@conference {3141, title = {Distributed Task-priority Based Control in Area Coverage \& Adaptive Sampling}, booktitle = {MTS/IEEE Oceans 2017}, year = {2017}, publisher = {IEEE}, organization = {IEEE}, address = {Aberdeen, Scotland, June 2017}, abstract = {

The paper presents the first simulative results and algorithmic developments of the task-priority based control applied to a distributed sampling network in an area coverage or adaptive sampling mission scenario. The proposed approach allowing the fulfilment of a chain of tasks with decreasing priority each of which directly related to both operability and safety aspects of the entire mission. The task-priority control is presented both in the centralized and decentralized implementations showing a comparison of performance. Finally simulations of the area coverage mission scenario are provided showing the effectiveness of the proposed approach.

}, keywords = {Robotics}, author = {T. Fabbri and E. Simetti and G. Casalino and L. Pallottino and A. Caiti} } @article {3002, title = {On the Minimum-Time Control Problem for Differential Drive Robots with Bearing Constraints}, journal = {Journal of Optimization Theory and Applications}, year = {2017}, month = {04/2017}, pages = {1-27}, abstract = {

This paper presents a study of analysis of minimum-time trajectories for a differential drive robot equipped with a fixed and limited field-of-view camera, which must keep a given landmark in view during maneuvers. Previous works have considered the same physical problem and provided a complete analysis/synthesis for the problem of determining the shortest paths. The main difference in the two cost functions (length vs. time) lays on the rotation on the spot. Indeed, this maneuver has zero cost in terms of length and hence leads to a 2D shortest path synthesis. On the other hand, in case of minimum time, the synthesis depends also on the orientations of the vehicle. In other words, the not zero cost of the rotation on the spot maneuvers leads to a 3D minimum-time synthesis. Moreover, the shortest paths have been obtained by exploiting the geometric properties of the extremal arcs, i.e.,\ straight lines, rotations on the spot, logarithmic spirals and involute of circles. Conversely, in terms of time, even if the extremal arcs of the minimum-time control problem are exactly the same, the geometric properties of these arcs change, leading to a completely different analysis and characterization of optimal paths. In this paper, after proving the existence of optimal trajectories and showing the extremal arcs of the problem at hand, we provide the control laws that steer the vehicle along these arcs and the time-cost along each of them. Moreover, this being a crucial step toward numerical implementation, optimal trajectories are proved to be characterized by a finite number of switching points between different extremal arcs, i.e.,\ the concatenations of extremal arcs with infinitely many junction times are shown to violate the optimality conditions.

}, keywords = {Robotics}, doi = { 10.1007/s10957-017-1110-7}, url = {http://download.springer.com/static/pdf/641/art\%253A10.1007\%252Fs10957-017-1110-7.pdf?originUrl=http\%3A\%2F\%2Flink.springer.com\%2Farticle\%2F10.1007\%2Fs10957-017-1110-7\&token2=exp=1492507070~acl=\%2Fstatic\%2Fpdf\%2F641\%2Fart\%25253A10.1007\%25252Fs10957-017-111}, author = {A. Cristofaro and Salaris, P. and L. Pallottino and Giannoni, F. and A. Bicchi} } @conference {3087, title = {Noninteracting Constrained Motion Planning and Control for Robot Manipulators}, booktitle = {IEEE International Conference of Robotics and Automation, ICRA2017}, year = {2017}, pages = {4038 - 4043}, publisher = {IEEE}, organization = {IEEE}, abstract = {

In this paper we present a novel geometric approach
to motion planning for constrained robot systems.
This problem is notoriously hard, as classical sampling-based
methods do not easily apply when motion is constrained in
a zero-measure submanifold of the configuration space. Based
on results on the functional controllability theory of dynamical
systems, we obtain a description of the complementary spaces
where rigid body motions can occur, and where interaction
forces can be generated, respectively. Once this geometric setting
is established, the motion planning problem can be greatly
simplified. Indeed, we can relax the geometric constraint, i.e.,
replace the lower{\textendash}dimensional constraint manifold with a fulldimensional
boundary layer. This in turn allows us to plan
motion using state-of-the-art methods, such as RRT*, on points
within the boundary layer, which can be efficiently sampled. On
the other hand, the same geometric approach enables the design
of a completely decoupled control scheme for interaction forces,
so that they can be regulated to zero (or any other desired
value) without interacting with the motion plan execution.
A distinguishing feature of our method is that it does not
use projection of sampled points on the constraint manifold,
thus largely saving in computational time, and guaranteeing
accurate execution of the motion plan. An explanatory example
is presented, along with an experimental implementation of the
method on a bimanual manipulation workstation.

}, keywords = {Robotics}, doi = {10.1109/ICRA.2017.7989463}, url = {http://ieeexplore.ieee.org/document/7989463/}, author = {M. Bonilla and L. Pallottino and A. Bicchi} } @article {3137, title = {WALK-MAN: A High-Performance Humanoid Platform for Realistic Environments}, journal = {Journal of Field Robotics}, volume = {34}, year = {2017}, month = {06/2017}, pages = {1 - 34}, abstract = {

In this work, we present WALK-MAN, a humanoid platform that has been developed to operate in realistic unstructured environment, and demonstrate new skills including powerful manipulation, robust balanced locomotion, high-strength capabilities, and physical sturdiness. To enable these capabilities, WALK-MAN design and actuation are based on the most recent advancements of series elastic actuator drives with unique performance features that differentiate the robot from previous state-of-the-art compliant actuated robots. Physical interaction performance is benefited by both active and passive adaptation, thanks to WALK-MAN actuation that combines customized high-performance modules with tuned torque/velocity curves and transmission elasticity for high-speed adaptation response and motion reactions to disturbances. WALK-MAN design also includes innovative design optimization features that consider the selection of kinematic structure and the placement of the actuators with the body structure to maximize the robot performance. Physical robustness is ensured with the integration of elastic transmission, proprioceptive sensing, and control. The WALK-MAN hardware was designed and built in 11 months, and the prototype of the robot was ready four months before DARPA Robotics Challenge (DRC) Finals. The motion generation of WALK-MAN is based on the unified motion-generation framework of whole-body locomotion and manipulation (termed loco-manipulation). WALK-MAN is able to execute simple loco-manipulation behaviors synthesized by combining different primitives defining the behavior of the center of gravity, the motion of the hands, legs, and head, the body attitude and posture, and the constrained body parts such as joint limits and contacts. The motion-generation framework including the specific motion modules and software architecture is discussed in detail. A rich perception system allows the robot to perceive and generate 3D representations of the environment as well as detect contacts and sense physical interaction force and moments. The operator station that pilots use to control the robot provides a rich pilot interface with different control modes and a number of teleoperated or semiautonomous command features. The capability of the robot and the performance of the individual motion control and perception modules were validated during the DRC in which the robot was able to demonstrate exceptional physical resilience and execute some of the tasks during the competition.

