Dissertations / Theses on the topic 'Actuators - Design and construction'
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1
Wan, Weijie 1982. "Simulation and optimization of MEMS actuators and tunable capacitors." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99798.
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Micro-Electro-Mechanical Systems (MEMS) have played an important role in modern microelectronics, thermal, mechanical and hybrid systems. MEMS technology is a very promising means that might have a great impact on almost every corner of the society. Although many design methodology of MEMS already exists, not as much attention was given to the synthesis and optimization of MEMS devices. This thesis focuses on the optimization of MEMS actuators and MEMS tunable comb drive capacitors. The optimization is based on changing device geometry to achieve desired output parameter profile. For example in the design of MEMS tunable comb drive capacitors, the output parameter is the capacitance tuning range. Numerical experiments were performed to show the successful implementation of the optimization method.
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Hopkinson, David P. "Development of stress gradient enhanced piezoelectric composite unimorph actuators." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/16372.
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McCray, Thomas Wade. "Construction and characterization of removable and reusable piezoelectric actuators." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06232009-063342/.
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Wei, Yu Zhang. "Design and development of new micro-force sensors." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691170.
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Tognetti, Lawrence Joseph. "Actuator design for a haptic display." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16926.
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Wu, Zhi Gang. "Design, analysis and experiment of novel compliant micromanipulators with grippers driven by PZT actuators." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691021.
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Creyts, Don Stafford IV. "Design and fabrication of a MEMS magnetic bistable valve." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17950.
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Hudson, Tina Ann. "A biomorphic integrated-circuit implementation of muscular contraction." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14976.
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Oates, William Sumner. "Piezoelecytric pump design and system dynamic model." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17679.
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Webber, Kyle Grant. "Characterization of Actuation and Fatigue Properties of Piezoelectric Composite Actuators." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7127.
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Epoxy composite laminated piezoelectric stress-enhanced actuators (ECLIPSE) have been developed for potential applications by the United States Air Force and others. This class of actuators offers several advantages over other unimorph actuators such as lighter weight, design flexibility, and short production time. Anisotropic differential thermal expansion is utilized in the design of the actuators to achieve large out-of-plane curvature and place the brittle piezoelectric ceramic in residual compression. The numerous composite material choices and configurations can be used to control characteristics of the actuator such as radius of curvature and force output.
ECLIPSE actuators were characterized during this study. They were made from layers of Kevlar 49/epoxy composite and a lead zirconate titanate ceramic (PZT) plate. All ECLIPSE actuators tested were built with a PZT plate with the same dimensions and material, but had different layup configurations. By changing the stacking order of the composite and PZT material, characteristics of the actuator were altered. The performance of each ECLIPSE actuator was compared. The maximum achievable displacement of each actuator was measured by cyclically applying an electric field at low frequency between zero and the maximum electric field allowable for the piezoelectric material. The frequency was also increased to a resonance condition to characterize the fatigue behavior of these actuators. In addition, the force output of various actuators was measured with a four-point bending apparatus. The experimental data was compared to a classical lamination theory model and an extended classical lamination theory model. These models were used to predict actuator behavior as well as to calculate the stress and strain distribution through the thickness of the actuator.
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Sutanto, Bintoro Jemmy. "An Electromagnetic Actuated Microvalve Fabricated on a Single Wafer." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4891.
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Microvalves are essential components of the miniaturization of the fluidic systems to control of fluid flow in a variety of applications as diverse as chemical analysis systems, micro-fuel cells, and integrated fluidic channel arrangements for electronic cooling. Using microvalves, these systems offer important advantages: they can operate using small sample volumes and provide rapid response time.
This PhD dissertation presents the world first electromagnetically actuated microvalve fabricated on a single wafer with CMOS compatibility. In this dissertation, the design, fabrication, and testing results of two different types of electromagnetic microvalves are presented: the on/off microvalve and the bistable microvalve with latching mechanism. The microvalves operate with power consumption of less than 1.5 W and can control the volume flow rate of DI water, or a 50% diluted methanol solution in the range 1 - 50 µL in. The leaking rate of the on/off microvalve is the order of 30 nL/min. The microvalve demonstrated a response time for latching of 10 ms in water and 0.2 ms in air. This work has resulted in a US patent, application no. 10/699,210.Other inventions that have been developed as a result of this research are bidirectional, and bistable-bidirectional microactuators with latching mechanism, that can be utilized for optical switch, RF relay, micro mirror, nano indenter, or nano printings.
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Ha, Kwangtae. "A Combined Piezoelectric Composite Actuator and Its Application to Wing/Blade Tips." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7575.
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A novel combined piezoelectric-composite actuator configuration is proposed and analytically modeled in this work. The actuator is a low complexity, active compliant mechanism obtained by coupling a modified star cross sectional configuration composite beam with a helicoidal bimorph piezoelectric actuator coiled around it. This novel actuator is a good candidate as a hinge tension-torsion bar actuator for a helicopter rotor blade flap or blade tip and mirror rotational positioning. In the wing tip case, the tip deflection angle is different only according to the aerodynamic moment depending on the hinge position of the actuator along the chord and applied voltage because there is no centrifugal force. For an active blade tip subject to incompressible flow and 2D quasi steady airloads, its twist angle is related not only to aerodynamic moment and applied voltage but also to coupling terms, such as the trapeze effect and the tennis racquet effect. Results show the benefit of hinge position aft of the aerodynamic center, such that the blade tip response is amplified by airloads. Contrary to this effect, results also show that the centrifugal effects and inertial effect cause an amplitude reduction in the response. Summation of these effects determines the overall blade tip response. The results for a certain hinge position of Xh=1.5% chord aft of the quarter chord point proves that the tip deflection target design range[-2,+2] can be achieved for all pitch angle configurations chosen.
