Shape Memory Alloys in Textile Platform: Smart Textile-Composite Actuator and Its Application to Soft Grippers

In recent years, many researchers have aimed to construct robotic soft grippers that can handle fragile or unusually shaped objects without causing damage. This study proposes a smart textile-composite actuator and its application to a soft robotic gripper. An active fiber and an inactive fiber are combined together using knitting techniques to manufacture a textile actuator. The active fiber is a shape memory alloy (SMA) that is wire-wrapped with conventional fibers, and the inactive fiber is a knitting yarn. A knitted textile structure is flexible, with an excellent structure retention ability and high compliance, which is suitable for developing soft grippers. A driving source of the actuator is the SMA wire, which deforms under heating due to the shape memory effect. Through experiments, the course-to-wale ratio, the number of bundling SMA wires, and the driving current value needed to achieve the maximum deformation of the actuator were investigated. Three actuators were stitched together to make up each finger of the gripper, and layer placement research was completed to find the fingers' suitable bending angle for object grasping. Finally, the gripping performance was evaluated through a test of grasping various object shapes, which demonstrated that the gripper could successfully lift flat/spherical/uniquely shaped objects.

Automated summary

In recent years, researchers have focused on developing robotic soft grippers that can handle fragile or unusually shaped objects without causing damage. This study introduces a smart textile-composite actuator for a soft robotic gripper. By combining an active fiber (a shape memory alloy) with an inactive knitting yarn using knitting techniques, a flexible and high-compliance textile actuator is manufactured. The actuator's driving source is the shape memory alloy wire, which deforms when heated. Experimental investigations were conducted to determine the optimal course-to-wale ratio, number of bundled SMA wires, and driving current value for maximum actuator deformation. The gripper was assembled using three actuators and evaluated through tests on various object shapes, demonstrating its ability to successfully lift flat, spherical, and uniquely shaped objects.