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Design and Characterization of a Biomimetic Piezoelectric Pump Inspired on Group Fish Swimming Effect

VATANABE, Sandro L.; CHOI, Andres; LIMA, Cicero R. de; SILVA, Emilio Carlos Nelli
Fonte: SAGE PUBLICATIONS LTD Publicador: SAGE PUBLICATIONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.97%
Flow pumps are important tools in several engineering areas, such as in the fields of bioengineering and thermal management solutions for electronic devices. Nowadays, many of the new flow pump principles are based on the use of piezoelectric actuators, which present some advantages such as miniaturization potential and lower noise generation. In previous work, authors presented a study of a novel pump configuration based on placing an oscillating bimorph piezoelectric actuator in water to generate flow. It was concluded that this oscillatory behavior (such as fish swimming) yields vortex interaction, generating flow rate due to the action and reaction principle. Thus, following this idea the objective of this work is to explore this oscillatory principle by studying the interaction among generated vortex from two bimorph piezoelectric actuators oscillating inside the same pump channel, which is similar to the interaction of vortex generated by frontal fish and posterior ones when they swim together in a group formation. It is shown that parallel-series configurations of bimorph piezoelectric actuators inside the same pump channel provide higher flow rates and pressure for liquid pumping than simple parallel-series arrangements of corresponding single piezoelectric pumps...

A biomimetic piezoelectric pump: Computational and experimental characterization

LIMA, Cicero R. de; VATANABE, Sandro L.; CHOI, Andres; NAKASONE, Paulo Henrique; PIRES, Rogerio Felipe; SILVA, Emilio Carlos Nelli
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.91%
Flow pumps have been developed for classical applications in Engineering, and are important instruments in areas such as Biology and Medicine. Among applications for this kind of device we notice blood pump and chemical reagents dosage in Bioengineering. Furthermore, they have recently emerged as a viable thermal management solution for cooling applications in small-scale electronic devices. This work presents the performance study of a novel principle of a piezoelectric flow pump which is based oil the use of a bimorph piezoelectric actuator inserted in fluid (water). Piezoelectric actuators have some advantages over classical devices, such as lower noise generation and ease of miniaturization. The main objective is the characterization of this piezoelectric pump principle through computational simulations (using finite element software), and experimental tests through a manufactured prototype. Computational data, Such as flow rate and pressure curves, have also been compared with experimental results for validation purposes. (C) 2009 Elsevier B.V. All rights reserved.

The gas flow rate increase obtained by an oscillating piezoelectric actuator on a micronozzle

Wiederkehr, Rodrigo Sérgio; Salvadori, Maria Cecilia Barbosa da Silveira; BRUGGER, J.; Degasperi, Francisco Tadeu; Cattani, Mauro Sergio Dorsa
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.16%
Micronozzles with piezoelectric actuator were fabricated and investigated. The micronozzles were fabricated in glass substrates using a powder-blasting technique, and the actuator is a bimorph structure made from a piezoelectric polymer. The actuator was located at the nozzle outlet, and was driven in an oscillating mode by applying an alternating voltage across the actuator electrodes. With a pressure difference between inlet and outlet, the gas flow rate through the device was increased. This effect was quantified, and compared to a similar micronozzle with no actuator. The increase in the flow rate was defined as the gas flow through the micronozzle with actuator oscillating minus the gas flow without actuator, was found to depend on the inlet pressure, the pressure ratio, and the nozzle throat diameter. (C) 2008 Elsevier B.V. All rights reserved.

Computational and experimental characterization of a low-cost piezoelectric valveless diaphragm pump

Choi, Andres; Vatanabe, Sandro Luis; Lima, Cicero Ribeiro de; Silva, Emilio Carlos Nelli
Fonte: SAGE PUBLICATIONS LTD; LONDON Publicador: SAGE PUBLICATIONS LTD; LONDON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.91%
Flow pumps act as important devices in areas such as Bioengineering, Medicine, and Pharmacy, among other areas of Engineering, mainly for delivering liquids or gases at small-scale and precision flow rate quantities. Principles for pumping fluids based on piezoelectric actuators have been widely studied, since they allow the construction of pump systems for displacement of small fluid volumes with low power consumption. This work studies valveless piezoelectric diaphragm pumps for flow generation, which uses a piezoelectric ceramic (PZT) as actuator to move a membrane (diaphragm) up and down as a piston. The direction of the flow is guaranteed by valveless configuration based on a nozzle-diffuser system that privileges the flow in just one pumping direction. Most research efforts on development of valveless flow pump deal either with computational simulations based on simplified models or with simplified physical approaches based on analytical models. The main objective of this work is the study of a methodology to develop a low-cost valveless piezoelectric diaphragm flow pump using computational simulations, parametric study, prototype manufacturing, and experimental characterization. The parametric study has shown that the eccentricity of PZT layer and metal layer plays a key role in the performance of the pump.; FAPESP (Sao Paulo State Foundation Research Agency); FAPESP (Sao Paulo State Foundation Research Agency) [2004/14675-0...

