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Due to the limitations of electromagnetic signals, underwater scenarios increase the complexity of developing accurate navigation systems. In the last decades, Ultra-Short BaseLine (USBL) positioning systems have been widely and efficiently used for Autonomous Underwater Vehicles (AUVs) localization, endorsing to be a suitable solution to limit the navigation drift without requiring periodic surfacing for Global Positioning System (GPS) resets. Typically, in the localization context, USBL measurements are exploited as observations within the on-board navigation filter where, most of the time, Extended Kalman Filter (EKF) or Unscented Kalman Filter (UKF) solutions are employed. In a break-away from the above-mentioned approaches, in this study, the localization task is solved as a Maximum A Posteriori (MAP) estimation problem. The presented solution is validated through the use of data gathered in October 2020 during EUMarineRobots (EUMR) tests in La Spezia (Italy) within the activities of the SEALab, the joint research laboratory between the Naval Support and Experimentation Center (Centro di Supporto e Sperimentazione Navale, CSSN) of the Italian Navy and the Interuniversity Center of Integrated Systems for the Marine Environment (ISME).

This article proposes two novel strategies to estimate the complete attitude of a stationary body, exploiting the measurements of a commercial micro electromechanical system composed of a triaxial gyroscope and a triaxial accelerometer. These methods, both based on the Kalman Filter framework, can solve the problem of the North seeking with high accuracy, without the use of digital magnetic compasses or fiber optic gyrosopes. The first method, called one axis carouseling, is an extension of the classic carouseling approach, and makes use of a noncontinuous rotation about one axis and of an active roll and pitch compensation system. The two axes carouseling is based on two noncontinuous rotations about different axes. Both methods have been validated with simulation tests, based on real sensor and rotary stages characteristics, where the body heading was estimated with high accuracy after convergence. Preliminary experimental tests with the novel one axis strategy have been performed; the results are very promising in light of future developments.

Computer Numerical Control (CNC) milling is still today the elective process for the production of single-piece impellers, as it can reliably produce complex geometries, removing the need for additional manufacturing processes. Nevertheless, Additive Manufacturing is winning more and more ground due to its ability to make components of any geometry that cannot be produced using subtractive techniques. As a result, the use of this technology can eventually be seen as the key to develop high-performance rotor components. In this scenario, the design of 3D impellers does not make an exception. Accordingly, the present paper proposes a general framework for engineered re-design and manufacture of 3D impellers installed on centrifugal compressors by exploiting Topology Optimization and Additive Manufacturing's potential. The procedure investigates also the rotoric component's best configuration for both static and dynamic behavior. Finally, the topology-optimized component is produced with AM through the use of suitable materials that can ensure efficient mechanical efficiency to prove the manufacturability of the entire procedure. To validate the proposed framework, the complete re-design of a 3D impeller of a major Italian-based Oil & Gas company is carried out, demonstrating that the re-thinking of the component in terms of Topology Optimization is a straightforward approach to increase the overall performance of the produced rotoric part.

In the widespread field of underwater robotics applications, the demand for increasingly intelligent vehicles is leading to the development of Autonomous Underwater Vehicles (AUVs) with the capability of understanding and engaging the surrounding environment. Consequently, the automatic recognition of targets is becoming one of the most investigated topics and Deep Learning-based strategies have shown astonishing results. In the context of this work, two different neural network architectures, based on the Single Shot Multibox Detector (SSD) and on the Faster Region-based Convolutional Neural Network (Faster R-CNN), have been trained and validated, respectively, on optical and acoustic datasets. The models have been trained with the images acquired by FeelHippo AUV during the European Robotics League (ERL) competition, which took place in La Spezia, Italy, in July 2018. The proposed ATR strategy has then been validated with FeelHippo AUV in an on-board postprocessing stage by exploiting the images provided by both a 2D Forward Looking Sonar (FLS) as well as an IP camera mounted on-board on the vehicle., https://youtu.be/6e_Ks924daQ

Every day more and more robotic aids, of different shapes, sizes, and functions, enter the clinics to take part in the rehabilitative and assistive paths for patients with reduced mobility. Accompanying discharged patients with robotics-based remote rehabilitation and home assistance seems to be one of the most promising avenues to follow to increase the success rate of these practices and lighten the overall burden on national health systems. However, to get out of clinics effectively, robotics must become wearable and, therefore, based on the use of embedded low-power electronics, both for practicality and safety reasons. The point is further complicated when it comes to assisting or rehabilitating lost hand functionalities due to the small size and complex mobility of such a limb; moreover, ensuring the real-time execution of gesture classification algorithms for controlling these devices hence becomes a vital engineering challenge. A hand gesture classification solution, specifically designed for the implementation of embedded electronics, based on surface electromyography, and ensuring real-time action, will be presented in this paper.

Robotic-based human assistance is increasingly spreading both in clinical practice and in the industrial sector. The use of wearable robots, such as exoskeletons, is considered one of the most promising applications since it allows for merging human flexibility and creativity with machine endurance. Such devices shall be comfortable and lightweight to be as transparent as possible to the user’s perception. At the same time, they shall also be stiff enough to drive body parts while bearing the exchanged forces efficiently. The gold standard methodology to achieve such results is the topology optimization, which, even if used mainly in structural optimization, is still relatively new to wearable robots. In this paper, the authors propose a topology-optimization-based design strategy suitable to be applied, if adapted case by case, to a generic design of a wearable system. The presented test case, used as a benchmark to assess the optimization-based design process, focuses on a hand exoskeleton made of aluminum alloy, resorting to an additive manufacturing process.

