Development of A Small Clamper for Tendon-sheath Artificial Muscle

Many artificial muscles have been reported in recent years, in addition to the most popular pneumatic artificial muscles, there are many other artificial muscles that based on smart materials or composite materials. Artificial muscles usually have compliant structure, light weight, or high power-to-weight ratio. However, they also expose many defects that caused by their structure or material, moreover they are not developed in line with muscle mechanics. Therefore, based on Hill muscle model, we proposed a novel tendon-sheath artificial muscle with slender structure and light weight, it can meet the requirements of robotic applications like exoskeleton. Moreover, a small clamper driven by electromagnet is developed in this paper for the switching control of muscle activation and inactivation. The clamper is designed for clamping wire rope with diameter of 1-2mm which refers to the inner tendon of the tendon-sheath mechanism, and the maximum clamping force is 800N. The clamping performance of the clamper was tested on an experiment platform. The experimental results illustrated that the small clamper can clamp the moving wire rope effectively. On average, it takes 230ms for the small clamper from receiving the control signal to starting clamping, and another 150ms is taken for fully clamping.