The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Vadim I. Utkin - One of the best experts on this subject based on the ideXlab platform.
-
tracking the gradient of artificial Potential Fields sliding mode control for mobile robots
International Journal of Control, 1996Co-Authors: J. Guldner, Vadim I. UtkinAbstract:Artificial Potential Fields and artificial force Fields are widely used in robotics for path planning and collision avoidance, both for robot manipulators and for mobile robots. Despite intensive research in designing suitable artificial Potential Fields, little attention has been devoted to tracking control for following the gradient of an artificial Potential field. However, good tracking control is vital for successful application of the artificial Potential field method in order to guarantee safe operation of the robot. In this paper, we extend previous results on a sliding mode control strategy to include actuator dynamics and non-holonomic motion constraints of mobile robots into the gradient tracking control algorithm.
-
sliding mode control for gradient tracking and robot navigation using artificial Potential Fields
International Conference on Robotics and Automation, 1995Co-Authors: J. Guldner, Vadim I. UtkinAbstract:This paper introduces a sliding mode control strategy for tracking the gradient of an artificial Potential field. The control methodology is applicable to fully actuated holonomic robotic systems with n-degrees of freedom. The controller yields exact tracking of the gradient lines and is invariant with respect to parametric uncertainty and disturbances in system dynamics. A detailed case study for mobile robots introduces the equilibrium point placement method for designing harmonic planar Potential Fields for circular obstacle security zones. Diffeomorph mappings can be utilized for more complex obstacle security zones. The gradient of the harmonic Potential field is shown to always lead away from the obstacle security zone and to continuously approach the goal point. >
-
Tracking gradients of artificial Potential Fields with non-holonomic mobile robots
Proceedings of 1995 American Control Conference - ACC'95, 1Co-Authors: J. Guldner, Vadim I. Utkin, Hideki Hashimoto, Fumio HarashimaAbstract:Artificial Potential Fields have enjoyed growing popularity for path planning and collision avoidance both of robot manipulators and mobile robots. Although many artificial Potential Fields have been proposed. Few works discuss suitable control for tracking the gradient of an artificial Potential field. This deficit is surprising since good tracking control is vital for successful implementation of the artificial Potential field method. This paper extends previous results of a sliding mode control strategy for fully actuated holonomic robots to gradient tracking of non-holonomic mobile robots.
Lorenzo Cascone - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale analysis of Potential Fields by a ridge consistency criterion: the reconstruction of the Bishop basement
Geophysical Journal International, 2011Co-Authors: Maurizio Fedi, Giovanni Florio, Lorenzo CasconeAbstract:SUMMARY We use a multiscale approach as a semi-automated interpreting tool of Potential Fields. The depth to the source and the structural index are estimated in two steps: first the depth to the source, as the intersection of the field ridges (lines built joining the extrema of the field at various altitudes) and secondly, the structural index by the scale function. We introduce a new criterion, called ‘ridge consistency’ in this strategy. The criterion is based on the principle that the structural index estimations on all the ridges converging towards the same source should be consistent. If these estimates are significantly different, field differentiation is used to lessen the interference effects from nearby sources or regional Fields, to obtain a consistent set of estimates. In our multiscale framework, vertical differentiation is naturally joint to the low-pass filtering properties of the upward continuation, so is a stable process. Before applying our criterion, we studied carefully the errors on upward continuation caused by the finite size of the survey area. To this end, we analysed the complex magnetic synthetic case, known as Bishop model, and evaluated the best extrapolation algorithm and the optimal width of the area extension, needed to obtain accurate upward continuation. Afterwards, we applied the method to the depth estimation of the whole Bishop basement bathymetry. The result is a good reconstruction of the complex basement and of the shape properties of the source at the estimated points.
