Academic literature on the topic 'Mechanical actuators'
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Journal articles on the topic "Mechanical actuators"
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Bazghaleh, Mohsen, Steven Grainger, and Morteza Mohammadzaheri. "A review of charge methods for driving piezoelectric actuators." Journal of Intelligent Material Systems and Structures 29, no. 10 (October 11, 2017): 2096–104. http://dx.doi.org/10.1177/1045389x17733330.
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Piezoelectric actuators are the most commonly used actuators in nanopositioning. They provide excellent operating bandwidth and precision. These actuators are normally driven by voltage amplifiers; however, the relationship of the applied voltage on the actuator and its position is nonlinear and complex due to phenomena such as hysteresis. This adversely influences actuator’s position control which is the core component of nanopositioning. However, the electrical charge applied on a piezoelectric actuator has a significantly less complex relationship with its position. As a result, driving piezoelectric actuators with charge amplifiers has attracted significant attention. In this article, charge driving methods are classified, and their advantages, major issues and the solutions to these issues are critically reviewed.
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Copaci, Dorin, Dolores Blanco, and Luis E. Moreno. "Flexible Shape-Memory Alloy-Based Actuator: Mechanical Design Optimization According to Application." Actuators 8, no. 3 (August 14, 2019): 63. http://dx.doi.org/10.3390/act8030063.
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New robotic applications, among others, in medical and related fields, have in recent years boosted research in the development of new actuators in the search for solutions that are lighter and more flexible than conventional actuators. Shape-Memory Alloy (SMA)-based actuators present characteristics that make them an excellent alternative in a wide variety of applications. This paper presents the design, tests (with the control description) and analysis of various configurations of actuators based on SMA wires: flexible SMA actuators, different mechanical design to multiply the displacement and different configurations for actuators with multiple SMA wires. The performance of the actuators has been analyzed using wires of different activation temperatures. The influence of the Bowden sheath of the flexible actuator has been tested, as has the thermal behavior of actuators with several wires. This work has allowed determination of the most effective configuration for the development of a flexible actuator based on SMA, from the point of view of dimensions, efficiency, and work frequency. This type of actuator has been applied in the development of soft robots and light robotic exoskeletons.
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Zhou, Ling, Xue Jin Shen, Zhen Lu Wang, and Yi Hu. "Performance Comparison of Typical Electrothermal Actuators." Key Engineering Materials 562-565 (July 2013): 528–33. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.528.
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As the power producer, the micro actuator is an important part of the micro electro- mechanical system, which is used as the conversion of energy, motion and force producing. In this paper, the mechanical models of three bent beam electrothermal actuators are summarized to make comparison with each other and analyze mechanical performance. For Π-shaped actuators, the tip displacements are proportional to temperature increment and length, having no relationship with the beam width and thickness. However, the displacement of Π-shaped actuators is smaller than the one of V-shaped actuators with the same parameters. For V-shaped actuators, the tip displacements of cascaded V-shaped actuators are larger than the ones of single V-shaped actuators with the same parameters. Especially, cascaded V-shaped actuator with secondary beam having no current has the largest displacement.
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Massey, K. C., J. McMichael, T. Warnock, and F. Hay. "Development of mechanical guidance actuators for a supersonic projectile." Aeronautical Journal 112, no. 1130 (April 2008): 181–95. http://dx.doi.org/10.1017/s0001924000002128.
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Abstract In this paper, the results of a series of experiments funded by DARPA to determine the feasibility of using small actuators to provide directional control for a supersonic projectile are presented. Controlling the flight of the projectile was accomplished by taking advantage of complex shock-boundary-layer interactions produced by mechanical devices. Experimental tests were conducted at GTRI to screen several control concepts and actuator locations. Further experiments were conducted on a scale projectile in a supersonic stream to investigate the rise time of the forces. Several different mechanical actuators were tested which served to provide guidance for future actuator designs. CFD results were also used to predict the results in flight as well as gain insights into the fluid mechanics involved. Flight tests of a Mach 4 round proved the viability of the guidance actuator.
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Zhang, Yu Fang. "Review of Mechanical Structure of Force Actuator for Optical Astronomical Telescope." Advanced Materials Research 765-767 (September 2013): 25–28. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.25.
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Reviewed the application of force actuators in the optical astronomical telescopes, and introduced the working principle, mechanical structure, performance requirements and basic components of the force actuators; then compared the advantages and disadvantages of force actuator types which commonly used in astronomical telescopes, finally, propose a outlook of the development trend of the actuator on the great telescope application requirements.
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Gallo, Carlos Alberto, Fernando Lessa Tofoli, Domingos Alves Rade, and Valder Steffen. "Piezoelectric actuators applied to neutralize mechanical vibrations." Journal of Vibration and Control 18, no. 11 (October 26, 2011): 1650–60. http://dx.doi.org/10.1177/1077546311422549.
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Piezoelectric actuators are widely used in smart structural systems to actively control vibration and noise, and to enhance performance. Because of the highly capacitive nature of these actuators, special power amplifiers, capable of delivering high currents, are required to drive these systems. In this paper, a study to reduce the reactive energy that is necessary in such systems is carried out. This is accomplished by associating the actuator with its capacitive characteristic circuit. Also, non-idealities of the circuit performance are addressed, along with theoretical limits regarding possible power savings and practical difficulties in achieving them. The proposed converter introduces energy to correct the difference of phase between current and voltage that is supplied to the piezoelectric transducer (PZT) actuator. This process is optimized by the introduction of reactive power to the characteristic process of the PZT’s actuator circuit. Therefore the system is supposed to present an electric characteristic that is close to resistive, and is not capacitive any more.
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Liu, Yonggang, Aoke Zeng, Shuliang Zhang, Ruixiang Ma, and Zhe Du. "An Experimental Investigation on Polarization Process of a PZT-52 Tube Actuator with Interdigitated Electrodes." Micromachines 13, no. 10 (October 18, 2022): 1760. http://dx.doi.org/10.3390/mi13101760.