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Swanson, Davin Karl. "Implementation of arbitrary path constraints using dissipative passive haptic displays." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/17606.
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Almaghrawi, Ahmed Almaamoun. "Collaborative design in electromagnetics." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103363.
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We present a system architecture and a set of control techniques that allow heterogeneous software design tools to collaborate intelligently and automatically. One of their distinguishing features is the ability to perform concurrent processing. Systems based on this architecture are able to effectively solve large electromagnetic analysis problems, particularly those that involve loose coupling between several areas of physics. The architecture can accept any existing software analysis tool, without requiring any modification or customization of the tool. This characteristic is produced in part by our use of a neutral virtual representation for storing problem data, including geometry and material definitions. We construct a system based on this architecture, using several circuit and finite-element analysis tools, and use it to perform electromagnetic analyses of several different devices. Our results show that our architecture and techniques do allow practical problems to be solved effectively by heterogeneous tools.On présente une architecture de système et un ensemble de techniquesde contrôle qui permettent aux logiciels d'analyse hétérogènes de collaborerde façon intelligente et automatique. Un de ses traits caractéristiques est sacapacité d'effectuer simultanément plusieurs traitements. Les systèmes baséssur cette architecture sont capables de résoudre de manière efficace des grandsproblèmes dans le domaine de l'analyse électromagnétique, particulièrementceux où existe un accouplement dégagé entre plusieurs domaines de physique.L'architecture peut accepter n'importe quel logiciel d'analyse existant; ellen'exige pas que les logiciels soyent modifiés ou fabriqués sur mesure. Cettecaractéristique est produite en partie par notre utilisation d'une représentationneutre virtuelle pour représenter les données du problème, y inclus sa géométrieet les proprietés de ses matériels. On construit un système basé sur cettearchitecture, comprenant plusieurs logiciels de simulation, et on l'emploie pourexécuter des analyses électromagnétiques de plusieurs appareils différents. Nosrésultats montrent que notre architecture et nos techniques permettent desproblèmes pratiques d'être résolus efficacement par les outils hétérogènes.
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Wittig, Michael B. (Michael Brian). "The design and construction of a modular force control actuator." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/85719.
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Zhu, Haihong. "Practical Structural Design and Control for Digital Clay." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7270.
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Digital Clay is a next generation human-machine communication interface based on a tangible haptic surface. This thesis embraces this revolutionary concept and seeks to give it a physical embodiment that will confirm its feasibility and enable experimentation relating to its utility and possible improvements. Per the approach adopted in work, Digital Clay could be described as a 3D monitor whose pixels can move perpendicularly to the screen to form a morphing surface. Users can view, touch and modify the shape of the working surface formed by these pixels. In reality, the pixels are the tips of micro hydraulic actuators or Hapcel (i.e. haptic cell, since the Digital Clay supports the haptic interface). The user can get a feel of the desired material properties when he/she touches the working surface. The potential applications of Digital Clay cover a wide range from computer aided engineering design to scientific research to medical diagnoses, 3D dynamic mapping and entertainment. One could predict a future in which, by using Digital Clay, not only could the user watch an actor in a movie, but also touch the face of the actor!
This research starts from the review of the background of virtual reality. Then the concept and features of the proposed Digital Clay is provided. Research stages and a 5x5 cell array prototype are presented in this thesis on the structural design and control of Digital Clay. The first stage of the research focuses on the design and control of a single cell system of Digital Clay. Control issues of a single cell system constructed using conventional and off-the-shelf components are discussed first in detail followed by experimental results. Then practical designs of micro actuators and sensors are presented.
The second stage of the research deals with the cell array system of Digital Clay. Practical structural design and control methods are discussed which are suitable for a 100x 100 (even 1000X 1000) cell array. Conceptual design and detailed implementations are presented. Finally, a 5 x 5 cell array prototype constructed using the discussed design solutions for testing is presented.
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Benafan, Othmane. "Design, Fabrication and Testing of a Low Temperature Heat Pipe Thermal Switch with Shape Memory Helical Actuators." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6222.
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This work reports on the design, fabrication and testing of a thermal switch wherein the open and closed states are actuated by shape memory alloy elements while heat is transferred by a heat-pipe. The motivation for such a switch comes from NASA's need for thermal management in advanced spaceport applications associated with future lunar and Mars missions. For example, as the temperature can approximately vary between 40 K to 400 K during lunar day/night cycles, such a switch can reject heat from a cryogen tank in to space during the night cycle while providing thermal isolation during the day cycle. By utilizing shape memory alloy elements in the thermal switch, the need for complicated sensors and active control systems are eliminated while offering superior thermal isolation in the open state. Nickel-Titanium-Iron (Ni-Ti-Fe) shape memory springs are used as the sensing and actuating elements. Iron (Fe) lowers the phase transformation temperatures to cryogenic regimes of operation while introducing an intermediate, low hysteretic, trigonal R-phase in addition to the usual cubic and monoclinic phases typically observed in binary NiTi. The R-phase to cubic phase transformation is used in this application. The methodology of shape memory spring design and fabrication from wire including shape setting is described. Heat transfer is accomplished via heat acquisition, transport and rejection in a variable length heat pipe with pentane and R-134a as working fluids. The approach used to design the shape memory elements, quantify the heat transfer at both ends of the heat pipe and the pressures and stresses associated with the actuation are outlined. Testing of the switch is accomplished in a vacuum bell jar with instrumentation feedthroughs using valves to control the flow of liquid nitrogen and heaters to simulate the temperature changes. Various performance parameters are measured and eported under both transient and steady-state conditions. Funding from NASA Kennedy Space Center for this work is gratefully acknowledged.M.S.
