Publications

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Authors: AREA MIN. 07 - Scienze agrarie e veterinarie

Published: title_year

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Authors: Celesti-Grapow, L; Alessandrini, A; Arrigoni, PV; Banfi, E; Bernardo, L; Bovio, M; Brundu, G; Cagiotti, MR; Camarda, I; Carli, E; Conti, F; Fascetti, S; Galasso, G; Gubellini, L; La Valva, V; Lucchese, F; Marchiori, S; Mazzola, P; Peccenini, S; Poldini, L; Pretto, F; Prosser, F; Siniscalco, C; Villani, MC; Viegi, L; Wilhalm, T; Blasi, C; Dept Plant Biol; Dept Plant Biol; Bot Garden; Dept Bot & Plant Ecol; Dept Appl Biol; Dept Environm Sci; Dept Biol; Landscape Study Dept; In this paper we present a comprehensive inventory of the non-native vascular flora of Italy, which was produced within the project "A survey of the Italian non-native flora", funded by the Italian Ministry for the Environment. Previously published floristic accounts were the main source of information. Historical records were critically revised and integrated with recent literature, data from herbaria and some unpublished information, so as to obtain a complete, up-to-date catalogue of the non-native vascular plant species that occur spontaneously in Italy. The inventory lists 1023 non-native species and subspecies, which account for 13.4% of all the Italian flora. The Italian non-native flora was divided, according to its residence time, into 103 archaeophytes and 920 neophytes. According to its current invasion status, it was classified into 437 casual (42.7% of all non-native) and 524 established taxa, the latter being divided into 361 naturalized non-invasive (35.3%) and 163 invasive taxa (15.9%). The inventory includes a group of 62 species (6.1%) that lack recent records (i.e. since 1950). By combining local expertise into a unified, nationwide scheme using a standardized method and terminology, the inventory provides the essential scientific basis for the development of plant invasion research and management in the country. © 2009 Società Botanica Italiana. Celesti-Grapow; Alessandrini; Arrigoni; Banfi; Bernardo; Bovio; Brundu; Cagiotti; Camarda; Carli; Conti; Fascetti; Galasso; Gubellini; la Valva; Lucchese; Marchiori; Mazzola; Peccenini; Poldini; Pretto; Prosser; Siniscalco; Villani; Viegi; Wilhalm; Blasi

Journal: English

Published: doi

DOI: WOS:000272170900017

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Volume: PLANT BIOSYSTEMS###1126-3504 Pages: 430-Inventory of the non-native flora of Italy

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Authors: AREA MIN. 07 - Scienze agrarie e veterinarie

Published: title_year

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Authors: Cocuzza, S; Pretto, I; Debei, S; CISAS G Colombo; CISAS G Colombo; Dept Mech Engn; This paper presents two novel redundancy resolution schemes aimed at locally minimizing the reaction torque transferred to the spacecraft during manipulator manoeuvres. The subject is of particular interest in space robotics because reduced reactions result in reduced energy consumption and longer operating life of the attitude control system. The first presented solution is based on a weighted Jacobian pseudoinverse and is derived by using Lagrangian multipliers. The weight matrix is defined by means of the inertia matrix which appears in the spacecraft reaction torque dynamics. The second one is based on a least squares formulation of the minimization problem. In this formulation the linearity of the forward kinematics and of the reaction torque dynamics equations with respect to the joint accelerations is used. A closed-form solution is derived for both the presented methods, and their equivalence is proven analytically. Moreover, the proposed solutions, which are suitable for real-time implementation, are extended in order to take into account the physical limits of the manipulator joints directly inside the solution algorithm. A software simulator has been developed in order to simulate the performance of the presented solutions for the selected test cases. The proposed solutions have then been experimentally tested using a 3D free-flying robot previously tested in an ESA Parabolic Flight Campaign. In the test campaign the 3D robot has been converted in a 2D robot thanks to its modularity in order to perform planar tests, in which the microgravity environment can be simulated without time constraints. Air-bearings are used to sustain the links weight, and a dynamometer is used to measure the reaction torque. The experimental validation of the presented inverse kinematics solutions, with an insight on the effect of joint flexibility on their performance, has been carried out, and the experimental results confirmed the good performance of the proposed methods. In particular, two test cases have been analyzed in order to validate and evaluate the performance of both the unconstrained solution and the solution which takes into account the robot physical limits. Cocuzza; Pretto; Debei

Journal: English

Published: Cocuzza S.; Pretto I.; Debei S.