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The manipulator is the key component of the micromanipulator. Using the axial expansion and contraction properties, the piezoelectric tube can drive the manipulator to achieve micro-motion positioning. It is widely used in scanning probe microscopy, fiber stretching and beam scanning. The piezoceramic tube actuator used to have continuous electrodes inside and outside. It is polarized along the radial direction. There are relatively high polarization voltages, but poor axial mechanical properties. A new tubular actuator is presented in this paper by combining interdigitated electrodes and piezoceramic tubes. The preparation, polarization and mesoscopic mechanical properties were investigated. Using Lead Zirconate Titanate (PZT-52) as a substrate, the preparation process of interdigitated electrodes by screen printing was studied. For initial polarization voltage determination, the local characteristic model of the actuator was extracted and the electric field was analyzed by a finite element method. By measuring the actuator’s axial displacement, we measured the actuator’s polarization effect. Various voltages, times and temperatures were evaluated to determine how polarization affects the actuator’s displacement. Optimal polarization conditions are 800 V, 60 min and 150 °C, with a maximum displacement of 0.88 μm generated by a PZT-52 tube actuator with interdigitated electrodes. PZT-52 tube actuators with a continuous electrode cannot be polarized under these conditions. The maximum displacement is 0.47 μm after polarization at 4 kV. Based on the results, the new actuator has a more convenient polarization process and a greater axial displacement from an application standpoint. It provides technical guidance for the preparation and polarization of the piezoceramic tube actuator. There is potential for piezoelectric tubular actuators to be used in a broader range of applications.
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Sardesai, Aditya N., Xavier M. Segel, Matthew N. Baumholtz, Yiheng Chen, Ruhao Sun, Bram W. Schork, Richard Buonocore, Kyle O. Wagner, and Holly M. Golecki. "Design and Characterization of Edible Soft Robotic Candy Actuators." MRS Advances 3, no. 50 (2018): 3003–9. http://dx.doi.org/10.1557/adv.2018.557.
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ABSTRACTOne of the goals of soft robotics is the ability to interface with the human body. Traditionally, silicone materials have dominated the field of soft robotics. In order to shift to materials that are more compatible with the body, developments will have to be made into biodegradable and biocompatible soft robots. This investigation focused on developing gummy actuators which are biodegradable, edible, and tasty. Creating biodegradable and edible actuators can be both sold as an interactive candy product and also inform the design of implantable soft robotic devices. First, commercially available gelatin-based candies were recast into pneumatic actuators utilizing molds. Edible robotic devices were pneumatically actuated repeatedly (up to n=8 actuations) using a 150 psi power inflator. To improve upon the properties of actuators formed from commercially available candy, a novel gelatin-based formulation, termed the “Fordmula” was also developed and used to create functional actuators. To investigate the mechanics and functionality of the recast gummy material and the Fordmula, compression testing and biodegradation studies were performed. Mechanical compression tests showed that recast gummy materials had similar properties to commercially available candies and at low strain had similar behavior to traditional silicone materials. Degradation studies showed that actuation was possible within 15 minutes in a biologically relevant solution followed by complete dissolution of the actuator afterwards. A taste test with elementary aged children demonstrated the fun, edible, and educational appeal of the candy actuators. Edible actuator development was an entry and winning submission in the High School Division of the Soft Robotics Toolkit Design Competition hosted by Harvard University. Demonstration of edible soft robotic actuators created by middle and high school aged students shows the applicability of the Soft Robotics Toolkit for K12 STEM education.
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Wiegand, Roland, Bastian Schmitz, Christian Pylatiuk, and Stefan Schulz. "Mechanical Performance of Actuators in an Active Orthosis for the Upper Extremities." Journal of Robotics 2011 (2011): 1–7. http://dx.doi.org/10.1155/2011/650415.
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The aim of the project OrthoJacket is to develop a lightweight, portable, and active orthosis for the upper limps. The system consists of two special designed fluidic actuators which are used for supporting the elbow function and the internal rotation of the shoulder. A new design of flexible fluid actuator (FFA) is presented that enables more design options of attaching parts, as it is allowed by conventional actuators with a stationary centre of rotation. This advantage and the inherent flexibility and the low weight of this kind of actuator predestined them for the use in exoskeletons, orthoses, and prostheses. The actuator for the elbow generates a maximum torque of 32 Nm; the internal rotation is supported with 7 Nm. Both actuators support the movement with up to 100% of the necessary power. The shells for the arm and forearm are made of carbon reinforced structures in combination with inflatable cushions.
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Li, Chong, Robert N. Dean, and George T. Flowers. "Nonlinear Observability Analysis of Micro-machined Electrostatic Actuators Using Self-Sensing." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, DPC (January 1, 2016): 001632–62. http://dx.doi.org/10.4071/2016dpc-wp36.
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Micro-machined electrostatic actuators (MEA) like parallel plate actuators (PPAs) and comb drive actuators (GCAs) are commonly used in many applications, including gyroscopes, resonators and RF switches. The detection of an actuators' mechanical motion is desired when they are combined with feedback control techniques, especially when the application requires high performance or is affected by disturbances. The motion can be detected by a variety of sensing techniques, including capacitive, piezoresistive and optical. Electrostatic parallel plate actuators can be modeled as a type of variable capacitor, which depends on the gap between a fixed electrode and a movable electrode. Thus, the displacement of the actuator can be obtained by measuring the capacitance. However, this practical method often requires high frequency excitation signal sources or additional sensing structures. The excitation power source not only affects the performance in the actuator's steady state, but it may also generate harmonics that distort the measurement signals due to the nonlinear characteristics of the actuator. In addition, the information about velocity may not be obtained without specific sensing structures. The additional structures occupy more space in each die, which could increase the cost and size, or decrease the performance. In this study, an estimator with a series resistor configuration is proposed. The estimator can estimate the displacement and velocity by measuring the voltage of the power supply and the voltage across the actuator itself. To evaluate the feasibility, a nonlinear observability analysis is applied. The analysis shows the observability index among different system states. A simulation study verified the proposed theories.
Dissertations / Theses on the topic "Mechanical actuators"
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Madden, John David Wyndham 1968. "Conducting polymer actuators." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/8820.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references.
Conducting polymers are unusual organic materials featuring high electronic conductivity. Recently it has been observed that some of these polymers change in dimension when their oxidation state is altered. Dimensional changes induced by electrochemical activation in the conducting polymer polypyrrole are investigated. Swept sine and step voltage and current inputs are employed to investigate the nature of this electro-mechanical coupling. Strains of up to 6 %, strain rates of 4 %/s, power to mass ratios of 40 W/kg and forces of up to 34 MN/m2 are achieved. Polypyrrole nearly equals mammalian skeletal muscle in power to mass and exceeds it in force by two orders of magnitude. A model is developed which predicts the electrochemical impedance, and relates electrical input to mechanical output. Observations and modeling indicate that diffusion and capacitive charging limit strain rate. The use of thinner films is predicted to increase strain rate and power to mass ratios by at least two orders of magnitude. Initial applications are likely to be in microelectromechanical systems.
by John David Wyndham Madden.
