A Bio-inspired Variable-Stiffness Method Based on Antagonism

Flexible manipulators need the variable-stiffness function to accomplish different tasks, which is also a challenge for the research of flexible manipulators. This paper proposed a novel bio-inspired variable stiffness method based on muscle antagonism. The variable-stiffness finger is actuated by two tendons to simulate the flexion/extension movement of the human finger. The finger's stiffness is changed by changing the tension on the extensor tendon and flexor tendon. We constructed a variable-stiffness finger prototype to research the variable stiffness performance. It turns out that the finger's stiffness increases with the increase of the tension on the extensor tendon, which verifies the effectiveness of the design. Furthermore, we also assembled a variable-stiffness manipulator to test the variable stiffness performance. The proposed variable-stiffness method indicates the potential application in robots and prosthetic hands.