}, keywords = {Robotics}, issn = {1556-4967}, doi = {10.1002/rob.21702}, url = {http://onlinelibrary.wiley.com/doi/10.1002/rob.21702/epdf}, author = {N. G. Tsagarakis and D. G. Caldwell and F. Negrello and W. Choi and L. Baccelliere and V. G. Loc and J. Noorden and L. Muratore and A. Margan and A. Cardellino and L. Natale and E. Mingo Hoffman and H. Dallali and N. Kashiri and J. Malzahn and J. Lee and P. Kryczka and D. Kanoulas and M. Garabini and M. G. Catalano and M. Ferrati and V. Varricchio and L. Pallottino and C. Pavan and A. Bicchi and A Settimi and A. Rocchi and A. Ajoudani} } @conference {2880, title = {APRICOT: Aerospace PRototypIng COntrol Toolbox. A Modeling and Simulation Environment for Aircraft Control Design}, booktitle = {International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016}, volume = {9991 of the book series Lecture Notes in Computer Science (LNCS)}, year = {2016}, pages = {139 - 157}, publisher = {Springer}, organization = {Springer}, address = {Rome, Italy, June 15-16, 2016}, abstract = {

A novel MATLAB/Simulink based modeling and simulation environment for the design and rapid prototyping of state-of-the-art aircraft control systems is proposed. The toolbox, named APRICOT, is able to simulate the longitudinal and laterodirectional dynamics of an aircraft separately, as well as the complete 6 degrees of freedom dynamics. All details of the dynamics can be easily customized in the toolbox, some examples are shown in the paper. Moreover, different aircraft models can be easily integrated. The main goal of APRICOT is to provide a simulation environment to test and validate different control laws with different aircraft models. Hence, the proposed toolbox has applicability both for educational purposes and control rapid prototyping. With respect to similar software packages, APRICOT is customizable in all its aspects, and has been released as open source software. An interface with Flightgear Simulator allows for online visualization of the flight. Examples of control design with simulation experiments are reported and commented.

}, keywords = {Embedded Control, Robotics}, doi = { 10.1007/978-3-319-47605-6_11}, url = {http://link.springer.com/chapter/10.1007/978-3-319-47605-6_11}, author = {A. Ferrarelli and D. Caporale and A Settimi and L. Pallottino} } @article {2791, title = {Controllability analysis of a pair of 3D Dubins vehicles in formation}, journal = {Robotics and Autonomous Systems}, volume = {83}, year = {2016}, month = {09/2016}, pages = {94 - 105}, abstract = {

In this paper we consider the controllability problem for a system consisting of a pair of Dubins vehicles moving in a 3D space (i.e.\ pair of 3D{\textendash}Dubins vehicles) while maintaining constant distance. Necessary and sufficient conditions for the existence of a limited control effort to steer the system between any two configurations are provided. The proposed controllability analysis and the developed motion planning algorithm are a step toward the solution of planning problems for example in case the robots are physically constrained to a payload to be deployed. Moreover, results obtained in this paper are relevant in order to solve formation control problems for multiple robots as aerial or underwater vehicles, which move in 3D spaces. Simulation results highlight the sufficiency of the obtained conditions showing that even from critical configurations an admissible control can be determined.

}, keywords = {Embedded Control, Robotics}, doi = {10.1016/j.robot.2016.05.015}, url = {http://www.sciencedirect.com/science/article/pii/S0921889015301202}, author = {H. Marino and Salaris, P. and L. Pallottino} } @conference {2818, title = {A game theoretic approach for antagonistic-task coordination of underwater autonomous robots in asymmetric threats scenarios}, booktitle = {OCEANS 2016}, year = {2016}, month = {12/2016}, abstract = {

This work proposes a game theoretic approach
to tackle the problem of multi-robot coordination
in critical scenarios where communication is
limited and the robots must accomplish different tasks
simultaneously. An important application falls in underwater
robotic framework where robots are used to
protect a ship against asymmetric threats guaranteeing
simultaneously the coverage of the area around the ship
and the tracking of a possible intruder. The problem is
modelled as a potential game for which novel learning
protocols are introduced. Indeed, a general extension
of pay-off based algorithms is herein proposed where
the main difference with state-of-the-art protocols is
that the trajectory optimization is considered instead
of single action optimization. Moreover, the proposed
T-algorithms, steer the robots toward Nash equilibria
that will be shown to correspond to the accomplishment
of different, possibly antagonistic, goals. Finally, performances
of the algorithms, under different scenarios,
have been evaluated in simulations.

}, keywords = {Embedded Control, Robotics}, doi = {10.1109/OCEANS-Genova.2015.7271413}, url = {http://ieeexplore.ieee.org/document/7761346/}, author = {S. Nardi and T. Fabbri and A. Caiti and L. Pallottino} } @conference {2879, title = {Indoor Real-Time Localisation for Multiple Autonomous Vehicles Fusing Vision, Odometry and IMU Data}, booktitle = {International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016}, volume = {9991 of the book series Lecture Notes in Computer Science (LNCS)}, year = {2016}, pages = {288 - 297}, publisher = {Springer}, organization = {Springer}, address = {Rome, Italy, June 15-16, 2016}, abstract = {

Due to the increasing usage of service and industrial autonomous vehicles, a precise localisation is an essential component required in many applications, e.g. indoor robot navigation. In open outdoor environments, differential GPS systems can provide precise positioning information. However, there are many applications in which GPS cannot be used, such as indoor environments. In this work, we aim to increase robot autonomy providing a localisation system based on passive markers, that fuses three kinds of data through extended Kalman filters. With the use of low cost devices, the optical data are combined with other robots{\textquoteright} sensor signals, i.e. odometry and inertial measurement units (IMU) data, in order to obtain accurate localisation at higher tracking frequencies. The entire system has been developed fully integrated with the Robotic Operating System (ROS) and has been validated with real robots.

}, keywords = {Embedded Control, Robotics}, doi = { 10.1007/978-3-319-47605-6_24}, url = {http://link.springer.com/chapter/10.1007/978-3-319-47605-6_24}, author = {A. Faralli and N. Giovannini and S. Nardi and L. Pallottino} } @conference {2893, title = {Motion Primitive Based Random Planning for Loco{\textendash}Manipulation Tasks}, booktitle = {IEEE International Conference on Humanoid Robots (HUMANOIDS 2016)}, year = {2016}, note = {
This work is supported by the European commission project Walk-Man EU FP7-ICT no. 611832 and the ECs Horizon 2020 robotics program ICT-23-2014 under grant agreement 644727 (CogIMon)
}, publisher = {IEEE}, organization = {IEEE}, address = {Cancun, Mexico, 15-17 Nov. 2016 }, abstract = {

Several advanced control laws are available for
complex robotic systems such as humanoid robots and mobile
manipulators. Controls are usually developed for locomotion or
for manipulation purposes. Resulting motions are usually executed
sequentially and the potentiality of the robotic platform
is not fully exploited.
In this work we consider the problem of loco{\textendash}manipulation
planning for a robot with given parametrized control laws
known as primitives. Such primitives, may have not been
designed to be executed simultaneously and by composing
them instability may easily arise. With the proposed approach,
primitives combination that guarantee stability of the system
are obtained resulting in complex whole{\textendash}body behavior.
A formal definition of motion primitives is provided and a
random sampling approach on a manifold with limited dimension
is investigated. Probabilistic completeness and asymptotic
optimality are also proved. The proposed approach is tested
both on a mobile manipulator and on the humanoid robot
Walk-Man, performing loco{\textendash}manipulation tasks.