DOI: WOS:000291173900009

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Pages: 1721-Novel reaction control techniques for redundant space manipulators: Theory and simulated microgravity tests

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Authors: This paper presents the analysis and validation of a Least Squares based Inverse Kinematics solution for the control of the reaction torque transferred to the floating base of a redundant space manipulator. The solution, which is suitable for real-time implementation and can be extended in order to take into account the joint angle, velocity and acceleration limits, has been recently developed and experimentally validated by the authors in the case of a fixed-based planar manipulator. In this study, the solution is validated in the case of a planar three degrees of freedom free-floating manipulator by using a software simulator. Moreover, the operations of a free-floating robot and of a fixed-based robot are compared in different ways. First, the possibility to use fixed-based kinematic and dynamic models in order to reduce the computations necessary for the proposed solution is investigated. In particular, a limit base/arm mass ratio is derived, for which the approximated model can be favourably used, taking into account the requirements on base attitude pointing accuracy and end-effector trajectory accuracy. Then, the requirements on the maximum joint variables of a free-floating and of a fixed-based robot are compared for a given task. Higher joint angles, velocities and accelerations are expected with respect to a fixed-based robot that performs the same task, due to the base rotation displacements. This effect can be limited thanks to the proposed torque minimization solution, since motions can be studied in which a fixed base orientation is maintained, if sufficient redundant degrees of freedom are present. Finally, the study of the workspace in which a zero reaction torque can be obtained is performed for different base/arm mass ratios, both taking into account the physical joint limits or not. Cocuzza; Pretto; Debei

Journal: 2009

Published: Cocuzza S.; Pretto I.; Debei S.

DOI: 359006029

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Authors: AREA MIN. 09 - Ingegneria industriale e dell'informazione; ITA

Published: title_year

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Authors: A manipulator that is performing a manoeuvre generates reaction forces and torques that dynamically load the supporting base. A special interest in the control of the base reactions arises for robots mounted on a moving base, due to the interaction between the motion of the manipulator and the motion of the base itself, which in many cases needs to be controlled at the same time. In this paper the problem of tracking an arbitrary base reaction profile is considered. The present work gives a contribution to the subject of the kinematic control of spacecraft mounted manipulators and their dynamical effects in terms of reaction forces and torques, and can be used for the development of centralized control systems aimed at controlling multiple robots mounted on the same spacecraft, where a non-operating manipulator can cooperate to compensate the disturbances generated by a second operating robot, together with the reaction control system actuators. The solution to the problem is given in the form of a kinematic law for the joint variables of the manipulator, and the joint acceleration trajectories related to the desired base reaction profile are obtained. Furthermore, the influence of the degree of redundancy of the robot is analyzed, with respect both to the kinematic and the dynamic tasks. The availability of the redundancy can be exploited in order to prescribe a desired trajectory to the end-effector, and specifically the problem of realizing a defined base reaction profile and in the meantime achieve the best approximation of an end-effector trajectory is considered. The proposed solutions are developed in terms of pseudoinverse formulations, and the reaction control problems are set in local optimization form, leading to the definition of constrained least squares problems. The implementation of the proposed kinematic schemes in a robot simulator allowed to test the capabilities of the proposed concepts. Pretto; Cocuzza; Debei

