Model-Based Feedforward-Feedback Actuator Control for Real-Time Hybrid Simulation

Substructure hybrid simulation is a powerful, cost-effective alternative for testing structural systems, closely coupling numerical simulation and experimental testing to obtain the complete response of a structure. In this approach, well-understood components of the structure are modeled numerically, while the components of interest are tested physically. Generally, an arbitrary amount of time may be used to calculate and apply displacements at each step of the hybrid simulation. However, when the rate-dependent behavior of the physical specimen is important, real-time hybrid simulation (RTHS) must be used. Computation, communication, and servohydraulic actuator limitations cause delays and lags that lead to inaccuracies and potential instabilities in RTHS. This paper proposes a new model-based servohydraulic tracking control method including feedforward-feedback links to achieve accurate tracking of a desired displacement in real time. The efficacy of the proposed approach is demonstrated through RTHS for a single-degree-of-freedom system and a 9-story steel building, each using a 200-kN large-scale magnetorheological damper as the rate-dependent physical specimen.