A Mode Localized Force Transducer with Reduced Feedthrough via 1:2 Internal Resonance Actuation

This paper, for the first time, reports that the feedthrough signal can be significantly diminished, and the effective linear sensing range can be enhanced in a triple mass coupled resonator with 1:2 internal resonance (IR) actuation. Thanks to the unique structural design and flexible electrostatic tuning, the frequencies of the second and third modes can be independently tuned to be twice as that of the first mode. Nonlinear mode interaction between the first and second modes occurred when the first mode was driven in the nonlinear Duffing regime. The feedthrough signal by direct actuation (DA) was about 6.2% of the driving signal, while that by IR was almost independent from the driving signal, i.e. no-feedthrough. The experimental result showed the stiffness sensitivity of the second mode under DA was 1230, however the linear region of stiffness, ?k/k, was only 0.8%. On the contrary, the same sensitivity could be obtained by the IR actuation with a wider linear region as high as 2.2%. The stability of both frequency and amplitude ratio were also enhanced under IR actuation compared with DA driving.