Masters
Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
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Anderson, Theodore E. "Simulation and Fabrication of a Formable Surface for the Digital Clay Haptic Device." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14494.
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A formable surface is part of an effort to create a haptic device that allows for a three dimensional human-computer interface called digital clay. As with real clay, digital clay allows a user to physically manipulate the surface into some form or orientation that is sensed and directly represented in a computer model. Furthermore, digital clay will allow a user to change the computer model by manipulating the inputs that are directly represented in the physical model. The digital clay device being researched involves a computer-interfaced array of vertically displacing actuators that is bound by a formable surface. The surface is composed of an array of unit cells that are constructed of
compliant spherical joints and translational joints.
As part of this thesis, a series of unit cells were developed and planar surfaces were fabricated utilizing the additive manufacturing process of stereolithography. The process of computing the resultant shape of a manipulated surface was modeled mathematically through energy minimization algorithms that utilized least squares analysis to compute the positions of the unit cells of the surface. Simulation results were computed and analyzed against the movement of a fabricated planar surface.
Once the mathematical models were validated against the manufactured surface, a
method for attaching the surface to an array of actuators was recommended.
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Tam, Kuok San. "Design and analysis of an electro-hydro-mechanical variable valve actuator for four-stroke automobile engines." Thesis, University of Macau, 2011. http://umaclib3.umac.mo/record=b2493685.
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Voglewede, Philip Anthony. "Measuring Closeness to Singularities of Parallel Manipulators with Application to the Design of Redundant Actuation." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5202.
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At a platform singularity, a parallel manipulator loses constraint. Adding redundant actuation in an existing leg or new leg can eliminate these types of singularities. However, redundant manipulators have been designed with little attention to frame invariant techniques.
In this dissertation, physically meaningful measures for closeness to singularities in non-redundant manipulators are developed. Two such frameworks are constructed. The first framework is a constrained optimization problem that unifies seemingly unrelated existing measures and facilitates development of new measures. The second is a clearance propagation technique based on workspace generation.
These closeness measures are expanded to include redundancy and thus can be used as objective functions for designing redundant actuation. The constrained optimization framework is applied to a planar three degree of freedom redundant parallel manipulator to show feasibility of the technique.
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Murphy, Bryan Craig. "Design and construction of a precision tubular linear motor and controller." Texas A&M University, 2004. http://hdl.handle.net/1969.1/101.
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A design for a novel tubular high-precision direct-drive brushless linear motor has been developed. The novelty of the design lies in the orientation of the magnets in the mover. In conventional linear motors the magnets of the armature are arranged such that the attractive poles are adjacent throughout, in an NS-NS-NS orientation, where N denotes the north pole and S denotes the south pole of the magnet. In the new design, the magnets in the moving part are oriented in an NS-NS-SN-SN orientation. This change in orientation yields greater magnetic field intensity near the like-pole region. The magnets of the mover are encased within a brass tube, which slides through a three-phase array of current-carrying coils. As the coils are powered, they induce a force on the permanent magnets according to the Lorentz force equation. The primary advantages of the motor are its compact nature, fast, precise positioning due to its low-mass moving part, direct actuation, extended travel range, and ability to extend beyond its base. The linear motor is used in conjunction with a position sensor, power amplifiers, and a controller to form a complete solution for positioning and actuation requirements.
Controllers were developed for two applications, with a lead-lag as the backbone of each. For the first application, the principal requirements are for fast rise and settling times. For the second application, the primary requirement is for near-zero overshoot. With the controller for application 1, the motor has a rise time of 55 ms, a settling time of 600 ms, and 65% overshoot. With the controller for application 2 implemented, the motor has a rise time of 1 s, a settling time of 2.5 s, and 0.2% overshoot. The maximum force capability of the motor is measured to be 26.4 N. The positioning resolution is 35 ?m. This thesis discusses the motor's physical design, construction, implementation, testing, and tuning. It includes specifications of the components of the motor and other necessary equipment, desired and actual motor performance, and the primary limitations on the precision of the system.
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Chen, Yi S. B. Massachusetts Institute of Technology. "Lorentz force actuator and carbon fiber co-winding design, construction and characterization." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45772.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 66-67).
Carbon fiber composites are materials that present many benefits to engineering applications, ranging from aerospace to medicine. This thesis provides background on carbon fiber properties and manufacturing techniques, and outlines the methodology for manufacturing a co-wound carbon fiber and copper coil for use in linear Lorentz force actuators. A conventionally-wound, plastic-bobbin actuator coil and the new, co-wound coil were then tested to compare their electrical, thermal, and mechanical performance. In a needle-free injection application, the cowound coil demonstrated improved performance over the conventional coil configuration. The carbon fiber coil is lighter by 3.75 ± 0.155 grams, increases the transient heat transfer by 15.7 %, is 2.18 ± 0.13 times stiffer, and can survive a higher compressive force than the conventional plastic bobbin.
by Yi Chen.
S.B.
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Koujili, Mohamed. "Design and construction of a new actuator for the LHC wire scanner." Thesis, Belfort-Montbéliard, 2013. http://www.theses.fr/2013BELF0196/document.