}, keywords = {Robotics}, isbn = {978-1-5090-4718-5 }, doi = {10.1109/HUMANOIDS.2016.7803402}, url = {http://ieeexplore.ieee.org/document/7803402/}, author = {A Settimi and D. Caporale and P. Kryczka and M. Ferrati and L. Pallottino} } @conference {2810, title = {Multi{\textendash}object handling for robotic manufacturing}, booktitle = {IECON 2016: 42nd Annual Conference of the IEEE Industrial Electronics Society}, year = {2016}, month = {12/2016}, pages = {6887 - 6893}, publisher = {IEEE}, organization = {IEEE}, address = {Florence, Italy, October 24-27}, abstract = {

The purpose of this work is to move a step toward the automation of industrial plants through full exploitation of autonomous robots. A planning algorithm is proposed to move different objects in desired configurations with heterogeneous robots such as manipulators, mobile robots and conveyor belts.
The proposed approach allows different objects to be handled by different robots simultaneously in an efficient way and avoiding collisions with the environment and self{\textendash}collisions between robots. In particular, the integrated system will be capable of planning paths for a set of objects from various starting points in the environment (e.g. shelves) to their respective final destinations. The proposed approach unifies the active (e.g., grasping by a hand) and passive (e.g., holding by a table) steps involved in moving the objects in the environment by treating them as end{\textendash}effectors with constraints and capabilities.
Time varying graphs will be introduced to model the problem for simultaneous handling of objects by different end{\textendash}effectors.
Optimal exploration of such graphs will be used to determine paths for each object with time constraints. Results will be validated through simulations.

}, keywords = {Robotics}, doi = {http://ieeexplore.ieee.org/document/7793936/?reload=true}, url = {http://ieeexplore.ieee.org/document/7793936/?reload=true}, author = {M. Ferrati and H. Marino and A Settimi and S. Nardi and L. Pallottino} } @conference {2877, title = {NoStop: An Open Source Framework for Design and Test of Coordination Protocol for Asymmetric Threats Protection in Marine Environment}, booktitle = {International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016}, volume = {9991 of the book series Lecture Notes in Computer Science (LNCS)}, year = {2016}, pages = {176 - 185}, publisher = {Spronger}, organization = {Spronger}, address = {Rome, Italy, June 15-16, 2016}, abstract = {

NoStop\ is an open source simulator dedicated to distributed and cooperative mobile robotics systems. It has been designed as a framework to design and test multi{\textendash}agent collaborative algorithms in terms of performance and robustness. The particular application scenario of a team of autonomous guards that coordinate to protect an area from asymmetric threat is considered. NoStop\ system is an integrated tool able to both evaluate the coordination protocol performance and to design the team of guards involved in the asymmetric threat protection. Moreover, NoStop\ is designed to validate robustness of coordination protocol through the use of a remote pilot that control the intruder motion to escape from the guards that monitor the area and accomplish its mission. The project core is a simulation server with a dynamic engine and a synchronization facility. Different coordination protocol can be designed and easily integrated in NoStop. The framework is fully integrated with the Robot Operating System (ROS) and it is completed by a control station where the remote pilot moves the intruder following the guards evolution in a 3D viewer.

}, keywords = {Embedded Control, Robotics}, doi = {10.1007/978-3-319-47605-6_14}, url = {http://link.springer.com/chapter/10.1007/978-3-319-47605-6_14}, author = {S. Nardi and L. Pallottino} } @conference {2889, title = {Robust Optimization of System Compliance for Physical Interaction in Uncertain Scenarios}, booktitle = {IEEE International Conference on Humanoid Robots (HUMANOIDS2016)}, year = {2016}, note = {
This work was supported by the European Commission projects (FP7 framework) Walk-Man and the European Commission Grant no. H2020- ICT-645599 {\textquotedblleft}SOMA{\textquotedblright}: SOft MAnipulation
}, publisher = {IEEE}, organization = {IEEE}, address = {Cancun, Mexico, 15-17 Nov. 2016 }, abstract = {

Compliance in robot design and control is often introduced to improve the robot performance in tasks where interaction with environment or human is required. However a rigorous method to choose the correct level of compliance is still not available. In this work we use robust optimization as a tool to select the optimal compliance value in a robotenvironment interaction scenario under uncertainties. We propose an approach that can be profitably applied on a variety of tasks, e.g.manipulation tasks or locomotion tasks. The aim is to minimize the forces of interaction considering model constraints and uncertainties. Numerical results show that: i) in case of perfect knowledge of the environment stiff robots behave better in terms of force minimization, ii) in case of uncertainties the optimal stiffness of the robot is lower than the previous case and optimal solutions provide a faster task accomplishment, iii) the optimal stiffness decreases as a function of the uncertainty measure. Experiments are carried out in a realistic set-up in case of bi-manual object handover.

}, keywords = {Robotics}, isbn = {978-1-5090-4718-5 }, doi = { 10.1109/HUMANOIDS.2016.7803381}, url = {http://ieeexplore.ieee.org/document/7803381/}, author = {Gasparri, G. M. and F. Fabiani and M. Garabini and L. Pallottino and M. G. Catalano and G. Grioli and R. Persichini and A. Bicchi} } @article {2749, title = {The Walk-Man Robot Software Architecture}, journal = {Front. Robot. AI}, year = {2016}, month = {05/2016}, abstract = {

A software and control architecture for a humanoid robot is a complex and large project, which involves a team of developers/researchers to be coordinated and requires many hard design choices. If such project has to be done in a very limited time, i.e., less than 1 year, more constraints are added and concepts, such as modular design, code reusability, and API definition, need to be used as much as possible. In this work, we describe the software architecture developed for Walk-Man, a robot participant at the Darpa Robotics Challenge. The challenge required the robot to execute many different tasks, such as walking, driving a car, and manipulating objects. These tasks need to be solved by robotics specialists in their corresponding research field, such as humanoid walking, motion planning, or object manipulation. The proposed architecture was developed in 10 months, provided boilerplate code for most of the functionalities required to control a humanoid robot and allowed robotics researchers to produce their control modules for DRC tasks in a short time. Additional capabilities of the architecture include firmware and hardware management, mixing of different middlewares, unreliable network management, and operator control station GUI. All the source code related to the architecture and some control modules have been released as open source projects.

}, keywords = {Robotics}, doi = { http://dx.doi.org/10.3389/frobt.2016.00025}, url = {http://bit.ly/2jAPke2}, author = {M. Ferrati and A Settimi and L. Muratore and N. G. Tsagarakis and L. Natale and L. Pallottino} } @conference {2429, title = {Coordination of unmanned marine vehicles for asymmetric threats protection}, booktitle = {MTS/IEEE Oceans 2015}, year = {2015}, publisher = {IEEE}, organization = {IEEE}, address = {May 18-21, Genoa, Italy}, abstract = {

A coordination protocol for systems of unmanned marine vehicles is proposed for protection against asymmetric threats. The problem is first modelled in a game theoretic framework, as a potential game. Then an extension of existing learning algorithms is proposed to address the problem of tracking the possibly moving threat. The approach is evaluated in scenarios of different geometric complexity such as open sea, bay, and harbours. Performance of the approach is evaluated in terms of a security index that will allow us to obtain a tool for team sizing. The tool provides the minimum number of marine vehicles to be used in the system, given a desired security level to be guaranteed and the maximum threat velocity.