Ph.D.
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Broström, Carl. "Development of Tactile Actuators : Actuators for arm mounted hearing device." Thesis, Karlstads universitet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-79063.
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This report is a thesis work for a Master of Science in Mechanical Engineering at Karlstad University. More than 8.5 million people in the world are deaf but unable to get cochlear implants. It has been shown that by the use of actuators that stimulate the skin nerves in different patterns, people can learn to feel the sound on their skin. Invencon AB has developed a actuator concept that uses an electromagnetic actuator with a moving permanent magnet. The problem with this concept is that it locks itself in its upper position due to the permanent magnets around it. The aim of this project was to develop a new actuator concept without the problem of locking-up by starting from the beginning through a systematic product development process. Through research of actuator technology, dividing the project into phases and tasks used in the industry and methods presented in literature such as systematic and creative concept generation, a product development project was made on a product with the main function of imprinting the skin in recognizable patterns. It resulted in an actuator concept similar but different to the existing concept. The resulting concept solved the problem presented by utilizing a moving coil instead of a moving permanent magnet. A 3D model was made and a prototype was 3D printed and tested. Future work includes designing a suitable spring, a research on how wire management should be done, how to minimize the environmental impact from transport, if there are any hazardous substances during elimination and if the income from recycled material can be greater than the elimination cost.Denna rapport är ett examensarbete för civilingenjörsexamen i maskinteknik vid Karlstads universitet. Mer än 8,5 miljoner människor i världen är döva men är olämpliga för cochleaimplantat. Det har visats att användningen av aktuatorer som stimulerar hudnerverna i olika mönster kan lära människor att känna och lära sig ljudet på huden. Invencon AB har utvecklat ett aktuator koncept som använder sig utav en elektromagnetiskt aktuator med en rörlig permanent magnet. Problemet med detta koncept är att det låser sig i sitt övre läge på grund av de omringande permanenta magneternas påverkan. Syftet med detta projekt var att utveckla ett nytt aktuatorkoncept som inte fastnar i sitt övre läge genom att tillämpa systematisk produktutvecklings-process. Genom undersökandet av nuvarande aktuator teknologi, uppdelning av projektet i faser och uppgifter som används i branschen och metoder som presenteras i litteratur, såsom systematisk och kreativ konceptgenerering, gjordes ett produktutvecklingsprojekt på en produkt med huvudfunktionen att trycka på huden i igenkännbara mönster. Det resulterade i ett aktuatorkoncept som liknar men skiljer sig från det befintliga konceptet. Det resulterande konceptet löste problemet som presenterades genom att använda en rörlig spole i stället för en rörlig permanent magnet. En 3D-modell och sedan en prototyp framställdes och testades. Framtida arbete inkluderar utformningen av en lämplig fjäder, en undersökning om hur koppartråden bör hanteras, hur man minimerar miljöpåverkan från transport på produkten, undersöka om det finns några farliga ämnen under elimineringen av produkten och om intäkterna från återvunnet material kan vara större än elimineringskostnaden.
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Ismail, Ziad M. A. "Microprocessor control of electro-mechanical actuators." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/11785.
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This thesis is concerned with the use of all-electric systems for the closed loop position control of mechanical (valve) actuators. It embraces a wide range of topics including * the use of 3-phase induction motors and their speed/torque control using Pulse Width Modulation techniques * implementation of both analogue and digital (PID) controllers * Using computer simulation methods for the development of digital control algorithms and tuning techniques * the use of Computer Assisted Tuning methods for tuning up the position control loop. The major hardware activities described here are concerned with the design, development and construction of a 3-phase 115 volt inverter unit, an analogue controller, and interfaces to a single board microcomputer (SBC). The construction and test of the SBC is also described in the text. Details of the use of an analog controller to study and determine the transfer function of the inverter/actuator system is presented. Digital implementation of PID control (for actuator's position) by microcomputer is also described, together with the theoretical development of the control algorithm. Software activities consist of two major parts, plant simulation and software development for the microprocessor (embedded) controller. The derivation of a plant model from the results of on-line testing is given; from this a computer simulation is developed to study the effects of controller tuning parameters on the loop performance. Software development for the embedded controller covers Man-Machine Interfacing, tuning, and control functions. A new approach to the tuning of control systems is developed here, that of computer assisted tuning. Test results are given showing the effectiveness of CAT techniques for the tuning of the actuator position control loop; these tests also demonstrate the performance achieved using a digital PID controller. It is concluded that, provided plant parameters can be established, Computer Aided Tuning enables plant tuning to be carried out to meet specific performance targets (e.g. rise time, overshoot) set by the plant operator. Furthermore this can be carried out by a relatively unskilled operator.
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Torras, Andrés Núria. "Smart Opto-mechanical actuators for tactile applications." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/363930.
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La discapacitat visual és una greu amenaça que limita la capacitat de les persones per comunicar-se. Amb els anys, s’han explorat diverses propostes tecnològiques basades tan en estímuls auditius com tàctils per aportar solucions reals a la gent que pateix aquest tipus de discapacitat. Entre les més rellevants destaquen les tècniques d’audiodescripció i els dispositius Braille basats en actuació piezoelèctrica, que són els que actualment es troben al mercat.
A dia d’avui, al vell mig de la cursa tecnològica, hi ha una demanda creixent de comunicació rica i fluida mitjançant el tacte. Tan és així que la majoria interruptors, botons i tecles de gran part dels dispositius electrònics del nostre entorn estan essent substituïts per pantalles tàctils, afegint barreres físiques i augmentant les dificultats de comunicació de les persones cegues.
Noves generacions de materials, principalment els polímers, han despertat un gran interès en els darrers anys gràcies a les seves atractives propietats, que poden adaptar-se a la carta en funció de les necessitats. De tots ells, els elastòmers de cristalls líquids, LCE, en són un clar exemple. Els LCE tenen la capacitat intrínseca d’auto-organitzar-se a nivell molecular, desencadenant canvis controlats i totalment reversibles en les seves dimensions a escala macroscòpica, en resposta a diversos tipus d’estímuls externs; canvis que poden adaptar-se per desenvolupar actuadors capaços de produir tan esforços mecànics de tracció com d’empenta.
