Abstract
Recently many humanoid robots which have many functions such as a walking, dancing and fighting have been developed, so that those are very popular among the people and called "Entertainment Robot". The purpose of this research is to design and develop the joint mechanism having enough torque being able to bow or to bent knees or to stand by one leg. In this paper a basic research of the joint mechanism using a ball screw in humanoid size robot is focused especially. The human being withstands the load by skeleton, muscle. Thus we focus on the joint mechanism generating enough torque against the load as human musculoskeletal. A lower body worthy of the robot height of 150cm is designed.
