Papers by alessio turetta
OCEANS'11 MTS/IEEE KONA, 2011
The paper deals with the problem of underwater localization for Autonomous Underwater Vehicles (A... more The paper deals with the problem of underwater localization for Autonomous Underwater Vehicles (AUVs) by using a set of acoustic transponders located in known fixed positions. More specifically, the work proposes an effective technique for enabling an AUV to on-line estimate its 3D position, by only employing the measurements of the Time-of-Flights (ToFs) of the signals exchanged with the transponders, without any a-priori information on the Speed of Sound (SoS) of the considered water area. The value of SoS is indeed considered as an additional unknown parameter within the estimation procedure. For any set of received ToFs, a cost function (dependent on the AUV coordinates and the SoS value) is defined and minimized via a standard gradient-descent technique. The optimization process exhibits very good properties in terms of speed of convergence, thanks to the simple structure of the considered cost function. The algorithm has been first tested in a simulated environment and then ex...
IEEE/ASME Transactions on Mechatronics, 2021
The article discusses the main methodologies and key technologies behind the ROBUST project, fund... more The article discusses the main methodologies and key technologies behind the ROBUST project, funded by the European Union within the Horizon 2020 framework, whose goal is the development of an autonomous underwater vehicle manipulator system for deep sea mining exploration. This article focuses on the developed control and perception framework and related mechatronics, and presents the experimental results from the sea trials in Sardinia, Italy, supporting the proposed methodologies.
IFAC Proceedings Volumes, 2004
The design and main features of a very low cost underwater vehicle for coastal oceanographic appl... more The design and main features of a very low cost underwater vehicle for coastal oceanographic applications are illustrated. The key to a low cost but still effective design, in this case, is the limitation of the vehicle features and capabilities solely to those strictly required for the fullfillment of the mission. In terms of navigation and control capabilities, in particular, this allows for the use of GPS-driven algorithms when transiting from one sampling location to another, and the use of a robust closed-loop steering law automatically generating smooth transit trajectories.
OCEANS 2016 MTS/IEEE Monterey, 2016
The WAVE (Wave-powered Autonomous Vehicle for marine Exploration) project involves the developmen... more The WAVE (Wave-powered Autonomous Vehicle for marine Exploration) project involves the development of a novel hybrid oceanographic glider/Autonomous Underwater Vehicle (AUV) with power recharging capabilities from environmental renewable sources, aiming at enhancing the endurance of a typical marine mission. In this paper we present a brief description of the project, and the steps followed in the realization of the first version of the vehicle. The results emerged after a preliminary sea-trial of the prototype show the practical feasibility of the proposed approach.
Ieee Robotics Automation Magazine, 2010
IFAC Proceedings Volumes, 2012
Abstract The need for actual autonomy in underwater vehicle is rapidly increasing. Many challengi... more Abstract The need for actual autonomy in underwater vehicle is rapidly increasing. Many challenging issues derive from such a trend, one in all the need of controlling the motion of an I-AUV to accomplish complex tasks. To this aim, this work presents a control coordination strategy based on Task Priorities and Dynamic Programming techniques for an I-AUV endowed with a redundant manipulator. The resulting algorithmic structure is able to manage prioritized tasks of both equality and inequality type, while also establishing motion priorities among the composing mechanical subsystems. Simulative results are presented with respect to the floating manipulator which is currently under development within the EU-FP7 funded TRIDENT project.
This paper deals with the design of embedded FPGA-based control systems for tendon actuated multi... more This paper deals with the design of embedded FPGA-based control systems for tendon actuated multifingered human-like robotic hands. A specific example of tendon actuated mechanical design (DIST-Hand) is first considered, as a reference system, without loss of generality; then a general modular approach to the relevant motion control problem features is provided. Finally, the most significant implementation issues related to the candidate distributed control architecture are presented
IFAC Proceedings Volumes, 2006
The work deals with modular complex kinematic chains governed by an embedded distributed control ... more The work deals with modular complex kinematic chains governed by an embedded distributed control system. More precisely, every joint of is assumed equipped with a simple local processing unit for properly driving its motion. As a consequence, each one of them plus the associated link is considered as a defective "1-dof only" separately controlled atomic manipulator, which is required to act in team with all the others, in order to accomplish to a common task specified in the operational space. In this framework the paper proposes a computationally distributed kinematic inversion technique that, via the on-line application of dynamic programming (based on a moderate data exchange among the processing units), allows the establishment of a global selforganizing behaviour; thus allowing the task execution by solely exploiting the control capabilities of each local processing unit, while also not requiring any acknowledge about the overall structure geometry and kinematics.
ABSTRACT Visual Odometry is very important for a mobile robot, above all in a planetary scenario,... more ABSTRACT Visual Odometry is very important for a mobile robot, above all in a planetary scenario, in such a way to accu-rately estimate the rover occurred motion. The present work deals with the possibility to improve a previously developed Visual Odometry technique by means of ad-ditional image processing, together with suitable mech-anisms such as the classical Extended/Iterated Kalman Filtering and also Sequence Estimators. The possible em-ployment of both techniques is then addressed and conse-quently a better behaving integration scheme is proposed. Moreover, the eventuality of exploiting other localization sensors is also investigated, leading to a final multi-sensor scheme.
The protection of civilian harbours has received an increasing interest after September 11th. One... more The protection of civilian harbours has received an increasing interest after September 11th. One of the areas currently under major investigation is the use of a team of Unmanned Surface Vehicles (USVs), which could be exploited for patrolling purposes and to investigate suspect situations, increasing the effectiveness of the harbor protection system while lowering the number of humans directly exposed to threats. To achieve such aims, the USVs must be properly coordinated by an intelligent Swarm Management Unit (SMU), whose realization is the goal of an ongoing research project carried out by the authors' organizations. This paper presents the latest results of the SMU project, i.e. a menace interception system, that off-line optimizes the positioning of the USV team and on-line selects the most suitable USV for intercepting any possible menace.
