45 research outputs found
Comparison between Optimal Control Allocation with Mixed Quadratic & Linear Programming Techniques
No full textThe paper provides a comparison between different control allocation techniques in over-actuated Autonomous Underwater Vehicles. The pseudoinverse, Linear Programming (LP), Quadratic Programming (QP), Mixed Integer Linear Programming (MILP) and Mixed Integer Quadratic Programming (MIQP) are evaluated in simulation on the V-Fides vehicle model. The MILP and MIQP techniques allow to include in their implementations a more detailed characterization of the non-linear static behaviour of the actuators. This customizability can be also exploited to improve the practical stability of the system. The metrics used for comparison include the maximum attainable forces and torques, the integral of the error allocation and the required thrusters effort. Our simulation results show that, in particular with respect to thrusters effort, MILP and MIQP are the preferred allocation methods. The computational complexity associated to both methods is not such to compromise their implementation in operating vehicles; in particular, the MILP version is currently implemented in the V-Fides vehicle
A NLPCA hybrid approach for AUV thrusters fault detection and isolation
No full textThe objective of this paper is to address the problem of Fault Detection and Isolation (FDI) on thrusters of an over-actuated Autonomous Underwater Vehicle (AUV) under on/off abrupt faults. The goal is pursued through Non-Linear Principal Component Analysis (NLPCA), which is the non-linear extension of the popular Principal Component Analysis (PCA). While the Fault Detection (FD) system directly exploits the model-free nature of NLPCA (data-driven approach), the Fault Isolation (FI) is achieved by properly train off-line Artificial Neural Network (ANN). The consistency and robustness of the proposed method is verified in realistic simulation
The Age.Vol.A App and Weportal: Bridging the communicative gap between the elderly, their families and foreign caregivers
No full textWith this paper, we wish to present the Age.Vol.A (Ageing, Volunteers, Assistants. Multilingual Tools for Assisting the Ageing) App, whose pilot version is currently being finalized at the Universities of Varese and Milan (Italy), and is being released in June 2022. The App is the main practical output of a four-year research project bearing the same name (2018-2022) that received major funding by Fondazione Cariplo (2021), one of the world’s main philanthropic organizations. The project’s aim consists in facilitating communication between elderly Italian citizens living in the northern Province of Varese (Italy) and assisted by foreign caregivers, the elderly’s families and the foreign caretakers themselves. The wider scope of the project is to ultimately improve the health and wellbeing of all the social actors involved in these often delicate family settings (Vicentini/Grego 2019). For example, (foreign) caregivers, who “are not family members but often end up making up for weak or non-existent family networks, and their relationship with the older people they look after often merges into that of an unofficial relative. They are relied upon, confided in” (Brannigan et al. 2020).
Age.Vol.A started off with the objective of shedding light on the experience of assisted ageing in a country which ranks among the four oldest countries in the world (Istat 2020) and provide technological tools for bridging the communicative and cultural gaps between the three above mentioned social groups. Specifically, the Age.Vol.A App is introduced, illustrating the mixed-method – linguistic, statistical and sociological – research applied in the collection of the data, administration of interviews and needs analysis carried out among the interested social groups, in order to determine the content of the App (Russo et al. 2020). The selection process of the material to include is then described, together with the recommendations received by local institutional parties (the Varese Town Council, health authority and welfare institute) about specific themes and aspects they considered relevant. Finally, the step of translation and localization into six languages (English included) of the output of the research is outlined, focusing on how the actual languages (e.g. Ukranian rather than lingua-franca Russian), or even the local varieties of the standard languages (e.g. Spanish and Russian) spoken by the caregivers in the Varese Province were specifically targeted, based on the statistical research carried out at the beginning.
The Age.Vol.A. App shall be distributed free of charge to all involved social actors, and is hoped to represent a practical output of multi-disciplinary, applied research that is beneficial to society, albeit at a limited local level thus far, and that brings the academia closer to the needs and expectations of their territory-s population.
Keywords: Northern Italy, elderly care, foreign caregivers, sociolinguistics, statistics, translation.
References
Brannigan Michael, Vicentini Alessandra, Grego Kim, Bacchini Simone C. (2020) (eds), Practical perspectives on older people, caregivers, families and organisations, Special issues, “Working with Older People”, 5(3), Emerald, London.
Fondazione Cariplo (2021), https://www.fondazionecariplo.it/en/the-foundation/la-fondazione.html).
Istat (2020), Rapporto annuale 2020. La situazione del Paese, https://www.istat.it/storage/rapporto-annuale/2020/Rapportoannuale2020.pdf.
Russo Daniel, Grechi Daniele, Vicentini Alessandra, Grego Kim (2020), ‘Sociolinguistic and statistical methods to survey the communicative needs of home-assisted elderly, their families, and foreign caregivers in Northern Italy’, in Davis Boyd, Vicentini Alessandra, Grego Kim (2020) (eds), Seniors, foreign caregivers, families, institutions: Linguistic and multidisciplinary perspectives, Mimesis international, Milan/London.
