1,720,969 research outputs found
On-line Identification and Convergence Analysis of Excitation -Force and Drag-Force Models for Moored Floating Structures
Get PDFThis work presents an approach to identify hydrodynamic models for incident, diffraction and viscous forces acting on a moored floating structure. An important aspect treated here is the analysis of the unknown initial condition of the hydrodynamic state for the potential-radiation force. There is established its influence on the parameter convergence and the long-term effects. Afterwards the persistency of excitation of the regressor is analyzed in the case of both poor and rich excitation conditions. Theoretical results show that asymptotic convergence of the estimates takes place under arbitrary conditions of the wave excitation. A case study consisting in the identification of a moored semisubmersible is carried out to exemplify the application of the approach.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin
Test for Global Identifiability for Nonlinear Model Structures
No full textn the present work an algorithm for testing global identifiability for a wide class of nonlinear model structures with bounded signals is presented. The objective functional applied for parameter estimation is assumed to be nonconvex and analytic in a broad region of the parameter space. The supporting theory is given in lemmas which concern the existence and uniqueness of straight slots of nonconvex functionals and the convergence of polynomial mu-approaches. The method is exhaustive and hence the detection of the global minimum (if there is anyone) is practically sure. It is shown that the algorithm can be implemented with a few amount of system information.Fil: Bambill, Héctor. Universidad Nacional del Sur; ArgentinaFil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentin
Nonlinear identification of mooring lines in dynamic operation of floating structures
Get PDFAn adaptive algorithm for on-line estimation of physical coefficients of cables in viscous environment is presented. The procedure is useful for obtaining cable characteristics, which are needed in stability analysis and control system design for moored floating structures. It uses measurements of position and forces from on-board instrumentation. It is also able to track changes in the depth and to test for parameter consistency in order to confer the esti- mation robustness with respect to dynamic perturbations. It is based on nonlinear solvers, which can cope with transcendental functions o fthe model structure. The proo fo fasymp- totic convergence is presented. Finally, three basic case studies are analyzed.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; ArgentinaFil: Beltran Aguedo, Reinel. Universidad Nacional del Sur; Argentin
A Method for Continuous-Time Identification of Moored Systems
Get PDFAn adaptive algorithm for on-line estimation of physical coefficients of cables in viscous environment is presented. The procedure is useful for obtaining cable characteristics, which are needed in stability analysis and control system design for moored floating structures. It uses measurements of position and forces from on-board instrumentation. It is also able to track changes in the depth and to test for parameter consistency in order to confer the estimation robustness with respect to dynamic perturbations. It is based on nonlinear solvers, which can cope with transcendental functions of the model structure. The proof of asymptotic convergence is presented. Finally, three basic case studies are analyzed.Fil: Beltran Aguedo, R.. Universidad Nacional del Sur; ArgentinaFil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentin
A Recursive Algorithm for Set-Valued Observers with Dynamic Uncertainties
No full textIn this work we present a new algorithm for set-valued state propagation in observers with dynamic uncertainties. In comparison with recently results published in the specialized literature, the novel approach presents the same numerical features and equal bound tightness for state uncertainties, but additionally has the advantage of distributing the computational burden uniformly in time. This makes the approach attractive for on-line applications. Convergence results for the centroids of the state polytopes are given in the presence of bounded state and output perturbations.Fil: Morel, Jorge O.. Universidad Nacional de Misiones; ArgentinaFil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin
On the Global Convergence of Nonlinear Nonconvex Estimators
No full texthe main contribution in this paper is focused mainly in obtaining insight in the requirements of excitation from the geometric properties of a general nonalgebraic nonconvex cost functional for parameter identification when global and local structural identifiability are assumed previously. In this analysis we give a detailed account of the mathematical aspects without assuming a particular estimator or adaptive law. Furthermore the formulation is mainly devoted to continuous-time estimation but the extension to the discrete-time case is straightforward.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Bambill, Héctor R.. Universidad Nacional del Sur; Argentin
An Adaptive Vision-based Sensor for Underwater Line Detection Employing Shape and Color Image Segmentation
