Application of a Fractional Order Integral Resonant Control to increase the achievable bandwidth of a nanopositioner

The congress program will essentially include papers selected on the highest standard by the IPC, according to the IFAC guidelines www.ifac-control.org/publications/Publications-requirements-1.4.pdf, and published in open access in partnership with Elsevier in the IFAC-PapersOnline series, hosted on the ScienceDirect platform www.sciencedirect.com/science/journal/24058963. Survey papers overviewing a research topic are also most welcome. Contributed papers will have usual 6 pages length limitation. 12 pages limitation will apply to survey papers.Publisher PD

Increasing the damping of oscillatory systems with an arbitrary number of time varying frequencies using fractional-order collocated feedback

Acknowledgements: This research was sponsored in part by the Spanish Government Research Program with the project DPI2016-80547-R (Ministerio de Economía y Competitividad), in part by the University of Castilla-La Mancha under Project 2019-GRIN-26969 and in part by the European Social Fund (FEDER, EU).Peer reviewedPublisher PD

Flexible link arm with a passive gravity compensation mechanism: design and modeling

[Abstract] The gravity compensation of flexible link manipulators using mechanisms based on counterweights has been previously studied in the research literature. However, as far as we are concerned, no attempt has been done to study the difficulties and benefits of constructing mechanisms for the same purposes based on springs. This paper presents a gravitational mechanism based on springs for a single-link flexible arm. In specific, we address the mechanical design of the mechanism and the dynamic modeling of the resulting system. To assess the effectiveness of the mechanism and the validity of the dynamic model, we present experimental results.[Resumen] La compensación por gravedad de los manipuladores de enlace flexible que utilizan mecanismos basados en contrapesos se ha estudiado previamente en la literatura de investigación. Sin embargo, en lo que a nosotros respecta, no se ha hecho ningún intento de estudiar las dificultades y los beneficios de construir mecanismos para los mismos propósitos basados en resortes. Este artículo presenta un mecanismo gravitatorio basado en resortes para un brazo flexible de un solo enlace. En concreto, abordamos el diseño mecánico del mecanismo y el modelado dinámico del sistema resultante. Para evaluar la efectividad del mecanismo y la validez del modelo dinámico, presentamos resultados experimentales.Ministerio de Economía y Competitividad; DPI2016-80547-

Fractional-order identification based on time domain methodology for hydraulic canal system

[Abstract] This paper discusses the identification of hydraulic canal system with a fractional-order model. The identification procedure is carried out by using a time domain technique. A pseudorandom binary signal (PRBS) is considered, the auto-correlation of the input signal, as well as, the impulsive response of the system has been concluded, and the obtained model are discussed in order to show the effect of using the PRBS signal in comparison with a fundamental step signal. Finally, we put the accent into the improvisation of the fractional-order model of the considered prototype that has a significant impact on improving the performance of canal monitoring, control, and supervisory systems.[Resumen] Este artículo discute la identificación del sistema de canal hidráulico con un modelo de orden fraccional. El procedimiento de identificación se lleva a cabo utilizando una técnica de dominio de tiempo. Se considera una señal binaria pseudoaleatoria (PRBS), se ha concluido la autocorrelación de la señal de entrada y la respuesta impulsiva del sistema, y se analiza el modelo obtenido para mostrar el efecto del uso de la señal PRBS. En comparación con una señal de paso fundamental. Finalmente, ponemos el acento en la improvisación del modelo de orden fraccional del prototipo considerado que tiene un impacto significativo en la mejora del rendimiento de los sistemas de supervisión, control y supervisión del canal

A new truck prototype for transporting flexible manipulators

[Resumen] Este trabajo se ocupa del diseño mecánico y la descripción de los diferentes componentes de una base móvil novedosa para un manipulador móvil flexible. Un manipulador móvil flexible normalmente se compone de múltiples enlaces flexibles montados en una plataforma móvil. Este trabajo se centra en la descripción de la plataforma móvil. La plataforma móvil de este trabajo tiene dos configuraciones diferentes para llevar a cabo diferentes tareas. Además, en este trabajo se muestran algunas hipótesis y resultados experimentales como un primer paso para poder obtener un modelo cinemático del sistema más adelante.[Abstract] This work is concerned with the mechanical design and the description of the different components of a novel mobile base for a flexible mobile manipulator. A flexible mobile manipulator is normally composed of multiple flexible links mounted on a mobile platform. This work is focused on the description of the mobile platform. The mobile platform of this work has two different configurations in order to carry out different tasks. Also, some hypothesis and experimental results are shown in this work as a first step to be able to obtain a kinematic model of the system later.Ministerio de Educación, Cultura y Deporte; FPU14/02256Ministerio de Economía, Industria y Competitividad; DPI2016-80547-

