Palabras que calan: la escritura de Julio Torri

Entre la diversidad de opiniones sobre la obra de Julio Torri destacan como características principales y muy relacionadas entre sí la brevedad, la mezcla de géneros, el humor, la ironía, lo fantástico, la calidad literaria y el esteticismo de su prosa, el estilo pulcro y perfecto de su escritura, su preferencia por la prosa (así se llame poética), su exigencia y rigor ante lo que escribe, la innegable relación de sus textos con otros de diferentes culturas y autores; pero, a nuestro juicio, lo sobresaliente es la apreciación que se tiene sobre la originalidad y actualidad de la obra de Julio Torri

ONLINE PARAMETRIC IDENTIFICATION OF MASS-SPRING-DAMPER MECHANICAL SYSTEMS USING ACCELERATION MEASUREMENTS

AbstractImplementation of active vibration control schemes, failure detection and monitoring tasks of the suitable operation of flexible mechanical structures can require the use of on-line parametric identification techniques. Measurements of acceleration signals are preferred in several applications of parameter identification of vibrating mechanical systems. In this article, an on-line parameter estimation approach in time domain is proposed for linear mass-spring-damper mechanical systems of n degrees of freedom using acceleration measurements solely. Integration by parts is properly used in the synthesis of the proposed parameter identification method. In this fashion, a priori knowledge of the initial conditions of the system becomes unnecessary. The introduced identification method can be extended for real-time parametric estimation of nonlinear fully actuated or under-actuated nonlinear vibrating mechanical systems. Some numerical results are provided to show the effectiveness of the on-line estimation approach of the mass, stiffness and damping parameters combined with closed-loop reference trajectory tracking tasks specified for the vibrating mechanical system.Keywords: Active vibration control, mass-spring-damper systems, mechanical vibration systems, parameter identification.IDENTIFICACIÓN PARAMÉTRICA EN LÍNEA DE SISTEMAS MECÁNICOS DE MASA-RESORTE-AMORTIGUADOR UTILIZANDO MEDICIONES DE ACELERACIÓNResumenImplementación de esquemas de control activo de vibraciones, detección de fallas o tareas de monitoreo de la operación adecuada de estructuras mecánicas flexibles pueden requerir el uso de técnicas de identificación paramétrica ejecutadas en línea. Mediciones de señales de aceleración se usan en varias aplicaciones de identificación de parámetros en sistemas mecánicos vibratorios. En este artículo se propone un enfoque para estimación de parámetros en línea en el dominio del tiempo para sistemas mecánicos del tipo masa-resorte-amortiguador de n grados de libertad, usando únicamente mediciones de aceleración. Se usa integración por partes en la síntesis del método de identificación de parámetros propuesto. De esta manera, conocimiento previo de las condiciones iniciales del sistema son innecesarias. El método de estimación propuesto se puede extender para estimación paramétrica en tiempo real para sistemas mecánicos vibratorios no lineales, completamente actuados o sub-actuados. Se incluyen algunos resultados de simulación numérica para mostrar la efectividad del enfoque de estimación de parámetros de masa, rigidez y amortiguamiento, combinado con tareas de seguimiento de trayectorias de referencia en lazo-cerrado especificadas para el sistema mecánico vibratorio.Palabras Claves: control activo de vibraciones, identificación de parámetros, sistemas mecánicos vibratorios, sistemas masa-resorte-amortiguador

On Active Vibration Absorption in Motion Control of a Quadrotor UAV

Conventional dynamic vibration absorbers are physical control devices designed to be coupled to flexible mechanical structures to be protected against undesirable forced vibrations. In this article, an approach to extend the capabilities of forced vibration suppression of the dynamic vibration absorbers into desired motion trajectory tracking control algorithms for a four-rotor unmanned aerial vehicle (UAV) is introduced. Nevertheless, additional physical control devices for mechanical vibration absorption are unnecessary in the proposed motion profile reference tracking control design perspective. A new dynamic control design approach for efficient tracking of desired motion profiles as well as for simultaneous active harmonic vibration absorption for a quadrotor helicopter is then proposed. In contrast to other control design methods, the presented motion tracking control scheme is based on the synthesis of multiple virtual (nonphysical) dynamic vibration absorbers. The mathematical structure of these physical mechanical devices, known as dynamic vibration absorbers, is properly exploited and extended for control synthesis for underactuated multiple-input multiple-output four-rotor nonlinear aerial dynamic systems. In this fashion, additional capabilities of active suppression of vibrating forces and torques can be achieved in specified motion directions on four-rotor helicopters. Moreover, since the dynamic vibration absorbers are designed to be virtual, these can be directly tuned for diverse operating conditions. In the present study, it is thus demonstrated that the mathematical structure of physical mechanical vibration absorbers can be extended for the design of active vibration control schemes for desired motion trajectory tracking tasks on four-rotor aerial vehicles subjected to adverse harmonic disturbances. The effectiveness of the presented novel design perspective of virtual dynamic vibration absorption schemes is proved by analytical and numerical results. Several operating case studies to stress the advantages to extend the undesirable vibration attenuation capabilities of the dynamic vibration absorbers into trajectory tracking control algorithms for nonlinear four-rotor helicopter systems are presented

Vibration Analysis and Control in Mechanical Structures and Wind Energy Conversion Systems

This book focuses on recent and innovative methods on vibration analysis, system identification, and diverse control design methods for both wind energy conversion systems and vibrating systems. Advances on both theoretical and experimental studies about analysis and control of oscillating systems in several engineering disciplines are discussed. Various control devices are synthesized and implemented for vibration attenuation tasks. The book is addressed to researchers and practitioners on the subject, as well as undergraduate and postgraduate students and other experts and newcomers seeking more information about the state of the art, new challenges, innovative solutions, and new trends and developments in these areas. The six chapters of the book cover a wide range of interesting issues related to modeling, vibration control, parameter identification, active vehicle suspensions, tuned vibration absorbers, electronically controlled wind energy conversion systems, and other relevant case studies

Adaptive Neural Trajectory Tracking Control for Synchronous Generators in Interconnected Power Systems

The synchronous generator is one of the most important active components in current electric power systems. New control methods should be designed to guarantee an efficient dynamic performance of the synchronous generator in strongly interconnected nonlinear power systems over a wide range of variable operating conditions. In this context, active suppression capability for different uncertainties and external disturbances represents a current trend in the development of new control design methodologies. In this paper, a new adaptive neural control scheme based on differential flatness with a modified structure including B-spline Neural Networks for transient stabilization and tracking of power-angle reference profiles for synchronous generators in interconnected electric power systems is introduced. These features are attained due to the advantages extracted of these two approaches: (a) a control design stage based on a power system model by differential flatness and (b) an adaptive performance using a correct design of B-spline Neural Networks, minimizing parameter dependency. The effectiveness of the proposed algorithm is demonstrated by simulation results in two test systems: single machine infinite bus and an interconnected power system. Transient stability and robust power-angle reference profile tracking are both verified