Caracterização de uma microválvula fabricada usando o polímero piezoelétrico poli(fluoreto de vinilideno) (PVDF) integrada a saída de um microbocal sônico; Characterization of a microvalve using the piezoelectric polymer poly(viniyidene fluoride) (PVDF) integrated to a micronozzle end

Wiederkehr, Rodrigo Sérgio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/12/2007 PT
Relevância na Pesquisa
47.11%
Este trabalho descreve a seqüência de fabricação de uma microválvula piezoelétrica posicionada na saída de um microbocal sônico. A técnica usada para fabricar os microbocais foi o jateamento utilizando pó de alumina e o substrato usado foi de vidro. As microválvulas são atuadores fabricados com o polímero poli(fluoreto de vinilideno) (PVDF) que é um material piezoelétrico. Os microbocais têm um formato convergente-divergente com diâmetro na entrada de 1 mm e com diâmetro na garganta em cerca de 240 microns. O atuador foi fabricado no modo bimorfo (duas folhas do polímero coladas com polarização opostas) com dimensões de 3 mm de largura por 6 mm de comprimento. Ambas as folhas do polímero são recobertas por um filme condutor de 200 nm de espessura usados como eletrodos. Aplicando uma voltagem entre os eletrodos uma folha expande enquanto a outra contrai gerando um movimento vertical do atuador. O movimento vertical pode ser maior ou menor dependendo do valor da tensão aplicada. Os dispositivos foram testados usando uma linha de gás, aplicando tensões DC e AC nos eletrodos do atuador. Para controle, também foram realizadas medidas em bocais sem atuadores. No caso onde foram aplicadas tensões DC nos atuadores...

Estudo de viabilidade de atuadores piezelétricos bilaminares para bombeamento de líquidos.; Viability study of bilaminar piezoelectric actuators for liquid pumping.

Vatanabe, Sandro Luis
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/11/2008 PT
Relevância na Pesquisa
46.95%
As bombas de fluxo, além das aplicações clássicas em Engenharia, são instrumentos importantes em áreas como a Bioengenharia, seja para o bombeamento de sangue ou dosagem de reagentes e medicamentos, e na área de refrigeração de equipamentos eletrônicos. Muitos dos novos princípios aplicados no desenvolvimento desse tipo de bomba de fluxo baseiam-se no uso de atuadores piezelétricos. Esses atuadores apresentam certas vantagens em relação a outros tipos tradicionalmente utilizados, como maior potencial de miniaturização, menor geração de ruídos e número reduzido de partes móveis. Entre os vários tipos de bombas de fluxo piezelétricas destacam-se as baseadas nos movimentos ondulatórios e oscilatórios, como o nadar dos peixes. É bem conhecido que os peixes ao nadarem não provocam a morte de micro-organismos ao seu redor, o que torna esse princípio bem promissor para as aplicações em Biotecnologia, por exemplo. Assim, o presente trabalho de mestrado dedica-se ao estudo de novas configurações de atuadores piezelétricos bilaminares associados em paralelo e série para bombeamento de líquidos através do princípio oscilatório, a fim de se obter maiores vazões ou pressões. O escopo deste projeto abrange...

Desenvolvimento de uma bomba de fluxo piezelétrica de diafragma.; A low cost piezoelectric valve-less diaphragm pump.

