Design and experimental validation of a piezoelectric actuator tracking control based on fuzzy logic and neural compensation

This work proposes two control feedback-feedforward algorithms, based on fuzzy logic in combination with neural networks, aimed at reducing the tracking error and improving the actuation signal of piezoelectric actuators. These are frequently used devices in a wide range of applications due to their high precision in micro- and nanopositioning combined with their mechanical stiffness. Nevertheless, the hysteresis is one the main phenomenon that degrades the performance of these actuators in tracking operations. The proposed control schemes were tested experimentally in a commercial piezoelectric actuator. They were implemented with a dSPACE 1104 device, which was used for signal generation and acquisition purposes. The performance of the proposed control schemes was compared to conventional structures based on proportional-integral-derivative and fuzzy logic in feedback configuration. Experimental results show the advantages of the proposed controllers, since they are capable of reducing the error to significant magnitude orders.The authors wish to express their gratitude to the Basque Government, through the project EKOHEGAZ (ELKARTEK KK-2021/00092), to the Diputación Foral de Álava (DFA), through the project CONAVANTER, and to the UPV/EHU, through the project GIU20/063, for supporting this work

Advanced Control of Piezoelectric Actuators.

168 p.A lo largo de las últimas décadas, la ingeniería de precisión ha tenido un papel importante como tecnología puntera donde la tendencia a la reducción de tamaño de las herramientas industriales ha sido clave. Los procesos industriales comenzaron a demandar precisión en el rango de nanómetros a micrómetros. Pese a que los actuadores convencionales no pueden reducirse lo suficiente ni lograr tal exactitud, los actuadores piezoeléctricos son una tecnología innovadora en este campo y su rendimiento aún está en estudio en la comunidad científica. Los actuadores piezoeléctricos se usan comúnmente en micro y nanomecatrónica para aplicaciones de posicionamiento debido a su alta resolución y fuerza de actuación (pueden llegar a soportar fuerzas de hasta 100 Newtons) en comparación con su tamaño. Todas estas características también se pueden combinar con una actuación rápida y rigidez, según los requisitos de la aplicación. Por lo tanto, con estas características, los actuadores piezoeléctricos pueden ser utilizados en una amplia variedad de aplicaciones industriales. Los efectos negativos, como la fluencia, vibraciones y la histéresis, se estudian comúnmente para mejorar el rendimiento cuando se requiere una alta precisión. Uno de los efectos que más reduce el rendimiento de los PEA es la histéresis. Esto se produce especialmente cuando el actuador está en una aplicación de guiado, por lo que la histéresis puede inducir errores que pueden alcanzar un valor de hasta 22%. Este fenómeno no lineal se puede definir como un efecto generado por la combinación de acciones mecánicas y eléctricas que depende de estados previos. La histéresis se puede reducir principalmente mediante dos estrategias: rediseño de materiales o algoritmos de control tipo feedback. El rediseño de material comprende varias desventajas por lo que el motivo principal de esta tesis está enfocado al diseño de algoritmos de control para reducir la histéresis. El objetivo principal de esta tesis es el desarrollo de estrategias de control avanzadas que puedan mejorar la precisión de seguimiento de los actuadores piezoeléctricos comerciale

High-Performance Tracking for Piezoelectric Actuators Using Super-Twisting Algorithm Based on Artificial Neural Networks

Piezoelectric actuators (PEA) are frequently employed in applications where nano-Micr-odisplacement is required because of their high-precision performance. However, the positioning is affected substantially by the hysteresis which resembles in an nonlinear effect. In addition, hysteresis mathematical models own deficiencies that can influence on the reference following performance. The objective of this study was to enhance the tracking accuracy of a commercial PEA stack actuator with the implementation of a novel approach which consists in the use of a Super-Twisting Algorithm (STA) combined with artificial neural networks (ANN). A Lyapunov stability proof is bestowed to explain the theoretical solution. Experimental results of the proposed method were compared with a proportional-integral-derivative (PID) controller. The outcomes in a real PEA reported that the novel structure is stable as it was proved theoretically, and the experiments provided a significant error reduction in contrast with the PID.This research was funded by Basque Government and UPV/EHU projects

