Control system for 1DOF vibrating machine for soil scale model by centrifugal forces

This article presents the non-linear mathematical model of a one-freedom degree electro-hydraulic shaking table for simulating earthquakes in soil scale models that are influenced by a centrifugal force. The problem presents two challenges: The first one is that when a body is exposed to a certain centrifugal force to simulate gravity force on it, the time and the magnitude of the displacement should be divided by the gravity number (N) that is being applied to get a model N times bigger; and the second one, is that the friction in the servo valves will increase, therefore, the hydraulic system will require a high bandwidth. The model is used to design two feedback control techniques: Linear Quadratic Gaussian with loop transfer recovery (LQG-LTR) and Model Predictive Control. Simulations with the non-linear model are presented for the earthquakes of Umbria Italy in 29/04/1984, Mammoth Lakes - Aftershock USA in 26/05/1980 and Mexico in 19/09/1985. To implement the mentioned control techniques, software architecture and a “black box” model is presented which is obtained by using a closed loop algorithm (CLOE) that is used to recalculate the controllers and obtain experimental results.