Choi, Andres
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/10/2009 PT
Relevância na Pesquisa
46.93%
Bombas de fluxo são dispositivos importantes em áreas como a Bioengenharia, Medicina, Farmácia, entre outras aplicações clássicas de Engenharia. Princípios para o bombeamento de fluidos baseados em atuadores piezelétricos estão sendo estudados no Departamento de Engenharia Mecatrônica e de Sistemas Mecânicos da Escola Politécnica, que permitem a construção de bombas de fluxo de pequena escala, ou seja, bombas de fluxo de pequena potência para deslocamento de pequenos volumes de fluido com baixo consumo de energia. O presente trabalho estuda bombas de fluxo piezelétricas de diafragma do tipo valve-less para geração de vazão. A bomba de fluxo piezelétrica de diafragma utiliza cerâmica piezelétrica como atuador para mover uma membrana (diafragma) para cima e para baixo como um pistão, que causa uma seqüência de aumento e diminuição do volume da câmara da bomba, forçando a entrada e a saída do fluido na bomba. A direção do fluxo é garantida por válvulas que privilegiam o fluxo em apenas um sentido. O objetivo deste trabalho é o estudo da metodologia de desenvolvimento de uma bomba de fluxo piezelétrica de diafragma de baixo custo do tipo valve-less. Para tanto, será utilizado a modelagem por Método dos Elementos Finitos (MEF) para a realização de análises de sensibilidade dos parâmetros geométricos e construtivos da bomba de fluxo. Serão realizadas simulações de escoamento de fluido pelo Método de Volumes Finitos (MVF) para a realização de análises de sensibilidade dos parâmetros geométricos dos elementos difusor/bocal e o levantamento das curvas características da bomba de fluxo. Por fim...

Projeto de atuadores de múltiplos graus de liberdade baseados em placas piezelétricas utilizando o método de otimização topológica.; Design of multiple degrees of freedom actuators based on piezoelectric plates using the topologic optimization method

Demarque, Vinícius Michelan
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/08/2012 PT
Relevância na Pesquisa
57.1%
Atuadores piezelétricos são dispositivos que permitem a conversão de energia elétrica em energia mecânica. Dentre os atuadores piezelétricos, destacam-se os bilaminares, que consistem em duas piezocerâmicas de polarização oposta (ou excitadas com cargas de sinal contrário) com um substrato entre elas. Os atuadores piezelétricos também podem ser miniaturizados, alcançando a escala de MEMS (Micro-Electric-Mechanical System). Este trabalho tem por objetivo desenvolver uma metodologia utilizando o Método de Otimização Topológica (MOT) para o projeto de atuadores piezelétricos com múltiplos graus de liberdade baseados no princípio bilaminar. A fase de projeto consiste na utilização do MOT para a determinação de uma configuração de atuadores que maximizem o deslocamento numa direção e sentido especificados para uma restrição na quantidade de material utilizado em cada camada, considerando a polarização da cerâmica piezelétrica presente nessa configuração e o acoplamento e simetria entre as camadas. Para a simulação do atuador é utilizado o Método dos Elementos Finitos (MEF) através de um elemento de placa piezelétrica isoparamétrico de oito nós expandido. O MOT, neste trabalho, utiliza o modelo de material denominado PEMAP-P (Material Piezelétrico com Penalização e Polarização). A técnica de projeção é utilizada junto ao MOT para a obtenção de um resultado com uma geometria bem definida. O problema de otimização é resolvido através de Programação Matemática Sequencial (PMS) através do algoritmo GCMMA (Globally Convergent Method of Moving Asymptotes). Como exemplo é estudado o projeto de um atuador piezelétrico para microespelhos. Dentre as configurações obtidas pelo MOT...

The gas flow rate increase obtained by an oscillating piezoelectric actuator on a micronozzle

Wiederkehr, R. S.; Salvadori, M. C.; Brugger, J.; Degasperi, F. T.; Cattani, M.
Fonte: Elsevier B.V. Sa Publicador: Elsevier B.V. Sa
Tipo: Artigo de Revista Científica Formato: 154-160
ENG
Relevância na Pesquisa
57.16%
Micronozzles with piezoelectric actuator were fabricated and investigated. The micronozzles were fabricated in glass substrates using a powder-blasting technique, and the actuator is a bimorph structure made from a piezoelectric polymer. The actuator was located at the nozzle outlet, and was driven in an oscillating mode by applying an alternating voltage across the actuator electrodes. With a pressure difference between inlet and outlet, the gas flow rate through the device was increased. This effect was quantified, and compared to a similar micronozzle with no actuator. The increase in the flow rate was defined as the gas flow through the micronozzle with actuator oscillating minus the gas flow without actuator, was found to depend on the inlet pressure, the pressure ratio, and the nozzle throat diameter. (C) 2008 Elsevier B.V. All rights reserved.