Design, Modeling, Identification and Control of Mechatronic Systems

Les societats modernes plantegen nous reptes que demanden noves maneres de tractar els projectes d'enginyeria. Els enginyers han d'afrontar aquests reptes i desenvolupar solucions òptimes i eficients pels problemes clàssics i nous. Els diferents avenços produïts en la tecnologia hi poden ajudar, però una nova manera de tractar els problemes enginyerils és també necessària, no considerant únicament les diferent especialitats de l'enginyeria aïlladament. En aquest context, podem parlar de la creació d'una nova filosofia de fer enginyeria: la Mecatrònica. La Mecatrònica s'ha definit com l'aplicació de decisions complexes a l'operació de sistemes físics. La Mecatrònica ha estat també definida com la integració o sinergia de diferents disciplines de l'enginyeria. Aquestes disciplines inclouen l'enginyeria mecànica, l'enginyeria elèctrica, l'enginyeria electrònica, l'enginyeria de control, les comunicacions industrials i l'enginyeria de software. No obstant, la importància del concepte no està únicament en la definició sinó a la filosofia que hi ha al fons. És important de veure, que la Mecatrònica no és només la suma dels resultats de diferents disciplines, sinó la filosofia enginyeril per afrontar els problemes com un de sol, fent servir les eines que subministren les diferents disciplines. La present tesi es divideix en dos parts que tracten problemes de diferent natura. La primera part es titula Regles de disseny i modelat d'actuadors per l'optimització de sistemes mecatrònics i es centra en proporcionar un anàlisis detallat de diferents actuadors utilitzant un procediment general, orientat a millorar el disseny de l'actuador. S'introdueix una nova metodologia per analitzar actuadors lineals electromagnètics i hidràulics modelitzant la seves magnituds mecàniques (força, treball i desplaçament) com a funcions de la geometria i les propietats del material, estudiant l'escalabilitat (en el sentit de produir la mateixa distribució de tensions i deformacions per diferents mides). La motivació de realitzar aquest treball neix de la necessitat d'estructures i sistemes lleugers i de volum reduït, que han de ser integrats en el procediment de disseny el més aviat possible. Per tant, s'estudien les relacions geomètriques, les proporcions i les propietats dels materials que maximitzen les magnituds mecàniques de sortida dels actuadors per un volum i pes limitat, així com l'escabilitat per la seva posterior integració en estructures. Els resultats són validats mitjançant anàlisi dimensional de les expressions obtingudes i comparant els resultats numèrics amb dades d'actuadors industrials. Es considera el comportament estàtic de diferents classes d'actuadors, incloent actuadors hidràulics i electromagnètics lineals. La segona part es titula Identificació i Control d'Actuadors Piezoelèctrics. Els actuadors piezoelèctrics estan demostrant ser una solució fiable per moltes aplicacions, des del microposicionament (màquines eina, dispositius òptics o microscopis moderns) al control actiu d'estructures. La principal motivació de la segona part de la tesis és aprofundir en models per representar el comportament histerètic dels actuadors piezoelèctrics per posteriorment aplicar els models al desenvolupament de controladors pels sistemes histerètics. Es desenvolupa inicialment un estudi general dels actuadors piezoelèctrics per després tractar la seva modelització. Degut a l'elevat comportament no-lineal observat es necessita un model d'histèresis. El model de Bouc-Wen ha estat escollit i s'ha treballat en la identificació dels paràmetres del model i la seva validació. Un cop el sistema ha estat modelat, s'olinebreak ha dissenyat un nou controlador lineal i s'ha implementat en una plataforma experimental utilitzant un DSP (Processador digital de senyal). Encara que les dues parts estan clarament diferenciades, la unitat de la tesis pot ser trobada a les arrels de la Mecatrònica. La tesis tracta la resposta a una sola pregunta: Com podem millorar un sistema mecatrònic? No obstant, la resposta és doble: Dissenyant i modelant actuadors òptims considerant el sistema o estructura complet i controlant el sistema adequadament fent servir els models desenvolupats.Fast changing societies come up with new challenges that require new engineering approaches. Engineers have to face such challenges and provide novel and more efficient solutions to classical and new problems. This can be done by using different relevant advances produced in technology. Furthermore, a new way of addressing the engineering problems has to be applied, not considering only isolated engineering specialties. In this frame, we can talk about the creation of a new engineering philosophy: Mechatronics. Mechatronics has been defined as the application of complex decision making to the operation of