Personalized medicine is an effective tool to improve the quality of rehabilitation and treatment for patients with disabilities. This study deals with the development of a low-cost hand scanner for the acquisition of anthropometric measures. The data acquired by the scanner is used, thanks to the developed procedure, to tailor the dimensions of a hand exoskeleton. The exoskeleton is used for assistive and rehabilitation purposes.

Due to the growing demand for very high performance in aeronautical mechanisms and systems, particular attention must be paid on the bearing modeling and design. In this framework, a fundamental role is played by high peripheral speed and very low power losses. Looking toward this direction, this paper presents an improved model of rolling bearings able to describe the system dynamic behavior and the important effect of different kinds of power losses (friction losses, fluid dynamic losses, etc.). The proposed model is characterized by a high numerical efficiency and allows the investigation of the rolling bearing behavior both under transient and steady conditions. A comparison between the experimental and simulated results is also presented in this paper. The analysis of the results is encouraging and shows a good agreement between experiments and model simulations.

Nowadays, the search for increasing performances in turbomachinery applications has led to a growing utilization of active magnetic bearings (AMBs), which can bring a series of advantages thanks to their features: AMBs allow the machine components to reach higher peripheral speeds; in fact there are no wear and lubrication problems as the contact between bearing surfaces is absent. Furthermore, AMBs characteristic parameters can be controlled via software, optimizing machine dynamics performances. However, active magnetic bearings present some peculiarities, as they have lower load capacity than the most commonly used rolling and hydrodynamic bearings, and they need an energy source; for these reasons, in case of AMBs overload or breakdown, an auxiliary bearing system is required to support the rotor during such landing events. During the turbomachine design process, it is fundamental to appropriately choose the auxiliary bearing type and characteristics, because such components have to resist to the rotor impact; so, a supporting design tool based on accurate and efficient models of auxiliary bearings is very useful for the design integration of the Active Magnetic Bearing System into the machine. This paper presents an innovative model to accurately describe the mechanical behavior of a complete rotor-dynamic system composed of a rotor equipped with two auxiliary rolling bearings. The model, developed and experimentally validated in collaboration with Baker Hughes a GE company (providing the test case and the experimental data), is able to reproduce the key physical phenomena experimentally observed; in particular, the most critical phenomenon noted during repeated experimental combined landing tests is the rotor forward whirl, which occurs in case of high friction conditions and greatly influences the whole system behavior. In order to carefully study some special phenomena like rotor coast down on landing bearings (which requires long period of time to evolve and involves many bodies and degrees of freedom) or other particular events like impacts (which occur in a short period of time), a compromise between accuracy of the results and numerical efficiency has been pursued. Some of the elements of the proposed model have been previously introduced in literature; however the present work proposes some new features of interest. For example, the lateral and the axial models have been properly coupled in order to correctly reproduce the effects observed during the experimental tests and a very important system element, the landing bearing compliant suspension, has been properly modelled to more accurately describe its elastic and damping effects on the system. Furthermore, the model is also useful to characterize the frequencies related to the rotor forward whirl motion.

Underwater vehicle propulsion performed by exploiting electrical motor is in general the most flexible solution and it is growing in popularity because of its high efficiency both at high and at low advance speed, quick and simple deployment, low costs, and encumbrance. In the present work, permanent magnet synchronous motors for underwater propulsion are proposed. In particular, advanced sensorless control techniques of permanent magnet synchronous motors permit reduced costs, high reliability, and performances. When dealing with small autonomous underwater vehicle propulsion, such devices are hard to find in the market. Hence, the authors focused the research in the development of a system able to perform a reliable rotational speed and torque sensorless estimation. The design and implementation of a complete solution for underwater propulsion are presented as well as a novel rotor polarity identification technique exploiting a high-frequency injection control. Pool tests for the identification of the performances and of the dynamic parameters of the propulsion system are presented. Finally, the possibility of operating a sensorless estimation of the thrust and torque exerted by the propeller and pool test measurements are presented. These features could be exploited to improve navigation accuracy and involves obvious benefits in terms of cost reduction and reliability of the system.

Autonomous underwater vehicles localization and navigation are challenging due to the lack of Global Positioning System underwater: alternative techniques have then to be used in order to measure the position of the vehicle. To this aim, sensor fusion methods based on acoustic positioning systems are often exploited. This article faces the study and the improvement of the localization of an underwater target through an ultra short baseline–aided buoy built by the Mechatronics and Dynamic Modelling Laboratory of the University of Florence. Such a buoy relies on an ultra short baseline device for the localization and is aided by a proper sensor set in order to compensate variations in its pose. First, a study of the underwater localization based on the ultra short baseline technique is provided. The measurement errors entailed by the buoy motion are then analyzed and preliminarily compensated, exploiting linear least squares methods. Subsequently, filtering techniques are considered with the aim to further increase the accuracy of the ultra short baseline measurements. Due to the nonlinearities of the sensors characteristics, extended Kalman filter has been used, with different models for stationary and moving targets. The solutions proposed have been validated through experimental tests conducted with MArine Robotic Tool for Archaeology autonomous underwater vehicles built by the Mechatronics and Dynamic Modelling Laboratory. The results evidence an improved vehicle localization, suggesting interesting future developments concerning both mechanical and computational solutions.

