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Design and Characterization of a Dielectric Elastomer Based Variable Stiffness Mechanism for Implementation onto a Dynamic Running Robot

Title: Design and Characterization of a Dielectric Elastomer Based Variable Stiffness Mechanism for Implementation onto a Dynamic Running Robot.
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Name(s): Newton, Jason, author
Clark, Jonathan, professor directing thesis
Oates, William, committee member
Hollis, Patrick, committee member
Department of Mechanical Engineering, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2014
Publisher: Florida State University
Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Biological systems show a reliance upon their capability to adapt limb stiffness as a means to achieve dynamically similar locomotion over a wide range of terrains. The versatility of robotic platforms falls short in comparison to their biological counterparts. One possible method to enhance the performance of these systems is to integrate a variable stiffness mechanism into the locomotive structure to aid in their adaptability. To date, many variable stiffness mechanisms have been designed, but they have multiple drawbacks. The current mechanisms are typically too slow to achieve rapid adaptations during dynamic locomotion or too large for implementation onto smaller platforms. It is desirable to have a variable stiffness mechanism that is able to achieve a large reduction in stiffness in the minimal amount of time. This work focuses on the development process of a dielectric elastomer based variable stiffness mechanism as a replacement for traditional springs on a legged hexapedal robot. A simulation is developed assessing the stability benefits of an ideal variable stiffness mechanism actuated over the period of a single stride during dynamic locomotion. The design process is detailed and the characterization of the mechanism in terms of its magnitude for stiffness reduction, transient response to stimuli, and implementability is presented. The newly developed system shows up to an order of magnitude reduction in stiffness at an actuation frequency approximated at 10 Hz. The system is implemented onto an adapted version of the dynamic running robot, iSprawl, and its performance is characterized with respect to forward velocity. Reliability issues in the current manufacturing process pose a potential problem, but new methods are proposed to increase durability and repeatability of the mechanism. Finally, the next generation design for implementation onto a new platform is presented.
Identifier: FSU_migr_etd-9058 (IID)
Submitted Note: A Thesis submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Master of Science.
Degree Awarded: Summer Semester, 2014.
Date of Defense: July 11, 2014.
Keywords: Compliance, Dielectric Elastomer, Dynamic, Robot, Smart Material, Variable Stiffness
Bibliography Note: Includes bibliographical references.
Advisory Committee: Jonathan Clark, Professor Directing Thesis; William Oates, Committee Member; Patrick Hollis, Committee Member.
Subject(s): Mechanical engineering
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_etd-9058
Use and Reproduction: This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them.
Host Institution: FSU

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Newton, J. (2014). Design and Characterization of a Dielectric Elastomer Based Variable Stiffness Mechanism for Implementation onto a Dynamic Running Robot. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_etd-9058