Fusion of different feedback control systems for the control of shaking tables (Interference compensation for control systems and design of controllers that can suppress specimen reaction forces)

Abstract

A shaking table is a device used to examine the vibration characteristics of a specimen by applying vibration to it, and is used to evaluate the earthquake resistance of buildings and the ride comfort and safety of vehicles. Therefore, it is necessary to accurately reproduce the target vibration on the shaking table in order to investigate the accurate vibration characteristics of the specimen. For this reason, experiments with shaking tables require a controller with good tracking performance. Generally, shaking tables are controlled by feedback control, which uses displacement or acceleration as the controlled variable. However, acceleration feedback control can easily achieve good tracking performance in the high-frequency range, but performance deteriorates in the low-frequency range. On the other hand, the displacement feedback control can improve the tracking performance in low frequency. Considering these characteristics of the control system, a method using a control system that fuses acceleration feedback control system and displacement feedback control system has been proposed. This method of fusing different feedback control systems is called as Controller Fusion. However, controller fusion causes problems such as deterioration of tracking performance due to interference in the control system. In this study, we formulate the interference in the control system caused by controller fusion and use its inverse characteristics as a compensator to propose a control system that does not deteriorate the tracking performance no matter what kind of feedback controller is used. Then, experiments are conducted with the specimen mounted on a 3-DOF shaking table to verify the effectiveness of the proposed control system.