Get PDFThis work aims the design and implementation of an adaptive vision-based sensor for detecting a pipe on underwater scenes in real time. The motivation is focused to future applications of vision servo control in underwater vehicles. The approach employs color and shape image segmentation together with an adjust mechanism that aims continuously in time to reach the best setup of a parameter set of the color image segmentation. The sensor performs very well even in the case of large and rapid changes in the scene illumination. On the basis of many experiments carried out in real scenes and the comparison with similar algorithms in the state-of-the-art field on the same application, the approach gets a better positioning with respect to related results above all in the case of extremely changing and poor luminance conditions. As drawback, the required computation time to achieve optimal values for the first time (auto-tuning phase) may be large; contrary to the adaptive ongoing process, in where the optimization is much more agile.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentina. Universidad Nacional del Sur. Departamento de Ingenieria Electrica y de Computadoras; ArgentinaFil: Trabes, Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentin
Linear algebra based controller design applied to a bench-scale o enological alcoholicfermentation
Get PDFThis work presents a controller design for a non-isothermal alcoholic fermentation to produce wines in a bench-scale bioreactor. The main controller objective is that the system tracks an optimal operation trajectory to produce wines with constant quality. This trajectory is previously determined for the biomass and for the CO2 produced by the fermentation. To meet the goal, the process is approximated using numerical methods, and then, the problem is posed like solving a system of linear equations. The necessary conditions for the system of linear equations has exact solution are analyzed. Afterwards the control action is obtained by solving the system of linear equations. The methodology success is shown using experimental results.Fil: Scaglia, Gustavo Juan Eduardo. Universidad Nacional de San Juan. Facultad de Ingenieria; ArgentinaFil: Scaglia, Gustavo Juan Eduardo. Universidad Nacional de San Juan. Facultad de Ingenieria; ArgentinaFil: Aballay, Pablo M.. Universidad Nacional de San Juan; ArgentinaFil: Aballay, Pablo M.. Universidad Nacional de San Juan; ArgentinaFil: Serrano, Mario Emanuel. Universidad Nacional de San Juan; ArgentinaFil: Serrano, Mario Emanuel. Universidad Nacional de San Juan; ArgentinaFil: Ortiz, Oscar A.. Universidad Nacional de San Juan; ArgentinaFil: Ortiz, Oscar A.. Universidad Nacional de San Juan; ArgentinaFil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Vallejo, Martha D.. Universidad Nacional de San Juan; ArgentinaFil: Vallejo, Martha D.. Universidad Nacional de San Juan; Argentin
Optimal Identification of Potential-Radiation Hydrodynamics for Moored Floating Structures - A New General Approach in State Space
Get PDFIn this paper, a new state-space model of the potential-radiation hydrodynamics in moored ocean engineering floating structures and its parameter identification are presented. The raw data for this goal are the added mass and potential-damping matrices in frequency discrete domain. In a preliminary study of existing approaches in the literature, two mathematical models and their estimation are comparatively analysed in detail. These served in the development of the new approach that shares certain main advantages of the previous approaches. The model is identified in a least-squares sense using a weighted norm and a free control parameter to accomplish a trade-off between quality and stability. This reduces numerical instability problems and also keeps the analytical and computational benefits of a para- metric state-space model. The model can be conveniently expressed in any usual canonical form in state space. The application of the model acceptably accurate reproduces the behaviour of the poten- tial-radiation hydrodynamic forces in time. Case studies involving a semisubmersible and buoys are shown to demonstrate the features of the proposed approach.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; ArgentinaFil: Beltran Aguedo, Reinel. Universidad Nacional del Sur; Argentin
An approach to improve the performance of adaptive predictive control systems: theory, simulations and experiments
Get PDFIn this paper an approach to improve the overall performance of indirect adaptive control systems tailored for non-linear stable plants is presented. The approach involves a commutation of a linear time-varying robustness filter in the feedback path of the control loop in synchronization with an adaptive controller. The algorithm is framed in the celebrated IMC structure for predictive control systems. It can automatically suit to structural changes in the system as order and dead-time, and can deal with plants with zero dynamics. The convergence and stability of the system is analysed in details. It is shown through numeric simulations and experimentation on a heat exchanger with cooling system, that undesired transients due to abrupt and significative changes in the dynamics can be efficiently damped down by the developed control algorithm, achieving a high-quality performance in steady state.Fil: Jordan, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; ArgentinaFil: Basualdo, Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Zumoffen, David Alejandro Ramon. Universidad Tecnológica Nacional; Argentin
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