Coastal zones are subjected to a wide range of phenomena acting on very different temporal and spatial scales: from decades to days and from hundreds of kilometers to tens of meters. Planning the management of such areas, thus, requires an accurate and updated knowledge of the ongoing processes. While standard monitoring activities are functional for the medium-long time scale and medium-large spatial scale, they struggle to provide adequate information concerning the short period (i.e., days) and small range (i.e., few meters). In addition, such operations are affected by high costs and logistic complexity since they generally involve the deployment of specific aircraft or maritime vehicles. On the contrary, the employment of robotic devices can represent a solution to these issues. Their proper use can allow for frequent surveys and enhance the coverage of the acquired data due to optimized mission strategies. Marine robotics has the potential to arise as an efficient complementary tool to standard monitoring techniques. Nevertheless, the use of marine robots is still limited and should be improved. The purpose of this paper is to discuss the current state of robotic technology, identifying both the benefits and shortcomings of its use for micro-tidal marine-coastal monitoring. The discussion will be supported by actual results, taken as an example, achieved using FeelHippo AUV, the compact Autonomous Underwater Vehicle (AUV) developed by the Department of Industrial Engineering at the University of Florence, Italy.

This paper presents the funded project DAMPS, that addresses the development of a multi-robot system for the position tracking of noise sources in underwater environment. The robots composing the team collaborate in order to fuse the local information coming from the analysis of a Passive Acoustic Monitoring sensor, with the final aim of estimating the position of a the acoustic source. The team is thus a distributed, modular and reconfigurable sonar system that can be controlled remotely from a Control&Command center. In this paper we highlight the functional architecture that will be implemented within the project, the possible algorithmic approaches to be employed within the submodules and possible application scenarios.

Robotic devices are being employed in more and more sectors to enhance, streamline, and augment the outcomes of a wide variety of human activities. Wearable robots arise indeed as of-vital-importance tools for telerehabilitation or home assistance targeting people affected by motor disabilities. In particular, the field of “Robotics for Medicine and Healthcare” is attracting growing interest. The development of such devices is a primarily addressed topic since the increasing number of people in need of rehabilitation or assistive therapies (due to population aging) growingly weighs on the healthcare systems of the nation. Besides, the necessity to move to clinics represents an additional logistic burden for patients and their families. Among the various body parts, the hand is specially investigated since it most ensures the independence of an individual, and thus, the restoration of its dexterity is considered a high priority. In this study, the authors present the development of a fully wearable, portable, and tailor-made hand exoskeleton designed for both home assistance and telerehabilitation. Its purpose is either to assist patients during activities of daily living by running a real-time intention detection algorithm or to be used for remotely supervised or unsupervised rehabilitation sessions by performing exercises preset by therapists. Throughout the mechatronic design process, special attention has been paid to the complete wearability and comfort of the system to produce a user-friendly device capable of assisting people in their daily life or enabling recorded home rehabilitation sessions allowing the therapist to monitor the state evolution of the patient. Such a hand exoskeleton system has been designed, manufactured, and preliminarily tested on a subject affected by spinal muscular atrophy, and some results are reported at the end of the article.

9 pages, 2 figures.-- Data Availability Statement: All datasets generated for this study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s, Marine animal forests are benthic communities dominated by sessile suspension feeders (such as sponges, corals, and bivalves) able to generate three-dimensional (3D) frameworks with high structural complexity. The biodiversity and functioning of marine animal forests are strictly related to their 3D complexity. The present paper aims at providing new perspectives in underwater optical surveys. Starting from the current gaps in data collection and analysis that critically limit the study and conservation of marine animal forests, we discuss the main technological and methodological needs for the investigation of their 3D structural complexity at different spatial and temporal scales. Despite recent technological advances, it seems that several issues in data acquisition and processing need to be solved, to properly map the different benthic habitats in which marine animal forests are present, their health status and to measure structural complexity. Proper precision and accuracy should be chosen and assured in relation to the biological and ecological processes investigated. Besides, standardized methods and protocols are strictly necessary to meet the FAIR (findability, accessibility, interoperability, and reusability) data principles for the stewardship of habitat mapping and biodiversity, biomass, and growth data, This perspective manuscript is the result of the 3DSeaFor online workshop funded by EUROMARINE Call 2019 Foresight Workshops. This work was partially supported by an Italian Research Projects of National Interest (PRIN), funded by the Italian Ministry of University and Research: “Reef ReseArcH – Resistance and resilience of Adriatic mesophotic biogenic habitats to human and climate change threats” (Call 205; Prot. 2015J922E; 2017-2020) and by the TAO (Tecnologie per il monitorAggio cOstiero) project in the frame of the program POR-FESR (European Regional Development Fund, ERDF) 2014-2020 of the Emilia-Romagna Region. This work was partially supported by the U.S. National Science Foundation under Grant No. OCE 16-37396 (and earlier awards) as well as a generous gift from the Gordon and Betty Moore Foundation, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Acoustic sensors play a fundamental role in underwater applications. They are used to perform a wide variety of tasks: from the perception of the surrounding environment to the support of inertial sensors in navigation strategies. The quality of the acquired images deeply affects the obtained results and, consequently, image enhancement approaches need to be developed and tested. Super-Resolution (SR) techniques are employed to reconstruct one high-resolution image by composing a sequence of low-resolution ones. By applying these strategies, the information content of an image can be considerably increased, but the required computational time is incompatible for real-time employment. Due to this limitation, an SR Generative Adversarial Network (SRGAN) approach has been developed in the presented work, where the SR images are used during the training phase of the GAN framework. The proposed approach, which has been developed for images provided by a Forward-Looking Sonar (FLS), can guarantee a solid trade-off between the quality of the generated high-resolution image and the run-time execution.

