Mixed H2/H∞ feedback control of multivariable dynamically substructured systems

Dynamically substructured system testing method divides an original system into several substructures. In the numerical substructure, linear components are simulated via real-time computation. In the physical substructure, a transfer system, which includes actuators and sensors, is installed to interface the numerical and physical parts. During the test, the unwanted disturbances and noise from the actuator inevitably cause synchronization errors between the outputs of numerical and physical substructures at the interface, and consequently result in unsuccessful tests. Therefore, this study proposes advanced control using the feedforward state-space linear substructuring controller plus the mixed H₂/H_∞ feedback controller to ensure optimal and robust synchronization. The synchronization problem is transformed to tracking design according to a numerical-substructure-based framework and is solved based on Riccati-like equations and linear matrix inequality. A multivariable mass-spring-damper substructured system is developed to verify the proposed control strategy via numerical studies.