Force signals time alignment using cross-correlation

Calibration of force in measuring systems where the force is time dependent i.e. dynamically changing, introduces additional complexities versus quasi-static calibration conditions. The basic need in the case of time variable force signals is to synchronise the measurement series from unit under test and the measurement series from the reference standard. As they are typically acquired by different measuring systems, post-processing is generally necessary to align the measured samples to try to eliminate the influence of the sample misalignment from the resulting testing machine indication error. The paper focuses on the time alignment of measurement series at testing machine calibration with cyclic force excitation using cross-correlation to determine the necessary time correction. The standard deviation of the error distribution for the two measured signals after time correction was below 0.2 % for 5 kN ± 1 kN cycling force for 1 Hz, 5 Hz, and 10 Hz cycling frequency.