Biomechanical considerations on the design of a humanoid shoulder girdle

Presents a comparison between the ranges of motion in the human shoulder complex and in the humanoid robotic shoulder complex developed as a parallel mechanism. The Elite motion analyser was used to obtain the three dimensional trajectories of markers attached to the selected anatomical points on the shoulder girdle. The measurements show an asymmetry of the extreme positions in the shoulder girdle and the difference when the arms are stretched downward and when the arms execute inclination in the plane of the girdle's motion. The mechanism has to be inclined upward and forward for about 10/spl deg/. The obtained results of the working cone of the arm show that the central axis is inclined about 60/spl deg/ forward in the horizontal plane and 15/spl deg/ upward in the frontal plane.