In recent years, seabed inspection has become one of the most sought-after tasks for Autonomous Underwater Vehicles (AUVs) in various applications. Forward-Looking Sonars (FLS) are commonly favored over optical cameras, which are not-negligibly affected by environmental conditions, to carry out inspection and exploration tasks. Indeed, sonars are not influenced by illumination conditions and can provide high-range data at the cost of lower-resolution images compared to optical sensors. However, due to the lack of features, sonar images are often hard to interpret by using conventional image processing techniques, leading to the necessity of human operators analyzing thousands of images acquired during the AUV mission to identify the potential targets of interest. This paper reports the development of an Automatic Target Recognition (ATR) methodology to identify and localize potential targets in FLS imagery, which could help human operators in this challenging, demanding task. The Mask R-CNN (Region-based Convolutional Neural Network), which constitutes the core of the proposed solution, has been trained with a dataset acquired in May 2019 at the Naval Support and Experimentation Centre (Centro di Supporto e Sperimentazione Navale - CSSN) basin, in La Spezia (Italy). The ATR strategy was then successfully validated online in the same site in October 2019, where the targets were replaced and relocated on the seabed.

Autonomous Underwater Vehicles (AUVs) are commonly used to autonomously explore or cover an entire area with a sensor to map the area or look for objects of interest using Automatic Target Recognition (ATR) algorithms. AUV surveys are typically pre-planned by operators, often using lawnmower or zig-zag paths, and are often conducted using acoustic sensors, such as Forward-Looking Sonars (FLS) and Side Scan Sonars (SSS). The performance of such acoustic sensors depends on several environmental, target, and sensor characteristics, which are difficult to predict, making it challenging to design a good path for the AUV tasks. Sensor-driven path planning algorithms emerged as an important tool to overcome such limitations. These solutions can avoid to perform several mission attempts, and thus reducing the time required for seabed inspections and explorations. The here presented work aims to investigate an AUV tailored sensor-driven path planning solution for seabed inspections using an FLS sensor, but suitable for any acoustic or optical sensor. A two-level planning layer system is presented where the well-known RRT* is used as a start-to-goal planner, while in the high-level planner, the possible next-best viewpoints are generated in an RRT fashion. Random trees are grown considering the Dubins vehicle kinematic constraints, where each node is evaluated according to the expected information gain. Besides, a rewiring strategy for coverage applications to find for each viewpoint the best parent is proposed. Simulation results demonstrate the effectiveness of the proposed solution.

Robotics for Medicine and Healthcare is undoubtedly an important emerging sector of the newborn third millennium. There are many aspects in which this branch of robotics already operates; in this article, the focus will be on the so-called “Robotic assistive technology”. In particular, a novel electromechanical design for an assistive Hand Exoskeleton System is presented here. Since freedom of movement plays a crucial role in making actually usable an assistive device, the main point of innovation of the proposed solution lies in the complete wearability of the resulting system: including mechanics, control electronics, and power supply. From the combination of the authors’ previous experience with the improvements presented in this article comes a fully standalone tailor-made assistive device.

The interaction with a highly complex anatomical morphology, the high performance in conjunction with the limits of the bearable wearability, and the frequent change of user make the development of rehabilitative devices for the hand a real engineering challenge. Considering the described scenario, the Department of Industrial Engineering of the University of Florence, in collaboration with MOV’IT S.r.l., has developed a modular remote actuated system with noteworthy characteristics. An overview of the mechanical design is reported.

Underwater robots are nowadays employed for many different applications; during the last decades, a wide variety of robotic vehicles have been developed by both companies and research institutes, different in shape, size, navigation system, and payload. While the market needs to constitute the real benchmark for commercial vehicles, novel approaches developed during research projects represent the standard for academia and research bodies. An interesting opportunity for the performance comparison of autonomous vehicles lies in robotics competitions, which serve as an useful testbed for state-of-the-art underwater technologies and a chance for the constructive evaluation of strengths and weaknesses of the participating platforms. In this framework, over the last few years, the Department of Industrial Engineering of the University of Florence participated in multiple robotics competitions, employing different vehicles. In particular, in September 2017 the team from the University of Florence took part in the European Robotics League Emergency Robots competition held in Piombino (Italy) using FeelHippo AUV, a compact and lightweight Autonomous Underwater Vehicle (AUV). Despite its size, FeelHippo AUV possesses a complete navigation system, able to offer good navigation accuracy, and diverse payload acquisition and analysis capabilities. This paper reports the main field results obtained by the team during the competition, with the aim of showing how it is possible to achieve satisfying performance (in terms of both navigation precision and payload data acquisition and processing) even with small-size vehicles such as FeelHippo AUV.

Despite the current industrial trend towards automation, many workers are still daily exposed to heavy loads during their duties. Regarding the construction industry, the shotcrete projection results in a particularly arduous whole-body effort for the so-called “concrete reinforcement workers”. In this paper, the design of a passive robotic human assistance tool to assist workers in dealing with the specific task of shotcrete projection will be described. If the design of an effective aid plays a crucial role in improving the job’s quality, following the guidelines given by the French company Eiffage Infrastructures; besides, the acceptance of the proposed solution shall have special consideration. Therefore, starting from an in-site assessment of the scenario, the presented solution has been profoundly adjusted to address the issues coming from this particular task. The exoskeleton adaptability to different lower-limb activities has been preserved without lowering its comfort during daily life in the working area. The developed solution’s operation range has been specifically optimized to assist the worker during specific efforts without hindering the other movements.