Polymeric piezoelectric actuator substrate for osteoblast mechanical stimulation

Frias, Clara; Reis, Joana; Capela silva, Fernando; Potes, José; Torres Marques, António; Simões, José
Fonte: Elesevier Publicador: Elesevier
Tipo: Artigo de Revista Científica Formato: 51105 bytes; application/pdf
ENG
Relevância na Pesquisa
56.87%
Abstract Bone mass distribution and structure are dependent on mechanical stress and adaptive response at cellular and tissue levels. Mechanical stimulation of bone induces new bone formation in vivo and increases the metabolic activity and gene expression of osteoblasts in culture. A wide variety of devices have been tested for mechanical stimulation of cells and tissues in vitro. The aim of this work was to experimentally validate the possibility to use piezoelectric materials as a mean of mechanical stimulation of bone cells, by converse piezoelectric effect. To estimate the magnitude and the distribution of strain, finite numerical models were applied and the results were complemented with the optical tests (Electronic Speckle Pattern Interferometric Process). In this work, osteoblasts were grown on the surface of a piezoelectric material, both in static and dynamic conditions at low frequencies, and total protein, cell viability and nitric oxide measurement comparisons are presented.

Polymeric piezoelectric actuator substrate for osteoblast mechanical stimulation.

Frias, C; Reis, J; Capela e Silva, F; Potes, J; Simões, J; Marques, AT
Fonte: Polymeric piezoelectric actuator substrate for osteoblast mechanical stimulation. Publicador: Polymeric piezoelectric actuator substrate for osteoblast mechanical stimulation.
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
77.03%
Bone mass distribution and structure are dependent on mechanical stress and adaptive response at cellular and tissue levels. Mechanical stimulation of bone induces new bone formation in vivo and increases the metabolic activity and gene expression of osteoblasts in culture. A wide variety of devices have been tested for mechanical stimulation of cells and tissues in vitro. The aim of this work was to experimentally validate the possibility to use piezoelectric materials as a mean of mechanical stimulation of bone cells, by converse piezoelectric effect. To estimate the magnitude and the distribution of strain, finite numerical models were applied and the results were complemented with the optical tests (Electronic Speckle Pattern Interferometric Process). In this work, osteoblasts were grown on the surface of a piezoelectric material, both in static and dynamic conditions at low frequencies, and total protein, cell viability and nitric oxide measurement comparisons are presented.

A new piezoelectric actuator induces bone formation in vivo: a preliminary study

Reis, J; Frias, C; Canto e Castro, C; Botelho, ML; Marques, AT; Simões JA, JA; Capela e Silva, F; Potes, J
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.03%
This in vivo study presents the preliminary results of the use of a novel piezoelectric actuator for orthopedic application. The innovative use of the converse piezoelectric effect to mechanically stimulate bone was achieved with polyvinylidene fluoride actuators implanted in osteotomy cuts in sheep femur and tibia. The biological response around the osteotomies was assessed through histology and histomorphometry in nondecalcified sections and histochemistry and immunohistochemistry in decalcified sections, namely, throughMasson’s trichrome, and labeling of osteopontin, proliferating cell nuclear antigen, and tartrate-resistant acid phosphatase. After one-month implantation, total bone area and new bone area were significantly higher around actuators when compared to static controls. Bone deposition rate was also significantly higher in the mechanically stimulated areas. In these areas, osteopontin increased expression was observed. The present in vivo study suggests that piezoelectric materials and the converse piezoelectric effect may be used to effectively stimulate bone growth.

Projeto, construção e caracterização de um amortecedor ativo controlado por atuador piezoelétrico; Design, construction and characterization controlled by Piezoelectric Actuato

Teixeira, Rafael Luís
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
57.1%
Esta tese apresenta o desenvolvimento de uma metodologia de projeto, a construção de um protótipo e a validação experimental de um amortecedor ativo de vibrações controlado por um atuador piezelétrico. O dispositivo proposto contém um circuito hidráulico constituído por dois foles metálicos flexíveis conectados a um reservatório rígido cheio com um fluido viscoso. Quando um dos foles é conectado a uma estrutura vibratória um fluxo de fluido é forçado através de um orifício variável, produzindo o efeito de amortecimento. O tamanho do orifício é ajustado por um sistema piezelétrico de controle que posiciona um obturador cônico numa cavidade cônica. O amortecedor é modelado pela técnica dos elementos finitos considerando que o corpo da válvula rígido e que existe interação entre o fluido interno e a estrutura flexível dos foles. Este modelo é discretizado utilizando uma formulação Lagrangeana–Euleriana. O atuador, composto por uma estrutura metálica flexível que amplifica o deslocamento produzido por uma pilha de cerâmicas piezelétricas, também é modelado pela técnica dos elementos finitos. Foi construído um protótipo do amortecedor e realizados ensaios experimentais com excitações impulsivas e harmônicas...

