Textile based pneumatic actuators have recently seen increased development for use in wearable applications thanks to their high strength to weight ratio and range of achievable actuation modalities. However, the design of these textile-based actuators is typically an iterative process due to the complexity of predicting the soft and compliant behavior of the textiles. In this work we investigate the actuation mechanics of a range of physical prototypes of unfolding textile-based actuators to understand and develop an intuition for how the geometric parameters of the actuator affect the moment it generates, enabling more deterministic designs in the future. Under benchtop conditions the actuators were characterized at a range of actuator angles and pressures (0 – 136 kPa), and three distinct performance regimes were observed, which we define as Shearing, Creasing, and Flattening. During Flattening, the effects of both the length and radius of the actuator dominate with maximum moments in excess of 80 Nm being generated, while during Creasing the radius dominates with generated moments scaling with the cube of the radius. Low stiffness spring like behavior is observed in the Shearing regime, which occurs as the actuator approaches its unfolded angle. A piecewise analytical model was also developed and compared to the experimental results within each regime. Finally, a prototype actuator was also integrated into a shoulder assisting wearable robot, and on-body characterization of this robot was performed on five healthy individuals to observe the behavior of the actuators in a wearable application. Results from this characterization highlight that these actuators can generate useful on-body moments (10.74 Nm at 90° actuator angle) but that there are significant reductions compared to bench-top performance, in particular when mostly folded and at higher pressures.
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Development and evaluation of pneumatic actuators for pediatric upper extremity rehabilitation devices
Textile pneumatic actuators were developed to provide full assistance to lift the arm of a model of an 11-year-old male beyond 120 degrees of shoulder abduction. Two fabrics and a variety of sealing techniques, methods of attachment, and actuator shapes were comparatively evaluated using textile and functional tests. The results identified that both fabrics and one of the three sealing techniques were effective for creating air-tight, functional actuators. Actuators were more effective when the bands attaching them were closer to the axilla. Rectangular and wing-shaped actuators, both lifting the model of an 11-year-old male’s arm above 120 degrees of abduction, were more effective than Y-shaped actuators. Multiple designs and materials may be acceptable for building textile pneumatic actuators to lift the full weight of a child’s arm. Compared to traditional hard robots, soft assistive
robots offer key potential benefits related to comfort, aesthetics, weight, bulk, and cost.
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- Award ID(s):
- 1722596
- NSF-PAR ID:
- 10285965
- Date Published:
- Journal Name:
- The Journal of The Textile Institute
- ISSN:
- 0040-5000
- Page Range / eLocation ID:
- 1 to 8
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1080/00405000.2021.1929704