}, keywords = {Robotics}, isbn = {978-1-4799-8736-8}, doi = {10.1109/OCEANS-Genova.2015.7271413}, url = {http://ieeexplore.ieee.org/document/7271413/}, author = {S. Nardi and C. Della Santina and D. Meucci and L. Pallottino} } @article {2473, title = {Distributed motion misbehavior detection in teams of heterogeneous aerial robots}, journal = {Robotics and Autonomous Systems information}, volume = {74 part A}, year = {2015}, month = {12/2015}, pages = {30-39}, abstract = {

This paper addresses the problem of detecting possible misbehavior in a group of autonomous mobile robots, which coexist in a shared environment and interact with each other and coordinate according to a set of common\ interaction rules. Such rules specify what actions each robot is allowed to perform in order to interact with the other members of the group. The rules are distributed, i.e., they can be evaluated only starting from the knowledge of the individual robot and the information the robot gathers from neighboring robots. We consider\ misbehaving\ those robots which, because of either spontaneous failures or malicious tampering, do not follow the rules and whose behavior thus deviates from the nominal assigned one. The main contribution of the paper is to provide a methodology to detect such misbehavior by observing the congruence of actual behavior with the assigned rules as applied to the actual state of the system. The presented methodology is based on a consensus protocol on the events observed by robots. The methodology is fully distributed in the sense that it can be performed by individual robots based only on the local available information, it has been theoretically proven and validated with experiments involving real aerial heterogeneous robots.

}, keywords = {Embedded Control, Robotics}, doi = {10.1016/j.robot.2015.06.008}, url = {http://www.sciencedirect.com/science/article/pii/S0921889015001360}, author = {S. Martini and D. Di Baccio and F. Alarc{\`o}n-Romero and A. Viguria-Jim{\'e}nez and L. Pallottino and G. Dini and A. Ollero} } @article {2530, title = {Epsilon-Optimal Synthesis for Unicycle-like Vehicles with Limited Field-Of-View Sensors}, journal = {IEEE Transactions on Robotics (T-RO)}, volume = {31}, year = {2015}, pages = {1404 - 1418}, abstract = {

In this paper we study the minimum length paths covered by the center of a unicycle equipped with a limited Field{\textendash}Of{\textendash}View (FOV) camera, which must keep a given landmark in sight. Previous works on this subject have provided the optimal synthesis for the cases in which the FOV is only limited in the horizontal directions (i.e. left and right bounds) or in the vertical directions (i.e. upper and lower bounds). In this paper we show how to merge previous results and hence obtaining, for a realistic image plane modeled as a rectangle, a finite alphabet of extremal arcs and the overall synthesis. As shown, this objective can not be straightforwardly achieved from previous results but needs further analysis and developments. Moreover, there are initial configurations such that there exists no optimal path. Nonetheless, we are always able to provide an e{\textendash}optimal path whose length approximates arbitrarily well any other shorter path. As final results, we provide a partition of the motion plane in regions such that the optimal or e{\textendash}optimal path from each point in thatregion is univocally determined.

}, keywords = {Embedded Control, Robotics}, doi = {10.1109/TRO.2015.2492878}, author = {P Salaris and A. Cristofaro and L. Pallottino} } @article {2207, title = {Epsilon{\textendash}optimal synthesis for vehicles with vertically bounded Field-Of-View}, journal = {IEEE Transactions on Automatic Control}, volume = {60}, year = {2015}, pages = {1204 - 1218}, abstract = {

This paper presents a contribution to the problem of obtaining an optimal synthesis for shortest paths for a unicycle guided by an on{\textendash}board limited Field Of{\textendash}View (FOV) sensor, which must keep a given landmark in sight. Previous works on this subject have provided an optimal synthesis for the case in which the FOV is limited in the horizontal directions (H{\textendash} FOV, i.e. left and right boundaries). In this paper we study the complementary case in which the FOV is limited only in the vertical direction (V{\textendash}FOV, i.e. upper and lower boundaries). With respect to the H{\textendash}FOV case, the vertical limitation is all but a simple extension. Indeed, not only the geometry of extremal arcs is different, but also a more complex structure of the synthesis is revealed by analysis. We will indeed show that there exist initial configurations for which the optimal path does not exist. In such cases, we provide an e{\textendash}optimal path whose length approximates arbitrarily well any other shorter path. Finally, we provide a partition of the motion plane in regions such that the optimal or e{\textendash}optimal path from each point in that region is univocally determined.

}, keywords = {Embedded Control, Robotics}, issn = {0018-9286}, doi = {10.1109/TAC.2014.2366271}, author = {Salaris, P. and Cristofaro, A. and L. Pallottino and A. Bicchi} } @conference {2338, title = {Sample-Based Motion Planning for Robot Manipulators with Closed Kinematic Chains}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2015)}, year = {2015}, note = {

softhands pacman walkman

}, pages = {2522 - 2527}, publisher = {IEEE}, organization = {IEEE}, address = {Seattle, USA, 25 - 30 May}, keywords = {Robotics}, doi = {10.1109/ICRA.2015.7139537}, author = {M. Bonilla and E. Farnioli and L. Pallottino and A. Bicchi} } @conference {2450, title = {Variable Stiffness Control for Oscillation Damping}, booktitle = {IEEE International Conference of Intelligent Robots and Systems (IROS2015)}, year = {2015}, note = {
This work is supported by the EC under the grant agreements no.611832 Walk-Man and ICT-287513 {\textquotedblleft}SAPHARI{\textquotedblright}
}, pages = {6543 - 6550}, publisher = {IEEE}, organization = {IEEE}, address = {Hamburg, Germany, September 28 - October 02, 2015}, keywords = {Robotics}, doi = {10.1109/IROS.2015.7354312}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7354312}, author = {G M Gasparri and M. Garabini and L. Pallottino and L. Malagia and M. G. Catalano and G. Grioli and A. Bicchi} } @conference {2129, title = {ASCARI: a component based simulator for distributed mobile robot systems}, booktitle = {Modelling \& Simulation for Autonomous Systems - MESAS2014}, volume = { Lecture Notes in Computer Science, Volume 8906, 2014}, year = {2014}, pages = {152-163}, publisher = {Springer}, organization = {Springer}, address = {Rome, 5-6 May 2014}, keywords = {Embedded Control, Robotics}, author = {M. Ferrati and A Settimi and L. Pallottino} } @conference {2223, title = {On Time-Optimal Trajectories for Differential Drive Vehicles with Field-Of-View Constraints}, booktitle = {IEEE Conference on Decision and Control (CDC2014)}, year = {2014}, pages = {2191 - 2197}, publisher = {IEEE}, organization = {IEEE}, address = {Los Angeles, USA, December 15-17}, abstract = {

This paper presents the first step toward the study of minimum time trajectories for a differential drive robot, which is equipped with a fixed and limited Field-Of-View (FOV) camera, towards a desired configuration while keeping a given landmark in sight during maneuvers. While several previous works have provided a complete synthesis of shortest paths in case of both nonholonomic and FOV constraints, to the best of our knowledge, this paper represents the first analysis of minimum time trajectories with the two constraints. After showing the extremals of the problem at hand, i.e. straight lines, rotations on the spot, logarithmic spirals and involute of circles, we provide the optimal control laws that steer the vehicle along the path and the cost in terms of time along each extremal. Moreover, we compare some concatenations of extremals in order to reduce the complexity of the problem toward the definition of a sufficient finite set of optimal maneuvers.

