Abstract
Recently, the requirements of sophisticated anti-seismic testing system are increasing year by year, especially for tests of non-linear and non-reversible phenomena, e. g. the plastic deformation of structures. In these tests, iterative equlization based on characteristics found through trial exitation cannot be applied. So we have adopted H∞ control to 3-D shaking table for the improvement of response. That is why we can design controller that perturbations of a plant is taken into account in advance. The points of this paper is as follows; 1) In MIMO system whose units of input variables or output variables are different, we have made a scaling of units that the difference of the maximum singular value plot of the plant and the minimum singular value plot of it becomes as small as possible. 2) We have adapted 4 block problem taking “state disturbance” into account in H∞ controller design.
As a result of experiments with 3-D shaking table, H∞ controller has extended its frequency response from 4.7Hz to 8.3Hz compared with conventional analog control, while harmonic distortion on acceleration stays at the same level.