Fractional order implementation of Integral Resonant Control – A nanopositioning application

This paper was sponsored by the Spanish FPU12/00984 Program (Ministerio de Educacion, Cultura y Deporte). It was also sponsored by the Spanish Government Research Program with the Project DPI2012-37062-CO2-01 (Ministerio de Economia y Competitividad) and by the European Social Fund.Peer reviewedPostprin

A Fast On-Line Estimator of the Two Main Vibration Modes of Flexible Structures From Biased and Noisy Measurements

Vibrations are present in many mechanical structures and machines, and are often associated with their elastic parts. Characterizing these vibrations, i.e., obtaining their frequencies, amplitudes and phases, is of most interest in many applications ranging from the maintenance of civil structures to motion control. This article presents a method for the on-line and reliable identification of the defining parameters of two unknown sinusoidal signals through the use of their measured sum in the presence of noise and an offset. It is based on the algebraic derivative approach, defined in the frequency domain, which yields exact calculation formulae for the unknown parameters of the signal, i.e., the amplitudes, phases and frequencies of the two sinusoids and the value of the constant term. The on-line estimation is performed in a time interval which is only a fraction of the first full cycle of the slower component of the measured signal. This feature allows the algorithm to be used to monitor time varying parameters in these vibration signals. This algorithm has been used in experiments with a flexible beam, which is a representative platform of a vibrating mechatronic system. It estimated all the vibration signal parameters quickly and accurately, proved to be insensitive to high frequency noises, and accurately tracked the time variations of the signal parameters

Advanced Motor Control for Improving the Trajectory Tracking Accuracy of a Low-Cost Mobile Robot

This research was funded by the Grant PID2019-111278RB-C21 funded by MCIN/AEI/ 10.13039/501100011033 and “ERDF A way of making Europe”.Peer reviewedPublisher PD

Two-Degrees-of-Freedom Controller delivering zero-error tracking of ramp-like trajectories for nanopositioning systems

Piezoelectrically actuated nanopositioning systems (tube or platform type) are widely employed in applications where fine mechanical displacements with resolution down to atomic scale are required. This paper presents the design, analysis, and validation of a new control scheme based on the structure of the traditional Two-Degrees-of-Freedom (2DOF) PID controller. The proposed controller is established based on a linear continuous input-output nominal model, and presents a simple structure composed by two second order transfer functions. Despite its simplicity, the controller studied in this paper is able to achieve zero error in the tracking of ramp input signals and, therefore, in the slopes of triangular signals, typically used in nanopositioning applications to trace a raster pattern. The controller also suppresses the unmodeled nonlinearities of the piezoelectric actuated nanopositioning systems without the need of an hysteresis model or a state observer. Moreover, the stability of the control system is proved, and its effectiveness is validated through experimental chattering-free control on a piezoelectric stack-actuated nanopositioning platform. Results demonstrate that the proposed controller is superior to the conventional polynomial-based, proportional-integral, and resonant controllers proposed in literature for motion-tracking tasks in nanopositioning systems

A Two-Stage Control Scheme of Single-Link Flexible Manipulators

A new control scheme composed of two independent stages utilised to achieve precise positioning of single-link flexible manipulators is presented herein. Traditional techniques for the control of single-link flexible manipulators utilise only one actuator and two types of sensor measurement (e.g the angular position of the motor and acceleration or strain measurements) to move the manipulator and in order to damp the residual vibrations produced in the displacement of the manipulator. However, in the proposed control scheme another additionally pair actuator-sensor is utilised to improve the speed and precision of the controlled system. On the one hand a motor and the readings of a rotary encoder are utilised in a first stage to displace the manipulator, using the strain measurements in order to damp the high amplitude and low frequency residual vibrations. On the other hand piezoelectric actuators are utilised in conjunction with displacement measures of the tip of the manipulator in order to damp the low amplitude and high frequency residual vibrations which deteriorate the accuracy of the positioning achieved by the traditional control techniques. Simulation and experimental results are carried out to illustrate these improvements