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Le LHC met en collision deux faisceaux de protons avec une énergie de 7 Tevchacun, entrainant ainsi un taux de particules d'environ 109 Hz. Le taux departicules est déterminé la production d'une coupe transversale, une constancenaturelle, la luminosité et un paramétre dépendant de l'accélérateurcapable de décrire les faisceaux de particules. La luminosité dépend dunombre de particules dans chaque faisceau linéairement et des dimensionstransversales du faisceau inversement. Elle augmente avec la densité dufaisceau de particules et en conséquence, la probabilité d'interactions estaccrue. Pour optimiser les tailles des faisceaux transversaux, on utilisedes dispositifs de contrle de pro_le, qui permettent de mesurer les changementsde paramétres dépendants. A l'intérieur du LHC, trois di_érentstypes de dispositifs de contrle des pro_les sont installés, savoir le WireScanner (WS), le Synchroton Light Monitor et le Rest Gas Pro_le Monitor.Le WS est considéré comme étant le plus précis de ces trois dispositifsde contrle et sert d'appareil de calibrage pour les deux autres. Ils'agit d'un appareil électromécanique qui mesure l'état de densité du faisceautransversale de faon intermittente. Lorsque le cble traverse le faisceau,l'interaction particule-matiére génére une cascade de particules secondaires.Ces derniers sont interceptés par un scintillateur, lequel est attaché un photo-multiplieur, et ce a_n de mesurer l'intensité de la lumiéreainsi produite. L'amplitude du signal lumineux est proportionnelle la densité de la portion de faisceau interceptée. L'acquisition de la position du_l et celle de l'intensité du signal sont synchronisées avec la fréquence dela révolution de particules puis sont combinées pour construire le pro_lede densité du faisceau transversal. Le WS est installé et mis en marchedans tous les accélérateurs circulaires du CERN sur une base réguliéreThe LHC collides two protons beams with an energy of 7 TeV each resultingin a aimed total particle rate of about 109 Hz. The particle rateis determined by the production cross section, a natural constant and theluminosity accelerator dependent parameter describing the particle beams.The luminosity depends on the number of particles in each beam linearlyand on the transverse dimensions of the particle beam inversely. It increaseswith the particle beam density and therefore the probability of interactions.To optimize the transverse beams sizes, pro_le monitors are used to measureparameter depending changes. Within the LHC, three di_erent typesof pro_le monitors are installed: Wire scanner (WS), Synchrotron lightmonitor and Rest Gas Pro_le Monitor. The WS monitor is considered tobe the most accurate of these monitors and serves as a calibration devicefor the two others. The WS is an electro-mechanical device which measuresthe transverse beam density pro_le in an intermittent way. As the wirepasses through the beam, the particle-matter interaction generates a cascadeof secondary particles. These are intercepted by a scintillator, which isattached to a photomultiplier in order to measure the intensity of the lightthereby produced. The light signal amplitude is proportional to the densityof the intercepted beam portion. The acquisitions of the wire position andthe intensity signal are synchronized with the particle revolution frequencyand are combined to construct the transverse beam density pro_le. TheWS is installed and operated in all circular accelerators of CERN on a dailybasis
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Tuncdemir, Safakcan. "Design Of Mini Swimming Robot Using Piezoelectric Actuator." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605682/index.pdf.
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This thesis deals with the design, fabrication and analysis of a novel actuator for a fish-like swimming mini robot. The developed actuator is tested on a mini boat. The
actuator relies on a novel piezoelectric ultrasonic motor, developed according to the design requirements of actuator for fish-like swimming mini robots. Developed motor is within the dimensions of 25x6x6 mm in a simple mechanical structure with simple driving circuitry compared to its predecessor. Bidirectional rotation of the motor is transformed to a flapping tail motion for underwater locomotion in a simple mechatronic structure. The simplicity in the motor and actuator enables
further development on the miniaturization, improvement on the performances as well as easy and low cost manufacturing. The developed actuator is a candidate to
be used in mini swimming robot with fish- like locomotion.
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Lagimoniere, Ernest Eugene Jr. "The Design and Construction of a High Bandwidth Proportional Fuel Injection System for Liquid Fuel Active Combustion Control." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34693.
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This last decade experienced a sudden increase of interest in the control of thermo-acoustic instabilities, in particular through the use of fuel modulation techniques. The primary goal of this research was to design, construct and characterize a high bandwidth proportional fuel injection system, which could be used to study the effect of specific levels of fuel modulation on the combustion process and the reduction of thermo-acoustic instabilities. A fuel injection system, incorporating the use of a closed loop piston and check valve, was designed to modulate the primary fuel supply of an atmospheric liquid-fueled swirl stabilized combustor operating at a mean volumetric fuel flow rate of 0.4 GPH. The ability of the fuel injection system to modulate the fuel was examined by measuring the fuel line pressure and the flow rate produced during operation. The authority of this modulation over the combustion process was investigated by examining the effect of fuel modulation on the combustor pressure and the heat release of the flame. Sinusoidal operation of the fuel injection system demonstrated: a bandwidth greater that 800 Hz, significant open loop authority (averaging 12 dB) with regards to the combustor pressure, significant open loop authority (averaging 33 dB) with regards to the unsteady heat release rate and an approximate 8 dB reduction of the combustor pressure oscillation present at 100 Hz, using a phase shift controller. It is possible to scale the closed loop piston and check valve configuration used to create the fuel injection system discussed in this work to realistic combustor operating conditions for further active combustion control studies.Master of Science
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Yang, Bintang. "Integrated design of magnetostrictive-material-based mini actuator for long-stroke and nanometric resolution positioning application." Compiègne, 2005. http://www.theses.fr/2005COMP1555.