La recerca presentada en aquesta tesi descriu les principals característiques dels LCE des del punt de vista de l’enginyeria i discuteix les seves possibles aplicacions com a actuadors, amb el principal objectiu d’aportar solucions innovadores als actuals sistemes tàctils, a partir del disseny, fabricació i caracterització de diferents actuadors basats en aquests materials i la seva foto-actuació a partir de llum visible. Propostes que combinen tècniques de processament de materials i tecnologia de microsistemes per aportar solucions tecnològiques innovadores cap a una nova generació d’actuadors intel·ligents.La discapacidad visual es una grave amenaza que limita la capacidad de las personas para comunicarse. Con los años. Se han explorado diversas propuestas tecnológicas basadas tanto en estímulos auditivas como en estímulos táctiles para aportar soluciones reales al colectivo que sufre este tipo de discapacidad. Entre las más relevantes destacan las técnicas de audio descripción y los dispositivos Braille basados en actuación piezoeléctrica, que son los que actualmente se encuentran en el mercado. A día de hoy, en medio de la carrera tecnológica, hay una demanda creciente de comunicación rica y fluida a través del tacto. Tanto es así que la mayoría de los interruptores, botones y teclas de gran parte de los dispositivos electrónicos a nuestro alcance están siendo reemplazados por pantallas táctiles, añadiendo barreras físicas y aumentando las dificultades de comunicación de las personas ciegas. Nuevas generaciones de materiales, principalmente los polímeros, han despertado un gran interés en los últimos años gracias a sus atractivas propiedades, que pueden adaptarse a la carta en función de las necesidades. De todos ellos, los elastómeros de cristales líquidos, LCE, son un claro ejemplo. Los LCE tienen la capacidad intrínseca de auto-organizarse a nivel molecular, produciendo cambios controlados y totalmente reversibles de sus dimensiones a escala macroscópica, en respuesta a varios tipos de estímulos externos; cambios que pueden adaptarse a demanda para desarrollar actuadores capaces de producir distintos tipos de esfuerzos mecánicos de tracción. La investigación recogida y presentada en este documento de tesis describe las principales características de los LCE desde el punto de vista de la ingeniería y discute sus posibles aplicaciones cómo actuadores, con el principal objetivo de aportar soluciones innovadoras a los actuales sistemas táctiles, a partir del diseño, fabricación y caracterización de distintos actuadores basados en estos materiales y su foto-actuación a partir de luz visible. Propuestas que combinan técnicas de procesado de materiales y tecnología de microsistemas para aportar soluciones tecnológicas innovadoras hacia una nueva generación de actuadores inteligentes.
Visual disability is a serious threat that limits the persons’ ability to communicate. Over the years several attempts for the development of technologies based on audio and tactile stimuli have been explored to provide real solutions to individuals with this disability. Among them, audio description techniques and Braille devices based on piezoelectric actuation are the most relevant solutions on the market. Nowadays, with all the technological improvements, there is a growing demand for rich communication through touch. Thus switches, buttons and keyboards of most commonly used electrical devices are being replaced by tactile displays, adding new physical barriers and increasing communications difficulties of blind people. New generation of materials, especially soft polymer composites, have been of increased interest in the last few years due to their many attractive properties, which can be tailored on demand to achieve a broad range of requirements. Liquid-crystalline elastomers, LCE, are a clear example. Such materials possess the intrinsic ability to self-organize at molecular level resulting in a controllable and fully reversible change on their dimensions at macroscale in response to applied external stimuli, which can be easily adapted to make actuators producing pulling or pushing forces. The research presented in this thesis describes the main characteristics of LCE materials from engineering point of view and discusses their potential applications as actuators with the main objective to provide innovative solutions towards current tactile available systems, through the design, fabrication and characterization of different actuator approaches based on these interesting elastomeric materials and their photo-induced actuation using visible light. Novel approaches combining material processing techniques and microsystems technology to provide original solutions towards a new generation of smart actuators.
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Güler, Kenan, and Milan Andelkovic. "Shock Load Absorption of Electro-mechanical Actuators." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300158.
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När ett ställdon får som krav att kunna överföra höga krafter i relativt höga hastigheter med en dessutom väldigt hög precision är elektromekaniska ställdon oftast att föredra. En traditionell pinjong-kuggstång-uppställning uppfyller vissa av de kraven, men om kraften ska ökas behövs det fler än ett pinjongpar. Begränsningar på tillverkningsprecisionen för dessa kugghjul gör att deras ansättning på kuggstången blir omöjlig för uppsättningar med fyra eller åtta pinjongpar eftersom ett sådant ställdon blir statiskt överbestämt och på grund av tillverkningstoleranser kan det bli svårt att erhålla jämn lastfördelning mellan pinjongerna. Därför utvecklade företaget Cascade Drives innovativa kugghjul (cdGear) med s.k. Flex Units som har en självinställningsfunktion i själva kugghjulen vilken tillgodogör för tillverkningstoleranser och spelet som ska undvikas. Flex Units består av bl.a. av gummielement som förutom att tillåta enstaka pinjongers rotation för inställning även har en mycket bra dämpningsförmåga, särskilt vad det gäller plötsliga stötlaster. Stötbelastningar förekommer ofta vid drift av arbetsmaskiner där Cascade Drives-ställdonet har hittat sin största användning. Plötsliga och höga stötbelastningar, som t.ex. när en grävmaskin kör in i ett gupp eller en snöröjare kör på en kantsten kan påverka maskinkomponenternas livslängd betydligt. Ett eventuellt maskinhaveri riskerar skador på både fordonet, föraren och omgivningen. Rapporten redogör för hur en teoretisk modell byggdes upp för att matematiskt beskriva dessa stötbelastningar och metoder som användes i datorprogrammet MATLAB för att beskriva det dynamiska förloppet i ställdonet under stötbelastningens inverkan. Ytterligare redogörs avgränsningar som görs på modellen och tills slut ges förslag på möjliga förbättringar för vidare arbete med modellen. Projektets syfte är inte att utvärdera hela Cascade Drives-ställdonet utan endast skapa en modell som kan tillämpas på alla möjliga scenarion av stötmoment. Rapporten innehåller några exempel på stötbelastningar och redogör för hur de påverkar olika kugghjul som ingår i ställdonet och hur det påverkar maskinen i sin helhet. För de scenarion som MATLAB-koden testades för noteras en mycket god dämpningsförmåga även vid förhållandevis höga laster (flera ton av last). Detta tack vore de patenterade flexenheterna och gummikutsarna, som kan dimensioneras och väljas för material beroende på tillämpningsområde och det tillåtna monteringsutrymmet i ställdonet. Denna modell baseras på dimensioner och materialdata tillförda av uppdragsgivaren för det aktuella ställdonet. Mer noggranna värden och en bättre kännedom om tillämpningsområdet skulle ge möjligheter för omdimensionering av flexenheterna och en mer optimal dämpnings- och momentöverföringsfunktion i ställdonet.When requirements for an actuator include big momentum, fast transfer of the forces with a very high positioning precision, electro-mechanical actuators are often the constructor's first choice. A traditional rack-pinion setup answers