Robust control of underactuated wheeled mobile manipulators using GPI disturbance observers

This article describes the design of a linear observer–linear controller-based robust output feedback scheme for output reference trajectory tracking tasks in the case of nonlinear, multivariable, nonholonomic underactuated mobile manipulators. The proposed linear feedback scheme is based on the use of a classical linear feedback controller and suitably extended, high-gain, linear Generalized Proportional Integral (GPI) observers, thus aiding the linear feedback controllers to provide an accurate simultaneous estimation of each flat output associated phase variables and of the exogenous and perturbation inputs. This information is used in the proposed feedback controller in (a) approximate, yet close, cancelations, as lumped unstructured time-varying terms, of the influence of the highly coupled nonlinearities, and (b) the devising of proper linear output feedback control laws based on the approximate estimates of the string of phase variables associated with the flat outputs simultaneously provided by the disturbance observers. Simulations reveal the effectiveness of the proposed approach

Iterative approximation of unstable limit cycles for a class of Abel equations

This report considers the analytical approximation of unstable limit cycles that may appear in Abel equations written in the normal form. The procedure uses an iterative approach that takes advantage of the contraction mapping theorem. Thus, the obtained sequence exhibits uniform convergence to the target periodic solution. The effectiveness of the technique is illustrated through the approximation of an unstable limit cycle that appears in an Abel equation arising in a tracking control problem that affects an elementary, nonminimum phase, second order bilinear power converter

Control of DC/DC Buck–Parallel Converter Implemented in FPGA

[ES] El presente artículo documenta el diseño e implementación de un controlador robusto para el convertidor CD/CD Reductor–Paralelo, bajo la perspectiva de la planitud diferencial y la técnica del control por rechazo activo de perturbaciones basado en un observador GPI. Los objetivos principales del controlador propuesto son: regular la tensión de salida y equilibrar las corrientes de los convertidores en paralelo. Para el modelado de la arquitectura hardware de este controlador se utiliza una herramienta con alto nivel de abstracción de hardware y se implementa en un FPGA Artix–7 de la compañía Xilinx. Finalmente, se muestran resultados experimentales del desempeño del controlador, cuando se somete al convertidor a diversas perturbaciones externas, desconocidas y variantes con el tiempo, y a cambios en los parámetros del mismo.[EN] This paper documents the design and implementation of a controller for DC/DC Buck–Parallel Converter under the perspective of differential flatness and active disturbance rejection control approach based on GPI extended state observer. The main objectives of the proposed controller are to regulate the output voltage and a balance of currents for parallel converters. The hardware architecture of this controller was modelled using tools with a high level of hardware abstraction and implemented in a FPGA Artix-7 of the Xilinx Company. Finally, the performance of the proposed controller is shown through a series of experiments that consisted of subjecting the converter to various external, unknown and variant over time disturbances, and changes in system parameters.Guerrero Ramírez, EO.; Martínez Barbosa, A.; Guzmán Ramírez, E.; Linares Flores, J.; Sira Ramírez, H. (2018). Control del Convertidor CD/CD Reductor–Paralelo Implementado en FPGA. Revista Iberoamericana de Automática e Informática industrial. 15(3):309-316. https://doi.org/10.4995/riai.2018.8925OJS309316153Alvarez, J., Lago, A., Nogueiras, A., Martínez, P., Marcos, J., Doval, J. y López, O. 2006, FPGA implementation of a fuzzy controller for automobile DC-DC converters. IEEE International Conference, 237-240.Cid-Pastor, A., Martìnez-Salamero, L., Alonso, C., Leyva, R., Singer S., 2007, Paralleling DC-DC switching converters by means of power gyrators, IEEE transactions on power electronics, no. 6, vol. 22, 2444-2453.Jaber, A., Qahouq, A., y Huang, L., 2008, N-phase sensorless current sharing digital controller, Power Electronics Specialist Conference, 1257-1262.Kailath, T., 1980, Linear Systems, Prentice-Hall Information.Lévine, J., Analysis and Control of Nonlinear Systems: A Flatness-based Approach, Springer Science & Business Media.Li, S., Yang, J., Chen, W.-H., Chen, X., 2014, Disturbance Observer-Based Control: Methods and Applications, CRC Press Taylor Francis.Linares-Flores, J., Barahona-Avalos, J.L., Sira-Ramírez, H. y Contreras-Ordaz, M.A., 2012, Robust Passivity-Based Control of a Buck-Boost-Converter/DC-Motor System: An Active Disturbance Rejection Approach, IEEE Transactions on Industry Applications, no. 6, vol. 48, 2362-2371.Qiao, L. y Jie, W., 2005, Implementation of a New Nonlinear Controller for DC-DC Converter Using Matlab and DSPACE DSP, IEEE ISIE, Dubrovnik, Croacia, 621-626.Sarvi, M., Derakhshan, M., Sedighizadeh, M., 2014, A new intelligent controller for parallel DC/DC converters, International Journal of Engineering, no. 1, vol. 27, 131-142.Shrud, M. A., Kharaz, A. H., Ashur, A. S. y Benamar, M., 2010, Analysis and simulation of automotive interleaved buck converter, World Academy of Science, Engineering and Technology, no. 3, vol. 4, 10-17.Shui-Chun, L. y Chin-Chin, T., 2004, Adaptive voltage regulation and equal current distribution of parallel-buck DC-DC converters using backstepping sliding mode control, 30th IEEE IECON, 1018-1023.Sira-Ramírez, H. y Agrawal, S. K., 2004, Diferentially Flat Systems, Marcel Dekker Inc.Sira-Ramírez, H., Linares-Flores, J., Luviano-Juárez, A. y Cortés-Romero, J., 2015, Ultramodelos Globales y el Control por Rechazo Activo de Perturbaciones en Sistemas No Lineales Diferencialmente Planos, RIAI, no. 2, vol. 12, 133-144.Sira-Ramírez, H., Luviano-Juárez, A. y Cortés-Romero, J., 2011, Control lineal robusto de sistemas no lineales diferencialmente planos, RIAI, no. 1, vol. 8, 14-28.Sira-Ramírez, H., Luviano-Juárez, A., Ramírez-Neria, M. y Zurita-Bustamante E. W., 2017, Active DisturbanceRejection Control of Dinamic Systems: A Flatness-Based Approach, Butterworth-Heinemann publications.Sira-Ramírez, H. y Rosales-Díaz, D., 2014, Decentralized Active Disturbance Rejection Control of Power Converters Serving a Time Varying Load, Proceedings of the 33rd Chinese Control Conference, Nanling, China, 4348-4353.Slotine, J.J.E., Li, W., 1991, Applied Nonlinear Control, Prentice-Hall.Ramos, R., Biel, D. y Fossas, E., 2011, Control en modo deslizante para un convertidor reductor multifase en entrelazado con ecualización de corriente, XVIII Seminario Anual de Automática, Electrónica Industrial e Instrumentación, 161-166

