This paper presents the design, development, and testing of an active textile-based wearable compression device that is capable of delivering a controlled pulsatile compression. The device uses low spring index nickel titanium (NiTi) coil actuators to produce an applied dynamic pressure of up to 5.5 kPa. The selected NiTi coil actuators produce pressure when thermally stimulated with Joule heating via an applied current (0.3 A), and generate recoverable strains up to 75% in extension. An optical fiber strain sensor was developed to monitor the textile strain and enable the indirect estimation of the applied pressure. A new approach using a passive NiBR spring (in parallel with the NiTi actuators) was also developed to assist the NiTi coils in recovering the detwinned martensite form after cooling. The pressure distribution around a rigid cylindrical shape was also evaluated, showing higher applied pressures (5.5 kPa) where the NiTi coil actuators were located. The strain sensor exhibits high accuracy compared to a reference commercial sensor (as indicated by the high correlation indexes of up to 0.97 between compression cycle measurements with both solutions).
Bibliographical noteFunding Information:
Manuscript received November 9, 2016; revised August 16, 2017, January 29, 2018, May 25, 2018, and October 5, 2018; accepted May 7, 2019. Date of publication May 10, 2019; date of current version August 14, 2019. Recommended by Technical Editor J. C. Koo. This work was supported in part by CeNTI—Centre for Nanotechnology and Smart Materials, MIT MVL—Man Vehicle Laboratory, and UMN WTL— Wearable Technology Laboratory, in part by the National Funds throught FCT - Portuguese Foundation for Science and Technology, Reference UID/CTM/50025/2013 and PhD grant SFRH/BD/52352/2013 (CG), and in part by FEDER funds through the COMPETE 2020 Programme under the project number POCI-01-0145-FEDER-007688. (Corresponding author: Carlos Gonc¸alves.) C. Gonc¸alves is with the Institute for Polymers and Composites IPC/I3N and MIT-Portugal program, University of Minho, Braga 4704, Portugal (e-mail:,firstname.lastname@example.org).
This work was supported in part by CeNTI-Centre for Nanotechnology and Smart Materials, MIT MVL-Man Vehicle Laboratory, and UMN WTL-Wearable Technology Laboratory, in part by the National Funds throught FCT - Portuguese Foundation for Science and Technology, Reference UID/CTM/50025/2013 and PhD grant SFRH/BD/52352/2013 (CG), and in part by FEDER funds through the COMPETE 2020 Programme under the project number POCI-01-0145-FEDER-007688.
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- Active materials
- Compression garments
- Fiber optic sensing
- Shape memory alloys
- Smart wearable textiles
- Soft orthotic devices
- Strain sensors