to some of the requirements, but if the goal is to increase the forces which the rack undergoes, more than one pair of pinions is necessary. Production limitations, inevitable tolerances and gaps as a result make it almost impossible to have setups of four or eight pinion-pairs on one single rack because a such actuator would be statically overdetermined and out of manufacturing costs it can be difficult to procure equal load distribution between the pinions. Overcoming this challenge helped the company called Cascade Drives based in Stockholm, Sweden, to patent a new type of gear they call cdGear. CdGear give pinion the ability to position itself to the rack automatically, due to the rubber parts inside the gear that also work as shock load-absorbers for the whole actuator. Shock loads are very frequent in the type of work where these actuators found their biggest application. Heavy-duty machines are often exposed to sudden and high loads on their moving parts, i.e. when an excavator drives over a bump or a snow-plowing machine drives into a curbstone. The sudden impact on the working parts will cause a greater stress on the equipment, shorten its lifespan and a machine part's failure can even cause serious damage on workers, machine, and the environment. This thesis describes a theoretical model created for the purpose of calculating the effects of shock loads on the actuator based on the mathematical description of gear behaviour during the impact. It also includes the methods used to create a model in MATLAB that simulates the dynamical forces, model's limitations, and suggestions on how to improve its accuracy. This project does not aim to improve the overall performance of the Cascade Drives-actuator, but rather deliver a sufficient virtual model that works for the most shock load scenarios, that in the end will give the commissioner useful data and clues on how to improve their product. The thesis does include a few different shock load scenarios that prove the code's functionality and give answers to how some shock loads affect gears inside the actuator and performance of the machine itself. For the virtual tests done Cascade Drives-actuator performs very good in damping the shock loads, even when the loads reach a corresponding force of a few tons. CdGear and elasticity inside its rubber parts are the main reason why the actuator performs so well, and the rubber parts inside the gear can be changed in respect to the application and the mounting space allowed. The model described in the report includes dimensions and material's data provided by the commissioner for the actuator in question. More exact and relevant results can be acquired if the input values are more precise, and the area of usage is described in more detail. More optimal rubber parts inside the CdGear would result in a better performing actuator that besides being able to transfer huge torque also could absorb the inevitable shock loads in a very satisfactory manner.
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Morrell, John Bryant. "Parallel Coupled Micro-Macro Actuators." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/7066.
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This thesis presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the Parallel Coupled Micro-Macro Actuator, or PaCMMA. In this system, the micro-actuator is capable of high bandwidth force control due to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft and increases the dynamic range of force. Performance improvement over single actuator systems was expected in force control, impedance control, force distortion and reduction of transient impact forces. A set of quantitative measures is proposed and the actuator system is evaluated against them: Force Control Bandwidth, Position Bandwidth, Dynamic Range, Impact Force, Impedance ("Backdriveability'"), Force Distortion and Force Performance Space. Several theoretical performance limits are derived from the saturation limits of the system. A control law is proposed and control system performance is compared to the theoretical limits. A prototype testbed was built using permanenent magnet motors and an experimental comparison was performed between this actuator concept and two single actuator systems. The following performance was observed: Force bandwidth of 56Hz, Torque Dynamic Range of 800:1, Peak Torque of 1040mNm, Minimum Torque of 1.3mNm. Peak Impact Force was reduced by an order of magnitude. Distortion at small amplitudes was reduced substantially. Backdriven impedance was reduced by 2-3 orders of magnitude. This actuator system shows promise for manipulator design as well as psychophysical tests of human performance.
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Del, Zio Michael R. (Michael Robert) 1982. "Conducting polymer actuators : temperature effects." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35656.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references.
In order to utilize conducting polymer actuators as a viable engineering solution, it is necessary to produce usable levels of force with a reasonable bandwidth. Polypyrrole actuated at temperatures as high as 100 °C increases stress magnitudes by as much as 4x and stress rates by 5x. The effect is caused by a combination of decreased solution resistance and increased ion diffusion within the polymer. However, these temperatures cause accelerated degradation due to the time-temperature correlation common to viscoelastic polymers. Actuation at these temperatures can decrease cycle life by as much as 20x. Excessive heating without actuation can also result in poor actuator performance. Impedance spectroscopy coupled with electro-mechanical analysis highlighted previous results and also showed an improved frequency response from actuation at high temperatures.
by Michael R. Del Zio.
S.M.
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Chen, Angela Y. (Angela Ying-Ju) 1982. "Large displacement fast conducting polymer actuators." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35659.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaves 93-96).
Conducting polymers are a promising class of electroactive materials that undergo volumetric changes under applied potentials, which make them particularly useful for many actuation applications. Polypyrrole , is one of the most common conducting polymers of choice for the development of actuator technologies and has been well characterized in its mechanical, electrical, and electrochemical response. Although capable of producing almost 10 times more active stress for a given cross-sectional area than skeletal muscle, strains are relatively low on the order of 1 to 2 %, as are strain rates, which are on the order of a couple percent per second. Small strains can be amplified to produce large bending displacements by configuring the conducting polymer film in a trilayer configuration with two conducting polymer films sandwiching an electrolyte gel layer. This thesis focuses on the development of conducting polymer bending actuators in air. There is a strong correlation found between applied voltage, temperature, and the speed of actuation. Several experiments were carried out to determine the effect of temperature on the mechanical, electrical, and electrochemical properties of the components of the trilayer.
(cont.) This data coupled with thermal profiles of trilayers during actuation, electrochemical profiles, and force generation plots of the trilayers shed light on how these bending actuators can be optimized and integrated into different applications such as propulsion mechanisms for autonomous underwater vehicles.
by Angela Ying Ju Chen.
S.M.
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Anquetil, Patrick A. T. (Patrick Armand T. ). 1973. "Large contraction conducting polymer molecular actuators." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30349.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2005.Vita. Leaf 239 blank.
Includes bibliographical references.