IFAC Proceedings Volumes, 2008
A distributed adaptive sampling algorithm suitable for a team of Autonomous Underwater Vehicles e... more A distributed adaptive sampling algorithm suitable for a team of Autonomous Underwater Vehicles exploring an oceanic region is proposed. The algorithm fulfils the following goals: the sampling stations are incrementally chosen in order to satisfy the accuracy requirements on the measured quantity, on the basis of the local smoothness of the measured field as estimated from the data; the vehicles in the team are spread over the region in order to maximize area coverage; the vehicles are constrained to maintain a maximum range from each other, in order to preserve a communication link among the team. To fulfil the goal, a multi-objective optimization problem is iteratively solved in a distributed fashion by the vehicles in the team through application of minimum-spanning-tree graph search algorithms. The simulation results reported show how the application of this approach determines a behaviour of the team in which the vehicles travel in formation, eventually reconfiguring the formation as it may become necessary in the course of the mission.
2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2012
ABSTRACT The need for actual autonomy in underwater robotic systems is rapidly increasing. Many c... more ABSTRACT The need for actual autonomy in underwater robotic systems is rapidly increasing. Many challenging issues derive from such a trend, one in all the requirement of coordinately controlling the motion of an underwater floating I-AUV endowing a robotic arm, to accomplish complex manipulation tasks. This work is aimed to present a strategy based on the prioritization of tasks of equality and inequality type, once combined with Dynamic Programming techniques, for coordinately controlling the motion of such I-AUV. A general algorithmic framework is developed and simulative results supporting its resulting effectiveness are presented.
Proceedings of the IEEE International Conference on Mechatronics, 2004. ICM '04.
ABSTRACT This paper deals with the design of embedded FPGA-based control systems for tendon actua... more ABSTRACT This paper deals with the design of embedded FPGA-based control systems for tendon actuated multifingered humanlike robotic hands. A specific example of tendon actuated mechanical design (DIST-Hand) is first considered, as a reference system, without loss of generality; then a general modular approach to the relevant motion control problem features is provided. Finally the most significant implementation issues related to the candidate distributed control architecture are presented.
2014 Oceans - St. John's, 2014
The use of Long Baseline (LBL) systems for localizing underwater vehicles is quite consolidated, ... more The use of Long Baseline (LBL) systems for localizing underwater vehicles is quite consolidated, as they guarantee a good nominal accuracy, not dependent on the operative depth and almost constant at any point inside the area delimited by the transponders. However the real achievable accuracy can be affected by different factors, mainly related with the knowledge of some environmental parameters (like the speed of sound), the quality of the employed instrumentations, and the level of calibration of the system, after its deployment in water. The paper specifically addresses the accuracy of a LBL-based localization procedure and presents the results of an error budget analysis. For each considered error source, a closed form of the induced localization error is derived and discussed with the intent of enabling the characterization of the real obtainable accuracy within a typical application. The overall study is finally supported and validated by a detailed set of simulative results.
2014 Oceans - St. John's, 2014
This work presents the first experimental results of the real-time motion planner developed withi... more This work presents the first experimental results of the real-time motion planner developed within an ongoing research project between DIBRIS, University of Genova and Selex-ES, Italy, one of the leading players for providing large systems aimed at security and surveillance. The ultimate goal of the research project is the development of a complete solution for managing and supervising a team of Unmanned Surface Vehicles (USVs), operating in a (semi-)autonomous manner within a civilian harbour. The proposed obstacle avoidance algorithm exploits the kinematic information of the vessels operating in the harbour in order to compute the optimal path to reach the target position, while at the same time avoiding any moving obstacle. The paper recalls the fundamentals of the proposed approach, introduces the developed USV prototypes and finally presents the adaptation of the motion planner for its use on the real tests. Field trials are presented to show the effectiveness of the approach even at high speeds.
Distributed Autonomous Robotic Systems 8, 2009
The paper deals with the problem of suitably coordinating the movement of two mobile manipulators... more The paper deals with the problem of suitably coordinating the movement of two mobile manipulators in order to accomplish a given task in a cooperative way, avoiding the arms' singular postures and joint limits. A dynamic programming approach is used for accomplishing such avoidance specifications.
OCEANS 2009-EUROPE, 2009
ABSTRACT This contribution addresses the problem of area coverage by a team of autonomous underwa... more ABSTRACT This contribution addresses the problem of area coverage by a team of autonomous underwater vehicle. The case addressed is the one in which the area map is not known in advance but adaptively estimated on-line by the vehicles themselves as they move along the area. The approach proposed is distributed, i.e., the vehicles in the team exchange information among themselves and autonomously take individual decisions on where to move next on the basis of the available information. Communication constraints among the vehicles, in terms of communication range and bandwidth, are explicitly taken into account by the algorithm, and can be dependent by the spatial position in the covered area. The paper proposes a series of algorithms for adaptive sampling with communication constraints in which the communication constraints are expressed in terms of connectivity of the graph of the vehicles. Depending on the structure of the graph (ordered serial graph, ordered tree graph, etc.) the algorithms take the structure of a distributed dynamic programming approach or of minimum spanning tree graph searching.
IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004, 2004
Absmicf - The paper deals with the problem of suitably COOTdinat&g the mauoeuying of a no... more Absmicf - The paper deals with the problem of suitably COOTdinat&g the mauoeuying of a non-bolonomic vehicle and - . the motion of a supported manipulator when the overall system is commanded to execute a given grasping or manipulation task. Tbe objective being ...
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Papers by alessio turetta