Suppression on Nonlinearity of Mode-Localized Sensors Using Algebraic Summation of Amplitude Ratios as the Output Metric

Compared with the classic frequency-modulated resonant sensors, the recently emerging sensing scheme based on the mode localization phenomenon of the weakly coupled resonators provides the improved sensitivity by more than 2 orders of magnitude using amplitude ratio as the output metric. However, the inherent loci veeringphenomenon of the amplitude ratio over stiffness perturbation curvegenerates strong or weak nonlinearities in different zones, severelylimiting the linear sensing ranges. In this paper, we propose to use the algebraic summation of the amplitude ratios of two vibrational modes for eliminating the nonlinear errors caused by loci veering, extending the linear sensing range to the fullscale. This new output metric was verified as being very effective to suppress the nonlinear errors using two mode-localized stiffness sensors with 2 and 3 degrees of freedom coupled resonators. This is the first theoretically and experimentally demonstrated full-scale linear output metric for mode-localized sensors, which will push forward more applications of the mode-localized sensing scheme.