Journal: 2009

Published: title_year

DOI: 358995151

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Authors: The control of the reactions exerted on the base spacecraft during manipulator operations is an important issue in space robotics applications, because it leads to reduced energy consumption of the Attitude Control System, thus extending the operating life of the entire system. This paper presents two novel redundancy resolution schemes aimed at locally minimizing the reaction torque transferred to the spacecraft during manipulator manoeuvres. The first presented solution is based on a weighted Jacobian pseudoinverse and is derived by using Lagrangian multipliers. The second one is based on a least squares formulation of the minimization problem. A closed-form solution is derived for both the presented methods, and their equivalence is proven analytically. Moreover, the proposed solutions, which are suitable for real-time implementation, are extended in order to take into account the physical limits of the manipulator joints. A software simulator has been developed in order to simulate the performance of the presented solutions for the selected test cases. The proposed solutions have then been experimentally tested using a 3D free-flying robot previously tested in an ESA Parabolic Flight Campaign. In the test campaign the 3D robot has been converted in a 2D robot thanks to its modularity in order to perform planar tests, in which the microgravity environment can be simulated without time constraints. Air-bearings are used to sustain the links weight, and a dynamometer is used to measure the reaction torque. The experimental validation of the presented inverse kinematics solutions, with an insight on the effect of joint flexibility on their performance, has been carried out, and the experimental results confirmed the good performance of the proposed methods. The solution is then validated in the case of a planar three degrees of freedom free-floating manipulator by using a software simulator, and the requirements on the maximum joint variables of a free-floating and of a fixed-based robot with the same configuration are compared for a given task. Finally, the study of the workspace in which a zero reaction torque can be obtained is performed for different base/arm mass ratios, both taking into account the physical joint limits or not. Cocuzza; Pretto; Debei

Journal: 2010

Published: Cocuzza S.; Pretto I.; Debei S.

DOI: 361984804

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Authors: Celesti-Grapow, L; Alessandrini, A; Arrigoni, PV; Assini, S; Banfi, E; Barni, E; Bovio, M; Brundu, G; Cagiotti, MR; Camarda, I; Carli, E; Conti, F; Del Guacchio, E; Domina, G; Fascetti, S; Galasso, G; Gubellini, L; Lucchese, F; Medagli, P; Passalacqua, NG; Peccenini, S; Poldini, L; Pretto, F; Prosser, F; Vidali, M; Viegi, L; Villani, MC; Wilhalm, T; Blasi, C; Dept Plant Biol; Dept Plant Biol; Dept Landscape Ecol; Dept Bot Ecol & Geol; Dept Appl Biol; Dept Environm Sci; Dept Bot; Dept Biol; Bot Garden; Dept Landscape Study; Dept Life Sci; In this paper, we provide an overview of the distribution and invasive status of non-native species in the Italian flora across its administrative regions, biogeographic regions and main land use types, and a synthesis of current knowledge on the threats they pose within the country. The information on non-native plant species collected during the project "A survey of the non-native Italian flora" was used to compile comprehensive regional and national databases. The number of nonnative species within a given administrative region increases in proportion to its size, resident population density and latitude, reaching the highest values in the intensively cultivated, heavily industrialized and urbanized Po Plain in northern Italy. The number of casual species is positively correlated with the number of yearly visitors in each region and negatively correlated with the proportion of mountainous terrain within the region. If compared with the Continental and Mediterranean biogeographic regions, the Alpine region yields the lowest number of non-native species and lowest proportion of casual species. The number and density of introduced species is highest in artificial land use types, particularly in urban areas. A negative impact is reported to be exerted by 203 species, most of which are agricultural weeds. © 2010 Societ̀ Botanica Italiana. Celesti-Grapow; Alessandrini; Arrigoni; Assini; Banfi; Barni; Bovio; Brundu; Cagiotti; Camarda; Carli; Conti; del Guacchio; Domina; Fascetti; Galasso; Gubellini; Lucchese; Medagli; Passalacqua; Peccenini; Poldini; Pretto; Prosser; Vidali; Viegi; Villani; Wilhalm; Blasi

Journal: English

Published: doi

DOI: WOS:000277672800002

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Volume: PLANT BIOSYSTEMS###1126-3504 Pages: 28-Non-native flora of Italy: Species distribution and threats

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Authors: Non assegn

Journal: Mimesis

Published: title_year