Summary This paper deals with the application of model predictive control (MPC) to optimize power flows in a network of interconnected microgrids (MGs). More specifically, a distributed MPC (DMPC) approach is used to compute for each MG how much active power should be exchanged with other MGs and with the outer power grid. Due to the presence of coupled variables, the DMPC approach must be used in a suitable way to guarantee the feasibility of the consensus procedure among the MGs. For this purpose, we adopt a tailored dual decomposition method that allows us to reach a feasible solution while guaranteeing the privacy of single MGs (ie, without having to share private information like the amount of generated energy or locally consumed energy). Simulation results demonstrate the features of the proposed cooperative control strategy and the obtained benefits with respect to other classical centralized control methods.

UR - https://onlinelibrary.wiley.com/doi/abs/10.1002/oca.2504 ER - TY - JOUR T1 - Exact Task Execution in Highly Under-Actuated Soft Limbs: An Operational Space Based Approach JF - IEEE Robotics and Automation Letters Y1 - 2019 A1 - C. Della Santina A1 - L. Pallottino A1 - D. Rus A1 - A. Bicchi VL - Volume: 4 , Issue: 3 , July 2019 ER - TY - Generic T1 - Towards the Design of Robotic Drivers for Full-Scale Self-Driving Racing Cars T2 - 2019 International Conference on Robotics and Automation (ICRA) Y1 - 2019 A1 - D. Caporale A1 - A. Settimi A1 - F. Massa A1 - F. Amerotti A1 - A. Corti A1 - A. Fagiolini A1 - M. Guiggiani A1 - A. Bicchi A1 - L. Pallottino JF - 2019 International Conference on Robotics and Automation (ICRA) ER - TY - JOUR T1 - Aerial Co-Manipulation With Cables: The Role of Internal Force for Equilibria, Stability, and Passivity JF - IEEE Robotics and Automation Letters Y1 - 2018 A1 - M. Tognon A1 - C. Gabellieri A1 - L. Pallottino A1 - A. Franchi KW - Admittance KW - Aerial systems: mechanics and control KW - distributed robot systems KW - Force KW - mobile manipulation KW - multi-robot systems KW - Robot kinematics KW - Stability criteria KW - Transportation VL - 3 ER - TY - CONF T1 - Autonomous 3D exploration of large areas: A cooperative frontier-based approach T2 - International Conference on Modelling and Simulation for Autonomous Systems Y1 - 2018 A1 - A. Mannucci A1 - S. Nardi A1 - L. Pallottino JF - International Conference on Modelling and Simulation for Autonomous Systems VL - 10756 LNCS Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in N1 -Cited By :1

ER - TY - CONF T1 - Design of an indoor autonomous robot navigation system for unknown environments T2 - International Conference on Modelling and Simulation for Autonomous Systems Y1 - 2018 A1 - L. Silvestri A1 - L. Pallottino A1 - S. Nardi JF - International Conference on Modelling and Simulation for Autonomous Systems VL - 10756 LNCS Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in N1 -Cited By :1