}, keywords = {Embedded Control, Robotics}, isbn = {978-1-4799-7746-8}, doi = {10.1109/CDC.2014.7039723}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7039723}, author = {Cristofaro, A. and Salaris, P. and L. Pallottino and Giannoni, F. and A. Bicchi} } @conference {1702, title = {Distributed Multi{\textendash}level Motion Planning for Autonomous Vehicles in Large Scale Industrial Environments}, booktitle = {IEEE International Conference on Emerging Technologies \& Factory Automation (ETFA)}, year = {2013}, month = {09/2013}, pages = {1-8}, abstract = {

In this paper we propose a distributed coordination algorithm for safe and efficient traffic management of heterogeneous robotic agents, moving within dynamic large scale industrial environments. The algorithm consists of a distributed resource{\textendash}sharing protocol involving a re{\textendash}planning strategy. Once every agent is assigned with a desired motion path, the algorithm ensures ordered traffic flows of agents, that avoid inter{\textendash}robot collision and system deadlock (stalls). The algorithm allows multi{\textendash}level representation of the environment, i.e. large or complex rooms may be seen as a unique resource with given capacity at convenience, which makes the approach appealing for complex industrial environments. Under a suitable condition on the maximum number of agents with respect to the capacity of the environment, we prove that the algorithm correctly allows mutual access to shared resources while avoiding deadlocks. The proposed solution requires no centralized mechanism, no shared memory or ground infrastructure support. Only a local inter{\textendash}robot communication is required, i.e. every agent must communicate with a limited number of other spatially adjacent robots. We finally show the effectiveness of the proposed approach by simulations, with application to an industrial scenario.

}, keywords = {Robotics}, doi = {10.1109/ETFA.2013.6647973 }, author = {L. Cancemi and A. Fagiolini and L. Pallottino} } @conference {1760, title = {Global Path Planning for Competitive Robotic Cars}, booktitle = {IEEE Conference on Decision and Control}, year = {2013}, pages = {4510 - 4516}, address = {Florence, Italy}, keywords = {Robotics}, author = {T. Rizano and D. Fontanelli and L. Palopoli and L. Pallottino and P Salaris} } @conference {1759, title = {Shortest paths for wheeled robots with limited Field-Of-View: introducing the vertical constraint}, booktitle = {IEEE Conference on Decision and Control}, year = {2013}, pages = {5143 - 5149}, address = {Florence, Italy}, keywords = {Robotics}, author = {P Salaris and A. Cristofaro and L. Pallottino and A. Bicchi} } @conference {1757, title = {A Subgradient Based Algorithm for Distributed Task Assignment for Heterogeneous Mobile Robots}, booktitle = {IEEE Conference on Decision and Control}, year = {2013}, pages = {3665 - 3670}, address = {Florence, Italy}, keywords = {Robotics}, author = {A Settimi and L. Pallottino} } @conference {1758, title = {A time expanded network based algorithm for safe and efficient distributed multi-agent coordination}, booktitle = {IEEE Conference on Decision and Control}, year = {2013}, pages = {2805 - 2810}, address = {Florence, Italy}, keywords = {Robotics}, author = {M. Ferrati and L. Pallottino} } @conference {1244, title = {Motion Planning for Two 3D-Dubins Vehicles with Distance Contraint}, booktitle = {International Conference of Intelligent Robots and Systems - IROS 2012}, year = {2012}, month = {October 7 - 12}, pages = {4702 - 4707 }, address = {Vilamoura, Algarve, Portugal}, keywords = {Robotics}, author = {H. Marino and M. Bonizzato and R. Bartalucci and P Salaris and L. Pallottino} } @article {1236, title = {Shortest Paths for Finned, Winged, Legged and Wheeled Vehicles with Side-Looking Sensors}, journal = {International Journal of Robotics Research}, volume = {31}, year = {2012}, pages = {997-1017}, keywords = {Robotics}, doi = {10.1177/0278364912446005}, author = {P Salaris and L. Pallottino and A. Bicchi} } @conference {PS11, title = {On constrained optimal control problems in robotics}, booktitle = {Automatica.it 2011}, year = {2011}, month = {September 7 - 9}, address = {Pisa, Italy}, keywords = {Robotics}, author = {L. Pallottino and P Salaris} } @conference {MFP11, title = {Decentralized Coordination System for Multiple AGVs in a Structured Environment}, booktitle = {2011 Congress of the International Federation of Automatic Control}, year = {2011}, month = {Aug 28 - Sept 1}, pages = {6005 - 6010}, address = {Milano, italy}, keywords = {Embedded Control, Robotics}, author = {S. Manca and A. Fagiolini and L. Pallottino} } @conference {SPHB11, title = {From Optimal Planning to Visual Servoing with Limited FOV}, booktitle = {2011 IEEE/RSJ International Conference on Intelligent RObots and Systems}, year = {2011}, month = {September 25 - 3}, pages = {2817-2824}, address = {S. Francisco, USA}, keywords = {Embedded Control, Robotics}, author = {P Salaris and L. Pallottino and S. Hutchinson and A. Bicchi} } @conference {2324, title = {Neighbourhood Monitoring for Decentralised Coordination in Multi-Agent Systems: A Case-Study}, booktitle = {IEEE Symposium on Computers and Communications}, year = {2011}, abstract = {

Decentralized coordination of multi-agents requires that every agent reliably and efficiently disseminates its state to neighbours
through a wireless network. If dissemination is unreliable, safety issues may ensue. Unfortunately, the broadcast service of
wireless network is efficient but unreliable (e. g., IEEE 802.11). The Neighbourhood Monitoring Protocol (NMP) [1] is an efficient
and scalable protocol that assures a reliable state dissemination between mobile agents, under some conditions of channel
utilization. NMP runs on top of IEEE 802.11. In this paper we evaluate NMP with a specific decentralized collision avoidance
algorithm based on the GRP policy [2]. The algorithm is particularly challenging because it accommodates an arbitrary number
non-holonomic agents. We show that NMP allows the system to scale well and provides a very high state delivery ratio even if it
operates on the unreliable broadcast service like 802.11. Doing so, NMP assures the correct state information to the collision
avoidance algorithm.

}, keywords = {Embedded Control, Robotics}, author = {G. Dini and Giurlanda, F. and L. Pallottino} } @booklet {11, title = {Optimal synthesis for nonholonomic vehicles with constrained side sensors}, year = {2011}, note = {