Vicentini Alessandra, Grego Kim (2019) (eds), Linguistic perspectives on ageing issues, ethics and ideology, “EXPRESSIO”, 3, Mila
Enhancing autonomy: Fault detection, identification and optimal reaction for over - Actuated AUVs
No full textThe adoption of fault detection and isolation (FDI) techniques is fundamental to ensure high levels of safety and productivity, especially in critical and expensive applications like Autonomous Underwater Vehicles (AUV). This paper describes a comparison between different techniques available in the literature, applied to over-actuated AUVs under single fault condition (SFC) and considering only abrupt faults. The main contribution of this work is twofold: first, we show how such techniques can be adapted to the case of over actuated AUVs in order to isolate and identify a faulty situation of one thruster. Moreover, we give a means for robust fault reaction by using an optimal control allocation problem, which is tightly coupled with the FDI algorithm. The proposed work is in the framework of the V - Fides project and the algorithms are demonstrated in simulation, employing the dynamical model of that vehicle
OptoCOMM and SUNSET to enable large data offloading in Underwater Wireless Sensor Networks
No full textIn this paper we present the initial implementation of an integrated optical and acoustic system that can enable large data transfer between mobile and static nodes in Underwater Wireless Sensor Networks (UWSNs). The proposed system is based on the OptoCOMM optical modem and on the SUNSET Software Defined Communication Stack (S-SDCS) framework. The OptoCOMM modem allows to overcome the limits of maximum data rate and bandwidth imposed by the use of acoustic communication by providing a data rate of 10Mbps. SUNSET SDCS instead has been used to provide networking and fragmentation capabilities to efficiently offload large data in UWSNs. The performance of the proposed approach has been evaluated through in lab experiments where large files with arbitrary sizes have been optically transferred. The results achieved show that our system is able to transfer up to 1.5 GBytes of data in short time
Optimal aided inertial navigation, augmented with inter-sensors self-calibration
No full textThe proposed work is in the framework of the V-Fides project, in which is a general purpose, 3000m depth rated underwater vehicle with highly maneuverability capabilities was developed. The project was co-funded by Tuscany Region (Italy) and developed by a team lead by WASS S.p.A. (Whitehead Sistemi Subacquei, Livorno) with the participation of several partners including two research institutions of the University of Pisa and Small-Medium Enterprises in the Pisa-Livorno area. The vehicle is equipped with a sensors payload for autonomous navigation. This contribution describes an integrated calibration/navigation filter capable of estimating the relative (rotational) calibration parameters between the IMU and the DVL, and producing the standard velocity and attitude navigation output together with accelerometers biases. The results were demonstrated with real data sets collected during extensive experimental campaigns. Finally the observability analysis is proposed in order to define the motion requirements for the asymptotic convergence of the parameter estimates
The project V-fides: A new generation AUV for deep underwater exploration, operation and monitoring
No full textThe proposed work is in the framework of the V-Fides project, aiming at developing a new generation of agile, over-actuated, long endurance Autonomous Underwater Vehicles, for deep underwater exploration, operation and monitoring. The project is co-funded by Tuscany Region (Italy) and is developed by a team lead by WASS S.p.A. (Whitehead Sistemi Subacquei, Livorno) with the participation of several partners including two research institutions of the University of Pisa and Small-Medium Enterprises in the Pisa-Livorno area. The vehicle is a general purpose, 3000m depth rated underwater vehicle with highly maneuverability capabilities, which can operate both as AUV and ROV. The vehicle is equipped with seven thrusters, with asymmetric input-output characteristic, and with a sensors payload for autonomous navigation, composed by: a tactical grade Inertial Measurement Unit (IMU), a Doppler Velocity Logger (DVL), a depth sensor, a magnetic compass and an acoustic modem for underwater communication and localization. This contribution gives an overview of the developed general architecture of the Navigation and Control module of the vehicle, from the algorithmic and system implementation stand-points
A nonlinear complementary filter for underwater navigation using inertial measurements
No full textThis paper describes a nonlinear complementary filter capable of estimating the course motion variables namely the position, velocity, heading and accelerometers bias of an agile, over-actuated AUV during underwater operations, using the inertial sensors (IMU), the DVL, the depth sensor and the compass. The proposed work is within the framework of the V-Fides project, co-funded by Tuscany Region (Italy) and developed by a team lead by WASS S.p.A. (Whitehead Sistemi Subacquei, Livorno). The aim of the project was to develop and evaluate an high-depth, over-actuated, long endurance Autonomous Underwater Vehicle (AUV). The paper proposes the mathematical development of the observer, together with some experimental results, able to demonstrate the capabilities of the estimation scheme, compared with the estimations obtained via a standard Kalman Filter
Venice workshop and Amsterdam installation
No full textREcall is a research project funded by EC Culture 2007-13 Programme (n. 2012 - 0927 / 001 - 001 CU7 COOP7) focused on the possible roles Museography can play when dealing with Difficult Heritage such as the ones coming from conflicts and wars. REcall wishes to envision new ways to the handling of Painful Places & Stories going beyond any traditional approach: there is the need to shift from the ‘simply’ commemoration attitude to more active involvement and participation of people in/with Places & Stories, through design strategies of ‘re-appropriation’ (www.recall-project.polimi.it).
The contribution is focused on two research-by-design experiments curated by the author
Rilevamento di guasti sugli attuatori di un veicolo marino sovra-attuato tramite Analisi delle Componenti Principali.
No full textQuesta tesi mostra come il metodo dell’Analisi delle Componenti Principali (PCA) possa essere
utilizzato per risolvere il problema di Fault Detection (FD) sugli attuatori di un veicolo marino
autonomo (AUV) sovra-attuato, in condizioni di guasto singolo improvviso. Dopo una breve descrizione
della tecnica utilizzata, vengono presentati tutti i passaggi necessari per l’elaborazione
dell’algoritmo, mettendone in luce le potenzialità e i limiti riscontrati. Si suggeriscono, inoltre,
nuove soluzioni per l’isolamento dei guasti (FI) da integrare con l’algoritmo proposto. Nella parte
finale della tesi vengono messi a confronto i risultati ottenuti applicando sia la PCA sia la sua
variante non lineare (NLPCA). Il presente lavoro si è svolto nell’ambito del progetto V-Fides, sul
quale modello dinamico sono simulati gli algoritmi
