LAUSR

Abstract This paper considers single-input-single-output (SISO) system identification of a fatigue test rig. The test rig consists of an aluminum-composite structure and four hydraulic actuators that are independently actuated. Because the test rig cannot be run in an open-loop manner, three different closed-loop system identification methods are considered. Specifically, direct, indirect, and dual-Youla closed-loop system identification methods are considered. The models obtained via system identification are used to generate inversion-based feedforward controllers of varying order. The feedforward controllers are implemented on the test rig in combination with a proportional-integral (PI) feedback controller, and together the feedforward and feedback controllers are used to track a random load profile. System identification and tracking results are presented.