Adaptive identification of hysteresis and creep in piezoelectric stack actuators

Minase, J.; Lu, T.F.; Cazzolato, B.; Grainger, S.
Fonte: Springer London Ltd Publicador: Springer London Ltd
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
47.24%
The adaptive identification of the non-linear hysteresis and creep effects in a piezoelectric actuator is proposed in this paper. Model uncertainties related to the hysteresis and creep effects, most prominently in the high frequency zone (to 100 Hz), large operating amplitude and/long operating time, can make a piezoelectric actuator-driven micro-positioning system unstable in the closed loop. Furthermore, these uncertainties may lead to inaccurate open-loop control and frequently cause harmonic distortion when a piezoelectric actuator is driven with a sinusoidal input voltage signal. In order to solve the above issues, it is important to determine an accurate non-linear dynamic model of a piezoelectric actuator. An unscented Kalman filter-based adaptive identification algorithm is presented, which accurately determines the non-linear dynamics of a piezoelectric stack type actuator such that the non-linear hysteresis and creep effects can be accurately predicted. Since hysteresis and creep are dominant in open loop, the actuator is driven in an open-loop mode in this investigation.; J. Minase, T.-F. Lu, B. Cazzolato and S. Grainger; © Springer-Verlag London Limited 2009

A review, supported by experimental results, of voltage, charge and capacitor insertion method for driving piezoelectric actuators

Minase, J.; Lu, T.F.; Cazzolato, B.; Grainger, S.
Fonte: Elsevier Science Inc Publicador: Elsevier Science Inc
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
57.31%
A piezoelectric actuator consists of ceramic material that expands or contracts when a positive or a negative potential voltage signal is applied. The displacement of a piezoelectric actuator is commonly controlled using a voltage input due to its ease of implementation. However, driving a piezoelectric actuator using a voltage input leads to the non-linear hysteresis and creep. Hysteresis and creep are undesirable characteristics which lead to large errors when a piezoelectric actuator is used in positioning applications. The amount of hysteresis and creep could be minimized to a large extent when a piezoelectric actuator is driven using a charge input. Another method which substantially reduces hysteresis and creep involves the insertion of a capacitor in series with a piezoelectric actuator which is driven using a voltage input. A review of voltage, charge and capacitor insertion methods for driving piezoelectric actuators is presented in this paper. Experimental results, for a piezoelectric actuator driven using the above three methods, are presented to validate the facts presented in this review.; J. Minase, T.-F. Lu, B. Cazzolato and S. Grainger

Fuzzy modeling of a piezoelectric actuator

Mohammadzaheri, M.; Grainger, S.; Bazghaleh, M.
Fonte: Korean Soc Precision Eng Publicador: Korean Soc Precision Eng
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.99%
In this research, a piezoelectric actuator was modeled using fuzzy subtractive clustering and neuro-fuzzy networks. In the literature, the use of various modeling techniques (excluding techniques used in this article) and different arrangements of inputs in black box modeling of piezoelectric actuators for the purpose of displacement prediction has been reported. Nowadays, universal approximators are available with proven ability in system modeling; hence, the modeling technique is no longer such a critical issue. Appropriate selection of the inputs to the model is, however, still an unsolved problem, with an absence of comparative studies. While the extremum values of input voltage and/or displacement in each cycle of operation have been used in black box modeling inspired by classical phenomenological methods, some researchers have ignored them. This article focuses on addressing this matter. Despite the fact that classical artificial neural networks, the most popular black box modeling tools, provide no visibility of the internal operation, neuro-fuzzy networks can be converted to fuzzy models. Fuzzy models comprise of fuzzy rules which are formed by a number of fuzzy or linguistic values, and this lets the researcher understand the role of each input in the model in comparison with other inputs...

