Finger joint aligned flat tube folding structure for robotic glove design

Abstract

Pneumatic soft actuators have been widely considered the safest actuation technology for use in wearable rehabilitation robots. For soft robotic gloves, researchers commonly put soft extending or bending actuators on dorsal fingers to assist hand flexion. In this research, we propose a novel pre-folded flat tube actuator (PFTA) to assist finger flex into a pre-set bending angle or contact force. The PFTA has three folds, aligned with each of the finger joint. Different from other soft actuators, the PFTA exerts bending torque directly on each finger joint without large actuator deformation. The PFTA made of heat shrink flat tube has a small profile, with low cost, easy fabrication, and high safety. When actuated, the PFTA has the tendency to unfold as well, we call this effect as unfolding flat tube actuation. This effect is characterized by a range of bending angles and input air pressures in which four distinct response regimes were observed. They are defined as shearing, collapsing, creasing, and flattening regimes. Similarly, experimental characterization of PFTAs is also conducted to evaluate the level of joint flexion assistance based on which design guidelines for robotic gloves are recommended. Finally, we build PFTAs on a soft wearable glove and demonstrate their capability in assisting the grasping operations of various object shapes.

3D-printed passive bellow actuator for portable soft wearable robots

“…Compared to the tendon-driven approach, fluid-driven methods ensure safer behavior for soft wearable robots when navigating unstructured environments during actuation [21][22][23]. The inherent softness of fluid-driven robots reduces the potential harm to the human body [24][25][26]. Nonetheless, fluiddriven robots face challenges, including susceptibility to punctures, complex and heavy fluidic systems, and limited controllability when responding to user or environmental feedback.…”