Humanoid finger with rigid-flexible-soft structure.

Soft robotic grippers offer adaptable and safe manipulation across diverse objects, but they often lack the output force and stability of rigid grippers. Developing fingers that deliver high force while delicately handling small or fragile objects remains a key challenge. Here, we design a humanoid finger with a rigid-flexible-soft structure, composed of rigid tubular bones, flexible joint springs with automatic reset and resistance to deformation under external forces, and a soft silicone skin. A pneumatic membrane actuator is placed between the bones and skin. To test its performance, we build various grippers using the proposed humanoid fingers and conduct experiments such as grasping tofu, pinching 0.1 mm paper, holding a 23.2 cm basketball, and supporting 5.275 kg weights. Our humanoid finger broadens the applications for rigid-flexible-soft robots.