In this study, we examined the frame model of a robot arm from the upper arm to the forearm based on human anatomy to develop a tendon-driven humanoid robot that incorporates human anatomical structures. We designed a 3D CAD model of a robotic arm incorporating human anatomical features, and evaluated its expected range of motion. The evaluation results demonstrated that incorporating human anatomical features resulted in an expanded range of motion compared to a structure without these features. In particular, the offset of the elbow joint affects the range of motion in flexion and extension of the elbow; it decreases the range of motion for extension but increases it for flexion. Similarly, the curvature of the ulna and radius affects the range of motion in forearm pronation and supination and decreases the range of motion for supination while increasing it for pronation. The prototype was able to perform the basic movements of elbow flexion and extension, as well as forearm pronation and supination; however, the pronation and supination movements were not smooth. Based on these findings, it can be concluded that incorporating human anatomical structures is sufficiently effective in enhancing the functionality of robot arms.

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