A Perceptive Bionic Finger with Clam-inspired Rigid-Soft Hybrid Joints

Human hand has unmatched capabilities in dexterous objects manipulations, performing precise or complex tasks, and is our important sensory organ to perceive the external world by touch. This paper presents a vacuum-driven perceptive bionic finger (PBF) with clam-inspired hybrid joints. The hybrid joint is made of a soft membrane and two rigid side surfaces and is optimized to minimize the stress concentration. The PBF is composed of rigid finger bones and three pneumatic-driven hybrid joints actuated by two air inlets channels, close to a human finger. The PBF can reach a maximum active bending angle of 135°.At each joint, a magnetic induction-based split angle sensing film is seamlessly embedded at its rigid side surface, which can detect bending angle change as small as 0.1°. Thus, both large bending angle changes due to actuation and subtle deformations due to external stimuli can be monitored precisely. The PBF prototype was fabricated, characterized, and demonstrated for texture recognition by simply sliding the finger on a surface. The sensing and actuation capabilities of the proposed finger allow it to achieve human-finger like touch perception and fine operation skills.