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L'objectif de ce travail est la conception et la réalisation d'un mini-actionneur magnétostrictif se déplaçant sur une course infinie avec une résolution nanométrique et une précision micrométrique. Un principe de déplacement inchworm comportant un module d'avance magnétostrictif et des pieds magnétiques a été choisi. Le fort couplage magnétomécanique du matériau à magnétostriction géante (GMM) choisi permet potentiellement de développer un effort important lors d'un déplacement précis pour un encombrement minimum de l'actionneur. La conception de l'actionneur a intégré les aspects électrique, magnétique et mécanique en tenant compte des contraintes de dimension et d'échauffement et de la résolution de positionnement souhaitée. Un prototype de mini-actionneur a été fabriqué et des tests expérimentaux ont permis de valider d'une part sa capacité à se déplacer rapidement (97,2 um/s) et d'autre part, sa capacité à réaliser des positionnements avec une résolution de 4 nmThe main objective of this dissertation work is the design and the realisation of a magnetostrictive mini- , actuator capable of moving on infinite long stroke with nanometric resolution and micrometric accuracy. Magnetostrictive effect and inchworm principle act as the comerstones in realising the actuator. Giant Magnetostrictive Material (GMM) bas been used due to its unique features of high magnetomechanical coupling. It bas potentials to render high force and precise displacement with a small volume. A design and a model integrating the driving material, the electrical, the magnetic and the mechanical design bas been completed. A mini-actuator prototype bas been constructed. Experimental tests show on the one band that the actuator can perform fast linear movement with velocity up to 97. 2 um/s, on the other band, that it bas the potential to achieve a positioning resolution of 4 nanometers. A long stroke movement with nanometric positioning could be implemented
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Agarwal, Sandeep. "Aeromechanical Stability Augmentation Using Semi-Active Friction-Based Lead-Lag Damper." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7547.
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Lead-lag dampers are present in most rotors to provide the required level of damping in all flight conditions. These dampers are a critical component of the rotor system, but they also represent a major source of maintenance cost. In present rotor systems, both hydraulic and elastomeric lead-lag dampers have been used. Hydraulic dampers are complex mechanical components that require hydraulic fluids and have high associated maintenance costs. Elastomeric
dampers are conceptually simpler and provide a ``dry" rotor, but are rather costly. Furthermore, their damping characteristics can degrade with time without showing external signs of failure. Hence, the dampers must be replaced on a regular basis. A semi-active friction based lead-lag damper is proposed as a replacement for hydraulic and elastomeric dampers. Damping is provided by optimized energy dissipation due to frictional forces in semi-active joints. An actuator in the joint modulates the normal force that controls
energy dissipation at the frictional interfaces, resulting in large hysteretic loops.
Various selective damping strategies are developed and tested for a simple system containing two different frequency modes in its
response, one of which needs to be damped out. The system reflects the situation encountered in rotor response where 1P excitation is present along with the potentially unstable regressive lag motion. Simulation of the system response is obtained to compare their effectiveness. Next, a control law governing the actuation in the
lag damper is designed to generate the desired level of damping for performing adaptive selective damping of individual blade lag
motion. Further, conceptual design of a piezoelectric friction based lag damper for a full-scale rotor is presented and various factors
affecting size, design and maintenance cost, damping capacity, and power requirements of the damper are discussed. The selective semi-active damping strategy is then studied in the context of
classical ground resonance problem. In view of the inherent nonlinearity in the system due to friction phenomena, multiblade transformation from rotating frame to nonrotating frame is not
useful. Stability analysis of the system is performed in the rotating frame to gain an understanding of the dynamic characteristics of rotor system with attached semi-active friction
based lag dampers. This investigation is extended to the ground resonance stability analysis of a comprehensive UH-60 model within the framework of finite element based multibody dynamics
formulations. Simulations are conducted to study the performance of several integrated lag dampers ranging from passive to semi-active ones with varying levels of selectivity. Stability analysis is performed for a nominal range of rotor speeds using Prony's method.
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Asveld, Jip. "Actuators as a Design Material." Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22860.
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This thesis is an explorative, design-based research study towards the expressive potential of using actuators as design materials. Over three distinct phases of experimentation –all with their own particular aim– various sketches are developed that showcase different expressive qualities. These sketches consist of a variety of kitchen devices that are expanded with actuators. These actuators do not necessarily add to the functionality of the device, but rather to its expressiveness. The development of and reasoning for the sketches is clarified in an extensive way to clearly present all the insights that are gained throughout the design process. In the end, the sketches are discussed and reflected upon on the basis of the process-insights and relevant design theories.
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Widdowson, G. P. "Design optimization of permanent magnet actuators." Thesis, University of Sheffield, 1992. http://etheses.whiterose.ac.uk/1849/.
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This study describes the design optimization of permanent actuators, of both rotary and linear topologies. Parameter scanning, constrained single and multi-criterion optimization techniques are developed, with due emphasis on the efficient determination of optimal designs. The modelling of devices by non-linear lumped reluctance networks is considered, with particular regard to the level of discretization required to produce accurate global quantities. The accuracy of the lumped reluctance technique is assessed by comparison with non-linear finite element analysis. Alternative methods of force/torque calculation are investigated, e.g. Lorentz equation, Virtual Work, and Maxwell Stress Integration techniques, in order to determine an appropriate technique for incorporation in a non-linear iterative optimization strategy. The application of constrained optimization in a design environment is demonstrated by design studies and experimental validation on selected prototype devices of both topologies.
