Realization of an automatic, contactless, acoustic levitation motor via degenerate mode excitation and autoresonance

Automatic traveling wave excitation of structures with imperfect cyclic symmetry

“…By using the complex notation employing Euler's formula, the amplitudes of the forward and backward propagating waves introduced in Eq. ( 1) are (see [34,45]):…”

“…These results validate the ability to use the TWAR method on continuous systems with multiple modes, using limited means of excitation and sensing. It is evident that the form of excitation suggested for the nominal system (𝜃 = 45, 𝜑 = 120 degrees [34]) without the defect results in a sub-optimal result of TWR=0.2. The use of TWAR-control results in an 8dB attenuation of the TWR.…”

“…The modal filtered AR feedback [33] can be used to excite a single desirable mode in multi-degrees of freedom (MDOF) systems. Reference [34] used the modal filtered AR (MFAR)…”

Nonlinear control of boundary impedance in an acoustic waveguide

“…The work of Gabai and Bucher 14 , and Halevi 33 in which the 1D wave-equation governed systems were controlled. The work of Gabai and Bucher 34 , Sirota and Halevi 35 , Musgrave et al 36 , and Davis et al 37 introduced control laws for systems governed by the 2D wave-equation. It was shown 14 that the open-loop model control is highly sensitive to model uncertainties; therefore, a model-based estimation closed-loop control should be used.…”