A Vibration-Based Quasi-Real-Time Cable Force Identification Method for Cable Replacement Monitoring

Abstract

Tension force is a crucial indicator in reflecting the stressing state of old cables during the cable replacement process. Even though the vibration-based method is popular in the cable force identification due to its simple calculation process and low cost, the frequency is hard to be recognized with both high time and frequency resolutions attributed to the Heisenberg uncertainty principle, which hinders its application in identifying time-varying cable force. In this paper, a novel quasi-real-time cable force identification method is presented based on a quasi-ideal time-frequency analysis method called multi-synchrosqueezing transform (MSST), by which the cable frequencies can be identified with appreciable time-frequency resolution. To achieve the identification in a real-time manner, an Automatic Frequency Order Identification (AFOI) algorithm is developed to recognize the frequency order automatically depending on the MSST result, in which the interference of fake modes and omitted modes to the identification of the actual frequency order is eliminated to a large extent. The performance of the proposed AFOI algorithm and the quasi-real-time cable force identification method is evaluated on a practical cable replacement engineering case. Results show that the correct orders of the multiple frequencies received from MSST can be identified along the time domain, which demonstrates the effectiveness of the proposed method. The variation of the tension force of not only the replaced cable but also its neighbor cables is estimated with desired time-frequency resolution, which promotes the safety state assessment of a cable in a real-time manner during the replacement process.