Physics-based modelling of a piezoelectric actuator using genetic algorithm

Miri, N.; Mohammadzaheri, M.; Chen, L.; Grainger, S.; Bazghaleh, M.
Fonte: IEEE; Online Publicador: IEEE; Online
Tipo: Conference paper
Publicado em //2013 EN
Relevância na Pesquisa
56.82%
A number of models have been presented to estimate the displacement of piezoelectric actuators; these models remove the need for accurate displacement sensors used in nanopositioning. Physics based models, inspired by physical phenomena, are widely used for this purpose due to their accuracy and comparatively low number of parameters. The common issue of these models is the lack of a non-ad-hoc and reliable method to estimate their parameters. Parameter identification of a widely accepted physics-based model, introduced by Voigt, is addressed in this paper. Non-linear governing equation of this model consists of five parameters needing to be identified. This research aims at developing/adopting an optimal and standard (non-ad-hoc) parameter identification algorithm to accurately determine the parameters of the model and, in a more general view, all physics-based models of piezoelectric actuators. In this paper, Genetic Algorithm (GA) which is a global optimisation method is employed to identify the model parameters.; Narges Miri, Morteza Mohammadzaheri, Lei Chen, Steven Grainger, Mohsen Bazghaleh

Hybrid digital control of piezoelectric actuators.

Bazghaleh, Mohsen
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2014
Relevância na Pesquisa
56.93%
Nanopositioning, as a core aspect of nanotechnology, concerns the control of motion at nanometre scale and is a key tool that allows the manipulation of materials at the atomic and molecular scale. As such it underpins advances in diverse industries including biotechnology, semiconductors and communications. The most commonly used nanopositioner is the piezoelectric actuator. Aside from being compact in size, piezoelectric actuators are capable of nanometre resolution in displacement, have high stiffness, provide excellent operating bandwidth and high force output. Consequently they have been widely used in many applications ranging from scanning tunnelling microscopes (STM) to vibration cancellation in disk drives. However, piezoelectric actuators are nonlinear in nature and suffer from hysteresis, creep and rate-dependencies that reduce the positioning accuracy. A variety of approaches have been used to tackle the hysteresis of piezoelectric actuators including sensor-based feedback control, feedforward control using an inverse-model and charge drives. All have performance limitations arising from factors such as parameter uncertainty, bandwidth and sensor-induced noise. This thesis investigates the effectiveness of a synergistic approach to the creation of hybrid digital algorithms that tackle challenges arising in the control of non-linear devices such as piezoelectric actuators. Firstly...

Modelling of forging processes assisted by piezoelectric actuators : principles and experimental validation

GIRAUD-AUDINE, Christophe; NGUYEN, T.H.; LEMAIRE-SEMAIL, B; ABBA, Gabriel; BIGOT, Régis
Fonte: IEEE Publicador: IEEE
EN
Relevância na Pesquisa
56.88%
This paper presents the modelling of a forging processes assisted by a piezoelectric actuator (PA), which is used to generate specific low frequency vibration waveforms. Experimental results show that such waveforms reduce the necessary forging force during upsetting tests. The main problems which remain are defining the appropriate waveforms, predicting their influence on the process and the actuator and designing the control. Due to the complexity of the interactions between the different components of the system, a complete model of the process is needed. Such a model is developed here using an energetic macroscopic representation to preserve causality throughout the modelling. Simulation results are then compared to representative experimental results.

Adaptive vibration suppression system: An iterative control law for a piezoelectric actuator shunted by a negative capacitor

Kodejska, Milos; Mokry, Pavel; Linhart, Vaclav; Vaclavik, Jan; Sluka, Tomas
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
47.12%
An adaptive system for the suppression of vibration transmission using a single piezoelectric actuator shunted by a negative capacitance circuit is presented. It is known that using negative capacitance shunt, the spring constant of piezoelectric actuator can be controlled to extreme values of zero or infinity. Since the value of spring constant controls a force transmitted through an elastic element, it is possible to achieve a reduction of transmissibility of vibrations through a piezoelectric actuator by reducing its effective spring constant. The narrow frequency range and broad frequency range vibration isolation systems are analyzed, modeled, and experimentally investigated. The problem of high sensitivity of the vibration control system to varying operational conditions is resolved by applying an adaptive control to the circuit parameters of the negative capacitor. A control law that is based on the estimation of the value of effective spring constant of shunted piezoelectric actuator is presented. An adaptive system, which achieves a self-adjustment of the negative capacitor parameters is presented. It is shown that such an arrangement allows a design of a simple electronic system, which, however, offers a great vibration isolation efficiency in variable vibration conditions.; Comment: This is a revised version of the paper published in IEEE TUFFC in Dec 2012...