Dynamic Analysis of Active Bend for Joint Driven by Linear Expandable Artificial Muscle

An original robotic joint with one degree of freedom was introduced, in which a linear expandable elastomeric bellows artificial muscle with pliability was driven by pneumatics tandem compound of pneumatics-hydraulics. The structure and principle of the joint were described, and the mathematical expression was established according to analysis of force, between angular displacement of the joint and pressure inside the bellows. The fitting equation was also found between linear elongation length of the bellows and its inner volume, and the dynamic model between angular displacement of the joint and time variable was proposed. The relation of pressure inside the bellows and angular displacement was also expressed. The simulation of dynamics was further given from a demonstration.