Bifurcations and aggregation in large scale systems

This paper deals with the following problem: assume that a qualitative analysis (behaviour modes, bifurcation points, type of atractors .•• ) of a nonlinear dynamical system has been carried out and that afterwards this dynamical system is transformed into a large scale system through a disaggregating process of some (or all) of its variables. The problem at stake is to analyze whether the disagaregation gives rise to new behaviour modes, as a consequence of the appearance of new bifurcations in the disaggregated dynamical system. That leads us to study whether the original system and the disaggregated one are "equivalents" or whether the second one is richer in behaviours than the first one.The paper develops general results for standard disaggregation forms. Furthermore, practical applications of the proposed methodology to urban dynamics models is included .Comisión Asesora de Investigación Científica y Técnica (CAICYT) 1102/8

A new controller for the inverted pendulum on a cart

This paper presents a complete solution to the problem of swinging-up and stabilization of the inverted pendulum on a cart, with a single control law. The resulting law has two parts: first, an energy-shaping law is able to swing and maintain the pendulum up. Then, the second part introduces additional control to stop the cart and it is based on forwarding control with bounded input. The resulting control law is the sum of both parts and does not commute between different laws although there exist switches inside the controller.MEC-FEDER DPI2006-0733

Stabilization of oscillations through backstepping in high-dimensional systems

This paper introduces a method for obtaining stable and robust self-sustained oscillations in a class of single input nonlinear systems of dimension n ≥ 2. The oscillations are associated to a limit cycle that is produced in a second-order subsystem by means of an appropriate feedback law. Then, the controller is extended to the full system by a backstepping procedure. It is shown that the closed-loop system turns out to be generalized Hamiltonian and that the limit cycle can be thought as born in a Hopf bifurcation after moving a parameter.Ministerio de Ciencia e Innovación (España

A family of smooth controllers for swinging up a pendulum

Es el primer envío que hago. Le agradeceré si me confirma que es todo correcto, especialmente el cumplimiento de los derechos de propiedad de la editorial. Mi email es [email protected] paper presents a new family of controllers for swinging up a pendulum. The swinging up of the pendulum is derived from physical arguments based on two ideas: shaping the Hamiltonian for a system without damping; and providing damping or energy pumping in relevant regions of the state space. A family of simple smooth controllers without switches with nice properties is obtained. The main result is that all solutions that do not start at a zero Lebesgue measure set converge to the upright position for a wide range of the parameters in the control law. Thus, the swing-up and the stabilization problems are simultaneously solved with a single, smooth law. The properties of the solution can be modified by the parameters in the control law. Control signal saturation can also be taken into account using the Hamiltonian approach.MCyT-FEDER DPI2006-0733

Acto Solemne de Investidura como Doctor Honoris Causa del Profesor Dr. D. Enrique Alarcón Álvarez [Universidad de Sevilla]

En primer lugar se presenta una laudatio a Enrique Alarcón Álvarez, realizada por D. Javier Aracil Santonja, y posteriormente se recoge la lección magistral del Prof. Dr. D. Enrique Alarcón en la que, además de referirse a su trayectoria y vivencias en Escuela de Ingenieros Industriales de Sevilla, trata del tema de la ingeniería sísmica

Asymptotic rejection of sinusoidal disturbances based voltage balance control in back-to-back power converters

This paper addresses the imbalance problem of the dc-link capacitor voltages in the three-level diode-clamped back-to-back power converter. In order to cope with it, a mathematical analysis of the capacitor voltage difference dynamics, based on a continuous model of the converter, is first carried out. It leads to an approximated model which contains explicitly several sinusoidal functions of time. In view of this result, the voltage imbalance phenomenon can be addressed as an output regulation problem, considering the sinusoidal functions as exogenous disturbances. Thus, a novel approach to deal with the mentioned problem in the back- to-back converter is presented. Then, the particular features of the disturbances are used to design several controllers. They all follow an asymptotic disturbance rejection approach. In this way, the estimations of the disturbances are used to apply a control law that cancels them while regulating the capacitor voltage balance as well. Finally, the performance of the proposed control laws is evaluated, presenting the simulation results obtained when the different controllers are implemented.MICINN-FEDER DPI2009-0966

Studies for the application of an adaptative controller to hydroturbine generators

This paper describes some studies made towards the automatization of hydroturbine generators with microcomputers. The overall design will include an automata controlling the starting-up and shutting-down procedure as well as an self-tuning regulator for the speed control. A self-tuning regulator based on the classical pole-assignment-method is studied. The algorithm uses a fast procedure for solving the polynomial equation implicit to selfturner regulator. This procedure is very simple from a computational point of view as only applications of elementary transformations on a 2 x 2 polynomial matrix are needed.The algorithm has been programmed on a Digital PDP 1103 computer and applied to some test problems

PPCar (Personal Pendulum Car): Vehículo basado en péndulo invertido

XXV Jornadas de Automática. Año 2004Este artículo presenta la descripción de un prototipo construido en la Escuela Superior de Ingenieros de Sevilla para el transporte de personas. Este vehículo basa su movimiento en la estabilización de un péndulo invertido. El sistema ha sido diseñado en su totalidad desde la estructura mecánica al diseño de los controladores, utilizando componentes comerciales y de bajo coste. El control del vehículo se realiza desde un microcontrolador a bordo, supervisado desde un PC y estando ambos comunicados a través de un enlace inalámbrico. El prototipo desarrollado tiene como finalidad servir de plataforma de investigación para técnicas de control.Ministerio de Ciencia y Tecnología DPI2004-06419Ministerio de Ciencia y Tecnología DPI2003-00429Ministerio de Ciencia y Tecnología HF2003-0237Ministerio de Ciencia y Tecnología SAB2003-008