Modern robotics is a field that is constantly involving more and more aspects of daily life, from industry to the healthcare sector. Nowadays, robotic assistance to hand-impaired people still represents a hurdle and a challenging task to achieve. The research work of recent years carried out by the Department of Industrial Engineering of the University of Florence has focused on the development of a tailor-made hand exoskeleton to assist people with hand disabilities. In this chapter the synthesis of the development process, sequentially ordered, is given in order to provide an exhaustive description of the design procedure yielding a fully portable and wearable robotics system. The final version of the designed robotic system presents two levels of personalization on the patient. A single-degree-of-freedom finger mechanism allows precise replication of the natural grasping gesture keeping a lightweight structure and an electromyography-based actuation strategy ensures a straightforward use of the device. These two characteristics lead to a fully patient-based solution for hand assistance.

The ability of acoustic waves to penetrate through waters in all visibility conditions and for long ranges has made SOund NAvigation Ranging (SONAR) devices increasingly widespread for underwater sensing. In particular, imaging sonars, such as Forward-Looking SONARs (FLSs), have become ubiquitous nowadays both for Autonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles (ROVs). However, the loss of elevation angle information during the 3D to 2D image projection lessens the ability to understand the underwater environment. This paper presents a probabilistic 3D occupancy mapping framework that employs FLS images, and it is specifically tailored to AUVs. The proposed method is tested through the use of data recorded during sea trials performed in 2018 with FeelHippo AUV, a vehicle developed by the Department of Industrial Engineering of the University of Florence (UNIFI DIEF), at the NATO Science and Technology Organization Centre for Maritime Research and Experimentation (CMRE), La Spezia (Italy).

In modern robotics, providing assistance to those patients who have lost or injured their hand skills, assuring them an independent and healthy life through the design of exoskeleton technologies is, surely, one of the most challenging goal. This research activity is focused on the development of a low-cost hand exoskeleton system (HES) which supports patients suffering from hand opening disabilities during the activities of daily living. The device is, then, designed to be also used during rehabilitative sessions in specific tasks to restore the dexterity of the user’s hand. In this paper, the authors propose an optimization-based strategy, using a completely automatic scaling procedure, to customize hand exoskeletons for different patients. The authors have tested and validated the proposed approach by building a real HES prototype. The testing phase, conducted in collaboration with the Don Carlo Gnocchi Foundation, has showed that the optimization process leads to devices which tailor the hand of generic patients and are able to reproduce the natural kinematics of the fingers.

Recently, the wearable robotic field has become extremely prolific in terms of active devices for human body assistance. Nevertheless, unfortunately, owing to strictly motor and sensor requirements in terms of mechanism, weight, size and dexterous manipulation capabilities, portable hand exoskeletons for rehabilitation and assistance have not been developed as much as the exoskeletons for lower and upper limbs; in fact, only a few of them present an outcome of their use in the clinical practice as positive as expected. This research work aims at designing an aid for the hand function based on exoskeleton technologies for patients who have lost or injured their hand skills. In particular, this paper presents a novel Series Elastic Transmission (SET) used as power transmission on a Hand Exoskeleton System (HES) based on a Series Elastic Actuator (SEA). The elastic element of the transmission has been designed through the innovative topology optimization approach which has led to manufacture a component whose mechanical features strictly replicate the desired ones. The authors have validated the proposed approach by testing a real elastic component. Suitable mechanical tests, whose results are reported in the paper, were executed in order to evaluate the goodness of the design procedure.

The paper describes the electromechanical design of a compact, light-weight Autonomous Underwater Vehicle (AUV) for archaeological applications; the vehicle is named Zeno (Zeno Environment Nautical Operator), protector of freshwater and flood victims, and was developed in the framework of the European project ARCHEOSUb; the AUV specifications, its navigation devices and payload are given. The main characteristics of the vehicle are described with particular attention to its system architecture, propulsion system and structural design. Zeno AUV is currently under assembly and its first tests are scheduled for Summer 2018.

In this research activity, a new methodology for the synthesis of hand exoskeleton mechanisms has been developed and validated through real prototypes. The innovative methodology is based on a new parallel mechanism and has been tested by building a robotic assistive device for hand opening disabilities applied to real cases. The studied robotic orthosis is designed to be a low-cost, adaptable and portable hand exoskeletons to assist people with hand opening disabilities in their activities of daily livings. As regards the methodology for the synthesis of hand exoskeleton mechanism, the authors propose to use a motion capture system to acquire the real hand phalanx trajectories and the geometrical characteristics of the patient’s hand, and to use optimization algorithms to properly defines the novel kinematic mechanism that better fits the finger trajectories. The preliminary testing phase of the prototype on a single patient is concluded; currently, through the collaboration with an Italian rehabilitation center, a group of patients are testing the proposed HES methodology.