-
improved scalfun analysis of Potential Fields by a criterion of ridge consistency
69th EAGE Conference and Exhibition incorporating SPE EUROPEC 2007, 2007Co-Authors: Maurizio Fedi, G Florio, Lorenzo CasconeAbstract:E022 Improved SCALFUN Analysis of Potential Fields by a Criterion of Ridge–Consistency M. Fedi* (University of Napoli Federico II) G. Florio (University of Napoli Federico II) & L. Cascone (University of Napoli Federico II) SUMMARY Ridge analysis is well known in the frame of the Continuous Wavelet Transform methods and was recently proposed as a main step of the Potential field interpretation method SCALFUN. The information related to more ridges converging to the same one-point source should be consistent otherwise a poor quality of the estimates of the source properties has to be expected. This can be due to an
Maurizio Fedi - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale analysis of Potential Fields by a ridge consistency criterion: the reconstruction of the Bishop basement
Geophysical Journal International, 2011Co-Authors: Maurizio Fedi, Giovanni Florio, Lorenzo CasconeAbstract:SUMMARY We use a multiscale approach as a semi-automated interpreting tool of Potential Fields. The depth to the source and the structural index are estimated in two steps: first the depth to the source, as the intersection of the field ridges (lines built joining the extrema of the field at various altitudes) and secondly, the structural index by the scale function. We introduce a new criterion, called ‘ridge consistency’ in this strategy. The criterion is based on the principle that the structural index estimations on all the ridges converging towards the same source should be consistent. If these estimates are significantly different, field differentiation is used to lessen the interference effects from nearby sources or regional Fields, to obtain a consistent set of estimates. In our multiscale framework, vertical differentiation is naturally joint to the low-pass filtering properties of the upward continuation, so is a stable process. Before applying our criterion, we studied carefully the errors on upward continuation caused by the finite size of the survey area. To this end, we analysed the complex magnetic synthetic case, known as Bishop model, and evaluated the best extrapolation algorithm and the optimal width of the area extension, needed to obtain accurate upward continuation. Afterwards, we applied the method to the depth estimation of the whole Bishop basement bathymetry. The result is a good reconstruction of the complex basement and of the shape properties of the source at the estimated points.
-
toward a full multiscale approach to interpret Potential Fields
Geophysical Prospecting, 2009Co-Authors: Federico Cella, Maurizio Fedi, Giovanni FlorioAbstract:The way Potential Fields convey source information depends on the scale at which the field is analysed. In this sense a multiscale analysis is a useful method to study Potential Fields particularly when the main field contributions are caused by sources with different depths and extents. Our multiscale approach is built with a stable transformation, such as depth from extreme points. Its stability results from mixing, in a single operator, the wavenumber low-pass behaviour of the upward continuation transformation of the field with the enhancement high-pass properties of n-order derivative transformations. So, the complex reciprocal interference of several field components may be efficiently faced at several scales of the analysis and the depth to the sources may be estimated together with the homogeneity degrees of the field. In order to estimate the source boundaries we use another multiscale method, the multiscale derivative analysis, which utilizes a generalized concept of horizontal derivative and produces a set of boundary maps at different scales. We show through synthetic examples and application to the gravity field of Southern Italy that this multiscale behaviour makes this technique quite different from other source boundary estimators. The main result obtained by integrating multiscale derivative analysis with depth from extreme points is the retrieval of rather effective information of the field sources (horizontal boundaries, depth, structural index). This interpretative approach has been used along a specific transect for the analysis of the Bouguer anomaly field of Southern Apennines. It was set at such scales, so to emphasize either regional or local features along the transect. Two different classes of sources were individuated. The first one includes a broad, deep source with lateral size of 45~50 km, at a depth of 13 km and having a 0.5 structural index. The second class includes several narrower sources located at shallowest depths, ranging from 3-6 km, with lateral size not larger than 5 km and structural indexes ranging from 1-1.5. Within a large-scale geological framework, these results could help to outline the mean structural features at crustal depths.
-
multiridge analysis of Potential Fields geometric method and reduced euler deconvolution
Geophysics, 2009Co-Authors: Maurizio Fedi, Giovanni Florio, Tatiana QuartaAbstract:A new method based on 3D multiridge analysis of Potential Fields assumes a 3D subset in the harmonic region and studies the behavior of Potential field ridges, which are built by joining extreme points of the analyzed field computed at different altitudes. Three types of ridges are formed by searching for the zeros of the first horizontal and first vertical derivatives of the Potential field (types I and II, respectively) and the zeros of the Potential field itself (type III). This method uses a redundant set of ridges, called a multiridge set, to determine source type and location. For homogeneous Potential Fields generated by simple sources, all of the ridges are straight lines converging to the source position. This method analyzes the multiridges by using a geometric criterion to find the source position at the intersection of the multiridge set and by solving the three reduced Euler equations associated with ridge types I, II, and III. The reduced Euler type I and II equations are used to obtain the structural index and the vertical and horizontal source positions; equation type III estimates the horizontal and vertical source positions. Tests on synthetic as well as the Bishop model field yield good results even with noise-corrupted data. Results obtained using magnetic data collected over the wreck of a military ship in the Tyrrhenian Sea successfully determine its vertical and horizontal positions and the structural index.
