Disturbance cancellation control for vibration of multi-degree-of-freedom systems with harmonic excitation.

This study is to derive a general design method of disturbance cancellation control systems which completely strike out harmonic excitation forces for a vibration system with multi-degree-of-freedom. In this paper, the output regulator theory with internal stability based on feedback and feedforward control in applied to a design of control system. First, the feedback control system is designed using modal co-ordinates after modeling the dynamics of a vibration system and a disturbance system. Two models are used for harmonic excitation forces. Next, the feedforward control system is designed for two disturbance models. Finally, some simulation results are described. The important conclusion of this study is following: The disturbance cancellation control for actual use is to design as if the disturbance frequencies were equivalent to natural frequencies on each mode. This means near-zero amplitudes at any position and any frequency.