The involvement of autonomous underwater vehicles for patrolling, monitoring or maintenance activities of submersed structures in the coastal strip, harbors or in proximity of off-shore plants (e.g. in oil& gas and military fields), can represent a high benefit for the economy of the related areas. For instance, continuous or more frequent monitoring can be possible, with a reduction of the necessary costs: The use of remotely operated vehicles with the linked implication of support ships and specialized pilots, or the involvement of professional divers, could be avoided or significantly reduced. The paper describes the FeelHippo autonomous underwater vehicles, the vehicle designed and built by the MDM Lab of the University of Florence; it is a low cost autonomous underwater vehicles suitable for these purposes. In particular, an onboard acoustic localization system, based on a low cost approach, has been implemented and preliminary experimental results are here reported.

This paper describes design methods for the plastic hull of an Unmanned Underwater Vehicle (UUV), with a particular focus on its cylindrical body and nearly spherical domes at the ends. With the proposed approach, the methodologies reported in the literature were compared, and suitable modifications and improvements were investigated and implemented to extend the classical theories and data to this case study. The investigated underwater vehicle, named FeelHippo, was designed and assembled by the Department of Industrial Engineering of the University of Florence. Its main hull is composed of an extruded PMMA (PolyMethyl MethAcrylate) cylinder and two thermoformed PMMA domes. Breakage of the hull results in destructive phenomena, namely, yielding and buckling. An experimental campaign and FEM (Finite Element Method) analysis were carried out to complete the theoretical study, and the collapse pressures were compared with the derived design values. In conclusion, the proposed innovative method is a lean and effective technique for designing underwater hull domes and predicting the collapse pressures.

This paper presents a mono visual odometry algo- rithm tailored for AUVs navigation. The main goal of the paper is to test different odometry solutions to find out which one is the most suitable for AUVs navigation. Two different features detector, SIFT and SURF, to compute the vehicle motion are compared. The algorithms were tested with a dataset acquired in September 2018 by the compact Zeno AUV in the Haifa bay, Israel, and the results were compared with the path followed by the vehicle, estimated exploiting GPS, IMU and DVL, that are more accurate than the camera. The achieved results are promising; the proposed strategy could support and enhance DVL-aided navigation or could represent an alternative, for instance, in DVL-denied scenarios or for low-cost AUVs (without a DVL on board).

The paper presents the electromechanical design of an Autonomous Surface Vehicle (ASV) developed by the Department of Industrial Engineering (DIEF) of the University of Florence (UNIFI), Italy. One of the main functions of this autonomous moving buoy is to localize underwater targets, such as Autonomous Underwater Vehicles (AUVs), through an Ultra Short BaseLine (USBL) and to enable the communication with them; furthermore, it is possible to equip the buoy with sensors or payloads, for instance cameras to detect the seabed. The buoy specifications and its navigation devices are described. The main features of the developed floating device are given, starting from its system architecture to its structural design. The buoy will be assembled during Summer 2019 and tested together with the UNIFI DIEF underwater vehicles.

Autonomous Underwater Vehicles (AUVs) need safe and reliable navigation systems in order to perform the required tasks. Unfortunately, it is well known that the Global Positioning System (GPS) cannot be exploited during underwater missions. As a consequence, the real-time position of the AUV is usually obtained by means of recursive navigation filters such as Kalman Filter (KF), Extended Kalman Filter (EKF), Unscented Kalman Filter (UKF) or dead reckoning techniques where direct speed measurements are usually provided by specialized underwater sensors such as the Doppler Velocity Log (DVL). The final aim of this work is to propose an underwater navigation solution where the AUV is able to safely navigate without the need of a DVL. In particular, linear speed estimations are obtained from a Forward-Looking SONAR (FLS) or, in its absence, exploiting a simple dynamic model. The proposed solution is validated making use of data obtained during test at sea performed in La Spezia (Italy).

The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the potential of Topology Optimization (TO) and Additive Manufacturing (AM). The method envisages the use of TO to define the best configuration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight. Eventually, the topology-optimized component is manufactured by using appropriate materials that can guarantee valid mechanical performances. The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness of a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and expanders, its application on rotor and stator components might unlock several benefits: tuning the natural frequencies, a reduction in the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing a single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing resources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are essential in the Oil and Gas context, when dealing with new projects but also for service operations.

Modern autonomous underwater vehicles (AUVs) are currently involved in complex tasks and scenarios, and require accurate and robust navigation systems to estimate their position. However, since the Global Positioning System cannot be exploited underwater, the AUV position is not directly measurable in real time (unless using dedicated acoustic-based sensors), making the availability of a reliable navigation system even more crucial. In this context, the main role is played by the filter used to estimate the AUV motion, usually relying on simple kinematic vehicle models and equations linearization. A navigation strategy specifically thought for AUVs and based on an unscented Kalman filter is proposed and experimentally validated by the authors. Preliminary tests of the developed strategy have been carried out by running the navigation filter on experimental data acquired during the FP7 European ARROWS project. This initial validation has been performed totally offline. The AUVs navigated in dead reckoning without using navigation filters, whereas the proposed strategy has been compared to standard extended Kalman filter based ones, highlighting encouraging performances. To further validate the proposed navigation system, suitable sea tests have been performed. The navigation filter has been implemented online on an AUV and the vehicle controller relied only on it to navigate. The new validation procedure, whose results are reported in this paper, showed again the good performance of the chosen strategy, yielding satisfying results in terms of accuracy of vehicle position estimation.

