Minimizing Actuator Tracking and Energy Errors for Real-Time Hybrid Simulation through a New Adaptive Compensation Scheme

Real-time hybrid simulation provides an economical and efficient experimental technique for performance evaluation of structures under earthquakes. A successful real-time hybrid simulation requires accurate actuator control so as to achieve reliable experimental results. The time delay due to servo-hydraulic dynamics, if not compensated properly, would lead to inaccurate or even unstable simulation results. The nonlinearities in both servo-hydraulic systems and experimental substructures however make the actuator delay difficult to be accurately estimated in practice. Actuator control therefore presents a great challenge for structural application of real-time hybrid simulation technique. This paper presents a recently developed adaptive compensation technique for real-time hybrid simulation. Adaptive control laws are established to minimize both phase and amplitude errors in the servo-hydraulic actuator response. A large-scale magneto-rheological damper subjected to band-limited white noise generated random displacement and variable current input is utilized to experimentally demonstrate that the proposed adaptive scheme enables accurate actuator control to be achieved by reducing not only the tracking error but also the associated energy error.