Document Type

Thesis

College

College of Engineering

Department

Mechanical Engineering

Degree

MSE in Mechanical Engineering

Date Completed

2015

First Committee Member

Riofrio, Jose

Second Committee Member

Shin, Moochul

Third Committee Member

Dini, Said

Additional Committee Member(s)

Khosrowjerd, Mohammad

Abstract

"This research examines the implementation of Nitinol wires as a complex shape actuation source specifically targeted for low-power muscle biomimetics. Nitinol is a type of shape memory alloy (SMA) which recovers its original shape after experiencing large deformation when heated above an austenite finish temperature. Previous preliminary work (by Prof. J. Riofrio, Prof. M.Shin, and Oliver Mestre) demonstrated successful closed-loop force control (i.e., recovery stress) using a simple proportional controller. The work presented in this report builds upon the previous work by improving the results of the force control, demonstrating closed-loop position control of various wire arrangements in the presence of inertial loads. A pre-deformed NiTi (4% pre-strain) wire is energized via Joule heating (martensite to austenite) and de-energized by conductive cooling (austenite to martensite). The main experimental platform utilized for the purposes of this work consisted of a horizontally arranged NiTi wire (or wire bundle) fixed at one end and connected to a hanging weight through a pulley on the opposite end. The angular displacement of the pulley was measured with a non-contact magnetostrictive angle sensor, thereby providing the control feedback signal for the wire displacement."

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