Design and modal analysis of feedback excitation control system for vertical series elastic manipulator

This paper describes a feedback excitation control system with consideration of gravity, which is a control method to obtain high kinetic energy by utilizing passive potential energy. In the case of a robot that has series elastic joints, peak kinetic energy becomes higher than that of a rigid robot with same motors. We have proposed the feedback excitation control for horizontal multiple-joint robots in our previous work. In this paper, we extend the feedback excitation control to systems that are affected by gravity, and we analyze the feedback excitation control system from the viewpoint of linear vibration mode. Validity of the proposed `coordinate or opposite phase controller´ is suggested by the modal analysis. We examine effective excitation controllers to utilize gravitational and elastic potential energy by simulations and experiments.