The development of powerful and efficient artificial muscles that mimic Nature will profoundly affect engineering sciences including robotics and prosthetics, propulsion systems, and microelectromechanical systems (MEMS). Biological systems driven by muscle out-perform human-engineered systems in many key aspects. For example, muscle endows animals with a level of dexterity and speed that has yet to be emulated by even the most complex robotic system to date. Conducting polymers were chosen for research as actuators, based on a review of the relevant properties of all known actuators and active materials. Key features of conducting polymer actuators include low drive voltages (1 - 2 V) and high active strength (10 - 40 MPa) but moderate active strains (2 %). Active strains of 20 %, which human skeletal muscle is capable of, are desirable for applications in life-like robotics, artificial prostheses or medical devices. This thesis focuses on two approaches to create large contraction in conducting polymer actuators. The first strategy utilizes polypyrrole (PPy), a conducting polymer actuator material that contracts and expands based on a bulk ion swelling mechanism. Optimization of the polymer activation environment via room temperature ionic liquids enables PPy actuators to generate large contractions (16.3 % recoverable strain at 2.5 MPa, 21 % max) at slow speeds (0.4 %/s). In addition, cycle life can reach 10⁵ cycles without significant polymer degradation. This thesis presents an in-depth characterization of the behavior of polypyrrole actuators in room temperature 1-butyl-3-methyl imidazolium tetrafluoroborate liquid salt electrolyte.
(cont.) The characterization includes the assessment of passive and electroactive mechanical properties as well as electrical and morphological properties. Using Nature's actin-myosin molecular engine as a source of inspiration, the second approach uses molecular mechanisms to create motion. In this bottom-up approach molecules are rationally designed from the molecular level for specific actuation properties. Such active molecular building blocks include shape changing, load bearing, passively deformable or hinge-like molecular elements. Several novel materials based on contractile molecular design were synthesized and their active properties characterized.
by Patrick A.T. Anquetil.
Ph.D.
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Yang, Dian. "Soft Pneumatic Actuators Using Negative Pressure." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493304.
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Soft robotics is a growing field where scientists and engineers collaborate to design machines that collaborate safely with humans (namely “collaborative robot”), and manipulate soft or delicate objects safely. Soft pneumatic actuators are excellent tools in building soft robots, since both the elastomer used in building the actuators and the air used to power them are naturally compliant. This compliance distributes the contact force over the area of contact, and limits the contact pressure. Soft pneumatic actuators changes shape with pressure, and use strain-limiting components imbedded in an elastomeric enclosure to generate various motions.
This dissertation explores design and fabrication of soft pneumatic actuators by combining vacuum with reversible buckling of elastomeric beams. Buckling is a classical mechanical instability often seen as a failure mode in hard materials. The reversible buckling of elastomeric beams, however, allows buckling to be harnessed as a method to generate a range of motion, and allows the fabrication of actuators that mimic the performance of actuators (i.e. muscles) found in nature.
Chapter 1 provides a short overview of the history of soft pneumatic actuators, and of the use of vacuum instead of pressure as a source of power. Chapter 2 and Appendix I describe rotary soft pneumatic actuators—the buckling actuator—based on vacuum and buckling of elastomeric beams. Chapter 3 and Appendix II describe the design of linear soft pneumatic actuators—vacuum-actuated muscle-inspired pneumatic structures (VAMPs)—based on the same technology, which mimics the mechanical performance and many useful features of human muscle. Chapter 4 and Appendix III describe a design of vacuum-actuated soft linear actuators (VASAs) that overcome the usual limit of one atmosphere in the output pressure by generating a mechanical advantage. Appendix IV demonstrates that the buckling of arrays of elastomeric beams can also be used in building soft metamaterials with useful functions, such as shape memory metamaterials. Beyond soft pneumatics actuators, novel methods of non-damaging manipulations, such as magnetic levitation, can prove useful in orientation and examination of objects (Appendix V, VI).Engineering and Applied Sciences - Engineering Sciences
Books on the topic "Mechanical actuators"
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Borboni, Alberto. Meso- to Micro- Actuators. London: Taylor and Francis, 2008.
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Tzou, H. S. Precision Sensors, Actuators and Systems. Dordrecht: Springer Netherlands, 1992.
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Gomis-Bellmunt, Oriol, and Lucio Flavio Campanile. Design Rules for Actuators in Active Mechanical Systems. London: Springer London, 2010. http://dx.doi.org/10.1007/978-1-84882-614-4.
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Mazzoleni, Mirko, Gianpietro Di Rito, and Fabio Previdi. Electro-Mechanical Actuators for the More Electric Aircraft. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-61799-8.
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Gomis-Bellmunt, Oriol. Design rules for actuators in active mechanical systems. London: Springer, 2010.
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United States. National Aeronautics and Space Administration., ed. 40 HP electro-mechanical actuator. [Washington, DC]: National Aeronautics and Space Administration, 1996.
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United States. National Aeronautics and Space Administration., ed. 40 HP electro-mechanical actuator. [Washington, DC]: National Aeronautics and Space Administration, 1996.
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Engineers, Society of Automotive, and International Scientific Conference on "Smart Mechanical Systems--Adaptronics" (2nd : 1997 : Otto von Guericke University of Magdeburg), eds. Smart mechanical systems--adaptronics. Warrendale, PA: Society of Automotive Engineers, 1998.
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United States. National Aeronautics and Space Administration., ed. Design and application of electromechanical actuators for deep space missions. [Washington, DC: National Aeronautics and Space Administration, 1993.
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Center, Langley Research, ed. Linear proof mass actuator. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.
Find full textBook chapters on the topic "Mechanical actuators"
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Stoecker, W. F., and P. A. Stoecker. "Actuators." In Microcomputer Control of Thermal and Mechanical Systems, 105–22. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-6560-0_6.
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Toi, Yutaka, and Seongwon Yoo. "Computational Modeling of Mechanical Sensors Using Ionic Electroactive Polymers." In Soft Actuators, 389–401. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-6850-9_23.
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Caux, Stéphane, and Maurice Fadel. "Observation of the Rotor Position to Control the Synchronous Machine without Mechanical Sensor." In Electrical Actuators, 405–59. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118558119.ch8.
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Kaltenbacher, Manfred. "Mechanical Field." In Numerical Simulation of Mechatronic Sensors and Actuators, 93–135. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40170-1_3.
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Kaltenbacher, Manfred. "Mechanical Field." In Numerical Simulation of Mechatronic Sensors and Actuators, 35–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-05358-4_3.
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Firoozian, Riazollah. "Actuators Based on Electro-Rheological Fluid." In Mechanical Engineering Series, 119–30. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-85460-1_8.