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Akgoz, Asli. "Optimal Design Of Truss Structures With Actuators." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12605613/index.pdf.
Full textAbstract:
Smart structures become highly popular with the developing technology. The aim of this study is to develop a basic model, which can be also used in the design of more complex systems by performing simultaneous optimization of a structure and associated controller with respect to some design parameters and feedback gains.
In this thesis work, two smart structures are used as case studies and their results are compared with the available results in the literature. The first case study is simple twobar
truss problem controlled by either one or two actuators. This problem is solved both numerically and analytically. The latter is a twenty-element parabolic truss, which is controlled by four actuators. This problem is solved numerically only.
In the optimization process, the design parameters are taken as the cross sectional areas of bar elements, positions and/or number of actuators, and the elements of closed loop gain matrix. In the second case study, in addition to these parameters, shape design parameters are also optimized.
A coordinate transformation is applied in both cases from the displacement space to the modal space. The modal model reduction method is used in the design of second problem.
The optimization goal in both cases studies is to minimize the system energy while satisfying some frequency and mass constraints. In the second case study, in addition
to the original objective function, system controllability and stability robustness are also maximized.
In the solution of design problem, two optimization algorithms are used one embedded within the other. In the outer loop, a hide and seek simulated annealing algorithm optimizes structural design parameters, and positions and/or number of
actuators. In order to generate a candidate design family for this level, optimal closed loop gain matrices are calculated by using MATLAB®.
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Meng, Fanliang. "Actuation system design with electrically powered actuators." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6282.
Full textAbstract:
This project addresses the actuation system architecture of future All-electric
aircraft (AEA) with electrically powered actuators (EPA).
Firstly, the information of EPAs is reviewed, and then an electro-hydrostatic
actuator (EHA) and electro-mechanical actuator (EMA) are selected for further
system research. The actuation system architecture of Boeing and Airbus is
then presented as a conventional design where the new design concepts are
also researched and the distributed architecture was proposed as another
design trend. To find out which one is better, both of them are selected for
further research.
The easily available data makes the Flying Crane a better choice for the case
study. Stall load, maximum rate and power are the main elements for electric
actuator requirements and power consumption, weight, cost and safety are the
most important aspects for civil aircraft actuation systems.
The conventional and distributed flight actuation system design considered the
redundancy of systems and actuators, and also the relationship of the power,
control channel and actuator work mode. But only primary flight actuation
control system specifications are calculated since this data has better precision
and also the limited time has to be taken into consideration. Brief comparisons
of the two system specifications demonstrate that the higher power actuator
have has higher efficiency and distributed actuators could reduce the system
weight through reduce the system redundancy with a power efficiency decline.
The electrically powered actuation system for future aircraft design is a balance
between actuator number, system weight and power consumption.
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Oscarsson, Mattias. "Modelling and design approaches of magnetostrictive actuators." Licentiate thesis, Stockholm : Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4435.
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Almajid, Abdulhakim A. "Design of high performance piezo composites actuators /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7130.
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Heyer, John Henry 1973. "Design of silent, miniature, high torque actuators." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80629.
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Ho, Wei Hsuan (Wei Hsuan Jessie). "Design, fabrication and characterization of polypyrrole trilayer actuators." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45850.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaf 48).
Conducting polymers are currently studied as artificial muscle materials. They are used instead of traditional actuators because they mimic the movements of animal muscles. They can generate larger active stresses than real muscles as well as generate small strains which can be amplified to cause larger motions. Traditionally, conductive polymers are immersed in liquid electrolytes. Utilizing a trilayer configuration by sandwiching the ions between two strips of polypyrrole films can be actuated in air. This thesis compares two methods of constructing polypyrrole trilayers: an electrolyte gel method and a gold coated PVDF membrane method. It will discuss the construction processes as well as properties of resulting trilayers by looking at force production, strain rate, etc.
by Wei Hsuan (Jessie) Ho.
S.B.
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Song, Changsik. "Design and synthesis of molecular actuators and sensors." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41554.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
To date, the most successful conducting polymer actuators are based on polypyrrole, which operates through incorporating and expelling counterions and solvent molecules to balance the charges generated by electrochemical stimuli (swelling mechanism). Although significant progress has been made, there still exists a need for developing new materials that would overcome the intrinsic limitations in the swelling mechanism, such as slow diffusion rate, limited expansion volume, etc. Our group has contributed this area with a different approach -- lecular mechanisms, which utilize a dimensional change of a single polymer chain. We propose two types of molecular mechanisms: contracting and expanding. We proposed earlier a calix[4]arenebased molecular actuator for the contracting mechanism, in which p-dimer formation was proposed as a driving force. In this dissertation, we first confirm by model studies that p-dimer formation can indeed be a driving force for the calix[4]arene-based system. We propose another molecular hinge, binaphthol moiety, for the contracting model. The syntheses of polymers with binaphthols and their characterization, including signatures of oligothiophene interactions, are described. Due to its chirality, we examined the possibilities of the binaphthol polymer as a chiral amine sensor. To create actuators that make use of the expanding model, we propose new conjugated seven-membered ring systems with heteroatoms (thiepin with sulfur and azepine with nitrogen) and their syntheses and characterization will be described. Inspired by the fact that sulfoxide has very low extrusion barrier in the related system, we applied the thiepin molecules to create a peroxide sensor.
