B-R1ING MoCap: registrazione e riproduzione dei movimenti umani su avatar 3D in realtà aumentata

Già da qualche anno si è stati introdotti alla possibilità di vivere in un mondo virtuale; basta indossare un paio di visori di realtà aumentata, virtuale e mista che riproducono nell’ambiente circostante oggetti che fisicamente non esistono. Negli ultimi mesi, inoltre, questa possibilità sta diventando sempre più concreta con l’introduzione, da parte dei colossi dell’informatica, del concetto di "Metaverso": un universo parallelo completamente digitale dove sarà possibile svolgere ogni attività sociale. L’obiettivo di questa tesi è quello di contribuire in piccola parte a questo enorme progetto creando una modalità di interazione tra utenti virtuale ma che si basa su comportamenti del tutto reali. A questo proposito il titolo dell’elaborato è: \textit{“B-R1ING MoCap: registrazione e riproduzione dei movimenti umani su avatar 3D in realtà aumentata”}. Lo scopo del progetto è quello di permettere a una persona di registrare un video in cui c’è un soggetto in movimento, salvare i movimenti del soggetto in un pacchetto dati e infine riprodurlo su un \textit{avatar} 3D che viene fatto agire in realtà aumentata. Il tutto farà parte di un’applicazione “social network” che permette l’interazione tra utenti in questo modo. Un utente può quindi registrare i movimenti umani e inviarli ad un altro utente che può riprodurre il messaggio in realtà aumentata tramite il suo smartphone. Viene introdotto così un nuovo tipo di comunicazione digitale indiretta passando dalla comunicazione scritta, ormai salda da decenni nei messaggi, alla comunicazione orale, introdotta da qualche anno tramite i messaggi vocali, alla comunicazione gestuale resa possibile dal lavoro in oggetto. Le fasi principali del progetto sono state due: una in cui, dopo aver individuato la tecnica migliore, è stato effettuato il "motion capture", un’altra in cui il movimento registrato è stato trasformato in animazione per un soggetto 3D che viene visualizzata in realtà aumentata.

Design of compliant mechanisms and their application to morphing wing technology

This thesis describes a study conducted for the development of a new approach for the design of compliant mechanisms. Currently compliant mechanisms are based on a 2.5D design method. The applications for which compliant mechanisms can be used this way, is limited. The proposed research suggests to use a 3D approach for the design of CM’s, to better exploit its useful properties. To test the viability of this method, a practical application was chosen. The selected application is related to morphing wings. During this project a working prototype of a variable sweep and variable AoA system was designed and made for an SUAV. A compliant hinge allows the system to achieve two DOF. This hinge has been designed using the proposed 3D design approach. To validate the capabilities of the design, two methods were used. One of these methods was by simulation. By using analysis software, a basic idea could be provided of the stress and deformation of the designed mechanism. The second validation was done by means of AM. Using FDM and material jetting technologies, several prototypes were manufactured. The result of the first model showed that the DOF could be achieved. Models manufactured using material jetting technology, proved that the designed model could provide the desired motion and exploit the positive characteristics of CM. The system could be manufactured successfully in one part. Being able to produce the system in one part makes the need for an extensive assembly process redundant. This improves its structural quality. The materials chosen for the prototypes were PLA, VeroGray and Rigur. The material properties were suboptimal for its final purpose, but successful results were obtained. The prototypes proved tough and were able to provide the desired motion. This proves that the proposed design method can be a useful tool for the design of improved CM’s. Furthermore, the variable sweep & AoA system could be used to boost the flight performance of SUAV’s.

Optimized methods to digital survey and 3D modelling of cultural heritage assets

Currently making digital 3D models and replicas of the cultural heritage assets play an important role in the preservation and having a high detail source for future research and intervention. In this dissertation, it is tried to assess different methods for digital surveying and making 3D replicas of cultural heritage assets in different scales of size. The methodologies vary in devices, software, workflow, and the amount of skill that is required. The three phases of the 3D modelling process are data acquisition, modelling, and model presentation. Each of these sections is divided into sub-sections and there are several approaches, methods, devices, and software that may be employed, furthermore, the selection process should be based on the operation's goal, available facilities, the scale and properties of the object or structure to be modeled, as well as the operators' expertise and experience. The most key point to remember is that the 3D modelling operation should be properly accurate, precise, and reliable; therefore, there are so many instructions and pieces of advice on how to perform 3D modelling effectively. It is an attempt to compare and evaluate the various ways of each phase in order to explain and demonstrate their differences, benefits, and drawbacks in order to serve as a simple guide for new and/or inexperienced users.

Nonlinear modelling of non-structural masonry walls under a low-intensity earthquake motion: calibration through a parametric study

This thesis aims to understand the behavior of a low-rise unreinforced masonry building (URM), the typical residential house in the Netherlands, when subjected to low-intensity earthquakes. In fact, in the last decades, the Groningen region was hit by several shallow earthquakes caused by the extraction of natural gas. In particular, the focus is addressed to the internal non-structural walls and to their interaction with the structural parts of the building. A simple and cost-efficient 2D FEM model is developed, focused on the interfaces representing mortar layers that are present between the non-structural walls and the rest of the structure. As a reference for geometries and materials, it has been taken into consideration a prototype that was built in full-scale at the EUCENTRE laboratory of Pavia (Italy). Firstly, a quasi-static analysis is performed by gradually applying a prescribed displacement on the roof floor of the structure. Sensitivity analyses are conducted on some key parameters characterizing mortar. This analysis allows for the calibration of their values and the evaluation of the reliability of the model. Successively, a transient analysis is performed to effectively subject the model to a seismic action and hence also evaluate the mechanical response of the building over time. Moreover, it was possible to compare the results of this analysis with the displacements recorded in the experimental tests by creating a model representing the entire considered structure. As a result, some conditions for the model calibration are defined. The reliability of the model is then confirmed by both the reasonable results obtained from the sensitivity analysis and the compatibility of the values obtained for the top displacement of the roof floor of the experimental test, and the same value acquired from the structural model.

Development of a state-variable filter for a motion control application.

In collaboration with G.D. SpA I attended an internship with the purpose of developing a filter for the position control of industrial machines during testing and maintenance operations. The filter elaborates a signal in position provided by an electonic handwheel, in order to enable the application to be controlled with a signal in velocity with arbitrarily dynamics chosen during the design phase. Limiting the dynamics of the filter provide a more stable and less demanding reference trajectory which reduce the vibrations and tracking errors of the motor controlled by it. It also prevents misusages of the handwheel from the technician which could end up in harmful interferences between the mechanical parts moved by the handwheel.