Control of a straight line stretching motion for a humanoid robot taking advantages of cooperation with biological bi-articular simultaneous drive

Research objective is motion control of a humanoid robot limb with considerations of characteristics of biological subjects. There are some differences between biological subjects and conventional humanoid robots from the point of its mechanisms and control method. From the point of mechanism, biological subjects have two joints simultaneous drive, which is called bi-articular simultaneous drive. In this paper, characteristics and advantages of the bi-articular simultaneous drive on static condition have been mathematically calculated and compared to previous measurement. Furthermore, dynamic motion of a specific straight line has been also calculated and considered. The authors have focused on one specific streching motion, which the torque of elbow joint during the motion is almost similar to the torque for external force at the tip point. Finally, moton control using the cooperation with bi-articular simulataneous drive have been summarized from the point of control and energy cost of view.