Robust Identification of Underdetermined Modal Parameters for Time-Varying Structures Based on Signal Change Rate and Variable Window Length
摘要
To address insufficient modal parameter identification accuracy for time-varying signals under underdetermined conditions, this study proposes the Adaptive Signal Window with Forgetting Factor (ASWFF) algorithm. The method integrates a tensor decomposition framework and dynamically adjusts sliding window size using signal change rates to adapt to time-varying dynamics. It further introduces a forgetting factor to optimize weight allocation, suppress noise, and enhance time-varying feature tracking. Modal parameters are progressively identified per window using sensor data within the sliding window, enabling continuous structural tracking via window shifting and parameter updating. Validation on a time-varying three-degree-of-freedom spring-mass oscillator and a liquid-filled cylindrical structure demonstrates that ASWFF significantly outperforms variance contribution rate (VCRWLA) and smoothness-based (SWLA) window length adaptive algorithms in modal consistency (MAC values) and inherent frequency accuracy. Crucially, ASWFF exhibits superior adaptability in time-varying scenarios.