ER - TY - JOUR T1 - A Game Theoretic Robotic Team Coordination Protocol For Intruder Herding JF - IEEE Robotics and Automation Letters Y1 - 2018 A1 - S. Nardi A1 - F. Mazzitelli A1 - L. Pallottino KW - autonomous agents KW - Cost function KW - distributed robot systems KW - game theory KW - Games KW - Protocols KW - Robot kinematics KW - Robot sensing systems VL - 3 ER - TY - JOUR T1 - Humanoids at Work: The WALK-MAN Robot in a Postearthquake Scenario JF - IEEE Robotics Automation Magazine Y1 - 2018 A1 - F. Negrello A1 - A Settimi A1 - D. Caporale A1 - G. Lentini A1 - M. Poggiani A1 - D. Kanoulas A1 - L. Muratore A1 - Luberto, E. A1 - G. Santaera A1 - L. Ciarleglio A1 - L. Ermini A1 - L. Pallottino A1 - D. G. Caldwell A1 - N. Tsagarakis A1 - A. Bicchi A1 - M. Garabini A1 - M. G. Catalano KW - Buildings KW - Earthquakes KW - Hardware KW - Legged locomotion KW - Robot sensing systems KW - Task analysis ER - TY - CONF T1 - A Planning and Control System for Self-Driving Racing Vehicles T2 - 2018 IEEE 4th International Forum on Research and Technology for Society and Industry (RTSI) Y1 - 2018 A1 - D. Caporale A1 - A. Fagiolini A1 - L. Pallottino A1 - A Settimi A1 - A. Biondo A1 - F. Amerotti A1 - F. Massa A1 - S. De Caro A1 - A. Corti A1 - L. Venturini JF - 2018 IEEE 4th International Forum on Research and Technology for Society and Industry (RTSI) CY - Palermo, Italy ER - TY - CONF T1 - A Study on Force-Based Collaboration in Flying Swarms T2 - Proc. of Swarm Intelligence Y1 - 2018 A1 - C. Gabellieri A1 - M. Tognon A1 - L. Pallottino A1 - A. Franchi JF - Proc. of Swarm Intelligence PB - Springer International Publishing CY - Cham SN - 978-3-030-00533-7 ER - TY - CHAP T1 - WALK-MAN Humanoid Platform T2 - The DARPA Robotics Challenge Finals: Humanoid Robots To The Rescue Y1 - 2018 A1 - N. G. Tsagarakis A1 - F. Negrello A1 - M. Garabini A1 - W. Choi A1 - L. Baccelliere A1 - V. G. Loc A1 - J. Noorden A1 - M. G. Catalano A1 - M. Ferrati A1 - L. Muratore A1 - P. Kryczka A1 - E. Mingo Hoffman A1 - A Settimi A1 - A. Rocchi A1 - A. Margan A1 - S. Cordasco A1 - D. Kanoulas A1 - A. Cardellino A1 - L. Natale A1 - H. Dallali A1 - J. Malzahn A1 - N. Kashiri A1 - V. Varricchio A1 - L. Pallottino A1 - C. Pavan A1 - J. Lee A1 - A. Ajoudani A1 - D. G. Caldwell A1 - A. Bicchi JF - The DARPA Robotics Challenge Finals: Humanoid Robots To The Rescue PB - Springer VL - 121 ER - TY - CONF T1 - Distributed Task-priority Based Control in Area Coverage & Adaptive Sampling T2 - MTS/IEEE Oceans 2017 Y1 - 2017 A1 - T. Fabbri A1 - E. Simetti A1 - G. Casalino A1 - L. Pallottino A1 - A. Caiti KW - Robotics AB -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.

JF - MTS/IEEE Oceans 2017 PB - IEEE CY - Aberdeen, Scotland, June 2017 ER - TY - JOUR T1 - On the Minimum-Time Control Problem for Differential Drive Robots with Bearing Constraints JF - Journal of Optimization Theory and Applications Y1 - 2017 A1 - A. Cristofaro A1 - Salaris, P. A1 - L. Pallottino A1 - Giannoni, F. A1 - A. Bicchi KW - Robotics AB -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.

UR - 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 ER - TY - CONF T1 - Noninteracting Constrained Motion Planning and Control for Robot Manipulators T2 - IEEE International Conference of Robotics and Automation, ICRA2017 Y1 - 2017 A1 - M. Bonilla A1 - L. Pallottino A1 - A. Bicchi KW - Robotics AB -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–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.

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.

VL - 34 UR - http://onlinelibrary.wiley.com/doi/10.1002/rob.21702/epdf IS - 4 ER - TY - CONF T1 - APRICOT: Aerospace PRototypIng COntrol Toolbox. A Modeling and Simulation Environment for Aircraft Control Design T2 - International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016 Y1 - 2016 A1 - A. Ferrarelli A1 - D. Caporale A1 - A Settimi A1 - L. Pallottino KW - Embedded Control KW - Robotics AB -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.

JF - International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016 PB - Springer CY - Rome, Italy, June 15-16, 2016 VL - 9991 of the book series Lecture Notes in Computer Science (LNCS) UR - http://link.springer.com/chapter/10.1007/978-3-319-47605-6_11 ER - TY - CONF T1 - Assessing the Potential of Autonomous Multi-agent Surveillance in Asset Protection from Underwater Threats T2 - International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016 Y1 - 2016 A1 - T. Fabbri A1 - S. Nardi A1 - L. Isgrò A1 - L. Pallottino A1 - A. Caiti AB -A Serious Game (SG) system for the assessment of the potential of the multi-vehicle surveillance is presented. The SG system is applied to the problem of protection of strategic assets from underwater asymmetric threats. The SG platform integrates the active sonar performance evaluator able to estimate the real performance on the basis of the environmental conditions. The final goal is to provide new technology tools to realize a Decision Support System (DDS) to support the design phase of a naval unit. The SG system is developed in the framework of the ProDifCon project supported by the (DLTM) (Italy).

