State space modeling and experimental verification of a single channel, moving load cell structural test

Full-scale aircraft structural fatigue tests are extremely complex from a control systems viewpoint. There are usually a large number of actuators with significant interactions between them. Control is made more difficult because the load cells usually move with the actuators. In order to better understand these tests and improve the control, some modeling of the tests is required. This paper presents a linear state space model of a single channel structural test that can be simply expanded to a multi-channel configuration. The model is verified by comparing the predicted frequency response with measured data for several physical systems. The model predictions are shown to be sufficiently accurate to allow a greater understanding of these systems and predict the relative stability of different systems.