Impedance-Matching Control Design for Shake-Table Testing and Model-in-the-Loop Simulations

Keywords: Earthquake engineering, model-in-the-loop simulation, shake-table control, impedance matching, control-structure interaction, real-time feedback

Seismic isolation Abstract: Model-in-the-loop (MIL) simulation, often referred to as real-time hybrid simulation by earthquake engineers, involves physical testing of structures, systems, or components with the surrounding environment represented virtually using numerical models, and loading devices (actuators) controlled to simulate the effect of the virtual environment at the boundary of the test article. Designing actuator controls that enable accurate imitation of different virtual environments at the interface with the test article is key for executing MIL simulations. This report describes a novel approach for designing such actuator controls, namely, impedance matching control design for an example MIL configuration of 1D base-isolated equipment. Herein, a water-filled cylindrical vessel is the physical test article and a hydraulic shake table, driven by impedance-based MIL controls, is used to simulate acceleration boundary conditions corresponding to different seismic isolation systems at the base of the vessel. Key challenges associated with the design and implementation of MIL controls are identified and practical solutions are proposed. The utility of the solutions is evaluated by extensive testing, and a framework is developed to systematically design such tests as well as identify limitations.