JF - International Workshop on Modelling and Simulation for Autonomous Systems MESAS 2016 PB - Springer CY - Rome, Italy, June 15-16, 2016 VL - 9991 of the book series Lecture Notes in Computer Science (LNCS) UR - http://link.springer.com/chapter/10.1007/978-3-319-47605-6_17 ER - TY - JOUR T1 - Controllability analysis of a pair of 3D Dubins vehicles in formation JF - Robotics and Autonomous Systems Y1 - 2016 A1 - H. Marino A1 - Salaris, P. A1 - L. Pallottino KW - Embedded Control KW - Robotics AB -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–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.

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.

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’ 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.

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–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–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–manipulation tasks.

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)

ER -
TY - CONF
T1 - Multi–object handling for robotic manufacturing
T2 - IECON 2016: 42nd Annual Conference of the IEEE Industrial Electronics Society
Y1 - 2016
A1 - M. Ferrati
A1 - H. Marino
A1 - A Settimi
A1 - S. Nardi
A1 - L. Pallottino
KW - Robotics
AB - 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–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–effectors with constraints and capabilities.

Time varying graphs will be introduced to model the problem for simultaneous handling of objects by different end–effectors.

Optimal exploration of such graphs will be used to determine paths for each object with time constraints. Results will be validated through simulations.

*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–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 3*D* viewer.

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.

JF - IEEE International Conference on Humanoid Robots (HUMANOIDS2016) PB - IEEE CY - Cancun, Mexico, 15-17 Nov. 2016 SN - 978-1-5090-4718-5 UR - http://ieeexplore.ieee.org/document/7803381/ N1 -This work was supported by the European Commission projects (FP7 framework) Walk-Man and the European Commission Grant no. H2020- ICT-645599 “SOMA”: SOft MAnipulation

ER -
TY - JOUR
T1 - The Walk-Man Robot Software Architecture
JF - Front. Robot. AI
Y1 - 2016
A1 - M. Ferrati
A1 - A Settimi
A1 - L. Muratore
A1 - N. G. Tsagarakis
A1 - L. Natale
A1 - L. Pallottino
KW - Robotics
AB - 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.

UR - http://bit.ly/2jAPke2 ER - TY - CONF T1 - Coordination of unmanned marine vehicles for asymmetric threats protection T2 - MTS/IEEE Oceans 2015 Y1 - 2015 A1 - S. Nardi A1 - C. Della Santina A1 - D. Meucci A1 - L. Pallottino KW - Robotics AB -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.

JF - MTS/IEEE Oceans 2015 PB - IEEE CY - May 18-21, Genoa, Italy SN - 978-1-4799-8736-8 UR - http://ieeexplore.ieee.org/document/7271413/ ER - TY - JOUR T1 - Distributed motion misbehavior detection in teams of heterogeneous aerial robots JF - Robotics and Autonomous Systems information Y1 - 2015 A1 - S. Martini A1 - D. Di Baccio A1 - F. Alarcòn-Romero A1 - A. Viguria-Jiménez A1 - L. Pallottino A1 - G. Dini A1 - A. Ollero KW - Embedded Control KW - Robotics AB -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.

planet

ER - TY - JOUR T1 - Epsilon-Optimal Synthesis for Unicycle-like Vehicles with Limited Field-Of-View Sensors JF - IEEE Transactions on Robotics (T-RO) Y1 - 2015 A1 - P Salaris A1 - A. Cristofaro A1 - L. Pallottino KW - Embedded Control KW - Robotics AB -In this paper we study the minimum length paths covered by the center of a unicycle equipped with a limited Field–Of–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–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–optimal path from each point in thatregion is univocally determined.

VL - 31 IS - 6 ER - TY - JOUR T1 - Epsilon–optimal synthesis for vehicles with vertically bounded Field-Of-View JF - IEEE Transactions on Automatic Control Y1 - 2015 A1 - Salaris, P. A1 - Cristofaro, A. A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -This paper presents a contribution to the problem of obtaining an optimal synthesis for shortest paths for a unicycle guided by an on–board limited Field Of–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– 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–FOV, i.e. upper and lower boundaries). With respect to the H–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–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–optimal path from each point in that region is univocally determined.

