Adaptive time-delay compensation method combined with sliding mode control: Theory and verification

Delay compensation presents a key component to ensure an accurate and robust real-time hybrid test (RTHT). As RTHT continues to evolve, the scale and degrees of freedom of studied structures increase, requiring greater attention to the responses of higher-order modes. High-frequency components in structural responses at the boundaries of substructures must also be accurately imposed onto the specimen. Robust delay compensation for high-frequency signals loading in RTHT needs to be explored. This paper proposes an adaptive time delay compensation based discrete model strategy combined with sliding mode control method (ADM-SMC). In this method, combining with the robust sliding mode control (SMC), the least squares method is used to update the parameters of the discrete model of the SMC-loading system in real time, which provides a robust compensation method for the wide-band and high-frequency excitation loading. A delay compensation test and a RTHT were conducted to verify the feasibility of this method. The results indicate that the proposed method can compensate varying time delay precisely with robustness for different high-frequency excitation loading.