Algebraic estimation in partial derivatives systems: parameters and differentiation problems

International audienceTwo goals are sought in this paper: namely, to provide a succinct overview on algebraic techniques for numerical differentiation and parameter estimation for linear systems and to present novel algebraic methods in the case of several variables. The state-of-art in the introduction is followed by a brief description of the methodology in the subsequent sections. Our new algebraic methods are illustrated by two examples in the multidimensional case. Some algebraic preliminaries are given in the appendix

Sliding mode control: the delta-sigma modulation approach

This monograph presents a novel method of sliding mode control for switch-regulated nonlinear systems. The Delta Sigma modulation approach allows one to implement a continuous control scheme using one or multiple, independent switches, thus effectively merging the available linear and nonlinear controller design techniques with sliding mode control.   Sliding Mode Control: The Delta-Sigma Modulation Approach, combines rigorous mathematical derivation of the unique features of Sliding Mode Control and Delta-Sigma modulation with numerous illustrative examples from diverse areas of engineering. In addition, engineering case studies demonstrate the applicability of the technique and the ease with which one can implement the exposed results. This book will appeal to researchers in control engineering and can be used as graduate-level textbook for a first course on sliding mode control

Periodic sliding motions 1.

Periodic sliding motions 1.Sira Ramírez, Hebertt José.16 pá[email protected], [email protected] analíticosemestra

An algebraic framework for linear identification

A closed loop parametrical identification procedure for continuous-time constant linear systems is introduced. This approach which exhibits good robustness properties with respect to a large variety of additive perturbations is based on the following mathematical tools: (1) module theory; (2) differential algebra; (3) operational calculus. Several concrete case-studies with computer simulations demonstrate the efficiency of our on-line identification scheme