VL - 60 IS - 5 ER - TY - CONF T1 - Sample-Based Motion Planning for Robot Manipulators with Closed Kinematic Chains T2 - IEEE International Conference on Robotics and Automation (ICRA2015) Y1 - 2015 A1 - M. Bonilla A1 - E. Farnioli A1 - L. Pallottino A1 - A. Bicchi KW - Robotics JF - IEEE International Conference on Robotics and Automation (ICRA2015) PB - IEEE CY - Seattle, USA, 25 - 30 May N1 -softhands pacman walkman

ER - TY - CONF T1 - Variable Stiffness Control for Oscillation Damping T2 - IEEE International Conference of Intelligent Robots and Systems (IROS2015) Y1 - 2015 A1 - G M Gasparri A1 - M. Garabini A1 - L. Pallottino A1 - L. Malagia A1 - M. G. Catalano A1 - G. Grioli A1 - A. Bicchi KW - Robotics JF - IEEE International Conference of Intelligent Robots and Systems (IROS2015) PB - IEEE CY - Hamburg, Germany, September 28 - October 02, 2015 UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7354312 N1 -This work is supported by the EC under the grant agreements no.611832 Walk-Man and ICT-287513 “SAPHARI”

ER -
TY - CONF
T1 - ASCARI: a component based simulator for distributed mobile robot systems
T2 - Modelling & Simulation for Autonomous Systems - MESAS2014
Y1 - 2014
A1 - M. Ferrati
A1 - A Settimi
A1 - L. Pallottino
KW - Embedded Control
KW - Robotics
JF - Modelling & Simulation for Autonomous Systems - MESAS2014
PB - Springer
CY - Rome, 5-6 May 2014
VL - Lecture Notes in Computer Science, Volume 8906, 2014
ER -
TY - CONF
T1 - On Time-Optimal Trajectories for Differential Drive Vehicles with Field-Of-View Constraints
T2 - IEEE Conference on Decision and Control (CDC2014)
Y1 - 2014
A1 - Cristofaro, A.
A1 - Salaris, P.
A1 - L. Pallottino
A1 - Giannoni, F.
A1 - A. Bicchi
KW - Embedded Control
KW - Robotics
AB - 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.

JF - IEEE Conference on Decision and Control (CDC2014) PB - IEEE CY - Los Angeles, USA, December 15-17 SN - 978-1-4799-7746-8 UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7039723 ER - TY - CONF T1 - Distributed Multi–level Motion Planning for Autonomous Vehicles in Large Scale Industrial Environments T2 - IEEE International Conference on Emerging Technologies & Factory Automation (ETFA) Y1 - 2013 A1 - L. Cancemi A1 - A. Fagiolini A1 - L. Pallottino KW - Robotics AB -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–sharing protocol involving a re–planning strategy. Once every agent is assigned with a desired motion path, the algorithm ensures ordered traffic flows of agents, that avoid inter–robot collision and system deadlock (stalls). The algorithm allows multi–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–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.

JF - IEEE International Conference on Emerging Technologies & Factory Automation (ETFA) ER - TY - CONF T1 - Global Path Planning for Competitive Robotic Cars T2 - IEEE Conference on Decision and Control Y1 - 2013 A1 - T. Rizano A1 - D. Fontanelli A1 - L. Palopoli A1 - L. Pallottino A1 - P Salaris KW - Robotics JF - IEEE Conference on Decision and Control CY - Florence, Italy ER - TY - CONF T1 - Shortest paths for wheeled robots with limited Field-Of-View: introducing the vertical constraint T2 - IEEE Conference on Decision and Control Y1 - 2013 A1 - P Salaris A1 - A. Cristofaro A1 - L. Pallottino A1 - A. Bicchi KW - Robotics JF - IEEE Conference on Decision and Control CY - Florence, Italy ER - TY - CONF T1 - A Subgradient Based Algorithm for Distributed Task Assignment for Heterogeneous Mobile Robots T2 - IEEE Conference on Decision and Control Y1 - 2013 A1 - A Settimi A1 - L. Pallottino KW - Robotics JF - IEEE Conference on Decision and Control CY - Florence, Italy ER - TY - CONF T1 - A time expanded network based algorithm for safe and efficient distributed multi-agent coordination T2 - IEEE Conference on Decision and Control Y1 - 2013 A1 - M. Ferrati A1 - L. Pallottino KW - Robotics JF - IEEE Conference on Decision and Control CY - Florence, Italy ER - TY - CONF T1 - Motion Planning for Two 3D-Dubins Vehicles with Distance Contraint T2 - International Conference of Intelligent Robots and Systems - IROS 2012 Y1 - 2012 A1 - H. Marino A1 - M. Bonizzato A1 - R. Bartalucci A1 - P Salaris A1 - L. Pallottino KW - Robotics JF - International Conference of Intelligent Robots and Systems - IROS 2012 CY - Vilamoura, Algarve, Portugal ER - TY - JOUR T1 - Shortest Paths for Finned, Winged, Legged and Wheeled Vehicles with Side-Looking Sensors JF - International Journal of Robotics Research Y1 - 2012 A1 - P Salaris A1 - L. Pallottino A1 - A. Bicchi KW - Robotics VL - 31 IS - 8 ER - TY - CONF T1 - On constrained optimal control problems in robotics T2 - Automatica.it 2011 Y1 - 2011 A1 - L. Pallottino A1 - P Salaris KW - Robotics JF - Automatica.it 2011 CY - Pisa, Italy ER - TY - CONF T1 - Decentralized Coordination System for Multiple AGVs in a Structured Environment T2 - 2011 Congress of the International Federation of Automatic Control Y1 - 2011 A1 - S. Manca A1 - A. Fagiolini A1 - L. Pallottino KW - Embedded Control KW - Robotics JF - 2011 Congress of the International Federation of Automatic Control CY - Milano, italy ER - TY - CONF T1 - From Optimal Planning to Visual Servoing with Limited FOV T2 - 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems Y1 - 2011 A1 - P Salaris A1 - L. Pallottino A1 - S. Hutchinson A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems CY - S. Francisco, USA ER - TY - CONF T1 - Neighbourhood Monitoring for Decentralised Coordination in Multi-Agent Systems: A Case-Study T2 - IEEE Symposium on Computers and Communications Y1 - 2011 A1 - G. Dini A1 - Giurlanda, F. A1 - L. Pallottino KW - Embedded Control KW - Robotics AB -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.