Technical Report

}, keywords = {Embedded Control, Robotics}, author = {P Salaris and L. Pallottino and A. Bicchi} } @conference {SPB11, title = {Shortest Paths With Side Sensor}, booktitle = {2011 IEEE International Conference on Robotics and Automation}, year = {2011}, month = {May 9 - 13}, pages = {4875 - 4882}, address = {Shangai, China}, keywords = {Embedded Control, Robotics}, author = {P Salaris and L. Pallottino and A. Bicchi} } @conference {WPB-ICRA10, title = {Controllability for Pairs of Vehicles Maintaining Constant Distance}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2010)}, year = {2010}, month = {May 3 - 8}, pages = {342 - 349}, address = {Anchorage, Alaska}, keywords = {Embedded Control, Robotics}, author = {H. Wang and L. Pallottino and A. Bicchi} } @conference {WPB_cdc10, title = {Controllability Properties for Aircraft Formations}, booktitle = {International Conference on Decision and Control - CDC 2010}, year = {2010}, pages = {2047 - 2054}, keywords = {Embedded Control, Robotics}, author = {H. Wang and L. Pallottino and A. Bicchi} } @conference {WPb_cdc10_2, title = {Motion planning for Formations of Dubins Vehicles}, booktitle = {International Conference on Decision and Control - CDC 2010}, year = {2010}, pages = {2263 - 2269}, keywords = {Embedded Control, Robotics}, author = {H. Wang and L. Pallottino and A. Bicchi} } @article {SPFB10, title = {Shortest Paths for a Robot with Nonholonomic and Field-of-View Constraints}, journal = {IEEE Trans. on Robotics}, volume = {26}, number = {2}, year = {2010}, pages = {269 - 281}, keywords = {Embedded Control, Robotics}, author = {P Salaris and D. Fontanelli and L. Pallottino and A. Bicchi} } @article {BFP10, title = {Towards a Society of Robots: Behaviors, Misbehaviors, and Security}, journal = {IEEE Robotics and Automation Magazine}, volume = {17}, number = {4}, year = {2010}, month = {December}, pages = {26 - 36}, keywords = {Robotics}, author = {A. Bicchi and A. Fagiolini and L. Pallottino} } @conference {PSFB-CDC09, title = {Shortest Paths for Non-holonomic Vehicles with Limited Field of View Camera}, booktitle = {Proc. IEEE International Conference on Decision and Control}, year = {2009}, month = {December, 16 - 1}, pages = {8434 - 8439}, address = {Shangai, China}, abstract = {

This paper presents a complete characterization of shortest paths for unicycle-like nonholonomic mobile robots equipped with a pinhole camera rigidly fixed with limited Field-Of-View (FOV). We preliminarily provide an alphabet of optimal control words and then we demonstrate how to obtain the partition induced by shortest path in the vehicle plane. The word univocally associated to a region encodes the shortest path from any starting point in that region to the goal point of the mobile robot without violating the FOV constraints.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and P Salaris and D. Fontanelli and A. Bicchi} } @article {BDDLPPSS08, title = {Heterogeneous Wireless Multirobot System}, journal = {Robotics and Automation Magazine, IEEE}, volume = {15}, number = {1}, year = {2008}, pages = {62{\textendash}70}, keywords = {Robotics}, doi = {10.1109/M-RA.2007.914925}, url = {http://dx.doi.org/10.1109/M-RA.2007.914925}, author = {A. Bicchi and A. Danesi and G. Dini and La Porta, S. and L. Pallottino and I. M. Savino and R. Schiavi} } @conference {BDSP:ECC07, title = {A Component-Based Approach to Localization and Collision Avoidance for Mobile Multi-Agent Systems}, booktitle = {Proc. European Control Conference (ECC)}, year = {2007}, month = {July}, pages = {4285-4292}, abstract = {

In the RUNES project a disaster relief tunnel scenario is being developed in which mobile robots are used to restore the radio network connectivity in a stationary sensor network. A component-based software development approach has been adopted. Two components are described in this paper. A localization component that uses ultrasound and dead reckoning to decide the robot positions and a collision avoidance component that ensures that the robots do not collide with each other.

}, keywords = {Embedded Control, Robotics}, author = {P. Alriksson and J. Nordh and K -E Arz{\'e}n and A. Bicchi and A. Danesi and R. Schiavi and L. Pallottino} } @article {PSFB06-TRO, title = {Decentralized cooperative policy for conflict resolution in multi-vehicle systems}, journal = {IEEE Trans. on Robotics}, volume = {23}, number = {6}, year = {2007}, pages = {1170-1183}, abstract = {

In this paper we propose a novel policy for steering multiple vehicles between assigned independent start and goal configurations and ensuring collision avoidance. The policy rests on the assumption that agents are all cooperating by implementing the same traffic rules. However, the policy is completely decentralized, as each agent decides its own motion by applying those rules only on locally available information, and totally scalable, in the sense that the amount of information processed by each agent and the computational complexity of the algorithms are not increasing with the number of agents in the scenario. The proposed policy applies to systems in which new vehicle may enter the scene and start interacting with existing ones at any time, while others may leave. Under mild conditions on the initial configurations, the policy is shown to be safe, i.e. to guarantee collision avoidance throughout the system evolution. In the paper, conditions are discussed on the desired configurations of agents under which the ultimate convergence of all vehicles to their goals can also be guaranteed. To show that such conditions are actually necessary and sufficient, which turns out to be a challenging liveness verification problem for a complex hybrid automaton, we employ a probabilistic verification method. The paper finally reports on simulations for systems of several tens of vehicles, and with some experimental implementation showing the practicality of the approach.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and V. G. Scordio and E. Frazzoli and A. Bicchi} } @conference {FVPDB:CDC07, title = {Decentralized Intrusion Detection for Secure Cooperative Multi-Agent Systems}, booktitle = {Proc. IEEE Int. Conf. on Decision and Control}, year = {2007}, pages = {1553-1558}, abstract = {

In this paper we address the problem of detecting faulty behaviors of cooperative mobile agents. A novel decentralized and scalable architecture that can be adopted to realize a monitor of the agents

}, keywords = {Embedded Control, Robotics}, author = {A. Fagiolini and G. Valenti and L. Pallottino and G. Dini and A. Bicchi} } @booklet {FPD{\textquoteright}07, title = {Decentralized Intrusion Detection in Cooperative Multi-Agent Systems}, year = {2007}, note = {

Poster Presentation

}, month = {April}, abstract = {

We address the problem of detecting faulty behaviors of robots belonging to a multi-agent system. Our objective is to develop a scalable architecture that can be adopted to realize a completely decentralized intrusion detector monitoring the agents{\textquoteright} behavior. We want the solution to be independent from the set of {\textquoteleft}{\textquoteleft}rules{\textquoteright}{\textquoteright} describing the interaction among the agents, and from their dynamics; (non-invasive) mainly based on HW/SW components that are already present on-board of each agent. We focus on systems with decentralized cooperation schemes where cooperation is obtained by sharing a set of {\textquoteleft}{\textquoteleft}rules{\textquoteright}{\textquoteright} by which each agent plans its next {\textquoteleft}{\textquoteleft}action{\textquoteright}{\textquoteright} and where some of the agents may act not according to the rules due to spontaneous failure, tampering, or malicious introduction.

}, keywords = {Embedded Control, Robotics}, author = {A. Fagiolini and L. Pallottino and G. Dini} } @conference {PB06, title = {A Dynamic Programming Approach to Optimal Planning for Vehicles with Trailers}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {2007}, pages = {3098 - 3103}, abstract = {

In this paper we deal with the optimal feedback synthesis problem for robotic vehicles with trailers which can be modeled by differential equations in chained-form. With respect to classical methods for numerical evolution of optimal feedback synthesis via Dynamic Programming which are based on both input and state discretization, our method exploits the lattice structure naturally imposed on the reachable set by input quantization. A generalized Dijkstra algorithm can be used to obtain optimal feedback control laws, for chained-form vehicles with n-trailers, in an effective way.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and A. Bicchi} } @conference {FVPDB:CASE07, title = {Local Monitor Implementation for Decentralized Intrusion Detection in Secure Multi-Agent Systems}, booktitle = {3rd IEEE Conference on Automation Science and Engineering}, year = {2007}, pages = {454{\textendash}459}, abstract = {

This paper focuses on the detection of misbehaving agents within a group of mobile robots. A novel approach to automatically synthesize a decentralized Intrusion Detection System (IDS) as well as an efficient implementation of local monitors are presented. In our scenario, agents perform possibly different independent tasks, but cooperate to guarantee the entire system