Recently, robotics has increasingly become a companion for the human being and assisting physically impaired people with robotic devices is showing encouraging signs regarding the application of this largely investigated technology to the clinical field. As of today, however, exoskeleton design can still be considered a hurdle task and, even in modern robotics, aiding those patients who have lost or injured their limbs is surely one of the most challenging goal. In this framework, the research activity carried out by the Department of Industrial Engineering of the University of Florence concentrated on the development of portable, wearable and highly customizable hand exoskeletons to aid patients suffering from hand disabilities, and on the definition of patient-centered design strategies to tailor-made devices specifically developed on the different users&rsquo, needs. Three hand exoskeletons versions will be presented in this paper proving the major taken steps in mechanical designing and controlling a compact and lightweight solution. The performance of the resulting systems has been tested in a real-use scenario. The obtained results have been satisfying, indicating that the derived solutions may constitute a valid alternative to existing hand exoskeletons so far studied in the rehabilitation and assistance fields.

The number of scientific researches focusing on designing assistive or rehabilitative robotics devices has remarkably increased with respect to just a few decades ago. However, when it comes to developing such devices for children, literature becomes poor. This paper presents the work carried out by the researchers of the Department of Industrial Engineering of the University of Florence in order to design and develop an assistive hand exoskeleton for a child. The results of a preliminary ergonomics test are also given at the end of the paper.

Used in several industrial fields to create innovative designs, topology optimization is a method to design a structure characterized by maximum stiffness properties and reduced weights. By integrating topology optimization with additive layer manufacturing and, at the same time, by using innovative materials such as lattice structures, it is possible to realize complex three-dimensional geometries unthinkable using traditional subtractive techniques. Surprisingly, the extraordinary potential of topology optimization method (especially when coupled with additive manufacturing and lattice structures) has not yet been extensively developed to study rotating machines. Based on the above considerations, the applicability of topology optimization, additive manufacturing, and lattice structures to the fields of turbomachinery and rotordynamics is here explored. Such techniques are applied to a turbine disk to optimize its performance in terms of resonance and mass reduction. The obtained results are quite encouraging since this approach allows improving existing turbomachinery components’ performance when compared with traditional one.

Reliable navigation systems are fundamental for Autonomous Underwater Vehicles (AUVs) to perform complex tasks and missions. It is well known that the Global Positioning System (GPS) cannot be employed in underwater scenarios; thus, during missions below the sea's surface the real-time position is usually obtained with expensive sensors, such as the Doppler Velocity Log (DVL), integrated within a navigation filter such as an Extended Kalman Filter (EKF), Unscented Kalman Filter (UKF), or Dead Reckoning (DR) strategies. The goal of this work is to develop an underwater navigation system that does not rely on a DVL and where linear speed estimations are obtained exploiting data from a Forward-Looking SONAR (FLS) or, in its absence, taking advantage of a dynamic model that presents a reduced set of parameters. The proposed solution is validated through the use of navigation data obtained during sea trials undertaken in July 2018 with FeelHippo AUV at La Spezia (Italy), at the NATO Science and Technology Organization Center for Maritime Research and Experimentation (CMRE).

This paper’s goal is to present an online underwater mosaicing technique that suites the peculiarities of Forward-Looking Sonar images. In addition, exploiting acoustic information, an acoustic odometry solution is shown and the feasibility of both approaches is evaluated by means of data acquired during sea trials with an Autonomous Underwater Vehicle.

A new type of vehicle has been designed by the Department of Industrial Engineering of the University of Florence (DIEF); it is an AUV (Autonomous Underwater Vehicle) capable of switching its shape according to mission needs matching the best UUVs (Unmanned Underwater Vehicles) features: it is compact and near torpedo-shaped in case of long distance missions, such as surveillance and monitoring (closed configuration, typical of AUVs), on the other end it becomes isotropic for site inspection and on-site manipulation (open configuration, emblem of ROVs - Remotely Operated Vehicles). The main goal of the work is adding to the hydrodynamic vehicle the capability of changing its structure and its thruster configuration. The paper deals with the study and the design of the vehicle. Its main features, design choices and payloads, that can be equipped with, are described.

Among the most challenging aspects of the current bio-robotics trends, a place of honor is certainly reserved to the assistance to physically impaired people during the Activities of Daily Living (ADLs). The aim of this work is to assess the interaction between an assistive hand exoskeleton, controlled through surface ElectroMyoGraphy (sEMG) signals, and its user. A new control strategy, which focuses mainly on the wearability and the usability of the system, is presented. Promising results of two preliminary tests, conducted in collaboration with the “Don Carlo Gnocchi” Foundation, are also reported.

Developing wearable robotic systems for children’s hand rehabilitation highlights several issues during the design phase due to the difficult interactions with the patients and the high adaptability these devices require to fit fingers always growing. In this research work, the authors propose a model-based approach which exploits only a photograph of the hand to automatically generate a tailor-made device capable of replicating hand trajectories. A real device has been developed and tested on a patient after three growing steps in order to assess its kinematic compliance with fingers.

