Humanlike shoulder complex for musculoskeletal robot arms

In recent years, musculoskeletal robots are being intensively studied to exploit the advantages of biological musculoskeletal systems for robot developments. In these robots, it is very important to assure engineering, biomechanical, and anatomical plausibility at the same time. However, these requirements are often in contradiction. Especially, in the human´s shoulder complex, mimicking the glenohumeral joint and the scapulothoracic joint has been difficult because of the need to assure a wide range of movement and the joint´s stability at the same time. In this paper, we propose mechanical structures to realize the functions of the glenohumeral joints and scapulothoracic joint. These structures were used to develop a musculoskeletal robot arm driven by pneumatic artificial muscles. In addition, in order to verify the feasibility of the robot arm, we present a dynamic motion in which the robot arm throws a ball by a simple control strategy.