Preliminary results on multi-pocket pneumatic elastomer actuators for human-robot interface in hand rehabilitation

Abstract

Soft fluidic actuators have been used recently for developing wearable soft robotics for hand rehabilitation and power-assist. However, these actuators have mostly been made as single-pocket structures that are controlled by a single input for each digit. The next natural step would be to develop multi-pocket structures that could be controlled by multiple inputs to gain better control over the coupled digits' response. The purpose of this study is to explore the fabrication of this kind of soft multi-pocketed pneumatic elastomer actuators. For this paper, a comparison was made between two 2-pocket prototypes, one with internal and the other with external pressure input tubing. Otherwise they were fabricated in the same manner. The goal was to see whether an embedded pressure input tubing would affect the actuator's force output or motion trajectory. The fabrication process, and the force and trajectory measurements are described in detail. The prototypes had similar responses, which seemed not to be affected by the tubing. This showed that the described method could be used for making practical soft actuators with embedded input tubing that does not interfere with their response. However, further tests need to be done to confirm that the results apply to structures with three or more pockets.