chapter 8. The book includes two appendices summarizing the theoretical formulations allowing to write mathematical models of space robots including a variety of mechanical components, such as arms, legs, etc. The author found it necessary to include them since the participants to the course in Space Exploration and Development Systems have a much varied background and what may seem obvious to some students, could be difficult for other ones. In a similar ways, some of the readers of thi
Oil whip and unstable whirling in anisotropic rotors on lubricated bearings
No full texthe dynamics of rotors running on lubricated bearings is complex. While the linearized analysis allows to study the stability in the small and phenomena like oil whirl and oil whip, more complex behaviour, that may include chaotic motion, requires a fully nonlinear analysis. Since lubricated bearings behave like anisotropic supports, complex whirling pattern can be expected when the rotor is anisotropic. The aim of the present paper is to investigate to what extent the anisotropy of the rotor affects its dynamic behaviour. In particular, the interactions between the instability ranges due to rotating anisotropy and to oil whip are searched. The rotor models are built using DYNROT FEM code to build the basic rotor model and to obtain linearized solutions. The linear model of the rotor is then mated to nonlinerar bearing models and integrated numerically in time. Time domain results allow to draw some general conclusions applicable to simplified models as well as to real-world rotors
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