Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"piezoelectric stack"”.
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Modified Maxwell Model for hysteresis compensation of piezoelectric stack actuators
… new observations of the hysteresis behavior of piezoelectric stack actuators and proposes an Input-Range Dependent Maxwell Model for more accurate hysteresis compensation. Experimental studies show that the assumptions of the classical Maxwell model do not fully hold: the actuator behaves …
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Design and fabrication of a piezoelectric stack actuator for use in a needle-free jet injector
This thesis presents the design of a piezoelectric ceramic stack actuator for use with needle-free jet injection (NFJI) devices. While NFJI devices have been in use for over 60 years only recently have they been electronically actuated which allows for precise control of jet velocity, penetration …
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FPGA Operating System for Hard Real Time Applications
… that integrates logic and power devices to drive piezoelectric stack actuators and demonstrate experimentally the results in terms of control of piezoelectric stack tip displacement on atest bench. The electronic module controls up to four piezoelectric stack actuators and guarantees that the …
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Design, Modeling, and Analysis of Microscale Pneumatic Valve Architectures to Simplify Integration of Small Displacement Actuators
… in small displacement actuators, such as piezoelectric stack actuators, in control valves has the potential to break down barriers existing for conventional actuation methods. Piezoelectric stack actuators are useful as they have very low power consumption, nanometer displacement control …
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Semi-active control of elastic and inelastic building structures with piezoelectric friction dampers
… semi-active devices.</p> <p>In this study, a piezoelectric friction damper (PFD) was first introduced with its clamping force regulated by piezoelectric stack actuators. A new semi-active control algorithm, which consists of Coulomb friction, viscous and non-linear Reid damping mechanisms, was …
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Large gain amplification mechanism for piezoelectric actuators utilizing a rolling contact joint
Due to the limited displacement of piezoelectric stack actuators, common practice is to use some form of displacement amplification mechanism. An efficient, heavy-duty displacement amplification mechanism for piezoelectric stack actuators is presented in this thesis. The displacement amplification …
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Design and Validation of a Proportional Throttle Valve System for Liquid-Fuel Active Combustion Control
… system, discussed in this thesis, uses a 500-um piezoelectric stack coupled with an off-the-shelf valve. After comparing three other types of actuators, the piezoelectric stack was selected because of its compact size, bandwidth capabilities, and relatively low cost. Using the acoustic resonance …
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Power Regeneration in Actively Controlled Structures
… form for two different types of actuators: a piezoelectric stack actuator and a linear electromagnetic (EM) actuator. During regenerative operation, the power is flowing from the mechanical disturbance through the electromechanical actuator and its switching drive into the electrical storage …
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Design and Fabrication of an Oscillating Tool for Powder Spreading in Metal Additive Manufacturing
… developed for the mechanism, powered by either a piezoelectric stack or a voice coil linear motor. The machining of parts was qualified for runout and straightness, and the assembly of the piezo mechanism was built onto the testbed. Work remains to complete the system implementation and to test …
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Development and Analysis of the Lumped Parameter Model of a Piezo-Hydraulic Actuator
… rectification translates the low stroke of a piezoelectric stack into a desired amount of stroke per unit time. Thus, the low displacement, oscillatory motion of the piezoelectric device (coupled with a high frequency operation) is translated into a unidirectional motion of a hydraulic …
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Acoustic assisted actuation of Ni-Mn-Ga ferromagnetic shape memory alloys
… use of a sinusoidal stress wave generated by a piezoelectric stack actuator. The piezoelectric drive causes a time varying stress wave in the FSMA that resolves as a shear across the twin-boundaries and aids the twin boundary in overcoming defect-related obstacles. The FSMA shows increased …
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Large-strain piezoelectric actuators using controlled structural buckling
… beam. This thesis presents a novel large-strain piezoelectric actuator exploiting the buckling of a structure with imbedded piezoelectric stack actuators. The realization of this buckling actuator began by rethinking the paradigm of where PZT stacks are placed in traditional flexure-based …
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Vibration analysis and intelligent control of flexible rotor systems using smart materials
… rotors, smart materials particularly SMAs and piezoelectric stack actuators are introduced. The application of shape memory alloy (SMA) elements integrated within glass epoxy composite plates and shells has resulted in the design of a novel smart bearing based on the principle of antagonistic …
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Transverse acoustic actuation of Ni-Mn-Ga single crystals
… crystal. The first method employs two 33-mode piezoelectric stacks, mounted at 45 deg to the base of a single crystal, to produce a shear stress on the 110 planes. The second method utilizes a single 15-mode piezoelectric stack, normally incident to the crystal base, to generate shear pulses …
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Piezoelectric buckling actuators : form reduction, bidirectional control, and optimal switching
Piezoelectric stack actuators are generally described as having large force density, high bandwidth response, and limited yet precise displacement properties. As a result, these actuators have been widely applied to precision positioning devices, acoustical and optical instruments, and within …
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Design and characterization of acoustic pulse shape memory alloy actuators
… 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 …
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Design Concepts for High-Acceleration Linear Actuators for Precision Motion
… use of mechanical contact forces managed by a piezoelectric stack actuator (PEA). In this configuration, intermittent contact by the PEA can be used to apply forces to decelerate and reaccelerate the SS stage with respect to the LS stage during turnaround events. With such force assist, the …
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Understanding and development of combined acoustic and magnetic actuation of Ni₂MnGa single crystals
… application of an acoustic assist from a 33-mode piezoelectric stack is shown to improve MFIS of Ni-Mn-Ga single crystals by reducing the required threshold field and twinning-yield stress. Threshold field reductions of up to 1 kOe are observed, and the twinning-yield stress is reduced by up to …
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Micromechanical actuators for insect flight mechanics
… we integrated actuators onto the mounting kit. Piezoelectric film/sheet, piezoelectricbender and piezoelectric-stack were considered as the actuators. Live testing was also taken while the moth was resting or flapping its wings. The moth apparently responds to the mechanical stimulus under both …
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Harmonic poly-actuator : design and control of a new piezoelectric mechanism
Piezoelectric devices, e.g. piezoelectric stack actuators, have several salient features inherent to their structure. They are efficient, have a high bandwidth, and their capacitive loading allows for static loads to be maintained with virtually no power consumption. The major preventative drawback …
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