Improvement of Shaking-Table Control by Real-Time Compensation of Reaction Caused by a Specimen (2nd Report, Verification with Large Scale Shaking Table)

We have developed a new control method for a shaking table that compensates the reaction force caused by a specimen in real-time. In this work, we executed a series of verification tests to confirm the effectiveness of the developed method with a large-scale shaking table with a payload of fifty tons. The reaction force was calculated from the drive force of actuators and accelerations of the table. A compensator was designed to cancel any reaction force with frequency components ranging from DC to ten hertz. The specimen used for the tests consisted of a 20-ton mass and four columms to support the mass above the table. When the specimen was excited with a large acceleration, the columns were deformed to a plastic range. The characteristics of the specimen, therefore, became non-linear. The results of these tests show that the compensator successfully cancelled the reaction force. Therefore, the control method is effective for using a shaking table with a specimen whose characteristics change during excitation.