Technical Report

ER - TY - CONF T1 - Shortest Paths With Side Sensor T2 - 2011 IEEE International Conference on Robotics and Automation Y1 - 2011 A1 - P Salaris A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - 2011 IEEE International Conference on Robotics and Automation CY - Shangai, China ER - TY - CONF T1 - Controllability for Pairs of Vehicles Maintaining Constant Distance T2 - IEEE International Conference on Robotics and Automation (ICRA2010) Y1 - 2010 A1 - H. Wang A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - IEEE International Conference on Robotics and Automation (ICRA2010) CY - Anchorage, Alaska ER - TY - CONF T1 - Controllability Properties for Aircraft Formations T2 - International Conference on Decision and Control - CDC 2010 Y1 - 2010 A1 - H. Wang A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - International Conference on Decision and Control - CDC 2010 ER - TY - CONF T1 - Motion planning for Formations of Dubins Vehicles T2 - International Conference on Decision and Control - CDC 2010 Y1 - 2010 A1 - H. Wang A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - International Conference on Decision and Control - CDC 2010 ER - TY - JOUR T1 - Shortest Paths for a Robot with Nonholonomic and Field-of-View Constraints JF - IEEE Trans. on Robotics Y1 - 2010 A1 - P Salaris A1 - D. Fontanelli A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics VL - 26 ER - TY - JOUR T1 - Towards a Society of Robots: Behaviors, Misbehaviors, and Security JF - IEEE Robotics and Automation Magazine Y1 - 2010 A1 - A. Bicchi A1 - A. Fagiolini A1 - L. Pallottino KW - Robotics VL - 17 ER - TY - CONF T1 - Shortest Paths for Non-holonomic Vehicles with Limited Field of View Camera T2 - Proc. IEEE International Conference on Decision and Control Y1 - 2009 A1 - L. Pallottino A1 - P Salaris A1 - D. Fontanelli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. IEEE International Conference on Decision and Control CY - Shangai, China ER - TY - JOUR T1 - Heterogeneous Wireless Multirobot System JF - Robotics and Automation Magazine, IEEE Y1 - 2008 A1 - A. Bicchi A1 - A. Danesi A1 - G. Dini A1 - La Porta, S. A1 - L. Pallottino A1 - I. M. Savino A1 - R. Schiavi KW - Robotics VL - 15 UR - http://dx.doi.org/10.1109/M-RA.2007.914925 ER - TY - CONF T1 - A Component-Based Approach to Localization and Collision Avoidance for Mobile Multi-Agent Systems T2 - Proc. European Control Conference (ECC) Y1 - 2007 A1 - P. Alriksson A1 - J. Nordh A1 - K -E Arzén A1 - A. Bicchi A1 - A. Danesi A1 - R. Schiavi A1 - L. Pallottino KW - Embedded Control KW - Robotics AB -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.

