Experimental investigation of hybrid shape memory alloy pneumatic actuators

Makella Daley, Julianna M Abel

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


Pneumatic actuators are a lightweight, compliant means of exerting force and are especially promising for systems that interact with the human body. These actuators typically consist of an elastomeric bladder and a surrounding sleeve. The sleeve is created using traditional textile manufacturing processes (e.g., wrapping, braiding, and knitting) where the fibers within the textile sleeves are inextensible components that limit the local expansion of the bladder. By varying the fiber angles and applied pressure, different kinematic motions (extension, contraction, bending, and twisting) are achieved. Anti-symmetric fiber angles within the textile sleeve architecture result in axial and radial motion. In this experimental investigation, shape memory alloy (SMA) wires are integrated into two types of passive sleeves (wrapped and knitted) to increase the range of motion of the actuator. Applying pressure to the system pre-strains the martensitic SMA through radial expansion of the actuator. When heated above the austenite finish temperature, the shape memory effect enables contraction of the SMA wire. This fiber contraction causes reorientation of the textile architecture, resulting in additional motion. The effect of the control variables, air pressure and electrical current, on axial displacements and rotations are experimentally characterized using discrete marker tracking. This study explores two basic textile sleeve architectures for hybrid SMA-pneumatic actuators and sets the foundation for increased kinematic tailorability through the design of complex multi-functional actuating textile sleeves.

Original languageEnglish (US)
Title of host publicationBehavior and Mechanics of Multifunctional Materials XIII
EditorsHani E. Naguib
ISBN (Electronic)9781510625914
StatePublished - Jan 1 2019
EventBehavior and Mechanics of Multifunctional Materials XIII 2019 - Denver, United States
Duration: Mar 4 2019Mar 6 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceBehavior and Mechanics of Multifunctional Materials XIII 2019
Country/TerritoryUnited States


  • multifunctional textiles
  • pneumatic actuator
  • shape memory alloy
  • soft robotics


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