<title>Development of active 6-DOF microvibration control system using giant magnetostrictive actuator</title>

Abstract

An active 6-DOF microvibration control system using giant magnetostrictive actuators is developed in order to realize microvibration-free space for precision instruments which hate vibration. A giant magnetostrictive actuator is suitable as a displacement actuator for active microvibration control, because it is both compact and durable and also its response against input is fast and reliable. The developed device consists of a table, six air springs, eight magnetostrictive actuators and six accelerometers on the table. Four actuators are set in the horizontal directions, and another four in the vertical direction. Since air springs and actuators as a unit of vertical support system are arranged in parallel, readjustment of the system is quite easy, even when operating load on the table is changed. The dimension of table is 2000mm in length and 1400mm in width and 230mm in height and the weight of about 2 tons. Operating load on the table is 2 tons. A giant magnetostrictive rod is 6mm in diameter and 50mm in length. The actuators operate within the stroke range of +/- 25 micrometers . Feedback, control strategy using only six components of table acceleration on the table is adopted and the controller is designed by a model matching model. The obtained control performance of the system through two vibration control test can be summarized as follows: (1) Root-mean-square values of the table accelerations under micro-tremor are reduced to 1/3 to 1/10 of the floor accelerations, and kept less than 0.008cm/s2. (2) Induced vibrations by impacts acting on the table disappear in less than 0.05sec.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.