Time-delay tracing based adaptive compensation algorithm for real-time hybrid testing

The real-time hybrid testing method has drawn more attention in the field of structural test in the past 20 years due to its high efficiency and wide applicability. Although hardware technology has improved in recent years, it is still subjected to some restrictions. One of the most important factors is that the time delay of the control loop due to the actuator cannot apply real-time displacement on the specimen. Therefore, in the real-time hybrid testing, how to eliminate the influence of time delay becomes the key to the success of real-time hybrid test. To reduce the unfavorable effects of time delay, a real-time hybrid testing platform based on hydraulic servo drive system is established using Matlab/Simulink. Then, an adaptive compensation method based on time-delay tracking is proposed. Finally, numerical simulations are performed for parameter analysis and are validated by the specimen loading test. The results show that the algorithm is capable of adaptive compensation of time delays in different cases of loading patterns. Thus, it can avoid iteration during testing. This method does not need to change the original controller's inherent algorithm and does not need to perform parameter estimation or system identification for the time-delay system. It is only necessary to embed the proposed compensator into the system as a plugin component, which is efficient, practical, and robust. The algorithm also has a good compensation effect on the time-varying delay caused by the nonlinear system. The bending test of an aluminum alloy steel beam shows that the accuracy of the algorithm and can be widely applied to real-time structural simulation tests.