Abstract
This paper proposes a control method of an active isolation system with low stiffness and lightweight isolation table subjected to direct impulse excitation on it. In the case of large-size and lightweight isolation table, multi vibration modes appear on an isolation table in lower frequency region. Therefore, we construct a 5-DOF lumped model of the isolation table using the reduced order physical modeling method which is effective for controlling multi modal vibrations. For designing a controller, two-degree-of-freedom controller combining feed-forward controller for MIMO system with LQ is used. Usefulness of proposed modeling method and controller is confirmed through numerical simulations and experimental results.