}, keywords = {Embedded Control, Robotics}, author = {A. Fagiolini and G. Valenti and L. Pallottino and G. Dini and A. Bicchi} } @conference {PSFB07-ACC, title = {Probabilistic verification of decentralized multi-agent control strategies: a case study in conflict avoidance}, booktitle = {American Control Conference (ACC)}, year = {2007}, pages = {170-175}, abstract = {

Many challenging verification problems arise from complex hybrid automata that model decentralized control systems. As an example, we will consider decentralized policies that steer multiple vehicles in a shared environment: properties of safety and liveness, such as collision avoidance and ultimate convergence of all vehicles to their goals, must be verified. To formally verify the behavior of proposed policies, it is desired to identify the broadest class of start and goal configurations, such that safety and liveness would be guaranteed. Simple conditions are proposed to identify such a class: ideally, a formal proof that such conditions are necessary and sufficient for safety and liveness is requested. Unfortunately, in decentralized control frameworks classical approaches are difficult to apply. Hence, probabilistic verification method can be applied to quantify the accuracy and the confidence of the veridicity of the desired predicate. The probabilistic verification method is applied to a recently proposed cooperative and completely decentralized collision avoidance policy for non-holonomic vehicles.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and A. Bicchi and E. Frazzoli} } @conference {PSFB-MTNS06, title = {Decentralized and scalable conflict resolution strategy for multi-agents systems}, booktitle = {Int. Symp. on Mathematical Theory of Networks and Systems}, year = {2006}, abstract = {

A decentralized cooperative collision avoidance control policy for planar vehicle recently proposed is herein considered. Given some simple conditions on initial configurations of agents, the policy is known to ensure safety (i.e., collision avoidance) for an arbitrarily large number of vehicles. The method is highly scalable, and effective solutions can be obtained for several tens of autonomous agents. On the other hand, the liveness property of the policy, i.e. the capability of negotiating a solution in finite time, is not yet completely understood. First a 3D workspace extension is proposed. Furthermore, based on a condition on target configuration previously proposed, some general results on the liveness property are reported. Finally, qualitative evaluations on the strategy and on the proposed target sparsity condition are pointed out.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and V. G. Scordio and E. Frazzoli and A. Bicchi} } @conference {PSFB06, title = {Probabilistic verification of a decentralized policy for conflict resolution in multi-agent systems}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {2006}, note = {

Correct version

}, pages = {2448-2453}, abstract = {

In this paper, we consider a decentralized cooperative control policy proposed recently for steering multiple non-holonomic vehicles between assigned start and goal configurations while avoiding collisions. The policy is known to ensure safety (i.e., collision avoidance) for an arbitrarily large number of vehicles, if initial configurations satisfy certain conditions. The method is highly scalable, and effective solutions can be obtained for several tens of autonomous agents. On the other hand, the liveness property of the policy, i.e. the capability of negotiating a solution in finite time, is not yet completely understood. In this paper, we introduce a condition on the final vehicle configurations, which we conjecture to be sufficient for guaranteeing liveness. Because of the overwhelming complexity of proving the sufficiency of such condition, we assess the correctness of the conjecture in probability through the analysis of the results of a large number of randomized experiments.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and V. G. Scordio and E. Frazzoli and A. Bicchi} } @conference {DFPSSDB06, title = {A scalable platform for safe and secure decentralized traffic management of multiagent mobile systems}, booktitle = {ACM Workshop on Real-World Wireless Sensor Networks}, year = {2006}, abstract = {

In this paper we describe the application of wireless sensor networking techniques to address the realization of a safe and secure decentralized traffic management system. We consider systems of many heterogeneous autonomous vehicles moving in a shared environment. Each vehicle is assumed to have different and possibly unspecified tasks, but they cooperate to avoid collisions. We are interested in designing a scalable architecture capable of accommodating a very large and dynamically changing number of vehicles, guaranteeing their safety (i.e., collision avoidance), the achievement of their goals, and security against potential adversaries. By properly distributing and revoking cryptographic keys we are able to protect communications from an external adversary as well as to detect non-cooperative, possibly malicious vehicles and trigger suitable countermeasures. In our architecture, scalability is obtained by decentralization, i.e. each vehicle is regarded as an autonomous agent capable of processing information concerning its own state and the state of only a fixed, small number of {\textquoteleft}{\textquoteleft}neighboring{\textquoteright}{\textquoteright} agents. Ad-hoc wireless sensor networks are employed to provide support for this architecture.

}, keywords = {Embedded Control, Robotics}, author = {A. Danesi and A. Fagiolini and I. Savino and L. Pallottino and R. Schiavi and G. Dini and A. Bicchi} } @conference {PSFB05, title = {Decentralized Cooperative Conflict Resolution for Multiple Nonholonomic Vehicles}, booktitle = {Proc. AIAA COnf. on Guidance, Navigation and Control}, year = {2005}, abstract = {

In this paper, we consider the problem of collision-free motion planning for multiple nonholonomic planar vehicles. Each vehicle is capable of moving at constant speed along paths with bounded curvature, and is aware of the position and heading of other vehicles within a certain sensing radius. No other information exchange is required between vehicles. We propose a spatially decentralized, cooperative hybrid control policy that ensures safety for arbitrary numbers of vehicles. Furthermore, we show that under certain conditions, the policy avoids dead- and livelock, and eventually all vehicles reach their intended targets. Simulations and experimental results are presented and discussed.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and V. G. Scordio and E. Frazzoli and A. Bicchi} } @conference {BBCCCCPT05, title = {From tele-laboratory to e-learning in automation curricula at the university of Pisa}, booktitle = {Proc. IFAC World Congress}, year = {2005}, abstract = {

The design and development of computational infrastructures supporting existing tele-laboratory experiences in the field of automation and robotics are described. The goal of the activity is to provide a proper e-learning environment in which remote laboratory experiences are integrated in a coherent way. The addition of e-learning features, as self-assessment and progress monitoring tools, asynchronous tutor interaction, authentication, evaluation and follow-up features, has led also to the modification of the original tele-laboratory set-up.

}, keywords = {Robotics}, author = {A. Balestrino and A. Bicchi and A. Caiti and V. Calabr{\`o} and T. Cecchini and A. Coppelli and L. Pallottino and G. Tonietti} } @article {BCPT03, title = {On-line Robotic Experiments for Tele-Education at the University of Pisa}, journal = {Int. Journal of Robotic Systems}, volume = {22}, number = {4}, year = {2005}, note = {

Special Issue on Internet \& Online Robots for Telemanipulation

}, pages = {217-230}, abstract = {

In this paper we describe work being done at our department to make the Robotics Laboratory accessible to student and colleagues, to execute and watch real-time experiments at any time and from anywhere. We describe few different installations, and highlight the underlying philosophy, wich is aimed at enlarging the lab in all the dimensions of space, time, and available resources, through the use of Internet technologies.

