Takatoshi Hondo

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.

End-tip speed maximization for noncyclic swing motion based on time reversal integral in multiple-joint robots

This paper describes a control method for noncyclic swing motions such as throwing, hitting and kicking in multiple-joint robots by using “time reversal integral.” This method calculates a control input sequence and an initial posture of the robot to reach a designated terminal state by integrating a dynamic system without directly designating trajectories. The terminal end-tip speed is maximized by optimizing the target terminal state under constraints such as friction and the joint position limits. Feasibility of the method is evaluated by ball throwing experiments.