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Large gain amplification mechanism for piezoelectric actuators utilizing a rolling contact joint

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dc.contributor.advisor H. Harry Asada. en_US Torres, James, Ph. D. Massachusetts Institute of Technology. en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Mechanical Engineering. en_US 2012-11-19T19:20:56Z 2012-11-19T19:20:56Z 2012 en_US 2012 en_US
dc.description Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. en_US
dc.description Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references (p. 55-56). en_US
dc.description.abstract 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 gain is increased by a factor of more than 100 in a single stage by using a buckling mechanism combined with a novel rolling contact design. Unlike traditional flexure-type monolithic mechanisms, which are accurate but inefficient and fragile, the new mechanism consists of all rolling contact couples, providing high stiffness, durability and energy efficient characteristics. Furthermore, a new design of pre-loading mechanism using shape memory alloy doubles the possible cyclic work output and provides a desirable restoring force for constraining the rolling contact mechanism stably and efficiently. This mechanism is intended to be interfaced with a sinusoidal gear cam that acts as the load. The dynamics of the system are derived and are shown to be fifth order. Due to the significantly nonlinear amplification caused by the buckling phenomenon and the gear, the dynamics are run in simulation to gain insight into the dynamic performance of the actuator. There is shown to be an optimal speed at which to run the actuator to maximize the possible power output. Furthermore, due to the simple binary control significant benefits are achieved by varying the control timing based on the velocity to ensure the force and velocity of the output are in phase. Finally, a prototype was constructed to compare to the static model. The prototype had a peak to peak displacement of 6.8 mm, an amplification of over 150, and produced a peak charged force of 56 Newtons. en_US
dc.description.statementofresponsibility by James Torres. en_US
dc.format.extent 56 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri en_US
dc.subject Mechanical Engineering. en_US
dc.title Large gain amplification mechanism for piezoelectric actuators utilizing a rolling contact joint en_US
dc.type Thesis en_US S.M. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Mechanical Engineering. en_US
dc.identifier.oclc 816567882 en_US

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