}, keywords = {Robotics}, author = {A. Bicchi and A. Caiti and L. Pallottino and G. Tonietti} } @conference {PSB04, title = {Decentralized Cooperative Conflict Resolution Among Multiple Autonomous Mobile Agents}, booktitle = {cdc}, year = {2004}, pages = {4758-4763}, abstract = {

In this paper we consider policies for cooperative, decentralized traffic management among a number of autonomous mobile agents. The conflict resolution problem is addressed considering realistic restrictions on possible maneuvers. We formulate this problem as one in Mixed Integer Linear Programming (MILP). The method, which proves successful in a centralized implementation with a large number of cooperating agents, is also extended to a decentralized setting. Conditions for the existence of conflict avoidance maneuvers for a system of 5 autonomous agents with a transitive information structure are provided, along with the explicit policy to be applied by each agent.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and V. G. Scordio and A. Bicchi} } @conference {PPSB04, title = {Motion Planning through Symbols and Lattices}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {2004}, pages = {3914-3919}, abstract = {

In this paper we propose a new approach to motion planning, based on the introduction of a lattice structure in the workspace of the robot, leading to efficient computations of plans for rather complex vehicles, and allowing for the implementation of optimization procedures in a rather straightforward way. The basic idea is the purposeful restriction of the set of possible inputfunctions to the vehicle to a finite set of symbols, or {\em control quanta},which, under suitable conditions, generate a regular lattice of reachable points. Once the lattice is generated and a convenient description computed, standard techniques in integer linear programming can be used to find a plan very efficiently. We also provide a correct and complete algorithm to the problem of finding an optimized plan (with respect e.g. to length minimization) consisting in a sequence of graph searches.

}, keywords = {Embedded Control, Robotics}, author = {S. Pancanti and L. Pallottino and D. Salvadorini and A. Bicchi} } @conference {BBCCPPT04, title = {A Robotic Set-Up with Remote Access for {\textquoteleft}{\textquoteleft}Pick and Place{\textquoteright}{\textquoteright} Operations Under Uncertainty Conditions}, booktitle = {E-learning and Virtual and Remote Laboratories}, series = {Proc. VIRTUAL-LAB 2004}, year = {2004}, pages = {144{\textendash}149}, abstract = {

The work describes on-going work at the University of Pisa on the field of tele-laboratories and distance learning. In particular, the group is working at the evolution of existing tele-laboratory experiments in the field of robotics and control into learning units of a self-consistent didactic project. The pick-and-place system described has been designed to provide the set-up for robot arm motion planning with specific objectives and evaluation tools.

}, keywords = {Robotics}, author = {A. Balestrino and A. Bicchi and A. Caiti and T. Cecchini and L. Pallottino and A. Pisani and G. Tonietti}, editor = {P. Borza and L. Gomes and G. Scutaru} } @article {PFB02-TITS, title = {Conflict Resolution Problems for Air Traffic Management Systems Solved with Mixed Integer Programming}, journal = {IEEE Trans. Intelligent Transportation Systems}, volume = {3}, number = {1}, year = {2002}, month = {March}, pages = {3-11}, abstract = {

This paper considers the problem of solving conflicts arising among several aircraft that are assumed to move in a shared airspace. Aircraft can not get closer to each other than a given safety distance in order to avoid possible conflicts between different airplanes. For such system of multiple aircraft, we consider the path planning problem among given waypoints avoiding all possible conflicts. In particular we are interested in optimal paths, i.e. we want to minimize the total flight time. We propose two different formulations of the multi-aircraft conflict avoidance problem as a mixed-integer linear program: in the first case only velocity changes are admissible maneuvers, in the second one only heading angle changes are allowed. Due to the linear formulation of the two problems, solutions may be obtained quickly with standard optimization software, allowing our approach to be implemented in real time.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and E. Feron and A. Bicchi} } @inbook {PLPB02, title = {Optimal control of quantized input systems}, booktitle = {Hybrid Systems: Computation and Control}, series = {Lecture Notes in Computer Science}, volume = {LNCS 2289}, year = {2002}, pages = {351-363}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Heidelberg, Germany}, abstract = {

In this paper we consider the problem of optimal control (specifically, minimum-time steering) for systems with quantized inputs. In particular, we propose a new approach to the solution of the optimal control problem for an important class of nonlinear systems, i.e. chained-form systems. By exploiting results on the structure of the reachability set of these systems under quantized control, the optimal solution is determined solving an integer linear programming problem. Our algorithm represents an improvement with respect to classical approaches in terms of exactness, as it does not resort to any a priori state-space discretization. Although the computational complexity of the problem in our formulation is still formally exponential, it lends itself to application of Branch and Bound techniques, which substantially cuts down computations in many cases, as it has been experimentally observed.

}, keywords = {Embedded Control, Robotics}, author = {S. Pancanti and L. Leonardi and L. Pallottino and A. Bicchi}, editor = {C. Tomlin and M. Greenstreet} } @conference {PPB02, title = {On Optimal Steering of Quantized Input Systems}, booktitle = {Proceedings of the NSF/ONR Workshop on Future Directions in Nonlinear Control of Mechanical Systems}, year = {2002}, address = {Urbana, IL.}, abstract = {

In this paper we consider the problem of optimal control (specifically, minimum-time steering) for systems with quantized inputs. In particular, we propose a new approach to the solution of the optimal control problem for an important class of nonlinear systems, i.e. chained-form systems. By exploiting results on the structure of the reachability set of these systems under quantized control, the optimal solution is determined solving an integer linear programming problem. Our algorithm represents an improvement with respect to classical approaches in terms of exactness, as it does not resort to any a priori state-space discretization. Although the computational complexity of the problem in our formulation is still formally exponential, it lends itself to application of Branch and Bound techniques, which substantially cuts down computations in many cases, as it has been experimentally observed.

}, keywords = {Embedded Control, Robotics}, author = {S. Pancanti and L. Pallottino and A. Bicchi} } @conference {PBENEA02, title = {Risoluzione ottima dei conflitti tra agenti autonomi: applicazione al controllo del traffico aereo}, booktitle = {Proc. 1st. Natl. Conf. and Exhibit on Autonomous Intelligent Systems and Advanced Robotics}, year = {2002}, month = {October}, pages = {193-197}, address = {ENEA, Frascati}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and A. Bicchi} } @conference {PBP02, title = {Safety of a decentralized scheme for Free-Flight ATMS using Mixed Integer Linear Programming}, booktitle = {American Control Conference}, year = {2002}, month = {May}, pages = {742-747}, abstract = {

In this paper we consider policies for free-flight management of air traffic. We consider instantaneous and bounded heading angle deviation as conflict avoidance maneuvers. The corresponding model, resulting in a Mixed Integer Linear Programming (MILP) problem allow to solve both conflict detection and conflict resolution problems. The developed algorithm proved successful in a centralized implementation with a large number of cooperating aircraft. However, the application of such algorithm to a Free Flight environment, where cooperation can only be expected from neighboring aircraft, poses many challenges. We consider a model of the decentralized conflict resolution strategy that is based on a hybrid system, and sufficient conditions under which a 3-aircraft Free Flight MILP-based scheme guarantees safety of flight are provided.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and A. Bicchi and S. Pancanti} } @conference {PPB00, title = {Shortest paths for teams of vehicles}, booktitle = {Proc. WAC Int. Symp. on Robotics and Applications}, year = {2000}, month = {June}, pages = {124-129}, abstract = {

In this paper we consider the problem of planning motions of a team of vehicles that move in a planar environment. Each vehicle is modelled as a kinematic system with velocity constraints and curvature bounds. Vehicles can not get closer to each other than a predefined safety distance. When manipulating a common object cooperatively, further constraints apply. For such systems, we consider the problem of planning optimal paths in the absence of obstacles.

}, keywords = {Embedded Control, Robotics}, author = {L. Pallottino and G. Parlangeli and A. Bicchi} }