JF - Proc. European Control Conference (ECC) ER - TY - JOUR T1 - Decentralized cooperative policy for conflict resolution in multi-vehicle systems JF - IEEE Trans. on Robotics Y1 - 2007 A1 - L. Pallottino A1 - V. G. Scordio A1 - E. Frazzoli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

VL - 23 ER - TY - CONF T1 - Decentralized Intrusion Detection for Secure Cooperative Multi-Agent Systems T2 - Proc. IEEE Int. Conf. on Decision and Control Y1 - 2007 A1 - A. Fagiolini A1 - G. Valenti A1 - L. Pallottino A1 - G. Dini A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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

JF - Proc. IEEE Int. Conf. on Decision and Control ER - TY - ABST T1 - Decentralized Intrusion Detection in Cooperative Multi-Agent Systems Y1 - 2007 A1 - A. Fagiolini A1 - L. Pallottino A1 - G. Dini KW - Embedded Control KW - Robotics AB -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' behavior. We want the solution to be independent from the set of ``rules'' 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 ``rules'' by which each agent plans its next ``action'' and where some of the agents may act not according to the rules due to spontaneous failure, tampering, or malicious introduction.

N1 -Poster Presentation

ER - TY - CONF T1 - A Dynamic Programming Approach to Optimal Planning for Vehicles with Trailers T2 - Proc. IEEE Int. Conf. on Robotics and Automation Y1 - 2007 A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. IEEE Int. Conf. on Robotics and Automation ER - TY - CONF T1 - Higher order method for non linear equations resolution: application to mobile robot control T2 - Proc. European Control Conference Y1 - 2007 A1 - A. Balestrino A1 - L. Pallottino KW - Autonomous Vehicles KW - Navigation and Planning AB -In this paper a novel higher order method for the resolution of non linear equations is proposed. The particular application to the mobile robot navigation in an environment with obstacles is considered. The proposed method is based on the {\em embedded-relaxed} approach in which the dimension of the resolution space is augmented and a different and faster direction toward the root is computed. The method is proved to converge with higher order for the augmented resolution space of dimension 2 and 3. Finally, the method is applied to the problem of mobile robot navigation between obstacles considered as repulsive potentials.

JF - Proc. European Control Conference ER - TY - CONF T1 - Local Monitor Implementation for Decentralized Intrusion Detection in Secure Multi-Agent Systems T2 - 3rd IEEE Conference on Automation Science and Engineering Y1 - 2007 A1 - A. Fagiolini A1 - G. Valenti A1 - L. Pallottino A1 - G. Dini A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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

JF - 3rd IEEE Conference on Automation Science and Engineering ER - TY - CONF T1 - Probabilistic verification of decentralized multi-agent control strategies: a case study in conflict avoidance T2 - American Control Conference (ACC) Y1 - 2007 A1 - L. Pallottino A1 - A. Bicchi A1 - E. Frazzoli KW - Embedded Control KW - Robotics AB -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.

JF - American Control Conference (ACC) ER - TY - CONF T1 - Decentralized and scalable conflict resolution strategy for multi-agents systems T2 - Int. Symp. on Mathematical Theory of Networks and Systems Y1 - 2006 A1 - L. Pallottino A1 - V. G. Scordio A1 - E. Frazzoli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Int. Symp. on Mathematical Theory of Networks and Systems ER - TY - CONF T1 - Probabilistic verification of a decentralized policy for conflict resolution in multi-agent systems T2 - Proc. IEEE Int. Conf. on Robotics and Automation Y1 - 2006 A1 - L. Pallottino A1 - V. G. Scordio A1 - E. Frazzoli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. IEEE Int. Conf. on Robotics and Automation N1 -Correct version

ER - TY - CONF T1 - A scalable platform for safe and secure decentralized traffic management of multiagent mobile systems T2 - ACM Workshop on Real-World Wireless Sensor Networks Y1 - 2006 A1 - A. Danesi A1 - A. Fagiolini A1 - I. Savino A1 - L. Pallottino A1 - R. Schiavi A1 - G. Dini A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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 ``neighboring'' agents. Ad-hoc wireless sensor networks are employed to provide support for this architecture.

JF - ACM Workshop on Real-World Wireless Sensor Networks ER - TY - CONF T1 - Decentralized Cooperative Conflict Resolution for Multiple Nonholonomic Vehicles T2 - Proc. AIAA COnf. on Guidance, Navigation and Control Y1 - 2005 A1 - L. Pallottino A1 - V. G. Scordio A1 - E. Frazzoli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. AIAA COnf. on Guidance, Navigation and Control ER - TY - CONF T1 - From tele-laboratory to e-learning in automation curricula at the university of Pisa T2 - Proc. IFAC World Congress Y1 - 2005 A1 - A. Balestrino A1 - A. Bicchi A1 - A. Caiti A1 - V. Calabrò A1 - T. Cecchini A1 - A. Coppelli A1 - L. Pallottino A1 - G. Tonietti KW - Robotics AB -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.

