Smart textiles using fluid-driven artificial muscle fibers

Abstract

The marriage of textiles with artificial muscles to create smart textiles is attracting great attention from the scientific community and industry. Smart textiles offer many benefits including adaptive comfort and high conformity to objects while providing active actuation for desired motion and force. This paper introduces a new class of programmable smart textiles created from different methods of knitting, weaving, and sticking fluid-driven artificial muscle fibers. Mathematical models are developed to describe the elongation-force relationship of the knitting and weaving textile sheets, followed by experiments to validate the model effectiveness. The new smart textiles are highly flexible, conformable, and mechanically programmable, enabling multimodal motions and shape-shifting abilities for use in broader applications. Different prototypes of the smart textiles are created with experimental validations including various shape-changing instances such as elongation (up to 65%), area expansion (108%), radial expansion (25%), and bending motion. The concept of reconfiguring passive conventional fabrics into active structures for bio-inspired shape-morphing structures is also explored. The proposed smart textiles are expected to contribute to the progression of smart wearable devices, haptic systems, bio-inspired soft robotics, and wearable electronics.

Figure 1

Different approaches to create smart textiles from artificial muscle fibers.

Figure 2

Different prototypes of smart textiles are achieved by varying AMF configurations. (A) Knitting sheet made from three AMFs. (B) Bidirectional weaving sheet made from two AMFs. (C) A unidirectional weaving sheet made from one AMF and acrylic yarns could lift a 500 g load, which is 192 times heavier than its mass (2.6 g). (D) Radial expansion structure made from a single AMF and cotton yarns as radial constraints. Detailed specifications can be found in the “Methods” section.

Figure 3

Fabric reconfiguration by sticking AMFs to conventional fabrics. (A) Design concept of bending actuators made by sticking a folding AMF to a non-stretchable fabric. (B) Bending actuator prototype. (C) Reconfiguring a rectangular fabric into an active four-legged robot. Non-stretchable fabric: plain-woven cotton muslin; stretchable fabric: polyester. Detailed specifications can be found in the “Methods” section.

Figure 4

Characteristics of smart textile configurations. (A,B) Hysteresis profiles of input pressure and output elongation and force of the weaving sheet. (C) Area expansion of the weaving sheet. (D,E) Relationship between input pressure and output elongation and force of the knitting sheet. (F) Area expansion of the radial expansion structure. (G) Bending angles of three different lengths of bending actuators.

Figure 5

Analytical models to establish the elongation-force relationship. (A,B) Analytical model illustration for knitting and weaving sheets, respectively. (C,D) Comparison between analytical models and experimental data for knitting and weaving sheets, respectively. RMSE root mean square error.

Figure 6

Capabilities of unidirectional weaving sheets. (A) Shape programmability by sewing thread to produce shape-shifting structures. (B) Compression sleeve for a finger. (C) Another weaving sheet embodiment and its implementation as a forearm compression sleeve. (D) Another compression sleeve prototype made of an AMF type M, acrylic yarns, and a Velcro strap. Detailed specifications can be found in the “Methods” section.

Figure 7

Capabilities of a bidirectional weaving sheet, knitting sheet, and radial expansion structure. (A) Bidirectionally constraining a bidirectional weaving sheet to produce bidirectional bending. (B) Unidirectionally constraining a bidirectional weaving sheet to produce bending and elongating. (C) Highly conformable knitting sheet that could adapt to various surface curvatures or even form a tubular structure. (D) Constraining the centerline of a radial expansion structure to form a hyperbolic paraboloid shape (a potato chip).

Figure 8

Fabric reconfiguration to produce shape-morphing structures. (A) Sticking an AMF to passive fabric sheet’s boundaries to turn it into a controllable four-legged structure. (B–D) Another two examples of fabric reconfiguration that turn the passive fabric butterfly and flower into active ones. Non-stretchable fabric: plain-woven cotton muslin.