This paper presents an active microvibration isolation system using voice-coil linear motors, and pneumatic and piezoelectric actuators. This system is designed to reduce microvibration of the six degrees-of-freedom associated with the rigid body modes of the vibration isolation table by feeding back the pseudo absolute displacement and velocity of the table. To improve vibration isolation performance, a feed-forward control link is added to the sway components in each dimension. This system can also control bending modes of the table in the frequency range up to 200 Hz by employing a proposed Virtual Tuned-Mass Damper control strategy, which is a type of the pole assignment method. In this approach, the pole locations are chosen by a genetic algorithm. For ambient microvibration of the floor around 0.5 cm/s2 and for small earthquakes of around 8 cm/s2 a reduction by a factor of 100 was achieved in the acceleration of the vibration isolation table. Moreover, the vibration of the isolation table was decreased over the entire frequency range. This system also showed good vibration control performance when an impact excitation was applied directly to the table; vibration was damped out within about 0.1 sec. Additionally, the resonance amplitudes around the bending modes of the table were reduced from 1/5 to 1/15 by the Virtual Tuned-Mass Damper method.

Heiland, D., and Beyer, K., 1998, “Vibration in Semiconductor Fabs,” Workshop on Effect of High-Speed Vibration on Structures and Equipment, pp. 63–76, Taiwan, ROC.
Yang, Y. N., and Agrawal, A. K., 1998, “Protective System for Microvibration Reduction of Buildings,” Asia-Pacific Workshop on Seismic Design & Retrofit of Structures, pp. 319–333, Aug. 10–12.
Takahashi, Y., Katayama, K., Murai, N., and Fujita, T., 1989, “Active Vibration Control System Using Linear Motor,” 5th International Precision Engineering Seminar and Annual Meeting of the Precision Engineering Division, Monterey, California.
Fujita, T., Tagawa, Y., Kajiwara, K., Yoshioka, H., Takeshita, A., and Yasuda, M., 1992, “Active 6-DOF Microvibratoin Control System Using Piezoelectric Actuators,” Third International Conference on Adaptive Structures, pp. 514–528.
Fujita, T., Kajiwara, K., Takeshita, A., Yoshioka, H., and Yasuda, M., 1994, “Active Microvibration Control System with Elastic Vibration of Equipment-Table System,” 5th International Conference on Adaptive Structures, pp. 612–622.
Watanabe, K., Hara, S., Kanemitsu, Y., Haga, T., Yano, K., Mizuno, T., and Katamura, R., 1996, “Combination of H∞ and P1 Control for an Electromagnetically Levitated Vibration Isolation System,” Proceedings of the 35th Conference on Decision and Control, Kobe, Japan, pp. 1223–1228.
Yasuda, M., Osaka, T., and Ikeda, M., 1996, “Feedforward Control of a Vibration Isolation System for Disturbance Suppression,” Proceedings of the 35th Conference on Decision and Control, Kobe, Japan, pp. 1229–1233.
Yoshioka, H., and Murai, N., 1999, “Active Microvibration Control System by Pole Assignment Method using Genetic Algorithm,” Proc. of the SPIE Conference on Smart Structures and Integrated Systems, Newport Beach, California, pp. 980–986.
E. E.
D. H.
, and
C. H.
, “
Vibration Control Design of High Technology Facilities
Sound Vib.
, No.
, pp.
Meirovitch, L., and O¨z, H., 1980, “Active Control of Structures by Modal Synthesis,” Structural Control, H. H. E. Leipholz, ed., North-Holland Publishing Co., Amsterdam, pp. 505–521.
Yoshioka, H., Murai, N., Abe, T., and Hashimoto, Y., 1997, “Active Microvibration Control System by Considering Elastic Deformation Modes of Vibration Table,” IMAC-XV, Japan.
Goldberg, D. E., 1989, Genetic Algorithms in Search, Optimization & Machine Learning, Addison-Wesley, Reading, MA.
Dasgupta, D., and McGregor, D. R., 1993, “Genetically Designing Neuro-controllers for a Dynamic System,” Proceedings of the International Joint Conference on Neural Networks (IJCNN), pp. 2951–2955, Nagoya, Japan.
You do not currently have access to this content.