H∞ feedback design for the control of dynamically substructured systems

Dynamically substructured system is a hybrid testing method for performance evaluation of engineering systems, which includes numerical simulation and physical experiment processes. Linear components of an entire system are modeled numerically in real time, while the remaining critical subsystems are tested physically. In the physical substructure, an actuator system is installed in order to emulate the displacement output of numerical substructure, such that the numerical and physical outputs at their substructured interface are synchronized. However, the testing fidelity often suffers from internal parametric uncertainties and external disturbances relating to the actuator and sensor devices. Therefore, robust control design is essential for the tests, in order to guarantee synchronization accuracy and achieve successful and reliable testing tasks. This study is based on the design of numerical-substructure-based state-space linear substructuring controller, using H_∞ algorithm to tailor the feedback gain. In this manner, improvement of control robustness as well as testing quality can be achieved.