A Motion Coupling Method for Tendon-driven Jointless Finger Exoskeleton

When the traditional tendon-driven scheme is applied to the jointless finger exoskeleton, the farther finger joints maybe bend prior to the nearer ones, which is a wrong motion sequence. For this problem, a tendon-driven motion coupling scheme for the jointless finger exoskeleton is proposed by using a pair of coupling tendons. Two materials with different stiffness are adopted for the coupling tendons to avoid the interference between the bending and flexing motions. With the new scheme applied, the finger exoskeleton will output humanlike motion sequence toward the adjacent finger joints, while keeping the whole structure compact and portable. The basic theory of the new coupling scheme is introduced, calculated and simulated. An experimental hand prototype is developed, and all the exoskeleton parts are designed according to the hand prototype parameters. A testing setup is developed, and the kinematic experiments with motion coupling are carried out. The validity and feasibility of the proposed scheme are fully proved by the experiment result.