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Firoozian, Riazollah. "Actuators Based on Electro-Rheological Fluid." In Mechanical Engineering Series, 131–42. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-07275-3_8.
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Kern, Thorsten A., Henry Haus, Marc Matysek, and Stephanie Sindlinger. "Actuator Design." In Springer Series on Touch and Haptic Systems, 309–429. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04536-3_9.
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AbstractActuators are the most important elements of any haptic device. Their selection or design significantly influences the quality of the haptic impression. This chapter deals with commonly used actuators, organized according to their physical principle of operation. It focuses on the electrodynamic, electromagnetic, electrostatic and piezoelectric actuator principles. Each actuator type is discussed in terms of its main physical principles, with examples of sizing and one or more applications. Other, less frequently used actuator principles are mentioned in several examples. The preceding chapters focused on the basics of control engineering and kinematic design. They covered topics of structuring and fundamental character. This and the following chapters deal with the design of technical components as parts of haptic devices. Experience teaches us that actuators for haptic applications can rarely be found “off-the-shelf”. Their requirements always include some outstanding features in rotational frequency, power-density, working point, or geometry. These specialities make it necessary and helpful for users to be aware of the capabilities and possibilities for modifying existing actuators. Hence this chapter addresses both groups of readers: the users who want to choose a certain actuator and the mechanical engineer who intends to design a specific actuator for a certain device from scratch.
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Jiang, Lingling, Zhonghu Sun, Xianjian Jia, Xiaoyan Li, and Wulong Duan. "Controller Design for Electro-mechanical Actuators." In Lecture Notes in Electrical Engineering, 466–72. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7423-5_46.
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Kaltenbacher, Manfred. "Coupled Electrostatic-Mechanical Systems." In Numerical Simulation of Mechatronic Sensors and Actuators, 339–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40170-1_10.
Full textConference papers on the topic "Mechanical actuators"
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Huang, Shih-Lin, Chin-Chou Chu, Chien C. Chang, and Horn-Sen Tzou. "Spatial Electrostrictive Actuation of Circular Cylindrical Tubes." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67997.
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Circular cylindrical shells are common components in aerospace structures and many other engineering systems, e.g., rockets, tubes, piping systems, peristaltic pumps, storage tanks, etc. Electromechanical actuators laminated on the shell surfaces can certainly strengthen the shell when needed. Or, regulated inputs to the surface actuators can introduce prescribed surface waves to control the shell oscillation. This study is to evaluate spatial actuation characteristics of circular cylindrical shells using segmented electrostrictive actuators. Electrostrictive actuations induced by surface laminated electrostrictive actuators are defined first. Governing equations of a hybrid circular cylindrical shell/electrostrictive actuator system are formulated. The total electrostrictive actuation and its contributing circumferential membrane/bending and longitudinal bending components are evaluated with respect to shell modal characteristics, design parameters and control voltages. The actuator’s quadratic behavior only generate a positive control force or moment and thus an actuator patch can suppress (or amplify) the vibration in the positive (or negative) displacement. Accordingly, the quadratic electrostrictive actuation suggests that appropriate input voltage(s) need to be carefully applied to specific actuator(s) or regions in order to control, but not to amplify, the shell oscillations. Based on the spatially distributed modal actuation, generic design guidelines and optimal actuation locations are proposed.
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Wu, Chia-Che, Cheng-Chun Lee, G. Z. Cao, and I. Y. Shen. "Effects of Corner Frequency on Bandwidth and Resonance Amplitude in Designing PZT Thin-Film Actuators: An Experimental Demonstration." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79102.
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In the last decade, Lead Zirconate Titanate Oxide (PZT) thin-film actuators have received increasing attention because of their high frequency bandwidth, large actuation strength, fast response, and small size. The PZT film thickness is usually less than several microns as opposed to hundreds of microns for bulk PZT patches that are commercially available. As a result, PZT thin-film actuators pose unique vibration issues that do not appear in actuators with bulk PZT. Two major issues affecting actuator performance are the frequency bandwidth and the resonance amplitude. As an electromechanical device, a PZT thin-film actuator’s bandwidth and resonance amplitude depend not only on the lowest natural frequency ωn of the actuator’s mechanical structure but also on the corner frequency ωc of the actuator’s RC-circuit. For PZT thin-film actuators, the small film thickness implies large film capacitance C and small ωc. When the size of the actuator decreases, frequency ωn increases dramatically. As a result, improper design of PZT thin-film actuators could lead to ωc ≪ ωn substantially reducing the actuator bandwidth and the resonance amplitude. This paper is to demonstrate this phenomenon through calibrated experiments. In the experiments, frequency response functions of a fixed-fixed silicon beam with a 1-μm thick PZT film are measured through use of a laser Doppler vibrometer and a spectrum analyzer. The silicon beam has multiple electrodes with a wide range of resistance R and corner frequency ωc. The experimental results confirm that the actuator bandwidth and resonance amplitude are substantially reduced when ωc ≪ ωn.
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Sekhavat, P., N. Sepehri, and Q. Wu. "Asymptotic Impact Control of Hydraulic Actuators With Friction." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61275.
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The focus of this work is stabilization of hydraulic actuators during the transition from free motion to constraint motion and regulating the intermediate impacts that could drive the system unstable. In our past research, we introduced Lyapunov-based nonlinear control schemes capable of fulfilling the above goal by resting the implement on the surface of the environment before starting the sustained-contact motion. The hydraulic actuator’s stick-slip friction effect was, however, either not included in the analysis or not compensated by the control action. In this paper, the application of our previously introduced friction compensating position control scheme is extended to impact regulation of a hydraulic actuator. Theoretical solution and stability analyses as well as actual experiments prove that such control scheme is also effective for asymptotic impact control (with no position steady-state error) of hydraulic actuators in the presence of actuator’s dry friction.
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Jiang, X. N., P. W. Rehrig, W. S. Hackenberger, J. Moore, S. Chodimella, and B. Patrick. "Single Crystal Piezoelectric Actuators for Advanced Deformable Mirrors." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60504.
