Analysis of the 1-Joint Spring-Motor Coupling System and optimization criteria focusing on the velocity increasing effect

This paper describes analysis and design criteria of the 1-Joint Spring-Motor Coupling System (SMCS). A system including series elastic elements shows vibrational responses in the velocity space, and our concept is to use the velocity peak of the system for motions that need explosive power. By tuning parameters, we can obtain instantaneously higher velocity than without any spring. We constructed a mathematical model of a 1-Joint SMCS (including motor electrical properties) and confirmed the velocity increasing effect on SMCS by numerical analyses and real experiments. And we discovered existence of the most effective inertia balance between the motor shaft and the robot link, and proposed the optimum spring constant with consideration of the moveable range of the link. We confirmed the validity and the limitation of the criteria by the real experiments.