(cont.) In addition, during the investigation of phenol functional groups in conducting polymers, we found interesting properties that strategic positioning of phenol groups can render a conjugation-broken meta-linked system just as conductive as a fully conjugated para-linked isomeric system.
by Changsik Song.
Ph.D.
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Yang, Hee Doo. "Design, Manufacturing, and Control of Soft and Soft/Rigid Hybrid Pneumatic Robotic Systems." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100635.
Full textAbstract:
Soft robotic systems have recently been considered as a new approach that is in principle better suited for tasks where safety and adaptability are important. That is because soft materials are inherently compliant and resilient in the event of collisions. They are also lightweight and can be low-cost; in general, soft robots have the potential to achieve many tasks that were not previously possible with traditional robotic systems.
In this paper, we propose a new manufacturing process for creating multi-chambered pneumatic actuators and robots. We focus on using fabric as the primary structural material, but plastic films can be used instead of textiles as well. We introduce two different methods to create layered bellows actuators, which can be made with a heat press machine or in an oven. We also describe origami-like actuators with possible corner structures. Moreover, the fabrication process permits the creation of soft and soft/rigid hybrid robotic systems, and enables the easy integration of sensors into these robots. We analyze various textiles that are possibly used with this method, and model bellows actuators including operating force, restoring force, and estimated geometry with multiple bellows. We then demonstrate the process by showing a bellows actuator with an embedded sensor and other fabricated structures and robots.
We next present a new design of a multi-DOF soft/rigid hybrid robotic manipulator. It contains a revolute actuator and several roll-pitch actuators which are arranged in series. To control the manipulator, we use a new variant of the piece-wise constant curvature (PCC) model. The robot can be controlled using forward and inverse kinematics with embedded inertial measurement units (IMUs). A bellows actuator, which is a subcomponent of the manipulator, is modeled with a variable-stiffness spring, and we use the model to predict the behavior of the actuator. With the model, the roll-pitch actuator stiffnesses are measured in all directions through applying forces and torques. The stiffness is used to predict the behavior of the end effector. The robotic system introduced achieved errors of less than 5% when compared to the models, and positioning accuracies of better than 1cm.Doctor of Philosophy
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Bissal, Ara. "On the Design of Ultra-fast Electro-Mechanical Actuators." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121181.
Full textAbstract:
The continuously increasing demand for connecting electric grids with remote renewable energy sources such as wind power and photovoltaic cells has rekindled interest in high voltage direct current (HVDC) multi-terminal networks. Although HVDC networks have numerous benefits, their adoption relies entirely on the availability of HVDC circuit breakers which, compared to traditional alternating current circuit breakers, have to operate in a time frame of milliseconds. This thesis deals with the design of ultra-fast electro-mechanical actuators based on the so-called Thomson coil (TC) actuator. The simulation of a (TC) actuator constitutes a multi-physical problem where electromagnetic, thermal, and mechanical aspects must be considered. Moreover, it is complex since all those variables are co-dependent and have to be solved for simultaneously. As a result, a multi-physics simulation model that can predict the behavior and performance of such actuators with a high degree of accuracy was developed. Furthermore, other actuator concepts were also investigated and modeled in light of searching for a drive with a superior efficiency. The theory behind the force generation principles of two different types of ultra-fast electromechanical actuators, the TC and the double sided coil (DSC), were compared by the use of static, frequency, and comprehensive transient multi-physics finite element simulation models. Although, simulation models serve as a powerful tool for modeling and designing such state of the art actuators, without validation, they are weak and prone to errors since they rely on approximations and simplifications that might not always hold. Therefore, a prototype was built in the laboratory and the model was validated experimentally. Finally, it is important to note that the drives in this thesis are intended to actuate metallic contacts. As such, their behavior and performance upon mechanical loading was studied. Furthermore, some scaling techniques were applied to boost their performance and efficiency.QC 20130422
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Dhur, Michel. "Characterization and design of microstreaming actuators for microfluidic chips." Zürich : ETH, Eidgenössische Technische Hochschule Zürich, Department of Mechanical and Process Engineering, 2007. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=334.
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Hickey, Ryan. "Analysis and optimal design of micro-machined thermal actuators." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ63523.pdf.
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Reivich, Alejandro Cuauhtemoc Ramirez. "Comparative design study of quarter turn pneumatic valve actuators." Thesis, Lancaster University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309026.
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Bosworth, William R. Ph D. Massachusetts Institute of Technology. "Design and parametric simulation of radially oriented electromagnetic actuators." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67792.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 91-92).
This thesis presents the design and simulation of an electromagnetic actuator system capable of delivering large pulses of radial force onto a cylindrical surface. Due to its robust design, simple control scheme, and large output force capability, the actuator design is developed to be considered for wellbore manipulation and other downhole oil exploration and production activities. The complete simulation - including capacitor bank power supply, solid state switching circuit, transducer, and target formation - is a thirteen value lumped parameter model. The simulation was used heavily in the design and refining of two experimental prototype systems. These prototypes showed excellent model-experiment matching. The experimental prototypes are 2.5" radius, 12" length cylindrical transducers that exert nearly 10 psi onto a simulated rock formation with 2 MN/m radial stiffness, increasing the formation radius 3.5 mm during 5 ms pulse events. It is with this experimentally validated simulation that we project forward a manufacturable system capable of exerting pulses of hundreds of psi in magnitude over durations of 1 - 10 ms onto wellbore sized cylindrical surfaces.
by Will Bosworth.
S.M.
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Lederlé, Stéphane 1978. "Issues in the design of shape memory alloy actuators." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16830.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002."June 2002."