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In this paper, single crystal piezoelectric actuators are developed and demonstrated as a means of increasing actuator authority while maintaining strain precision for adaptive optics used large throw deformable mirror applications. Single crystal (PMN-PT crystal) stack actuators with foot print size of 5 mm × 5 mm and height varied from 16 mm to 21 mm have been designed, fabricated and tested. The actuation stroke larger than 50 μm is obtained under driving electric field of 15 KV/cm for single crystal stack actuators. In-plane actuation stroke is about 25 μm under 8KV/cm for single crystal plate actuators. The characterization results show that the single crystal piezoelectric actuators hold enhanced stroke and coupling coefficient (>0.83) under lower driving field comparing with PZT counterpart, while keep the nature of piezoelectric actuations with high precision, high resolution, fast response under high preload stress. The potential benefits of incorporating these actuators in a deformable mirror (DM) design were demonstrated by system modeling using the Integrated Optical Design Analysis Software (IODA) developed by SRS. The modeling shows that low order aberrations with peak to valley errors as large as 40 microns could be corrected to diffraction limited performance with a reasonable number of actuators and acceptable actuator forces and face sheet stresses. In the case of DM correction with 20 microns of 1st-Order Astigmatism-X error (Peak to valley: 38.74 μm, RMS error: 8.13 μm), the corrected wavefront error was reduced to PV of 0.26 μm and RMS error of 0.024 μm, which suggest promise for large throw DM applications.
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Wilde, Andreas, Peter Schneider, and Wellinton Presoto. "Modeling Electro-Mechanical Actuators." In 2006 IEEE Conference on Computer-Aided Control Systems Design. IEEE, 2006. http://dx.doi.org/10.1109/cacsd.2006.285469.
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Wilde, Andreas, Peter Schneider, and Wellinton Presoto. "Modeling electro-mechanical actuators." In 2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control. IEEE, 2006. http://dx.doi.org/10.1109/cacsd-cca-isic.2006.4776684.
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Jouppila, V., and A. Ellman. "Multiplexed Force Control of Pneumatic Muscles." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13645.
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Pneumatic actuators are often used in applications that require high power-to-weight ratio, combined with low price and clean and fast operation. However, due to the compressibility of air and highly nonlinear behavior of seal friction, the position and force control of these actuators is difficult to manage. As a result, pneumatic cylinders have been used for many years solely in simple repetitive tasks requiring only a very limited amount of system control. Nonetheless, the pneumatic actuators have properties such as compactness, high power-to-weight ratio, and simplicity that are desirable features in advanced robotics. To overcome the shortcomings, a number of advanced pneumatic components have been developed, of which the most promising is the pneumatic muscle. Compared to a cylinder, a pneumatic muscle not only has a higher power-to-weight and power-to-volume ratio but it is also almost frictionless and has zero leakage. In spite of the muscle actuator's nonlinear force-to-contraction characteristics, many motion and force control methods have been successfully applied to it. The characteristics of the actuator enable it to be used in simple positioning systems and as a variable gas spring. The actuator's almost linear pressure-to-force ratio is extremely well-suited to a variety of gripping and pressing applications. Due to the muscle actuator's characteristics and recent developments in pneumatic valve technology, there is an opportunity to share a single pressure control servo valve among multiple muscle actuators. The multiplexed control of the actuators with only one servo valve reduces the system costs significantly. In this paper we investigate the feasibility of employing multiplexed force control of four pneumatic muscle actuators. In the system, pressure is controlled by a single proportional pressure valve. High-speed switching valves are used for activating the pressure control for each muscle actuator in the desired manner. Pneumatic cylinders are attached to the other ends of the muscles in order to cause controllable position disturbances. The displacement, force and pressure of each muscle are measured with appropriate sensors. The system behavior is investigated under position disturbances.
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Seibel, Arthur, and Lars Schiller. "Integrated Curvature Sensing of Soft Bending Actuators Using Inertial Measurement Units." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87104.
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We introduce a sensor concept for an integrated measurement of the curvature angle of soft bending actuators using inertial measurement units (IMUs). In particular, IMUs are placed at both ends of the soft bending actuator, and the integrated magnetic sensors are used for small and the integrated acceleration sensors for medium and large inclination angles of the soft actuator’s bending plane. The experimental results show absolute measurement errors of up to 20° for small and less than 5° for medium and large inclination angles. Furthermore, we investigate experimentally whether the assumption of a constant curvature in our sensor concept is still fulfilled when the soft bending actuator is loaded by an external force at its free end. The results indicate that this is the case for loading masses of up to 30 g at large inclination angles.
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Bharti, Smita, and Mary Frecker. "Compliant Mechanical Amplifier Design Using Multiple Optimally Placed Actuators." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42658.
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The paper discusses a methodology for designing compliant mechanisms with piezoelectric actuation to obtain maximized deflection and force at output. The focus is on design of compliant mechanisms with multiple optimally placed and sized piezoelectric actuators. Thus the number, length and position of actuators in the body of the compliant mechanism are optimized in addition to maximizing the output deflection and force. Results demonstrate that compliant mechanisms with multiple, optimally placed actuators outperform those with a single actuator placed at a predetermined location.
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Webber, Kyle G., and Christopher S. Lynch. "Analysis of the Non-Linear Behavior of ECLIPSE Actuators." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81057.
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This work discusses the development and characterization of rectangular shaped Epoxy Composite Laminated Piezoelectric Stress-Enhanced actuators (ECLIPSE). ECLIPSE actuators are unimorph type d31 actuators that are manufactured with a lead zirconate titanate (PZT) plate sandwiched between unidirectional Kevlar 49/epoxy composite layers with dissimilar coefficients of thermal expansion in orthogonal directions. Cooling the actuator from an elevated curing temperature resulted in a residual stress gradient through the actuator, a compressive stress on the brittle piezoelectric plate, and a large out-of-plane deformation. Extended classical lamination theory (ECLT) is used to model the residual stress state and curvature of the actuator. The model results are compared to the classical lamination theory. The ECLT was developed by Hyer to explain the non-linear behavior of unsymmetric cross-ply laminates [1-3]. Three actuator layups were fabricated and characterized: [90/PZT/90/0], [90/90/PZT/90/0/0], and [90/90/90/PZT/90/0/0/0]. It is shown that geometric non-linearity is important to consider when modeling ECLIPSE actuators.
Reports on the topic "Mechanical actuators"
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Walraven, Jeremy Allen, Michael Sean Baker, Thomas Jeffrey Headley, and Richard Anton Plass. Final report : compliant thermo-mechanical MEMS actuators, LDRD #52553. Office of Scientific and Technical Information (OSTI), December 2004. http://dx.doi.org/10.2172/920746.
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Ferraris, John P., Ray H. Baughman, and Richard Vaia. SPRING Project on Mechanical Energy on Demand from High Strain Actuators. Fort Belvoir, VA: Defense Technical Information Center, September 2009. http://dx.doi.org/10.21236/ada563611.
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