Soft grippers and actuators have attracted increasing attention due to safer and more adaptable human-machine and environment-machine interactions than their rigid counterparts. In this study we present a novel soft humanoid hand that is capable of robustly grasping a variety of objects with different weights, sizes, shapes, textures, and stiffnesses. The soft hand fingers are made of flexible hybrid pneumatic actuators (FHPAs) designed based on a modular approach. A theoretical model is proposed to evaluate the bending deformation, grasping force, and loading capacity of the FHPAs, and the effects of various design parameters on the performance of the FHPA are investigated for optimizing the soft hands. This new FHPA achieves a balance of required flexibility and necessary stiffness, and the resulting soft humanoid hand has the merits of fast response, large grasping force, low cost, light weight, and ease of fabrication and repair, which shows promise for a variety of applications such as fruit picking, product packaging, and manipulation of fragile objects.
Keywords: flexible hybrid pneumatic actuators; rigid-flexible coupling; soft humanoid hand; soft pneumatic actuator; soft robotics.