Vibration and Motion Control of Flexible Structures by Hybrid Dynamic Absorber(Influence of Vibration System with Nonlinear Element)
Shinji Mitsuta*, Kazuto Seto**, Hiroyuki Ito and Akio Nagamatsu***
* Komatsu Ltd., 1200, Manda, Hiratsuka, Kanagawa, 254 Japan
** Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-Ku, Tokyo, 101 Japan
*** Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152 Japan
Recently, the necessity for making machines weighing less and operating at high speeds has increased. This paper is concerned with vibration and motion control by a control system which combines a servo controller and a hybrid dynamic absorber. In our method, vibration control and motion control are designed independently. First, the dynamics of a tower structure and a servo motor are modeled. Then, it is shown experimentally that although vibration control by the servo controller alone causes instability due to nonlinear elements such as friction or rattle, the hybrid dynamic absorber does not easily cause this sort of instability. On the comparison of vibration control effect and control force, the hybrid dynamic absorber requires less force. Finally, to know the effect of the new method, we evaluated the motions (triangular wave and sine wave) of the flexible structure. The effectiveness of this vibration and motion control method for the flexible structure was demonstrated by simulations and experiments.