Development of 6 Degrees of Freedom Parallel-Link Shaking Table for Three-Dimensional Movement on Centrifugal Loading Device

Abstract

In experimental studies in geotechnical engineering, vibration with three degrees of freedom (DOFs), similar to that in an actual earthquake, needs to be reproduced in a centrifugal field. However, a suitable shaking table has not been developed. A general multi-DOF shaking table requires a complicated mechanism and a large installation space and is unsuitable for centrifugal fields. In this paper, the world’s first shaking table capable of three-dimensional motion in a centrifugal field was developed. The mechanical and control system requirements were defined, and the use of a Stewart platform mechanism consisting of six direct-acting hydraulic cylinders was proposed. An air spring was installed to offset the centrifugal force on the inertial mass, and a pressurized spherical bearing was used to withstand the excitation force of the actuator while maintaining more than two DOFs for the bearing. The shaking table could operate up to a maximum of 50 G and generate a maximum of 10 G in a single axis.