JF - Proc. IFAC World Congress ER - TY - JOUR T1 - On-line Robotic Experiments for Tele-Education at the University of Pisa JF - Int. Journal of Robotic Systems Y1 - 2005 A1 - A. Bicchi A1 - A. Caiti A1 - L. Pallottino A1 - G. Tonietti KW - Robotics AB -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.

VL - 22 N1 -Special Issue on Internet & Online Robots for Telemanipulation

ER - TY - CONF T1 - Decentralized Cooperative Conflict Resolution Among Multiple Autonomous Mobile Agents T2 - cdc Y1 - 2004 A1 - L. Pallottino A1 - V. G. Scordio A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - cdc ER - TY - CONF T1 - Motion Planning through Symbols and Lattices T2 - Proc. IEEE Int. Conf. on Robotics and Automation Y1 - 2004 A1 - S. Pancanti A1 - L. Pallottino A1 - D. Salvadorini A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. IEEE Int. Conf. on Robotics and Automation ER - TY - CONF T1 - A Robotic Set-Up with Remote Access for ``Pick and Place'' Operations Under Uncertainty Conditions T2 - E-learning and Virtual and Remote Laboratories Y1 - 2004 A1 - A. Balestrino A1 - A. Bicchi A1 - A. Caiti A1 - T. Cecchini A1 - L. Pallottino A1 - A. Pisani A1 - G. Tonietti ED - P. Borza ED - L. Gomes ED - G. Scutaru KW - Robotics AB -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.

JF - E-learning and Virtual and Remote Laboratories T3 - Proc. VIRTUAL-LAB 2004 ER - TY - JOUR T1 - Conflict Resolution Problems for Air Traffic Management Systems Solved with Mixed Integer Programming JF - IEEE Trans. Intelligent Transportation Systems Y1 - 2002 A1 - L. Pallottino A1 - E. Feron A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

VL - 3 ER - TY - CHAP T1 - Optimal control of quantized input systems T2 - Hybrid Systems: Computation and Control Y1 - 2002 A1 - S. Pancanti A1 - L. Leonardi A1 - L. Pallottino A1 - A. Bicchi ED - C. Tomlin ED - M. Greenstreet KW - Embedded Control KW - Robotics AB -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.

JF - Hybrid Systems: Computation and Control T3 - Lecture Notes in Computer Science PB - Springer-Verlag CY - Heidelberg, Germany VL - LNCS 2289 ER - TY - CONF T1 - On Optimal Steering of Quantized Input Systems T2 - Proceedings of the NSF/ONR Workshop on Future Directions in Nonlinear Control of Mechanical Systems Y1 - 2002 A1 - S. Pancanti A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proceedings of the NSF/ONR Workshop on Future Directions in Nonlinear Control of Mechanical Systems CY - Urbana, IL. ER - TY - CONF T1 - Risoluzione ottima dei conflitti tra agenti autonomi: applicazione al controllo del traffico aereo T2 - Proc. 1st. Natl. Conf. and Exhibit on Autonomous Intelligent Systems and Advanced Robotics Y1 - 2002 A1 - L. Pallottino A1 - A. Bicchi KW - Embedded Control KW - Robotics JF - Proc. 1st. Natl. Conf. and Exhibit on Autonomous Intelligent Systems and Advanced Robotics CY - ENEA, Frascati ER - TY - CONF T1 - Safety of a decentralized scheme for Free-Flight ATMS using Mixed Integer Linear Programming T2 - American Control Conference Y1 - 2002 A1 - L. Pallottino A1 - A. Bicchi A1 - S. Pancanti KW - Embedded Control KW - Robotics AB -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.

JF - American Control Conference ER - TY - CONF T1 - Mixed Integer Programming for Aircraft Conflict Resolution T2 - AIAA Guidance, Navigation and Control Conference and Exhibit Y1 - 2001 A1 - L. Pallottino A1 - E. Feron A1 - A. Bicchi KW - Air Traffic Management Systems KW - Autonomous Vehicles KW - Navigation and Planning AB -This paper considers the problem of solving conflicts between several aircraft. Considering the case when only aircraft heading changes are allowed, we propose a formulation of the multi-aircraft conflict avoidance problem as a mixed-integer linear program, whose solution may be obtained within seconds with standard optimization software. While such a problem formulation and solution is still unsuitable for operational implementation, it may be used as part of a real or fast-time simulation.

