A black box design approach to avian-inspired SMA coil actuated wearable morphing angel wings

Sean Dalton, Henry Koon, Jennifer O'Malley, Julianna Abel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Black box design is a constraint driven design approach that distills essential elements of a physical process into inputs and outputs. This paper details the black box design implementation and validation of shape memory alloy (SMA) coil actuators as active members in a Watt I six bar avian-inspired wearable morphing angel wing mechanism. SMA coil actuators leverage the unique characteristics of high energy density SMA wire by providing a compact structural platform for large actuation displacement applications. The moderate force and displacement performance of low spring index coil actuators paired with their virtually silent actuation performance made them an attractive actuator solution to an avian-inspired wearable morphing wing mechanism for the University of Minnesota Department of Theatre Arts and Dance production of 'Marisol'. The wing design constraints (extended span of 7.5 ft, a closed span of 3 ft) required a tailorable actuator system with capacity to perform at particular target force and strain metrics cyclically. A low spring index parameter study was conducted to facilitate an accelerated phase of design prototyping. The parameter study featured six SMA coil actuator prototypes made with 0.012" diameter Dynalloy Flexinol® wire of varying spring indexes (C = 2.5-4.9). The coil actuators were manufactured through a CNC winding process, shape set in a furnace at 450 °C for 10 minutes, and water quenched for hardening. A series of thermomechanical actuation tests were conducted to experimentally characterize the low spring index actuation performances. The coil actuation characterizations demonstrated increased force and decreased actuator displacement corresponding to decreased spring indexes. Scaling these results aided an accelerated design of an actuator system. The actuator system consisted of four C = 3.05 coil actuators wound with 0.02" diameter SMA that were integrated into each Watt I mechanism. The characterization of the forcedisplacement profiles for low index SMA coil actuators provides an effective empirical design strategy for scaling actuator performance to mechanical systems requiring moderate force, moderate displacement actuators.

Original languageEnglish (US)
Title of host publicationModeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation; Structural Health Monitoring
PublisherAmerican Society of Mechanical Engineers
ISBN (Electronic)9780791858264
DOIs
StatePublished - Jan 1 2017
EventASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2017 - Snowbird, United States
Duration: Sep 18 2017Sep 20 2017

Publication series

NameASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2017
Volume2

Other

OtherASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2017
CountryUnited States
CitySnowbird
Period9/18/179/20/17

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Dalton, S., Koon, H., O'Malley, J., & Abel, J. (2017). A black box design approach to avian-inspired SMA coil actuated wearable morphing angel wings. In Modeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation; Structural Health Monitoring (ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2017; Vol. 2). American Society of Mechanical Engineers. https://doi.org/10.1115/SMASIS2017-3943