Position control of 2-DOF resonant system based on modal-space control design

Advanced robotic systems have been developed to realize robot society, a mechanism and a control theory of these systems have been researched for a long time. Due to some advantages such as low cost, safety and weight saving, these systems with a flexible mechanism are required in the future. However, the fast response of such systems which is regarded as a resonant system induces a vibration caused by mechanical resonances. Therefore, a lot of motion control theories for resonant system have been extensively researched to improve motion response, most of these control theories are directed to the state of tip mass. This paper focuses on control theory for the position of middle load mass and the length of a three-mass resonant system, proposes position control theory of 2-DOF resonant system. In this paper, some controllers are designed in modal space, such as the common mode and the differential mode. Generally, since a three-mass resonant system has the 1st resonance and the 2nd resonance, the control target is suppression of two resonances. The 1st resonance is suppressed by differential mode controllers, and the the 2nd resonance is suppressed by common mode controllers in this paper. Experiments verify the effectiveness of the proposed control theory.