Vibration Control of A Time-Varying Flexible Beam Using a Piezoelectric Servo-Damper
Chong-Won Lee*, Sung-Dae Kim**, Won-Ho Jee** and Sang-Ho Lee****
* Center for Noise and Vibration Control (NOVIC), Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Taejon 305-701, Korea
** Precision Instruments R&D Center, Samsung Aerospace Industries
*** Corporate Production Engineering Research Laboratory, Gold Star Corporation
**** Vehicle Test & Evaluation Department 1, Kia Motor Corporation
The purpose of this study is to reduce the transient operational vibration of the free end of an overhung flexible beam whose effective length is time-varying. The acceleration signals at its free end are measured by two accelerometers in the vertical and horizontal directions, and the beam is driven axially by a motor. The control device, a piezoelectric servo-damper mounted at the free end, consists of a sprung mass supported by two pairs of piezoelectric actuators which are placed perpendicular to each other. Modeling of the system is achieved experimentally and analytically for the horizontal and vertical directions when the beam length takes on the minimum, medium, and maximum values. Experimental results show that the performance of the control system can be well predicted by using the established model and that a fixed 1-gain which is derived from a beam of medium length is effective unless the time-varying property of system parameters is strong.