JF - AIAA Guidance, Navigation and Control Conference and Exhibit ER - TY - CONF T1 - Randomized parallel simulation of constrained multibody systems for VR/haptic applications T2 - Proc. IEEE Int. Conf. on Robotics and Automation Y1 - 2001 A1 - A. Bicchi A1 - L. Pallottino A1 - M. Bray A1 - P. Perdomi KW - Dynamics and Simulation for Virtual Reality KW - Haptics AB -In this paper, we consider the problem of efficiently simulating large interconnected mechanical systems. For applications such as haptic rendering of large, complex virtual environments, dynamic simulation software and hardware is still too slow to afford accurate performance in real-time. In particular, mechanisms with closed kinematic chains necessitate solutions to a set of differential equation with algebraic constraints (DAE's), that are often too heavy and stiff to be computed in real-time by present-day single-processor machines. On the other hand, the structure of most state-of-the-art algorithms does not easily lend itself to parallelization. In this paper, we propose and experimentally verify a technique for DAE simulation that profitably uses a degree of randomization to achieve efficient parallelization.

JF - Proc. IEEE Int. Conf. on Robotics and Automation VL - 3 ER - TY - CONF T1 - On the optimal conflict resolution for air traffic control T2 - Proc. IEEE Intelligent Transportation Systems Y1 - 2000 A1 - L. Pallottino A1 - A. Bicchi KW - Air Traffic Management Systems KW - Autonomous Vehicles KW - Navigation and Planning AB -In this paper, we consider optimal resolution of air traffic conflicts. Aircraft are assumed to cruise within a given altitude layer, and are modeled as a kinematic system with velocity constraints and curvature bounds. Aircraft can not get closer to each other than a predefined safety distance. For such system of multiple aircraft, we consider the problem of planning optimal paths among given waypoints. Necessary conditions for optimality of solutions are derived, and used to devise a parameterization of possible trajectories that turns into efficient numerical solutions to the problem. Simulation results for a simplified aircraft conflict scenario are provided.

JF - Proc. IEEE Intelligent Transportation Systems CY - Dearborn, MI ER - TY - JOUR T1 - On optimal cooperative conflict resolution for air traffic management systems JF - IEEE Trans. Intelligent Transportation Systems Y1 - 2000 A1 - A. Bicchi A1 - L. Pallottino KW - Air Traffic Management Systems KW - Autonomous Vehicles KW - Hybrid and Embedded Control Systems KW - Nonlinear Control Systems AB -In this paper, we consider optimal resolution of air traffic conflicts. Aircraft are assumed to cruise within a given altitude layer, and are modeled as a kinematic system with constant velocity and curvature bounds. Aircraft can not get closer to each other than a predefined safety distance. For such system of multiple aircraft, we consider the problem of planning optimal paths among given waypoints. Necessary conditions for optimality of solutions are derived, and used to devise a parameterization of possible trajectories that turns into efficient numerical solutions to the problem. Simulation results for a realistic aircraft conflict scenario are provided. A decentralized implementation of the optimal conflict resolution scheme is introduced that may allow free-flight coordination in a cooperative airspace management scheme. Impact of decentralization on performance and safety is finally discussed with the help of extensive simulations.

VL - 1 ER - TY - CHAP T1 - Optimal planning for coordinated vehicles with bounded curvature T2 - Algorithmic and Computational Robotics: New Directions Y1 - 2000 A1 - A. Bicchi A1 - L. Pallottino ED - B. Donald ED - K. Lynch ED - D. Rus KW - Air Traffic Management Systems KW - Autonomous Vehicles KW - Navigation and Planning AB -In this paper we consider the problem of planning motions of a system of multiple vehicles moving in a plane. 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. For such system of multiple vehicles, we consider the problem of planning optimal paths in the absence of obstacles. The case when a constant distance between vehicles is enforced (such as when cooperative manipulation of objects is performed by the vehicle team) is also considered.

JF - Algorithmic and Computational Robotics: New Directions PB - A K Peters, MA VL - 1 N1 -The Workshop on Algorithmic Foundations of Robotics

ER - TY - CONF T1 - Shortest paths for teams of vehicles T2 - Proc. WAC Int. Symp. on Robotics and Applications Y1 - 2000 A1 - L. Pallottino A1 - G. Parlangeli A1 - A. Bicchi KW - Embedded Control KW - Robotics AB -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.

JF - Proc. WAC Int. Symp. on Robotics and Applications ER -