physical systems. Mechatronics has been also defined as the integration or synergy of different engineering disciplines. Such disciplines may include Mechanical Engineering, Electrical Engineering, Electronics Engineering, Control Engineering, Industrial Communications and Software Engineering. Nevertheless, the importance of the concept does not lie only in the definition but in the philosophy behind it. It is very important to note that Mechatronics is not only the sum of the results of the different disciplines, but the engineering philosophy to face engineering problems as a whole, employing the tools provided by the different disciplines. The present thesis has been divided in two parts that deal with problems of different nature. The first part is titled Design Rules and Actuator Modeling for the Optimization of Mechatronic Systems and focuses on providing the detailed analysis of different actuators using a general procedure and oriented towards improving the actuator design. It introduces a new methodology to analyze linear electromagnetical and hydraulic actuators by modeling their maximum output mechanical quantities (force, work and stroke) as functions of the geometry and material properties and discusses the scalability (in the sense of producing the same stress and strain distribution for different sizes). The motivation to undertake such a work stems from the need for light and volume reduced structures and systems, which are to be integrated in the design procedure as early as possible. Hence, the geometric relationships, aspect ratios and material properties that maximize the actuator output quantities with a certain limited volume or weight, along with their scalability for the integration in structures are studied. A validation of the results is done by performing dimensional analysis of the expressions obtained and comparing numerical results with industrial actuator data. The static behavior of different classes of actuators is considered. Such actuators include linear hydraulic and electromagnetic actuators. The second part is titled Identification and Control of Piezoelectric Actuators}. Piezoelectric actuators are proving to be a reliable solution for many engineering applications, ranging from micro-positioning (machine tools, optic devices or modern microscopes) to active control of structures. The main motivation of this thesis part is to delve into models to represent the hystereticbehavior of piezoelectric actuators in order to apply them to the conception of controllers for such hysteretic systems. A general study of piezoelectric actuators is performed to later deal with the modeling of such actuators. Due to the high non-linear behavior observed, the problem of identifying and modeling the actuator requires a hysteresis model. The Bouc-Wen model has been chosen and investigations to identify its parameters and to validate the model have been undertaken. Once the system has been identified, a linear controller has been designed and implemented in a real platform, employing a DSP (Digital Signal Processor). Although the two parts are clearly differentiated, the thesis unity can be found in the roots of Mechatronics. The thesis deals with the response to one single question: How can we improve a mechatronic system? However, the answer is twofold: By designing and modeling optimum actuators taking into account the whole system or structure and by controlling the system appropriately using developed models.Postprint (published version

Discrete-Time Control Design for Piezo-Actuated Positioning Systems

芝浦工業大学2018年

Enhancing the Structural Performance with Active and Semi-Active Devices Using Adaptive Control Strategy

Changes in the characteristics of the structure, such as damage, have not been considered in most of the active and semi-active control methods that have been used to control and optimize the response of civil engineering structures. In this dissertation, a direct adaptive control which can deal with the existence of measurement errors and changes in structural characteristics or load conditioning is used to control the performance of structures. A Simple Adaptive Control Method (SACM) is modified to control civil structures and improve their performance. The effectiveness of the SACM is verified by several numerical examples. The SACM is used to reduce the structural response such as drift and acceleration using active and semi-active devices, and its performance is compared with that of other control methods. Also, a probabilistic indirect adaptive control method is developed and its behavior is compared to the SACM using a simple numerical example. In addition to the simplicity of the SACM implementation, the results show that SACM is very effective to reduce the response of structures with linear and non-linear behavior in comparison with other control methods