A New Approach For Acceleration Tracking of Shake Tables Using Combined Acceleration and Force Feedback Control

Abstract

This presentation introduces a new acceleration control method for shake tables that provides high-performance and robustness. Unlike the conventional displacement feedback control that is used in most servo hydraulic shake tables, the proposed control method adopts direct acceleration feedback control. While acceleration feedback is not practically employed due to stability issues associated with table drift, the proposed method allows the use of acceleration feedback by adding force feedback loop for stabilization. In this study, controllers for the acceleration and force feedback loops are designed using loop shaping techniques incorporating control-structure interaction. The proposed control method was experimentally investigated at the Johns Hopkins University under two loading conditions: without payload and with payload close to the capacity of the shake table. Experimental results showed that the proposed acceleration control method combining acceleration and force feedback provides better acceleration tracking and wider controllable frequency range than the conventional displacement feedback control in both loading conditions. This presentation will cover basic theory of the proposed method, experimental results, and requirements to upgrade existing shake tables with the proposed control method.