Includes bibliographical references (p. 93-96).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
This thesis considers the application of shape memory alloy (SMA) actuators for shape control of the undertray of a sports car. By deforming the shape of the structure that provides aerodynamic stability to the car, we expect to improve the overall performance of the vehicle by adapting its aerodynamics according to the vehicle speed. We then develop a methodology for designing SMA actuators in this application. The methodology is based on the integration of the different models involved: mechanical, thermal, and electrical. The constraints imposed on the device are also incorporated. Unfortunately, the analysis predicts an actuation time that is too slow for this particular application. Still, we use our assembled model to sketch the expected characteristics of SMA actuators. A significant result is that the actuation time is a function of the amount of energy the active material has to provide, and that there is a necessary trade-off between the mass of actuators and the actuation time. In particular, the expected energy density may have to be decreased to achieve acceptable actuation times. Finally, we propose a way to estimate a priori the suitability of SMA actuators for a particular application.
by Stéphane Lederlé.
S.M.
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Cole, Daniel G. "Design of, and initial experiments with, a MIMO plate control testbed." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-10062009-020045/.
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Popovic, Suzana. "Design of electro-active polymer gels as actuator materials /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/7053.
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Weston, Rebecca. "Design and analysis of miniature actuators for an electronic Jacquard." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313545.
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Liang, Yuanchang. "Design principle of actuators based on ferromagnetic shape memory alloy /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7072.
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Kumar, Guhan. "Modeling and design of one dimensional shape memory alloy actuators." Connect to resource, 2000. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1116879145.
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MacKenzie, Ian (Ross Ian). "Design and control methods for high-accuracy variable reluctance actuators." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100138.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 421-427).
This thesis presents the design and control techniques of a variable reluctance actuator for driving a reticle motion stage in photolithography scanners. The primary thesis contributions include the design and experimental demonstration of a magnetic flux controller that uses a sense coil measurement, the design and experimental demonstration of a novel method to estimate actuator hysteresis in real-time, and the development of an actuator model that incorporates the effects of eddy currents. The reticle stage in a scanning lithography machine requires high accelerations combined with sub-nanometer position accuracy. Reluctance actuators are capable of providing high force densities (force per moving mass) and lower power values relative to the present state-of-the-art Lorentz actuators that are used to drive the reticle stage. However, reluctance actuators are highly nonlinear with both current and air gap. They also display other nonlinear behavior from hysteresis and eddy currents. Linearizing the reluctance actuator is required for the high force accuracy required in the scanning stage. In this thesis, we present a way to linearize the reluctance actuator with flux control using a sense coil as the feedback measurement. Because the sense coil is AC-coupled, we design a low-frequency estimate of the magnetic flux based upon the actuator current and air gap measurements. We combine the low-frequency estimate with the sense coil measurement using a complementary filter pair that provides an estimate of the flux from DC to frequencies of several kHz. For the low-frequency estimate, we develop a novel method for estimating the actuator hysteresis in realtime. For this flux estimator, we use an observer to model the actuator flux which treats the changing air gap as a disturbance to the plant model. The use of an observer allows the identification of a single-variable hysteresis model of actuator current rather than a two-variable hysteresis model of current and air gap. We also introduce a novel way for expressing the actuator hysteresis, whereby we incorporate the linearizing effect of the air gap directly into a Preisach hysteresis model via a change of variables. We demonstrate experimentally that this method is numerically stable in the presence of a dynamically changing gap, in contrast to some alternative methods. We designed and built a reluctance actuator prototype and 1-DoF motion testbed to demonstrate the accuracy of the actuator models and control techniques. We experimentally demonstrated that we can achieve a flux control bandwidth of 4 kHz that is capable of reducing the stiffness of the reluctance actuator to less than 0.012 N/[mu]m for frequencies up to 100 Hz. This results in a force error of less than 0.03% of the full-scale force for a 10 [mu]m air gap disturbance at this frequency. We also demonstrate that the actuator hysteresis model is capable of estimating the actuator flux accurately in the presence of dynamic gap disturbances of at least 35 1m peak-to-peak and with a static offset from the nominal air gap of at least 50 [mu]m.
by Ian MacKenzie.
Ph. D.
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Chambers, Joshua Michael. "Design and characterization of acoustic pulse shape memory alloy actuators." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32378.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 175-177).
Single crystal Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) are active materials which produce strain when a magnetic field is applied. The large saturation strain (6%) of Ni-Mn-Ga, and material energy density comparable to piezoelectric ceramics make Ni- Mn-Ga an interesting active material. However, their usefulness is limited by the bulky electromagnet required to produce a magnetic field. In this thesis, a novel actuation method is developed for shape memory alloys in their martensitic phase, whereby asymmetric acoustic pulses are used to drive twin boundary motion. Experimental actuators were developed using a combination of Ni-Mn-Ga FSMA single crystals and a piezoelectric stack actuator. In bi-directional actuation without load, strains of over 3% were achieved using repeated pulses (at 100 Hz) over a 30 s interval, while 1% strain was achieved in under 1 s. The maximum strains achieved are comparable to the strains achieved using bi-directional magnetic actuation, although the time required for actuation is longer. No-load actuation also showed a nearly linear relationship between the magnitude of the asymmetric stress pulse and the strain achieved during actuation, and a positive correlation between pulse repetition rate and output strain rate, up to at least 100 Hz. Acoustic actuation against a spring load showed a maximum output energy density for the actuator of about 1000 J/m³, with a peak-to-peak stress and strain of 100 kPa and 2%, respectively.
by Joshua Michael Chambers.
S.M.