Nowadays, underwater acoustic communication is an interesting topic of research. This is especially true in the case of Autonomous Underwater Vehicles (AUVs): due to the limitations of the underwater environment, where WiFi and radio communications are limited, it is very important to rely on efficient and reliable tools for acoustic data exchange. Indeed, an underwater network of acoustic nodes can enhance the navigation and localization capabilities of one or more vehicles. However, cooperation and networking is not feasible in underwater networks composed of vehicles with different software architecture and multi-vendor modems due to the lack of communication standards. In this paper, the authors investigate the use of an AUV as a mobile bridging node within a network of fixed heterogeneous acoustic modems. In particular, MARTA AUV, developed and built by the Department of Industrial Engineering of the University of Florence, is employed to enable data transmission between modems of different manufacturers. The networking and the handling of multiple and multi-vendor modems are instead performed through the SUNSET Software Defined Communication Stack (SDCS) framework, developed by University of Rome La Sapienza jointly with WSENSE Srl. Different bridging tests have been performed in field to evaluate the feasibility of such approach, showing that AUVs can efficiently accomplish the role of gateway between the nodes of the network communicating through the SUNSET SDCS framework.

Despite the growing interest that marine engineering has received during the past few decades, autonomous underwater navigation can be still considered a daunting task. Unfavourable environmental conditions and limitations on the typologies of available sensors increase the difficulties autonomous vehicles encounter during the execution of planned missions. As of today, one of the main challenges researchers face is the precise localisation of underwater vehicles, where the limitation of the error drift over time becomes extremely important for long navigation missions. In recent years, the authors, within ISME—Interuniversity Center of Integrated Systems for the Marine Environment, extensively worked on autonomous underwater navigation, with special focus on positioning techniques. Working in parallel, research was conducted on the topics of both the improvement of state-of-the-art navigation techniques and on the employment of local sensor networks to periodically reset position errors. This contribution reports the most significative results obtained by the authors during these years.

SUMMARYIn accordance with strict requirements of portability, cheapness, and modularity, an innovative assistive device for hand disabilities has been developed and validated. This robotic orthosis is designed to be a low-cost, portable hand exoskeleton to assist people with physical disabilities in their everyday lives. Referring to hand opening disabilities, the authors have developed a methodology which, by starting from the geometrical characteristics of the patient's hand, defines the novel kinematic mechanism that better fits to the finger trajectories. The authors have validated the proposed novel mechanism by carrying out a Hand Exoskeleton System (HES) prototype, based on a single-phalanx mechanism, cable driven. The testing phase of the real prototype with a patient is currently on going.

In the last years, a challenging field of autonomous robotics is represented by cooperative mobile manipulation carried out in different environments (aerial, terrestrial and underwater environment). As regards cooperative manipulation of Intervention-Autonomous Underwater Vehicles (I-AUVs), this application is characterized by a more complex environment of work, compared to the terrestrial or aerial ones, both due to different technological problems, e.g. localization and communication in underwater environment. However, the use of Autonomous Underwater Vehicle (AUV) and I-AUV will necessarily grow up in the future exploration of the sea. Particularly, cooperative I-AUVs represent the natural evolution of single centralized I-AUV because they may be used in various underwater assembly tasks, such as complex underwater structure construction and maintenance (e.g. underwater pipeline and cable transportation can be carried out by multiple cooperative I-AUVs). Furthermore, underwater search and rescue tasks could be more efficient and effective if multiple I-AUVs were used.In this paper, the authors propose an innovative decentralized approach for cooperative mobile manipulation of I-AUVs. This decentralized strategy is based on a different use of potential field method; in particular, a multi-layer control structure is developed to in parallel manage the coordination of the swarm, the guidance and navigation of the I-AUVs and the manipulation task. The main advantage of the potential field method is that less information is necessary: navigation and control problems are reduced to the evaluation of the distance vector among the vehicles, object and obstacles. Moreover, because of the technological problems caused by the underwater environment, the reduction of the transmitted data is one of the keypoints of this architecture. In MATLAB?-Simulink?, the authors have simulated a transportation task of a partially known object along a reference trajectory in an unknown environment, where some obstacles are placed. The task is performed by an I-AUV swarm composed of four vehicles, each one provided of a 7 Degrees Of Freedom (DOFs) robotic arm. An innovative cooperative manipulation strategy for I-AUVs has been developed.A new control strategy based on potential field method has been tested.Accurate vehicle modelling has been used.The cooperative manipulation strategy has been tested through suitable simulation campaigns.

[Abridged] The Sardinia Radio Telescope (SRT) is the new 64-m dish operated by INAF (Italy). Its active surface will allow us to observe at frequencies of up to 116 GHz. At the moment, three receivers, one per focal position, have been installed and tested. The SRT was officially opened in October 2013, upon completion of its technical commissioning phase. In this paper, we provide an overview of the main science drivers for the SRT, describe the main outcomes from the scientific commissioning of the telescope, and discuss a set of observations demonstrating the SRT's scientific capabilities. One of the main objectives of scientific commissioning was the identification of deficiencies in the instrumentation and/or in the telescope sub-systems for further optimization. As a result, the overall telescope performance has been significantly improved. As part of the scientific commissioning activities, different observing modes were tested and validated, and first astronomical observations were carried out to demonstrate the science capabilities of the SRT. In addition, we developed astronomer-oriented software tools, to support future observers on-site. The astronomical validation activities were prioritized based on technical readiness and scientific impact. The highest priority was to make the SRT available for joint observations as part of European networks. As a result, the SRT started to participate (in shared-risk mode) in EVN (European VLBI Network) and LEAP (Large European Array for Pulsars) observing sessions in early 2014. The validation of single-dish operations for the suite of SRT first light receivers and backends continued in the following years, and was concluded with the first call for shared-risk/early-science observations issued at the end of 2015., 26 pages, 18 figures, accepted for publication in Section 13 'Astronomical instrumentation' of Astronomy & Astrophysics