A Pumpless Layflat Tube-Based Pneumatic Bending Actuator for Soft Assistive Glove

Layflat tube (LFT) is a soft tube that is pressed flat for easy winding onto a spool and continuous use. When inflating an LFT, the width of the FLT will contract, and the flat side of the FLT will expand. Based on this feature, a layflat tube-based pneumatic bending actuator (LFTPBA) is proposed and used for finger actuation in soft robotic glove design. Five LFTPBAs are mounted on a fabric glove to assist finger flexion. To eliminate noise and vibration of a normal pump system, a bellow actuation method is proposed. The finger flexion angle and bending speed can be controlled by motors directly. A mathematical model is developed to investigate the relationship between the LFTPBA flexion angle and bellow compression displacement. Besides, a finite element analysis of the LFTPBA bending trajectory versus pressure increase is also conducted. Compared with a fabric-based pneumatic bending actuator, the proposed system can generate 57% more blocked tip force (from 9 N to 14.13 N). A prototype assistive glove has been developed to demonstrate various grasping operations via a hand model.