-
improved scalfun analysis of Potential Fields by a criterion of ridge consistency
69th EAGE Conference and Exhibition incorporating SPE EUROPEC 2007, 2007Co-Authors: Maurizio Fedi, G Florio, Lorenzo CasconeAbstract:E022 Improved SCALFUN Analysis of Potential Fields by a Criterion of Ridge–Consistency M. Fedi* (University of Napoli Federico II) G. Florio (University of Napoli Federico II) & L. Cascone (University of Napoli Federico II) SUMMARY Ridge analysis is well known in the frame of the Continuous Wavelet Transform methods and was recently proposed as a main step of the Potential field interpretation method SCALFUN. The information related to more ridges converging to the same one-point source should be consistent otherwise a poor quality of the estimates of the source properties has to be expected. This can be due to an
-
dexp a fast method to determine the depth and the structural index of Potential Fields sources
Geophysics, 2007Co-Authors: Maurizio FediAbstract:We show that Potential Fields enjoy valuable properties when they are scaled by specific power laws of the altitude. We describe the theory for the gravity field, the magnetic field, and their derivatives of any order and propose a method, called here Depth from Extreme Points (DEXP), to interpret any Potential field. The DEXP method allows estimates of source depths, density, and structural index from the extreme points of a 3D field scaled according to specific power laws of the altitude. Depths to sources are obtained from the position of the extreme points of the scaled field, and the excess mass (or dipole moment) is obtained from the scaled field values. Although the scaling laws are theoretically derived for sources such as poles, dipoles, lines of poles, and lines of dipoles, we give also criteria to estimate the correct scaling law directly from the data. The scaling exponent of such laws is shown to be related to the structural index involved in Euler Deconvolution theory. The method is fast and...
Ginette Saracco - One of the best experts on this subject based on the ideXlab platform.
-
Identification of sources of Potential Fields with the continuous wavelet transform: Basic theory
Journal of Geophysical Research : Solid Earth, 1999Co-Authors: Frédérique Moreau, Dominique Gibert, Matthias Holschneider, Ginette SaraccoAbstract:The continuous wavelet transform is used to analyze Potential Fields and to locate their causative sources. A particular class of wavelets is introduced which remains invariant under the action of the upward continuation operator in Potential field theory. These wavelets make the corresponding wavelet transforms easy to analyze and the sources' parameters (horizontal location, depth, multipolar nature, and strength) simple to estimate. Practical issues (effects of noise, choice of the analyzing wavelet, etc.) are addressed. A field data example corresponding to a near-surface magnetic survey is discussed. Applications to the high-resolution aeromagnetic survey of French Guyana will be discussed in the next paper of the series.
-
Wavelet analysis of Potential Fields
Inverse Problems, 1997Co-Authors: Frédérique Moreau, Dominique Gibert, Matthias Holschneider, Ginette SaraccoAbstract:It is shown how a continuous wavelet technique may be used to locate and characterize homogeneous point sources from the field they generate measured in a distant hyperplane. For this a class of wavelets is introduced on which the Poisson semi-group essentially acts as a dilation.
J. Guldner - One of the best experts on this subject based on the ideXlab platform.
-
tracking the gradient of artificial Potential Fields sliding mode control for mobile robots
International Journal of Control, 1996Co-Authors: J. Guldner, Vadim I. UtkinAbstract:Artificial Potential Fields and artificial force Fields are widely used in robotics for path planning and collision avoidance, both for robot manipulators and for mobile robots. Despite intensive research in designing suitable artificial Potential Fields, little attention has been devoted to tracking control for following the gradient of an artificial Potential field. However, good tracking control is vital for successful application of the artificial Potential field method in order to guarantee safe operation of the robot. In this paper, we extend previous results on a sliding mode control strategy to include actuator dynamics and non-holonomic motion constraints of mobile robots into the gradient tracking control algorithm.
-
sliding mode control for gradient tracking and robot navigation using artificial Potential Fields
International Conference on Robotics and Automation, 1995Co-Authors: J. Guldner, Vadim I. UtkinAbstract:This paper introduces a sliding mode control strategy for tracking the gradient of an artificial Potential field. The control methodology is applicable to fully actuated holonomic robotic systems with n-degrees of freedom. The controller yields exact tracking of the gradient lines and is invariant with respect to parametric uncertainty and disturbances in system dynamics. A detailed case study for mobile robots introduces the equilibrium point placement method for designing harmonic planar Potential Fields for circular obstacle security zones. Diffeomorph mappings can be utilized for more complex obstacle security zones. The gradient of the harmonic Potential field is shown to always lead away from the obstacle security zone and to continuously approach the goal point. >
-
Tracking gradients of artificial Potential Fields with non-holonomic mobile robots
Proceedings of 1995 American Control Conference - ACC'95, 1Co-Authors: J. Guldner, Vadim I. Utkin, Hideki Hashimoto, Fumio HarashimaAbstract:Artificial Potential Fields have enjoyed growing popularity for path planning and collision avoidance both of robot manipulators and mobile robots. Although many artificial Potential Fields have been proposed. Few works discuss suitable control for tracking the gradient of an artificial Potential field. This deficit is surprising since good tracking control is vital for successful implementation of the artificial Potential field method. This paper extends previous results of a sliding mode control strategy for fully actuated holonomic robots to gradient tracking of non-holonomic mobile robots.
